Aug - American Radio History
www.americanradiohistory.com
AmericanRadioHistory.Com
Another way
RCA
serres you
through
Eleetrouies
HI -FI
DESIGNERS
i
9
"JAM SESSIONS"
...and they "dig" RCA TUBES "the most "!
One designer "blows a horn" for one tube type.
Another "beats the drum" for a 2nd. Everybody may
"sound off" -but when they "take five ", designers
agree that RCA Hi -Fi Tubes...7027 -A, 6973, 7025
and 7199... are "the most"
Want big power? A pair of RCA -7027 -A's in Class
AB1 can deliver up to 76 watts. (Four in twin, pushpull Class AB1 circuits are superb for stereo, too!)
Designing a more compact package, say, 20 watts
each stereo output stage or 40 watts monophonic?
Look into RCA -6973, a small tube with big plate
!
dissipation capabilities. And high -mu twin triode
RCA -7025 is tops in pre-amplifier stages when low
noise and low hum are a "must ". For versatility,
check RCA -7199, a triode -pentode that features low
hum and low noise in tone -control amplifier, phase splitter, and high -gain voltage -amplifier circuits.
So "get with" RCA Tubes for your hi -fi designs.
Your RCA Representative can give you the facts.
For data sheets, write RCA Commercial Engineering, Section II-91 -DE, Harrison, N. J.
Visit the RCA Booth at WESCON!
EAST:
FIELD OFFICES
744 Broad Street, Newark 2, N. J.
HUmboldt 5 -3900
RADIO CORPORATION OF AMERICA
e
Electron Tube Division
Harrison, N. J.
RCA tubes for High Fidelity also available from your local Authorized RCA Distributor
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MIDWEST:
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Chicago 54, Illinois, WHitehall 4 -2900
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THE
BRITISH
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Warm, universal endorsement by
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Loudspeakers and Systems
The rich, full range, yet non-strident sound developed by England's
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Speaker Enclosures
A complete, restyled line of the
original and patented high -performance, small -space speaker enclosures which are now a must for
stereo. Although R -J is the most
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in size and shape... no one has been
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formance principle.
River Edge
Customized Cabinets and
Do -It- Yourself Kits
The Series 100 modular kits are as
flexible for stereo as for mono systems...and most important. they
are built of Birch hardwood, to
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And...this one series is a complete
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5-Core Solder
Pioneering solder advancements.
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Origination and promotion of the
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PORT WASHINGTON, N. Y.
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AUGUST, 1959
VOL. 43, No. 8
Successor to RADIO, Est. 1917.
Discover for yourself why Sherwood
is the most honored line of high fidelity components in the field. Sherwood
Tuners (the first ever to achieve sensitivity under 0.95 microvolts) feature:
Inter -Channel Hush, a noise muting
system which makes FM tuning easier
than ever
FM Multiplex Output
"Feather -Ray" Tuning Eye
Automatic
Frequency Control
Flywheel Tuning.
Combine these tuners with either of
Sherwood's "mated" stereo amplifier
choices; 20 +20 watts or 36+36
watts. And only Sherwood offers all
these features: Single /Dual Bass &
Treble Controls
Mid -Range Presence
Rise
Stereo -Mono Function Indicator
Lights
Phase -Reverse Switch
Damping Factor selection. Sherwood
also offers either 36 or 60 watt monaural amplifiers, FM Multiplex Adapters
and a complete decorator- styledline of
cabinetry and 3 -way speaker systems
The Finest in High Fidelity. Sherwood
Electronic Laboratories, Inc., 4300 N.
California Avenue, Chicago 18, Illinois.
AU D Io
ENGINEERING
MUSIC SOUND REPRODUCTION
C. G.
McProud, Editor and Publisher
Henry A. Schober, Business Manager
Harrie K. Richardson, Associate Editor
Linda Sueskind, Assistant Editor
Janet M. Durgin, Production Manager
Edgar E. Newman, Circulation Director
-
Sanford L. Cahn, Advertising Director
-
Midwest Representative
W. A. Cook and Associates
161 East Grand Ave., Chicago 11,111.
West Coast Representative
lames C. Galloway
6535 Wilshire Boulevard, Los Angeles 48, Cali!.
Model
-
S
-5000. 20
+
20W
Slew
Dual Amplifier -5189.50
0 0 ©6) 450:
Model S-3000 U. FM Tuner -$105.50
CONTENTS
Audioclinic- Joseph Giovanelli
2
Letters
6
Model 5.4400. Stereo Peins,.
Audio ETC -Edward Tainan Canby
Editor's Review
12
C3.C,
f
36W Amp. - $159.50
©6)0.x.
18
Model S.200013, FM -AM Tuner -$145.50
Transistor Music System Using Direct Coupling- Richard S. Burwen
Hi -Fi Speaker Enclosure Damping Materials-James A. Huff, Jr.
21
©-
26
Tape Guide -What to Look for in a Tape Recorder-Herman Burstein
Variable Electronic Crossover and Biamplifier-George C. Kane
Hi -Fi for Lo -Do-S. G. Lucas
32
42
Model 5.1000 a, 36W Monaural Amplifier- 5109 50
only for those who want the ultimate:
50
Errors and Mistakes of Engineers-A lbert Woodruff Gray
Product Preview
Jazz and All That-Charles A. Robertson
56
67
STEREO
SG
Record Revue-Edward Tatnall Canby
Book Review The Audio Cyclopedia
92
99
About Music- Harold Lawrence
100
Coming Hi Fi Shows
101
Advertising Index
114
COVER PHOTO: Custom installation in North Stamford, Connecticut, designed by
C.
F. Barton, with cabinetry by Russ Lang Corp., Bridgeport Conn. Unit is 14 feet long
ill three sections; the record cabinet is two feet long and features an interior
light.
further data and a close -up picture of control panel, record changer compartment, For
and
ventilating ducts, turn to page 104. Photos by Frederick Schulze.
(title registered U. S. Pat. OP.) Is published monthly by Radio Magazines, Inc,
Henry A. Schober, President;
G. 3IcProud, Secretary. Executive and Editorial Omees, 204
Front St., Mineola. N. Y. Subscription rates -U. S.
Possessions, canada and Mexico, $4.00 for one year, $7.00 for two years,
all other countries. $5.00 per year. Single
copies 504. Printed In U.S.A. at Lancaster, P.. All rights reserved. Entire contents
copyrighted 1959 by Radio Magazines.
Inc. Entered as Second Class Matter February 9. 1950 at the Post Office.
Lancaster. Pa. under the act of March 3, 1879.
AUDIO
C.
RADIO MAGAZINES, INC., P. O. Box 629, MINEOLA, N. Y.
Postmaster: Send Form 3579 to AUDIO, P. O. Box 629, Mineola, N.
AUDIO
Y.
For complete technical details write Dept. -8.
AUGUST, 1959
1
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AmericanRadioHistory.Com
AUDIOCLINIC ??
JOSEPH
GIOVANELLI'
Power and Voltage Considerations
WAYS
To ENJoY
E
RoBERTS
%;;
!.+
HOW TAPE
EQUIPMENT SERVES
MANY AUDIO NEEDS
22 are discussed in new
Roberts boòk/et
Roberts Electronics Inc. has prepared
this 20 page booklet to demonstrate
the wide versatility and high quality reproduction of monaural and stereo tape
equipment. Eight ways to record live or
from broadcasts and to dub or copy from
disks and tapes are discussed, including the
correct way to tape stereo broadcasts.
Also included in this informative booklet
are ten methods to play back through
high level and low level external amplifier /speakers in both monaural and stereo.
Suggestions are given for the use of tape
equipment to "dub in" vocal or instrumental accompaniment by mixing and multiple
recording.
The booklet treats with the general use and
care of tape equipment and instructions for
tape splicing, microphone placement and recording procedure. A complete index and bibliography are included.
Before you buy a tape recorder, you will want to
read this valuable booklet, "22 Ways to Enjoy the
Roberts." For your copy, just fill out and mail
the coupon below.
ROBERTS ELECTRONICS INC.
1045 N. Sycamore. Los Angeles 38, Calif. Dept. D
Please send me a copy of "22 Ways to Enjoy the
-
Roberts. "'
NAME.
ADDRESS
CITY
.
ZONE
Q. The specifications of my Dynakit amplifier indicate that 1.6 volts input are required for 60 watts output. It therefore
seems like an easy matter to measure the
voltage at the output terminals when the
amplifier was fed by a 1.6 -volt signal. This
voltage was found to be approximately 40
volts. Since my speaker cannot handle 60
watts, this was a no -load measurement. I
could not experiment with a lower input
because I did not know the corresponding
output wattage. It would seem that the
Ohm's law a.c. formulas should be applicable to this problem. Please tell me a simple
way to determine wattage from voltage.
What is the relation between input voltage
and watts output! Tell me how to determine the phase angle, for I understand
that this may have some bearing upon the
problem. Richard Meyer, East Lansing,
Mich.
A. Power is a measure of the work being
done. Now, when you measured the amplifier's voltage output under no-load conditions, you arrived at a situation wherein
you had voltage developed, but that voltage
was doing no work of any kind because it
was fed into nothing. In order to determine
anything about the wattage of your amplifier, the signal must be fed into something
which would be indicative of the conditions
under which the amplifier normally works.
As you said,' your speaker system cannot
take all the power which can be provided
by the Dynakit, and in fact, neither could
your ears. What is needed, then, is a device
which will act as much like a speaker as
possible, but will make no sound. What is
doue in practice is to take a resistor equal
to the impedance of the amplifier tap selected for the experiment. This resistor
should be of as high a wattage rating as
possible since your amplifier delivers 60
watts. Don't be alarmed if you do not have
one that can handle that much power; a 10watt resistor can handle as much as 80
watts for a short while, probably long
enough for you to compute your data.
Under these conditions the transformer is
loaded, thereby reducing the back voltage
it produces. This, in turn, indicates that the
voltage at the output of the secondary will
be less than the unloaded value; measurement will bear this out.
When the impedance between a speaker
and its driving amplifier is matched, the
system is said to be resistive, and for this
reason, the phase angle need not be con-
sidered. Actually, the phase angle may
enter into the picture somewhat since the
match is not perfect, and the speaker behaves like an inductance or capacitance at
different parts of the spectrum.
In explaining just what is meant by the
phase angle a brief discussion of alternating current is needed. When a.c. flows
through a resistance, the voltage and current are in phase, which means that as the
voltage rises to a maximum in one direction, the current rises to a maximum in
STATE
Enclose lac (stamps, cash) for handling & postage
3420 Newkirk Ave., Brooklyn 3, N. 1'.
that same direction, and the two arrive at
that .maximum at the same instant. When
this same current is applied across the
terminals of an inductance, the situation
is quite different. This can be made clear
by considering what happens when d.c. is
applied to the inductance. When the voltage is applied, there is a magnetic field set
up around the inductance. This field cuts
the turns of the inductance, causing a
second voltage to be generated within the
coil. By the rules of magnetic theory we
know that when this happens, the direction
of this newly created back voltage is opposite to that of the originally applied voltage. This tends to oppose the flow of current. Soon the magnetic field reaches a
maximum intensity because we are feeding
d.c. to the coil, and this will ultimately
cause the current to stabilize. From that
time on, the inductance behaves as though
it were resistive. When the inductance is
fed from a.c., however, the voltage and
current can never catch up with each other,
for, as the current tries to do so, the cycle
reverses and the whole thing starts all
over again. We say that, for an inductance,
the voltage leads the current by 90 deg.
"How," you wonder "did the degrees enter
into thisl" A.c. is cyclical in character. A
cycle starts off at zero, rises to a maximum in one direction, falls back to zero,
and rises to a maximum of opposite polarity exactly equal in magnitude to that
of the first rise, and therm it returns to zero
again. It next starts all over again, rising
to a maximum in the first direction. (This
is based upon the assumption that the wave
described is a pure sine wave.) The whole
thing goes round and round. A circle could,
therefore, be drawn to represent this acit is considered that this cycle is
tion.
traveling in a counterclockwise direction,
the voltage will, when a pure inductance is
the only element involved, be 90 deg. to the
left. Unfortunatelly, we never get a pure
inductance: there is always some resistance
present. This reduces the leading or lagging effect, or, in other words, the phase
angle. Just how much this is reduced will
depend upon the amount of inductance and
upon the amount of resistance present. The
whole thing can be considered as a right
triangle whose hypotenuse represents the
combined effects of inductance and resistance. Naturally, all mathematical work will
proceed vectorially since the hypotenuse
represents the square root of the sum of
the squares of the other two sides of the
triangle. This concept is basic to Plane
Geometry and Trigonometry, and hence
will not be explained further here.
Capacitors behave in a manner opposite
to that of inductances. The current in a
capacitor leads the voltage by 90 deg. Capacitors contain resistance also and there
is no such thing as a pure capacitance.
The reasons for the behavior of a capacitor are best explained by considering
what happens when the capacitor is connected to d.c. Since the plates are neutral,
the electrons rush to crowd on to one plate
at the moment the circuit is closed. This
action is so great at the first instant that
If
AUDIO
2
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AmericanRadioHistory.Com
11
AUGUST, 1959
"Our All -New
eu: VR22
Stereo Cartridge
provides unsurpassed
performance in a
Garrard Changer."
In thanking Mr. Welsh for these personal
comments, we would like to point out that hundreds
of thousands of GE Monaural cartridges played
a vital part in making high fidelity history during
the past decade. Particularly significant is the fact
that more GE cartridges were used with Garrard
changers in fine component systems, than in all
other changers and turntables combined
Now, GE owners, and all others converting to
stereo, will be delighted to know that a Garrard
changer, such as the incomparable RC88,
guarantees the superlative performance that has
been built into the new GE stereo cartridges.
!
"Unsurpassed
Stereo Results
with the
VR22
in Garrard Changers,"
says Mr. S. J. Welsh,
Manager- Marketing, High Fidelity Components,
General Electric Company
"The new GE Stereo Classic cartridge Model VR22 has
a
'floating armature' design for increased compliance
and reduced record wear, and a flat frequency response
of 20- 20,000 cycles. To retain this performance, it is
necessary that a tone arm track freely and with the
recommended light pressure. The motor must also have a
very low rumble content.
"Therefore, we are gratified to report the excellent
results we found when testing with Garrard changers.
All of the rigid laboratory standards built into our
new cartridge were maintained. The result was
excellent
stereophonic music reproduction."
The same reasons why Garrard changers
so
magnificently with GE cartridges have alsoperform
made them
equally popular with all other manufacturers
of
fine
cartridges -Shure, Electro- Voice, Pickering, Fairchild,Stereo
etc.
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Vertical and lateral rumble completely inaudible. Wow
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Exclusive Aluminum tone arm precision- mounted at
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Unrestricted choice of stereo cartridges -any of them will
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The important convenience of manual play plus completely
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These are the FACTS, no one can deny them with authorityand they are backed by the 36 years of experience that have
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Send for free Garrard Comporaror Guide
For the best in Stereo...
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Wool
16R.Ofl
Division of British Industries Corporation, PORT
WASNINGTOYt,N. Y.
Conadion iiiniiiiliii lo Che, W, Ponton, Ltd., 66 Rocino Rood,
Ro.dale, Ont.
t ,
Territories other than U.S.A. and Ca ode to. Oo,,ord Enoinnrina
6 MI5. Co.. ltd., Swindon, Wills., Enalaa :
-
www.americanradiohistory.com
AmericanRadioHistory.Com
Tung -Sol audio tubes
dynamically balanced
and twin -packed
in matched pairs
by the manufacturer
5881
For service in
amplifiers of up to 50
watts.
6550
For service in
amplifiers and commercial audio equipment of
up to 100 watts.
you can come as close to
N
faultless sound reproduction as the design and circuitry
oNow
of your hi -fi equipment will
permit. Tung-Sol 5881 and 6550
beam -power amplifier tubes are
dynamically balanced and factory- matched to very tight performance limits to help you
achieve lowest distortion at all
volume levels.
Use of Tung -Sol 5881 and
6550 tubes has long been associated with amplifiers of the
very finest design. These tubes
have always been produced to
closest possible tolerances with
cathode current ranges held to
an absolute minimum.
Now, in twin -packed pairs,
they assure the hi -fi enthusiast
and the commercial sound engineer of replacement tubes that
will provide new standards of
-a
feature of
performance
special importance with the
newest amplifiers and loud-
speakers, particularly binaural
sound equipment. See your
parts supplier.
Tung -Sol Electric Inc.,
Newark 4, New Jersey.
TUNG-SOL
that the d.c. supply is
momentarily short -circuited. The voltage,
therefore, drops almost to zero. It does not
take long before the plate becomes fully
charged, or "crowded" with electrons. It requires more and more time for an electron
to find room. This means that the d.c.
supply is gradually unloaded. There will
finally come a time when there is no more
room for further electrons to gather, and
from any of the dealers in
the supply will then run at its normal opis
erating voltage. No more current being your city who are listed.
taken from it. When a.c. is applied to the
capacitor, the circuit can never arrive at
a stage of equilibrium. Note that the voltRADIO SHACK CORPORATION
730 Commonwealth Ave.
age lagged the current in this illustration.
Boston 17, Mass.
the
about
know
to
wished
Lastly, you
RE 4.1000
relationship of the variations in output
Branches
St.
dethe
power
to
167
Washington
amplifier
an
voltage of
Boston, Mass.
an
amof
input
the
load.
If
to
the
livered
230 Crown St.
plifier requires two volts for a power output
New Haven, Conn.
of 20 watts, the power output will be reCATANIA SOUND
duced to 5 watts if the input voltage is
1541 Fourth St.
San Rafael, Calif.
reduced to 1 volt. That is, the power varies
as the square of the voltage. However, the
KIERULFF SOUND CORP.
820 W. Olympic Blvd.
input and output voltages will vary diLos Angeles 15, Calif.
rectly. If I reduce the signal voltage to 1,
RI 7-0271
the output voltage will fall to % of what
Branches
18841 Ventura Blvd.
it had been before the reduction in input
Calif.
Tarzana,
voltage had been made.
6035 Magnolia
Riverside, Calif.
The next logical question is: "Why does
12024 Wilshire Blvd.
the power vary as the square of the volt W. Los Angeles, Calif.
aget" Power is equal to voltage times curWRIGHT'S HOUSE OF HI FI
rent, E x I. It does not matter that the
5140 El Cajon Blvd.
current is not known since we do know the
San Diego 15, Calif.
resistance into which the power is being
D'ERRICO FIDELITY RADIO
fed. We know that the current is equal to
3006 Wilshire Blvd.
Santa Monica, Calif.
the voltage divided by the resistance, E /R.
EX 4.6209
Thus wattage, W, equals E x E/E, or E' /R.
That is how the exponential business creeps
AUDIO WORKSHOP INC.
So. Main St.
in to destroy what would have been a simWest Hartford, Conn.
ple arithmetic problem.
GOLDEN EAR INC.
Assume an amplifier to which is con610 S. 3rd
nected a 16 -ohm resistor between the 16Louisville 3, Ky.
Branches
ohm tap and common. Assume a signal of
RI 3 -1784
one volt is applied to the input grid. AsWest Lafayette, Ind.
16.
the
read
across
sume that the voltage
ME 4-8761
Indianapolis, Ind.
ohm resistor under these signal conditions
St.
is
the
amplifier
Washington
power
What
is 20 volts.
Martinsville, Ind.
supplying to the resistor?
RADIO DOCTORS HI FI
Solution: in our derived formula, W
811 W. Springfield Ave.
E' /R, we can substitute our two knowns
Champaign, Ill.
Fleetwood 2 -6464
as follows: E = 20 volts, B= 16 ohms.
to
rewritten
be
can
the
formulas
Therefore,
AUDIO CENTER, INC.
17001 Kercheval Ave.
read W = 20r /16, or 400/16, which is 25
Grosse Points 30, Mich.
watts.
AUDIO KING CO.
If the input voltage is reduced to 0.5
913 West Lake St.
volt, the voltage as read across the 16 -ohm
Minneapolis 7, Minn.
resistor will be 10 volts. By applying our
DAVID BEATTY STEREO HI -FI
formula, we see that the power supplied to
1616 Westport Road
Kansas City 11, Mo.
the resistor under these conditions is 6.25
watts, rather than the 12.5 watts we might
ADSON RADIO ti ELECTRONICS CO.
have expected.
189 Greenwich St.
New York 7, N. Y.
The following information does not bear
LYRIC HI -FI, INC.
directly upon the foregoing problem, but
1190 Lexington Ave.
it is similar in some respects. Suppose it is
New York 28, N. Y.
necessary to determine the power being
WRYE COMPANY, LTD.
supplied to a resistance when only the
2410 W. Alabama
values of the current and of the resistance
Houston 6, Texas
JA 6-3033
are known. Voltage can be readily obtained
R.
by multiplying current by resistance, I x
THE RADIO HI -FI SHOP
603 Broadway North
The result can be multiplied by the current
Seattle 2, Washington
and the resulting answer will be the desired
HOUSE OF HI-FIDELITY
power. These operations, however, can be
20th Century Sales, Inc.
combined as follows: The voltage is equal
W. 1021 First Ave.
E
=
IR.
resistance,
Spokane, Washington
to the current times the
voltis
power
for
The fundamental formula
DOW RADIÒ, INC.
1759 E. Colorado St.
age times current, or EI. Since E is equal
California
Pasadena,
PR.
or
x
IR,
Æ
I
to
equal
to IR, power is
d.c. is applied
--
-
-
--
1
--
AUDIO
4
www.americanradiohistory.com
AmericanRadioHistory.Com
--
AUGUST, 1959
6.
the best of
J
110
..
AUDIO knowledge
A NEW compenr!irfm
SPECIAL
PRE - PUBLICATION
OFFER!
ORDER
1.'1
AND SAVE 25 %!
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torsrsin major cities have
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this Special
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RADIO
MAGAZINES,UINCPectal
"the best of AUDIO" Volume
I
features:
by Joseph Giovanelli ...noted audio engineer, authority and technical writer, and the original high fidelity answer -man. Here is a compilation of
his best work ... the most important issues and facts, the answers to some of the
most perplexing high fidelity problems covering all phases of AUDIO technicana
from microphones to stereo.
The AUDIO Clinic
THIS
OFFER
1959
.
by C. G. McProud ... Publisher and Editor of AUDIO,
the original magazine about high fidelity. Here, in Mr. McProud's matter-of -fact
style of writing is a profile analysis of high fidelity components in action. The
EQUIPMENT PROFILE is definitely not a test, but rather a factual and thorough
report of what makes a component tick ... what it does... how it does it ... a valuable
reference for the high fidelity shopper.
EQUIPMENT PROFILES edited
SPECIAL PRE -PUBLICATION OFFER
...$1.50!
.
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RADIO
Magazines, Inc.,
Dept. 98
'".
Post Office Box 629
Mineola, New York
Enclosed is my remittance or $1.50
Please send my copy of the
promptly by return mailbest,
Name
To be published July 15th at $2.00, the 1st Volume of "the best of AUDIO"
Address
is scheduled for shipment to bookstores September 1st, 1959... order your
volume now and receive shipment at least one full month early
City
and, SAVE 25 %!
Remit only money order
./
0000
ONLY UNTIL
AUGUST 25.
Zone
.
of
POSTPAIDAUDIO
State
or check. No cash or stamps please.
.
LETTERS
for less work and more play
GET THE TURNTABLE
THAT CHANGES RECORDS!
MIRACORD XS-200
No turntable and no record player,
in the history of high fidelity, gives
you more quality and more features
than the famous MIRACORD XS -200!
heavyweight, professional -type turntable -and a fully -automatic changer!
plays both stereo and monophonic!
push -button controlled throughout!
Magic Wand spindles eliminate
pusher platforms and stabilizing
arms!
intermixes 10" and
12
"; plays all
speeds; has a 4 -pole motor!
even as a turntable it shuts off
automatically when record is
finished and tone arm returns to
4
rest position.
-yet it costs
omit
$6 a
audiophile net
STEREOTWIN 200
the stereo cartridge that
ELIMINATES HUM!
the perfect magnetic
for stereo and monaural! It fits all record changers and
standard tone arms. And thanks to
special construction and MuMetal
shielding, it eliminates hum! Instant
stylus replacement, too.
STEREOTWIN is
hi -fi cartridge
NOW
$4450 audiophile
net
FAR AHEAD) THE FINEST BY FAR
Available at selected dealers.
For Free catalogue. please Irrite Dept. A
AUDIOGERSH CORP.
514 Broadway, New York 12, N.Y.
WORTH 6
-0800
Stereo Recording in Education
SIR:
For several years I have been studying,
including school committee work, some of
the possibilities for more effective use of
teacher competencies in our schools and
adult education. One of these involves the
use of stereo tape recording for improving
music programs and in the language teaching laboratory in elementary and high
schools. The latter art is fairly well developed and accepted at College levels, but
not in the lower levels. Perhaps some of
your readers may have developed some information that would be helpful.
Most of the experiments (including two
by one district by calling in professional
recorders) on the use of two- channel recorders in music programs have been considered by the school people as rather complete failures (in spite of their recognition
of the commercial acceptance of stereo reproducers in consumer products area,
though some think it is a fad).
Admitting that stereo-binaural pick -up
and recording is difficult does not justify
our continued neglect to provide some sort
of guides, suggestions, cautions, and more
specific considerations of the art. I have
written several recorder manufacturers
about this problem, and I have contacted
owners of this equipment. The story generally is that the equipment is not good
enough for the job, and I think there will
he a reaction against stereo recorder units
if this situation is not changed so that
these owners can get better results. I feel
that the trouble is not with recorders, but
with the pick -up and recording techniques.
It seems that the manufacturers have not
provided good application instructions for
the most effective stereo pick-up and recording results, with some discussions of
some of the "tricks" of the trade on how
to make the final results more desirable and
how to better adapt the system to the
particular musical demonstrations. The user
needs to know how to plan for different
applications of strings, banda, large and
small groups, music rooms, solo, choral, and
other types of work. All of this is a part
of the over -all use of and satisfaction from
this kind of equipment by the more discriminating users and for educational applications.
Perhaps this sort of thing has been done.
If so, I have not found it. I know of several
others in school work and citizen applications who have also looked for this kind of
information; some have relegated the
equipment to storage and relatively inconsequential use, somewhat discouraged that
they spent the money in the first place,
(not talking about disc equipment). If this
kind of information is available, perhaps
you can inform me, with references. If not,
perhaps you could get some articles in your
magazine on the more effective use of stereo
tape recorders.
As a school board member I feel that we
could improve our musical programs by
using stereo recorders. In addition I think
that such tapes could be used in demonstrations to further our already meagre
public relations programs. Such proposals
generally meet with the problems of poor
results, high costs, lack of time to experiment, and so on. If we had more information available as a sort of criteria for such
applications perhaps satisfying results
could be obtained; at least people would be
better apprised of the requirements and
correct procedures.
The school publication in the audio visual
fields do not seem to do anything about
this situation. Perhaps it takes an appreciably higher technical level of writing and
experience to get the idea over and to be
specific in enough areas, or to take such a
big subject and bring it into the language
of this type of prospective user of stereo
recording equipment. In my search I
reached an audio engineer in Hollywood
who had developed such instructions and
would provide an article or manual for $50
-too much for people in school activities.
At any rate here is the problem. Perhaps
some of your readers will be able to help
or to provide some references.
LLOYD P. MORRIS,
2947 N. 78th Court,
Elmwood Park,
Chicago 35, Ill.
(And a serious problem it is, too. Unfortunately, most stereo recording techniques are
regarded as at least "confidential" if not
"top secret," and it is rare that we are permitted to reproduce a photo of an actual
recording session with the microphones all
in place. However, we do not consider $50
too high if the manual were written to your
order -in fact, it is so low that it probably
wouldn't be worth even that amount. We
have never encountered anyone with professional experience who was willing to give
out any information. It would be desirable
for all the tape and recorder manufacturers
collectively to commission someone to write
such a book -and we hope they do, we'd
like to publish it. Here's hoping some reader
in your vicinity may volunteer to help you
out, and possibly to annotate his findings
for later publication for everyone interested. ED.)
More Desirable Subjects
SIR:
May I suggest a couple of topics that I
have not seen covered anywhere in more
than incidental fashion that should be
useful to many readers?
How about a really thorough article by
a competent authority on the use of voltage
regulator tubes, including possible uses and
applications, precautions and things to
avoid, and possible troubles and what to do
about them. The same suggestions go for
the design and use of regulated power supplies employing vacuum tubes with control
grids. Design of such circuits should not be
beyond the capabilities of the average technician or advanced amateur.
I would like to know of any books that
contain this information. The best I have
been able to find on VR tubes so far has
been from the Heathkit catalogues before
they started omitting values from the
schematics.
KEITH CONRAD,
816 W. Belle Plaine Ave.,
Chicago 13, Ill.
AUDIO
6
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
J
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AUGUST, 1959
Welding Cable
Aircraft Wires
Electronic Wires
Automotive Wire and Cable
7
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AmericanRadioHistory.Com
ANOTHER FIRST FOR HEATHKIT
amplifier power rating standards
...
to leading the way. We
is accustomed to pioneering
led the way into the kit field of electronic equipment. Now, we arc
leading the way to audio amplifier power rating standards . .
standards clearly defined to assure you of Heathkit quality . .
to enable you to compare before you buy.
The Heathkit amplifier standards have been established upon
these following beliefs after reviewing over one hundred published
treatises on the subject:
WE BELIEVE any amplifier should be rated for its intended
Hcathkit
.
.
use
.
.
.
be so nearly perfect that
no audible change occurs in the program material.
HIGH FIDELITY amplifiers must be almost as perfect, almost
PROFESSIONAL amplifiers must
as
1.
efficient.
UTILITY amplifiers
can be less perfect and still
does not exceed 1.0% at 1000 CPS.
fulfill their
2.
...
as
PROFESSIONAL RATING
Maximum power at which total harmonic distortion (THD)
4.
does not exceed 3.0% at 7000 CPS.
Maximum power at which response does not deviate by more
than ±1 db between 60 and 7000 CPS.
5.
Maximum equivalent single -frequency power at which intermodulation distortion does not exceed 3.0% (60 and
-
The professional power rating shall be that power which satisfies
the following five tests:
1. Maximum power at which total harmonic distortion (THD)
does not exceed 0.3% at 1000 CPS.
2. Maximum power at which total harmonic distortion (THD)
does not exceed 2.0% at 20 CPS.
3. Maximum power at which total harmonic distortion (THD)
does not exceed 2.0% at 20,000 CPS.
4. Maximum power at which response does not deviate by more
than ±1 db between 20 and 20,000 CPS.
'
5. Maximum equivalent single -frequency power at which
intermodulation distortion does not exceed 1.0% (60 and
6000 CPS, 4:1).
HIGH FIDELITY RATING
The high fidelity power rating shall be that power which satisfies
the following five tests:
1. Maximum power at which total harmonic distortion (THD)
does not exceed 0.7% at 1000 CPS.
2. Maximum power at which total harmonic distortion (THD)
does not exceed 2.0% at 30 CPS.
3. Maximum power at which total harmonic distortion (THD)
does not exceed 2.0% at 15,000 CPS.
4. Maximum power at which response does not deviate by more
than ±1 db between 30 and 15,000 CPS.
5. Maximum equivalent single-frequency power at which intermodulation distortion does not exceed 2.0% (60 and
6000 CPS, 4:1).
be
3.
6000 CPS, 4:1).
We at the Heath Company are now rating all our amplifiers to
these standards. To show you just how this rating system works,
let's look at the Heathkit EA -3 amplifier:
As a professional amplifier
1. Maximum Power at which T.H.D. does not exceed 0.3% at
1000 CPS: 15.1 watts
2. Maximum Power at which T.H.D. does not exceed 2.0% at
20 CPS: 13.9 watts
3. Maximum Power at which T.H.D. does not exceed 2.0% at
20,000 CPS: 15.3 watts
4. Maximum power at which response does not deviate more
than ±1 db between 20 and 20,000 CPS: 17.6 watts.
5. Maximum equivalent single -frequency power at which intermodulation distortion (60 and 6000 CPS, 4:1) does not
exceed 1%: 18.0 watts.
Taking that power which satisfies all five tests, we could rate the
EA -3 for professional use, at 13.9 watts. Its advertised professional
rating is a conservative 12 watts.
A review of the chart below shows why the EA -3 is rated at 14
watts for high fidelity applications, and 16 watts as a utility amplifier.
Notice that our specifications are set at rated power for one or
more classifications (when our customers need an amplifier for a
particular use, we believe thay want it to deliver its rated power
under those particular conditions). Observe that our distortion
figures are specified at the limits of the amplifier frequency range
as well as at the traditional 1000 CPS (the common practice of
rating distortion only at 1000 CPS does not tell you what happens
throughout the full range of the amplifier).
As an example of how these standards work on several corn petitive amplifiers, we have prepared the following chart. Notice
that if the amplifiers did not meet standards at rated output power,
we have determined the power output where they do meet the
standards set up under the three categories.
follows:
UTILITY RATING
The utility power rating shall
Maximum power at which total harmonic distortion (THD)
does not exceed 3.0% at 60 CPS.
practical job.
WE BELIEVE the rated power of an amplifier in any of the
above "use" categories should be that power which satisfies all
requirements in that category.
Each of the three "use" categories we have chosen has requirements which can be translated into performance specifications with
limits established by recognized authorrather definite limits
ities. The Heath requirements and their limits for each of the
categories are
Maximum power at which total harmonic distortion (THD)
that power which satisfies the
following five tests:
AMPLIFIER COMPARISON CHART
Amplifier
Description
_and Price
Kit
"A"
"12 w. HI FI"
$23.90
Assembled Amp.
"B" "14
w. HI FI"
$39.50
Kit "C"
"12 w. HI Fl"
$34.95
Assembled Amp.
" D" "15 w. HI FI"
$64.50
Heathkit EA-3
"14 w. H1 FI"
$29.95
Heath Standard Rating
Power
Classification
Professional
High Fidelity
Utility
Professional
(watts)
Disqualified
Disqualified
8.6 watts
0.3
Maximum Power Output Satisfying:
Power Rating
1 Stds.
at Test
Power Rating
al Test 2 Stds.
8.4 watts
9.1
9.8
4.7
0.02 watts
1.67
8.9
0.3
8.6
4.8
5.7
12.9
7.5
11.2
11.9
14.5
14.5
15.0
15.3
15.5
16.4
1.1
12.1
1.1
Utility
7.8
3.6.
13.2
11.0
11.8
12.0
13.2
14.3
14.7
7.8
8.0
Utility
11.9
Professional
High Fidelity
3.8
10.6
14.7
13.9
15.5
16.4
Utility
Professional
High Fidelity
Utility
15.1
16.2
16.5
0.65 watts
1.3
High Fidelity
Professional
High Fidelity
Power Rating
3 Stds.
at Test
3.6
8.0
12.0
3.8
10.6
14.7
13.9
15.8
16.6
Power Rating
Power Rating
at Test 4 Stds._ at Test 5 Stds.
Disqualified
Disqualified
12.3 watts
1.2
5.3
15.8
7.5
13.4
15.0
12.0
18.3
23.7
17.6
18.3
19.0
3.9 watts
5.9
11.6
4.0
8.2
13.9
6.5
14.3
14.9
14.6
16.3
17.0
18.0
18.9
19.5
Benton Harbor 25,
Michigan
a
subsidiary ofDaystrom, Inc.
The Hea WI amplifier power rating standards have been established as further assurance to you of the
high quality of our products. We will live by these standards until industry-wide standards are established.
AUDIO
8
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
H
.4
5
EATH KIT
style
performance
quality
STEREO EQUIPMENT CABINET KIT
cosfiä
MODEL SE -1 (center unit)
you, 644!
$14995
MODEL SC -1 (speaker enclosure)
Snug. Wt. 42 Ws
;3995 each
Superbly designed cabinetry to house your complete stereo system.
Delivered with pre-cut panels to fit Heathkit AM -FM tuner (PT-1),
stereo preamplifier (SP-I & 2) and record changer (RP -3). Blaik
panels also supplied to cut out for any other equipment you may now
own. Adequate space also provided for tape deck, speakers, record
storage and amplifiers. Speaker wings will hold Heathkit SS-2 or
other speaker units of similar size. Available in unfinished birch or
mahogany plywood.
MONAURAL- STEREO PREAMPLIFIER
KIT (Two Channel Mixer)
World's largest manufacturer of
electronic instruments in kit form
MODEL SP -2 (stereo) $56.95 Shpg. Wt. 15 lbs.
MODELSP -1 (monaural) $37.95Shpg. Wt. 13 lbs.
MODEL C -SP -1 (converts SP-1 to SP -2) $21.95
HEATH
COMPANY
Benton Harbor,
Michigan
Shpg. Wt.
5
25,
lbs.
Special "building block" design allows you to
purchase instrument in monaural version and add
stereo or second channel later if desired. The SP -I
monaural preamplifier features six separate inputs
with 4 input level controls. A function selector
switch on the SP -2 provides two channel mixing.
A 20' remote balance control is provided.
bsld/ary of Dayatrom, Inc.
,\
HIGH FIDELITY
RECORD CHANGER KIT
MODEL RP -3
PROFESSIONAL STEREO -MONAURAL
AM -FM TUNER KIT
MODEL PT
-1
$8995
The 10 -tube FM circuit features AFC (automatic
frequency control) as well as AGC. An accurate
tuning meter operates on both AM and FM while
a 3- position switch selects meter functions without
disturbing stereo or monaural listening. Individual flywheel tuning on both AM and FM. FM
sensitivity is three microvolts for 30 db of quieting.
The 3 -tube FM front end is prewired and prealigned, and the entire AM circuit is on one printed
circuit board for ease of construction. Shpg. Wt.
20 lbs.
AUDIO
$6495
Turntable quality with full) :un Un141IC
features! A unique "turntable pause" allows
record to fall gently into place while turntable is stopped. The tone
arm engages the motionless record. and a friction clutch assures
smooth start. Automatic speed selector plays mixed 331:, and 45
RPM records regardless of sequence. Four speeds available: 16, 331,.
45 and 78 RPM. Changer complete with GE -VR -I1 cartridge with
diamond LP and sapphire 78 stylus, changer base, stylus pressure
gauge and 45 RPM spindle. Shpg. Wt. 19 lbs.
"EXTRA PERFORMANCE" 55
WATT HI -FI AMPLIFIER KIT
A real work horse packed with top quality
features, this hi-fi amplifier represents a
remarkable value at less than a dollar per
watt. Full audio output at maximum
damping is a true 55 watts from 20 CPS
to 20 kc with less than 2''; total harmonic
distortion throughout the entire range.
Featuring famous "bas -bal" circuit, push pull EL34 tubes and new modern styling.
Shpg. Wt. 28 lbs.
AUGUST, 1959
9
www.americanradiohistory.com
AmericanRadioHistory.Com
HIGH FIDELITY AM TUNER KIT
MODEL BC -1A
NOTE THESE OUTSTANDING SPECIFICATIONS: Power Output:
18 watts. Utility. Power Response:
12
Hi-Fi; watts. Professional;
watts output. Total Harmonie Dlatarne.:
Irom 20cps to
*lelesswatts.
watts output. I,darmodulatlon Distorcos
than 2%.
1
db
20 kc at
14
to 15 kc at 14
30
1% at 16 watts output
tion: less than
Hum and Noise: snag. phono input.
phono. 63 db below
14 -WATT
14
using 60 cos and 6 kc signal mined 4:1
47 db below 14 watts: tuner and crystal
watts.
$2696
Designed especially for high fidelity applications
this AM tuner will give you reception close to
FM. A special detector is incorporated and the
IF circuits are "broadbanded" for low signal
distortion. Sensitivity and selectivity are excellent
and quiet performance is assured by a high
signal -to-noise ratio. All tunable components
are prealigned before shipment. Your "best buy"
in an AM tuner. Shpg. Wt. 9 lbs.
HI -FI ECONOMY AMPLIFIER KIT
MODEL EA -3
$2996
...
New
From HEATHKIT audio labs comes an exciting new kit
Styling, New Features, Brilliant Performance! Designed to function
the
preEA
-3
combines
the
your
hi
-fi
system,
as the "heart" of
amplifier and amplifier into one compact package. Providing a full
14 watts of high fidelity power, more than adequate for operating the
average system, the EA -3 provides all the controls necessary for
precise blending of musical reproduction to your individual taste.
Clearly marked controls give you finger -tip command of bass and
treble "boost" and "cut" action, switch selection of three separate
inputs, "on -off" and volume control. A hum balance control is also
provided. The convenient neon pilot light on the front panel shows
when instrument is on. Styled to blend harmoniously into any room
surroundings, the handsome cover is of black vinyl coated steel with
gold design and features the new "eyebrow" effect over the front panel
to match the other new Heathkit hi -fi instruments. The panel is satin
black with brush -gold trim strip, while the control knobs are black
with gold inserts. Shpg. Wt. 15 lbs.
"MSTER CONTROL" PREAMPLIFIER KIT
(Not Illustrated):
MODEL
master á cómplete high fidelity system
controls you need
Incorporated in this versatile instrument. Features 5 swttchselected inpu s each with level control Próvides tape recorder and
obtained within
frequency
ca hode-follower outputs. F
to the finest
35x000 GPS and will
I1dbfrom
LP, RIAA,
available program sources. Equalization is
AES, and early 78 records. Shpg. W 7 lbs.
ll
.
MODEL TR-IA: Monophonic halttrack record /pla
back with fast forward and rewind
functions. Shag. Wt. 24 lbs.
$9996
MODEL FM -4
$$496
(with cabinet)
tf
HIGH FIDELITY FM TUNER KIT (FM4)
The all new model FM-4 incorporates the latest
advancement in circuit design. Features include
better than 2.5 microvolt sensitivity for 20 db
of quieting, automatic frequency control (afc)
with defeat switch, flywheel tuning and prewired,
prealigned and pretested tuning unit. Prealigned
IF transformers and prewired tuning unit assure
easy .assembly with no further need of alignment
after unit is completed. The five tube circuit features a generous power supply utilizing a silicon
diode rectifier. Shpg. Wt. 8 lbs.
"UNIVERSAL"
12
WATT
HIGH FIDELITY AMPLIFIER KIT
MODEL UA-1 $2196
Ideal for stereo or monaural applications, this
12 -watt
power package features less than 2%
total harmonic distortion throughout the entire
audio range ( 30 to 15.000 CPS) at full I2 -watt
output. Use with preamplifier models WA -P2
or SP -I & 2. Taps for 4, 8 and 16 ohm speakers.
Shpg. Wt. 13 lbs.
NEW!
MODEL TR-1AH: Half -track monophonic and stereo
/E
record /playback with fast forward
and rewind functions.
Shag. WI. 35 lbs.
Si T 996
.7
MODEL TR -IAO: Ouarter.track monophonic and
stereo with record /playback fast forward and rewind
functions.
Shoe. Wt. 35 lbs.
$14996
NOW! TWO NEW STEREO -MONO TAPE
YOU'RE NEVER OUT OF DATE
WITH HEATHKITS
Offering complete versatility, the model TR -IA series tape recorders
enable you to plan your hi -fi system to include the functions you want.
Buy the new half-track (TR -I AH) or quarter -track (TR -I AQ) versions
which record and playback stereo and monophonic programming,
or the half-track monophonic record -playback version (TR -1 A).
Precision parts hold flutter and wow to less than 0.35%. Four -pole,
fan cooled motor. One control lever selects all tape handling functions.
Each tape preamplifier features NARTB playback equalization, separate record and playback gain controls, cathode follower output,
mike or line input, and two circuit boards for easy construction and
high stability. Complete instructions guide assembly.
Heathkit hl -fi systems are designed for maximum flexibility. Simple conversion from basic to complex systems
or from monaural to stereo is easily accomplished by
adding to already existing units. Heathkit engineering
skill is your guarantee against obsolescence. Expand
your hi -fi as your budget permits ... and, if you like,
spread the payments over easy monthly installments
with the Heath Time Payment Plan.
RECORDERS IN THE TR -1A SERIES
AUDIO
10
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
CONTEMPORARY
Model CE -1B Birch
Model CE -1M Mahogany
CHAIRSIDE ENCLOSURE KIT
MODEL CE -1
No Woodworking Experience
Required For Construction.
All Parts Precut á Predrilled
For Ease of Assembly.
TRADITIONAL
Model CE -IT Mahogany
Maximum Overall Dimensions:
x 24" H. x 35%" D.
18" W.
IT'S EASY .. IT'S FUN
AND YOU SAVE UP TO
WITH DO -IT- YOURSELF HEATHKITS
$4395 each
Control your complete home hi -fi system right from
your easy chair with this handsome chairside enclosure in either traditional or contemporary models. It is designed to house the Heathkit AM and
FM tuners (BC-IA and FM -3A) and the WA -P2
preamplifier, along with the RP -3 or majority of
record changers which will fit in the space provided.
Well ventilated space is provided in the rear of the
enclosure for any of the Heathkit amplifiers designed to operate with the WA -P2. The tilt -out
shelf can be installed on either right or left side as
desired during the construction, and the lift -top
lid in front can also be reversed. All parts are precut and predrilled for easy assembly. The contemporary cabinet is available in either mahogany
or birch, and the traditional cabinet is available in
mahogany suitable for the finish of your choice.
All hardware supplied. Shpg. Wt. 46 lbs.
"BASIC RANGE" HI -FI SPEAKER SYSTEM KIT
.
The modest cost of this basic speaker system makes it a spectacular buy for any
hi -fi enthusiast. Uses an 8' mid -range
woofer and a compression -type tweeter to
cover the frequency range of 50 to 12,000
CPS. Crossover circuit is built
in with balance control. Impedance is 16 ohms. Power rating 25 watts. Tweeter horn rotates so that the speaker may
be used in either an upright or
Putting together your own Heathkit can be one of the most
exciting hobbies you ever enjoyed. Simple step -by -step instructions and large pictorial diagrams show you where
every part goes. You can't possibly go wrong. No previous
electronic or kit building experience is required. You'll
learn a lot about your equipment as you build il, and, of
course, you will experience the pride and satisfaction of
having done it yourself.
horizontal position. Cabinet is
made of veneer -surfaced furniture-grade plywood suitable
for light or dark finish. All wood
parts are precut and predrilled
$3995
MODEL SS -2
Legs: No. 91 -26 Shpg. Wt.
DIAMOND STYLUS HI -FI
PICKUP CARTRIDGE
lb. $4.95
for easy assembly. Shpg. Wt.
26 lbs.
LEGATO HI -FI SPEAKER SYSTEM KIT
$2696
$29995
MODEL MF -1
Replace your present pickup
and enjoy the fullest fidelity
LP's has to offer. Designed to
tions to offer you one of the
with the MF -1
your library of
Heath specificafinest cartridges
available today. Nominally flat response from
20 to 20,000 CPS. Shpg. Wt. lb.
1
"RANGE EXTENDING" HI -FI
SPEAKER SYSTEM KIT
The SS -1B employs a 15' woofer and super
tweeter to extend overall response of basic
SS -2 speaker from 35 to 16,000 CPS t5 db.
Crossover circuit is built in. Impedance is 16
ohms, power rating 35 watts. Constructed of
3/4' veneer -surfaced plywood suitable for light
or dark finish. Shpg. Wt. 80 lbs.
MODEL HH -1
The startling realism of sound reproduction by the Legato is achieved
through the use of two 15' Altec
Lansing low frequency drivers and a
specially designed exponential horn
with high frequency driver. The special
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Describing over 100 easy -to -build
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AUDIO
AUGUST, 1959
11
www.americanradiohistory.com
AmericanRadioHistory.Com
U
61ward ratnall Canby
1. PLAY RECORDS AND LIKE IT
As of this writing, I am five days' regular
mail from home, two days' air mail, and
the territory seems so wholly removed from
the world of audio that I can scarcely get
myself to write on that honored subject.
But it is good for me, of course, to get
away from the hectic center of things and
see how records and hi fi look to the big
outside world in its millions of small corners, of which this is one. Where am If Not
Pakistan, nor Durban nor even Yokohama,
but just plain Tennessee. I got a letter
this morning from Peter Bartok of Bartok
records in New York that was mailed just
seven days ago. That's how far away I am.
Down here, audio, hi -fi and records make
a subject for an experiment in teaching
which I believe is quite novel and perhaps
untried to date. I'm teaching hi fi -plus
sixteenth century motets-to an enterprising batch of budding professional musicians, average age about sixteen, who are
being trained by a faculty of professional
symphony players. The Sewanee Summer
Music Center is encamped on a lovely old
mountain campus, the University of the
South, for five weeks of concentrated music making-fiddle players, trombones, horns,
bassoons, clarinets, oboes, each group
ardently coached by the professional symphony specialist for the given instrument.
When they rehearse, under a big tent on a
very green and leafy lawn, these kids play
manfully (and girlfully) with a concentration that should make any teacher envious.
They can't be stopped. They take their
harmony lessons to the swimming beach
with them and study between dips. They
eat, drink, blow, scrape and pound music
all day long.
It would make you envious too, I'm eure,
if you happened to be thinking about the
young engineering students whom you may
know. These kids get up at five in the
morning to practice, or stay out of bed
surreptitiously until the wee hours, against
camp regulations, to hide themselves in a
sound -proof practice room and hammer
away (or blow away) at their instruments.
No doubt about it, music -live music
is a vital, living thing for a surprisingly
large number of upcoming young folks.
They face up to the formidable, even terrifying complexities of skilled musical performance with the usual fortitude of youth,
and more than that. They study and play,
here, as though the world of the future
would certainly be conquered by clarinete
and bassoons, as though if only the right
embouchure, the correct stance, the exact
rhythm and lilt could finally be achieved by
each and every one of them, the problems
of nations and the nuclear bomb would
-
melt away. It's a nice feeling, a heartening
one, if slightly provincial.
You see, if the United Nations and the
Bomb don't get mentioned very often here,
because there isn't time to bother with
them and there's practicing to be done,
work to fill every moment of a musician's
life-then audio, too, seems generally distant and not so very important, all in all.
Records are nice, of course, but real work,
real music is so much more to the point
and practice, practice, practice; that's
what really has to count. Records are like
candy, and apt to make one sick if taken
in more than tiny doses -sick for lack of
music practice. Time is of the essence, and
it's not for leisure -especially, listening to
records.
To be sure, the bassoonist from the Pittsburgh Symphony who lives next door to me
in the big stone college dormitory named
Cleveland Hall, has a Magnavox and a cat.
Each morning before our 7:30 breakfast
he puts on one record, shaves, feeds the cat
and rushes out to play bassoon. Each noon
he comes back, plays a record, cleans up
the cat's mess, if any (often), and rushes
out to play bassoon again, or teach bassoon. Same, ditto, idem, various other
times. He gets a surprising amount of
music in, this way (hi -fi on records, I
mean), though it is only natural that almost every piece lie plays has a bassoon in
it. (Bassoons play in practically all music,
when you come down to it, so he has plenty
to choose from.)
I brought down some 500 records, about
four -fifths of them stereo, to represent the
huge present recorded library. The rear end
of my car practically hit the ground under
the weight. I also crammed in a pair of
AR -3 speakers and another pair of KLH
Sixes -plus my complete Dynakit system
and a spanking brand new Fisher 300
stereo outfit. Also mikes, tape, a four -track
recorder, and other paraphernalia galore.
You should have seen my packing job for
the thousand-mile jaunt over the Blue
Ridge Parkway!
Unfortunately I am not yet able to report very much on this lovely array of hi
fi. I can state positively that the Fisher
turned on and didn't blow a fuse, nor did
it hum. I can say equally well that both
the AR-3 speakers produced a large volume
of sound. But beyond this I am presently
stymied for two excellent reasons.
First, I have -inevitably -been assigned
a fine, big university class room for my
hi -fi lectures. It is the Devil's own first
choice as the prize horror -room for listening. Unbelievable! Solid concrete, utterly
rectangular, without one square inch of
padding or sound deadening of any sort,
-
and one side is solid windows, the other
sides mostly hard, shiny blackboards. Tile
floor, varnished wooden chairs carved in
fiat planes. Phew! The sound that emanates from my speakers is vaguely like the
rumble of a subway train on a sharp curve.
If you listen hard, you can tell that it is
music that is playing.l
The odd thing is (and I've noticed this
before, in other similar situations) that in
this hard, bright, utterly plane -surfaced
room, what you hear is all bass and no
highs. For a moment, I thought the AR -3's
were connected with the tweeters out. Not
at all; they were turned all the way up,
both highs and mid- range. I managed to
get a slight and relative improvement bybelieve it or not-boosting the highs to the
maximum and rolling off the bass all the
way, plus the rumble cut -off set at a fairly
drastic position.
Worst of all, it didn't seem to make
really very much difference what I did
with the controls, nor what I played. All
records, including the deadest ones I know,
sound ultra-live and thoroughly scrambled.
Two speakers. I tried to check their
phasing via a mono record played through
both -and found that it didn't make the
slightest difference which way I set the
polarity. The reverberation was so tremendous that every last vestige of phasing
was effectively blurred out. Stereo? Here I
had brought a thousand -odd dollars' worth
of stereo equipment all the way to this
blarsted room and I immediately found
that in it there was not the slightest audible difference between stereo and mono
sound -phasing quite aside!
It's an odd spot for an audio man to be
in, but not actually an unusual one, come
to think of it. Don't forget that records,
most providentially, sound decidedly at
their best in the acoustics of the average
home living room- indeed, they are tailor made for the living room and generally find
themselves painful misfits in most other
acoustics. Class rooms, lecture halls, student lounges and the like are not designed
for record listening and no reason why they
should be. But unfortunately, if one is to
give illustrated lectures on records, with
records, the class room is the place it ordinarily has to be done. You members of local hi -fi clubs will know all too well what I
mean. Have you found a really good place
to hold your musical meetings -one that
will hold the audience and treat the recorded sound rightly?
The physical blur of recorded music in
my class room (I've been spending today
trying to locate a replacement room somewhere else) is compounded by the second
reason for a alight delay in producing results here in this Tennessee music camp.
(I haven't been here very long yet.) That
is, of course, the musicians themselves.
My job, ever so tactfully, is to persuade
these excellent, ardent, hard -working live
musicians that recorded music has something to do with their lives. And, as of now,
I have to do my persuading in that room.
Ugh.
So my very first problem of all, is to find
a better listening place. People here, like
others everywhere, do not understand what
a whale of a difference room acoustics can
make -do make -in reproduced sound. Not
1
Why didn't you open the windows? ED.
AUDIO
12
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
NEW STEREOPHONIC EQUIPMENT
not illcs.' provides
AF -4 Complete Stereo Dual Amplifier
clean 4W per channel or 8W output. Usual solid EI:0 construction & trouble-free design. Inputs for ceramic /crystal stereo pickups. AM-FM stereo. FMMull: stereo: 6- positron stereo /mono
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Function Selector permits hearing each stereo channel individually. and reversing them: also use of unit for stereo or monophonic. play. Fulbwave rectifier tube power supply. 5- 124X7/
ECC83. 1.6 %4. 'Works with any high -quality stereo power amplifier
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Either input can be made common for both amplifiers by Service
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SPEAKER SYSTEMS (use 2 for STEREO)
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5144.95.
HFS1: Bookshelf Speaker System, complete with factory -built
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exponential horn tweeter. Smooth clean bass: olsp extended
highs. 7012.000 cps range. Capai ity 25 w. 8 ohms. HWD 11" x
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FM TUNER HFT90: A superior stable tuner easy to assemble
no instruments needed. Prewired. prealigned. temperature-compensated -front end" is drift -free, eliminates need for AFC. Pre wired exclusive precision eye-ironick traveling tuning indicator
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Sensitivity 6X that of other kit tuners: 1.5uv for 20db quieting:
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NEW AM TUNER HFT94: Matches 111190. Selects "hi-fis' wide
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Kit $39.95. 'Nued $69.95. Prices Inc,. Cover 8 F.F.T.
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In New
AUDIO
York hear
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The EICO Sterco Hour," WBAI -FM, 99.5 mc, Mondays, Thursdays and Saturdays, 7:00 P.M.
AUGUST, 1959
13
www.americanradiohistory.com
AmericanRadioHistory.Com
The AR-3 is a three -way speaker system.
combining an AR -I acoustic suspension
woofer with two high -frequency units developed
in AR's laboratory over the last year.
Like the AR woofer, the tweeters used in the AR -3
represent a radical departure from conventional
speaker design, and patent application has
been made.*
These new tweeters are neither cone -type nor
horn devices-they could be described technically
as hemispherical direct -radiators. We believe
that their uniformity and range of frequency
response, their low distortion, and their transient
and dispersion characteristics establish new
performance standards, and that the AR tweeters
make a contribution to treble reproduction
similar in degree to that made by AR's acoustic
suspension woofer to bass reproduction.
The AR -3 has the most musically natural sound
that we were able to create in a speaker,
without compromise.
Potent applied for by
E. M. Vilichor, assignor to Acoustic
Research, Inc.
even enough engineers understand it. Most
of us are lucky; our living rooms, by the
happy chance of current decorating styles,
are usually quite good for recorded sound.
A few years ago, many a living room was
too dead for listening comfortably, what
with rugs, pillows, heavy drapes, plush
sofas. Now, the modern trend has brought
in more hard furniture, less absorbent
drapery and upholstery. But it hasn't gone
so far as to leave our living rooms bare
and chilly, like the average classroom!
Not that.
To be sure, there's a marvelous listening
room up our University avenue a ways, in
a comfy old fraternity house with all sorts
of nooks, balconies, wooden paneling, car-
pets, a peaked roof. Superb -but it happens
to be in the Director's private home and
isn't properly available. There's chamber
music to be played there all day long (and
what a lovely sound), with small time left
for any other purpose. But ah! what a
lovely sound from a stereo tape, too, that
I played in there the other evening! I'm
going to have to wangle my way into that
room willy -nilly unless I can find its double
somewhere else.
(There surely is nothing like putting
your theories to the test. I'm testing my pet
ideas on recorded sound with a vengeance
here.)
But back to the musicians. The bassoon,
the clarinet, the horn are simply too busy
to spend their lives learning about records
and, as specialists in a very demanding art
I cannot in the least blame them. There's
work for them to do and no end to it, ever.
But what makes things more interesting is
that some other faculty members among
these musicians are a lot more than merely
indifferent to the joys of record listening
and the complexities of audio acoustics,
stereo and what -not. These others, like
many musicians the country over, actively
distrust, even hate recorded music. They
feel, and have told me so elsewhere as well
as here, that records are not only murderous to the actual sound of real music but,
more important, they are passionately convinced that recorded sound has already
threatened the entire art of music and is
well on its way towards killing off the
musicians himself and his livelihood. Records, from this musician's point of view,
are an ominous force that is undermining
their whole way of life. Audiences are
vanishing from their concerts, young people find jobs elsewhere, musicians are quitting by the hundreds, disillusioned, stanit's
dards of playing are going down
a dismal story to hear, and it does make
you pause to think.
Here I am, an enthusiast for this very
enemy of theirs, right in their own camp
teaching their own young musical hopefuls
all about records! It's a bit hard on the
musicians and not too easy for me, though
it is a tremendous challenge to see whether
I can't convince some of these pleasant
people here that neither I nor my records
and my hi -fl are here to bite them, so to
speak. In a microcosm, on this campus, we
have the very essence of the musician's
problem today. The situation, if it weren't
so real, so isolated, so intense, could be
tremendously interesting for all of usand probably will be before I leave.
The problem I face, of course, is not
how to solve these musicians' future for
....
-
The AR-3 speaker system, complete with the
necessary "bookshelf" size enclosure, is
$216 in mahogany or birch -prices in other woods
vary slightly. Literature on the AR -3 is
available for the asking.
ACOUSTIC RESEARCH, INC.
24 Thorndike St., Cambridge 41. Mash.
AUDIO
14
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
LESA -É ARRIVATO!
-
Translation: LESA
IT HAS ARRIVED! In any language, this is
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searching for professional quality at an amateur price. Just one quick
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-
You'll especially want to see the smartly styled CD2/21 record changer never before such
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Lesaphon Model 57 /SA with stereo cartridge
Lecostereo Model 1 /SA with shielded cable
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You've never seen a 4 -speed manual record player of the
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Model 4V3/11 with universal plug-in head
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SEND FOR FREE LITERATURE AND
NAME OF YOUR NEAREST DEALER
2 3
Electrophono & Parts Corp.
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Name
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AUDIO
AUGUST, 1959
lone
State
15
www.americanradiohistory.com
AmericanRadioHistory.Com
Fairchild is
a
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412-1 Double Belt -Drive Turntable.
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them, which I can't do, but simply to get
their attention. There aren't many arguments because everybody is much too busy
to argue -even the bassoonist with his
Magnavox. He plays records but he's not
interested in them as records, nor how they
work. He just wants to hear the music on
them. An admirable idea and, I must confess, a rather pleasant one for me, who
spend most of my time trying to persuade
hi -fi fans to pay more attention to music
and less to the cycles and the IM distortion.
And I confess, too, that my own resolution is hard put, here. I tend in this intense area of active music- making to lose
interest in my own records. I, myself, want
to hear this live music; I am almost apologetic when I suggest that maybe the students ought to have a few hours now and
then during which they could listen to my
500 discs and study what other musicians
are doing in the great, big outside world.
But I mustn't be apologetic. I tell myself
that records are here to stay, that audio is
a great, big field unto itself, that hi -fi, for
all its goofiness, is a big industry and an
even bigger cultural force in our life today. I assure myself, privately, that millions of people are interested in records
and in hi -fi, that an enormous new audience for music has been created by the
phonograph, that recording has revived
vast areas of long- forgotten art that would
never have been heard again were it not
for the art of sound reproduction.
I insist, to myself, that I am representing, here in the mountains of Tennessee,
one of the most dynamic artistic movements of our century, just as I am in this
magazine that you are now reading.
But it all seems very distant, in spite of
me. Last night I forsook my tape recorder
and went off to listen to Stravinsky, played
by seven of my new musician friends here.
It was terrific and lots better than any
record. This afternoon, the next -door bassoonist spent three hours teaching a lovely
young lady student how to cut her own
bassoon reeds. I was fascinated, for here
was old -line craftsmanship of a sort you
wouldn't believe could still exist. Each of
his double reeds is cut and shaped by hand
with a careful knife, the edge trimmed to
a millimeter, the thickness carefully
scraped down for hours to an exactly even
taper and a perfectly symmetrical curve.
The canes for the reeds grow only in one
part of France -they can't be had anywhere else. They last a week or so, and then
the bassoon (and oboe) player spends more
hours of handwork scraping and binding
another.
Sure, it's like building a hi -fi kit in a
way; but suppose you had to go out and
make your own resistors and capacitors,
draw your own copper wire and wind on
the insulation.
It's an interesting corner of the musical
world, here in Sewanee, and no two ways
about it. But I haven't yet been able to
play a single record all the way through
anywhere on the campus. I'm not really
Phew! What
sure I want to, at that
am I saying?
On with the Great Crusade, Canby. Get
out and teach these musicians to play records and like itl
(Continued on page 64)
-
AUDIO
16
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AUGUST, 1959
New Stereo Tape Recorder
Cybernetically engineered
for intuitive operation
Fluid smooth, whisper giiict ... with fcatherlight touch you control tape movement
with the central joystick of your Newcomb
SM -310. This exciting new stereophonic
record -playback tape machine has been
cybernetically engineered to fit you.
Intuitively, you sense how to operate this
handsome instrument. The natural movement, you find, is the correct movement.
Loading is utterly simple. It is almost impossible to make a mistake. The transport handles tape with remarkable gentleness, avoids
stretch and spilling.
mixing controls on both channels for combining "mike" and "line The SM -310 records and plays back half -track monaural
also. So versatile is the machine that you
may record and playback on either or both
channels in the same direction.
The SM -310 is a truly portable unit which
combines the features required by the professional and desired by the amateur for onlocation making of master stereo tapes. For
example, the SM-310 takes reels up to 101/2",
has two lighted recording level meters arranged pointer -to- pointer for ready compariThe Newcomb SM -310 records stereo- son, has a 4 digit counter to pinpoint position
phonically live from microphones or from without repeating on any size reel. For playbroadcast or recorded material. There are back there are a "balance" control and a
NEWCOMB AUDIO PRODUCTS CO., DEPT.
T -8,
ganged volume control. I lead cover removes,
giving direct access to tape for easy editing.
The Newcomb SM -310 is a sleek, rugged,
compact machine, discreetly styled by an
eminent industrial designer in easy-to -live.
with shades of warm gray and satin aluminum...a gratifying, precision instrument for
the creative individual who is deep in the
art of tape recording. Eight, tightly -spaced
pages are required in a new brochure to
describe the SM -310 in detail; send for your
free copy.
Advance showings in New York and Los
Angeles proves an unprecedented demand
for this instrument. We urge those who desire early delivery to place their orders now.
6824 LEXINGTON AVENUE, HOLLYWOOD 38, CALIFORNIA
NEWCOMB SALES REPRESENTATIVES
CALIFORNIA, San Francisco 3, William J. Purdy Co., 312 Seventh St.; COLORADO, Denver,
Cox Soles Co., P. O. Box 4201, So. Denver Station; FLORIDA,
Tampa 9, Morris F. Taylor Co., 4304 Corona St.; Winter Haven, M. F. Taylor
940 Lake Elbert Drive; GEORGIA, East Point, M. F. Taylor Co., Box 308;
INDIANA, Indianapolis 20, Thomas 8 Sukup, Inc., 5226 No. Keystone Avenue; Co.,
MASSACHUSETTS, Brookline 46, Kenneth L. Brown, 54 Atherton Road; MARYLAND, Silver Spring, M. F. Taylor Co., P. O. Box 111; MICHIGAN, Ferndale
20, Sholco, 23525 Woodward Ave.; Grand Rapids 6, Shako, 700 Rosewood Ave.,
S. E.; MISSOURI, Clayton 5, Lee W. Maynard Co., 139
N. Central; NEW YORK, East Meadow, Harry N. Reizes, 1473 Sylvia Lane; Syracuse 14, Poston
-Hunter
Co., P. O. Box 123, DeWitt Station; NORTH CAROLINA, Charlotte 5, M. F. Taylor
Co., 1224 Dresden Drive, West; OREGON, Portland 8, Don H. Burcham Co.,
P. O. Box 4098; PENNSYLVANIA, Hellertown, M. F. Taylor
Co., 534 Ellen St.; Lansdowne, M. F. Taylor Co., 275 Bryn Mawr Ave.; Pittsburgh 36, M. F. Taylor
Co., 5436 Youngridge Drive; TEXAS, Dallas I, Wyborny & Yount Co., 408 Merchandise
Mart Bldg.; WASHINGTON, Seattle 99, Don H. Burcham Co., 422 First
Ave., West.
www.americanradiohistory.com
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EDITOR'S REVIEW
AUDIO ENGINEERING SOCIETY
CONVENTION
WITH THE PRESENTATION Of papers from all over
this country as well as from Europe and South
America, the Eleventh Annual Convention of
the Audio Engineering Society will take place at the
Hotel New Yorker October 5th through the 9th. These
papers will cover the newest theories, developments,
and achievements in the audio field, and will include
a thorough discussion of stereo. There will be a broad
coverage of sound recording and reproduction.
The convention will be accompanied by the second
"noiseless" exhibit of professional audio equipment,
first introduced last year, and it is expected that the
number of displays will triple those of last year. Technical sessions will be presented on a three -a -day basis
commencing at 9 :00 a.m. on October 5, and the annual
banquet and presentation of awards will follow the
cocktail party on Thursday, October 8.
Beginning on the same day and continuing for one
day after the AES Convention closes, the New York
High Fidelity Show will take place across the street
from the New Yorker in the Trade Show Building
but will most certainly not be "noiseless." People who
come to see high fidelity equipment expect to hear it
-
also.
THE WEST COAST SHOWS
The Institute of High Fidelity Manufacturers has
just announced the dates and locations for the San
Francisco and Los Angeles Shows. In the Bay City,
the location is Brooks Hall at the Civic Center, and
the dates are January 27 to 31.
The Los Angeles show follows a few days later,
opening at the Shrine Exposition Hall on February 10
and continuing through the 14th.
We will have further information about these two
important shows during the next few months-you
will still have plenty of time to arrange for your
annual early-spring trip to the coast. In the meantime,
there are the Rigo shows in many of the smaller cities
nearly one a week throughout the fall season
along with the Chicago and New York shows -the
former at the Palmer House from September 18-20,
and the latter October 5-10, as mentioned above.
-
-
Paraphrasing the boast of the Philadelphia paper
that "nearly everybody reads the Bulletin," we believe
it is safe to say that "nearly everybody goes to the
New York Show " -at least that is what you think
when you are there.
CONSUMER MAGAZINES
Apparently we are not alone in deriding the supposed omniscience of consumer testing organizations
-the somewhat less than austere Punch had its innings in the January 14 issue, a copy of which we just
received from Gilbert Briggs. Punch "analysed"
copies of Which? and Shopper's Guide, England's two
consumer "guidance" journals.
This is one time we beat Punch to the punch
you remember our editorial of April, 1957. And we
have never had cause to change our opinion since.
-if
MONODIC
Turning to another British publication, we find this
interesting bit in the June issue of Wireless World. A
chap writing under the nom de plume of "Free Grid"
conducts a page each month titled UNBIASED, and his
lead article studies the language to find a really good
word for single -channel reproduction. He believes the
correct word is "monodic," after agreeing that monaural is more offensive than monophonic, which is just
plain dreadful. Cause of it all was BBC's patronage of
monophonic -which most of us use in this country as
an improvement over monaural, and which is officially
accepted by the IHFM. Monodic, by the way, is a contraction of monos (one or single) and hodos (a way,
path, or channel). Still quoting from Wireless World.
we find that in such combinations the "h" is usually
dropped, as in electrode.
The funny part comes when Free Grid attempts to
find the right word for two stereo channels sharing the
same radio channel-as in multiplex. He claims the
word should be homodic-same channel -but he expects it to become known as homostereo to distinguish
it from stereo broadcasting on two separate channels
which might be called heterostereo. He concludes by
expecting that the Yanks- that's us -will probably
fuse Latin and Greek and call it solo stereocasting.
All of which proves that there are many ways to
have fun -but most of us never went to Oxford.
AUDIO
18
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AmericanRadioHistory.Com
AUGUST, 1959
"IT
TAKES TWO TO STEREO"
*
...the perfect team for stereo!
For matchless reproducton of stereo recordings
- the
Model 196 UNIPOISE Arm
with integrated Stanton Stereo FLUXVALVE pickup
and the GYROPOISE 800 airborne Stereotable.
Only the Stanton Stereo FLUXVALVE
has the exclusive "T- GUARD" stylus assembly
with the parallel reproducing element so important for stereo...
only the GYROPOISE Stereotable revolves on a bearing-of-air
-
in
magnetic suspension
...
only the Stereo FLUXVALVE is warranted for
In plain truth, here is more to enjoy
-
a
lifetime.
from both stereophonic and monophonic records.
Fine quality high fidelity products
by PICKERING & Co., Inc., Plainview, N. Y.
FLU %VALVE, GYROPOISE, STEREOTASLE,
*
NEWLY REVISED
AUDIO
-"IT TAKES TWO TO
T -GUARD
STEREO
UNIPOIsE.
" -ADDRESS
DEPT
B89 FOR YOUR FREE COPY.
AUGUST, 1959
19
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AmericanRadioHistory.Com
Bell Telephone Laboratories
experiment in noise appraisal
A
"The native Hollander wears wooden shoes."
"Nebraska has no seacoast."
"The daisy is a common wildflower."
As these syllables, words and sentences come in over
the telephones, stand -ins for millions of Bell System subscribers rate them for clarity of reception.
From these tests, Bell Telephone Laboratories engineers
determine what is objectionable noise, and work to minimize it in telephone circuits. They begin by tape recording background noise associated with working telephone
circuits. Test statements of appropriate length and content (such as those above) are read onto a second tape,
and both are fed onto the test circuit under carefully controlled conditions. A third tape, of normal room noise,
is played through a loudspeaker in the test lab.
Several hundred listeners, meeting in small groups
several times a day for weeks at a time, are then asked to
rate the effect of noise on transmission of the various
simulated telephone calls.
For the Bell System, the results of the study will become part of the over -all transmission objectives. At Bell
Laboratories, they will influence apparatus and systems
development work.
Noise is a major distraction of modern day living. It
is also an enemy of the Bell System. In a telephone receiver during a call, it might be power line hum, switching
or thermal noise, or perhaps atmospheric static. Bell
Laboratories spends a great deal of time, effort and money
to keep this extraneous noise from becoming annoying
and to assure you of a trouble -free connection.
-
BELL TELEPHONE LABORATORIES
World center of communications research and development
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AmericanRadioHistory.Com
Transistor Music System
Using Direct Coupling
RICHARD
S.
BURWEN
Using 13 transistors with direct coupling and 57 db of negative feedback results in only .01
per cent low- frequency harmonic distortion in a 20 -watt class B battery- operated power amplifier. The 11- transistor control unit uses three direct- coupled feedback amplifier sections
to provide phono equalization, tone controls, a four-channel mixer, and speaker equalization.
DISTORTIONLESS PERFORMANCE in
transistor audio equipment requires
a great deal of negative feedback.
Direct coupling makes possible the use
of large amounts of stable feedback in
the music system to he described.
Three matched components comprise
the system : a 20 -watt power amplifier, a
tone-control preamplifier, and a speaker
system. Battery operation and compact
construction make the system suitable
for both home and portable use. To produce over -all pleasing sound and wide
acoustic frequency response, fixed equalization which compensates for speaker
system inefficiency at the extremes of the
audio range is incorporated in the tone
control preamplifier unit.
Power Amplifier
The power amplifier, Fig. 1, delivers
20 watts to an 8 -ohm load with an input
of 0.4 volts rms into 3300 ohms. Identical 55 -watt
power transistors, direct
coupled to the load, are mounted at the
upper left on a bracket which conducts
Boston Division, Minneapolis-Honey -
well Regulator Co.
their heat to the main chassis. The only
controls are on and off push buttons
which operate a latching relay. Not
shown are four mercury flashlight -size
cells and a 45 -volt battery somewhat
larger than the 8" x 6" x 31/2" aluminum
10MW
0.IW
20W
I
r
5
chassis.
In order to minimize the battery drain
and internal heat the output stage is
operated in class B with an efficiency of
69 per cent at maximum sinusoidal output. Since the average power input when
reproducing speech and music is much
smaller than for steady signals, the average current drain per hour may be as
low as 40 ma at 45 volts while 2.2- ampere
peaks are being delivered to the load occasionally. The current drain at no -signal is only 27 ma.
As a result of the low average power
input, battery life is between 10 and 100
hours depending upon how loudly music
is played. Smaller batteries can be used
when reduced life is acceptable, but the
power output is reduced because of their
lower output voltage at high currents.
Although capable of only 40 -watt undistorted peaks the amplifier can fre-
Fig. 1. 20 -watt direct- coupled transistor power am-
plifier.
AUDIO
IMW
10
AUGUST, 1959
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-20
-10
0
+10
TO 20 WATTS OUTPUT
Power amplifier total harmonic
distortion vs. power output at 10, 500,
and 10,000 cps
Fig. 2.
quently be operated under overload conditions with remarkably good results. Its
sharp overload characteristic and its
practically instantaneous recovery when
the input signal is reduced below the
clipping level minimizes the audible effect of overload during occasional peaks.
When used as a speech clipping amplifier feeding the associated speaker
system, the input signal may be increased
as much as 10 db above the overload
point with little audible distortion on
speech. Since the missing peaks do not
noticeably affect the average loudness,
the effective output is that of a 200 -watt
amplifier. Thus as a portable public address amplifier it has tremendous power.
When reproducing music fairly clean sounding signals can be delivered at effective outputs between 40 and 200
watts depending upon the low- frequency
content of the program material. Over21
www.americanradiohistory.com
AmericanRadioHistory.Com
loaded bass notes generally are intolerable whereas cymbals and brass instruments may sound undistorted when the
amplifier is delivering square waves 30
per cent of the time. The maximum increase in audible output when the amplifier is delivering square waves nearly all
the time and sounds very distorted is
about 13 db.
Direct Coupling
Except for one coupling capacitor at
the input all 13 transistors in the schematic, Fig. 3, are direct coupled. The
input transistor Q, is a low -noise emitter- follower needed to drive the high
a PNP commoninput capacitance of
emitter amplifier. Q, also compensates
changes in the base -to-emitter voltage of
Q, with temperature by means of the
opposite change in its own base -to -emitter voltage. Q, has a very high voltage
gain of 2500 obtained by using an extremely high collector load impedance.
This load impedance consists of the high
collector impedance of the NPN transistor Q, which is further increased by
emitter degeneration. Q, and Q, are
emitter -followers used to minimize the
loading on Q,, provide a low output impedance, and by means of a voltage divider reduce the d.c. output level to approximately ground potential.
This combination of three emitter-followers and one common- emitter stage has
a total voltage gain of 1800 at low fre-
Q
quencies with phase shift at high frequencies approaching that of only one
stage. In the megacycle region, the direct
signal path through the base-to- emitter
capacitances of the emitter-followers reduces their phase shift and helps stabilize the over -all feedback loop.
Following Q, are four stages of push pull class B amplification Q, through
Q1,- Except at the common input and
common output there is no connection
between the sides of the four push -pull
stages. Both power transistors Q1, and
Q1, are of the same 55 -watt PNP type.
Push -pull operation is accomplished by
a series connection with Q,t powered by
- 22.5 volts and Q,, by + 22.5 volts. In
order to establish the proper d.c. levels
and driving voltages the sequence of
NPN and PNP stages driving Q,, is
different from the sequence driving Q,,.
In the upper section of the circuit
all conduct at
stages Q Q Q,, and
the same time to deliver negative output
signals at J,,. Q, and Q, are common are
emitter stages while Q, and
emitter -followers. In the lower section
of the circuit Q9, Q, Q,,, and Q,, all
conduct at once to deliver positive output signals. Common- emitter stage Q, is
followed by two emitter-followers
and Q,, and then the final common emitter stage Q,,. Since there are two stages
in each section that invert phase and
two stages that do not, the output signals from Q,, and Q,, are in phase, re-
Q
Q
Q
suiting in true push -pull operation with
identical output transistors.
Examining the circuit more closely,
Q, feeds directly the base of the common
emitter PNP transistor Q, and through
two biasing diodes the base of the NPN
common -emitter transistor Q,. The collector signals of Q, and Q, are in phase
but referenced to different d.c. supply
voltages. Q, then feeds a three-stage
feedback amplifier Q Q and Q1,.
Common emitter NPN transistor Q, delivers a low- current signal centered near
ground potential with a swing of ± 18
volts. Emitter- follower Q capable of.
100 ma output, drives emitter follower
Q,, to deliver 2.2 ampere peaks to an Band J,,.
ohm load connected between
In the lower section, Q, feeds emitterwhich amplify the
followers Q10 and
signal current to provide up to 100 ma
drive for the common -emitter output
has a large collector
stage Q,,. Only
J
Q
Q
swing.
For push -pull class -B operation at low
distortion only one output transistor
must conduct at a given time except during a small overlap region which is
necessary to prevent crossover distortion. When Q,, is conducting its current
output per volt delivered by Q or
transconductance, must equal the current
delivered by Q,, when it conducts. At
crossover each transistor should contribute one -half the total output signal
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amplifier.
AUDIO
22
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
I
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Fig. 4. Power amplifier maximum power output and low -level frequency response.
current and the total transconductance temperature but in opposite directions
should be the same.
so that they cancel.
These conditions are met by establishStabilization of the feedback is acing the operating points and gains by complished at high frequencies by means
means of local feedback. Emitter degen- of local feedback paths from the output
eration stabilizes the voltage gain of Q,
through small capacitors to the base
at 1.8 and that of Q, at 2.2. Local feed- circuits of Q, and Q and from the colback developed by the collector current
of Q across a 1 -ohm resistor in series
with the emitter of Q, stabilizes the combined three-stage transconductance of
Q Q, and Q at 0.83 amperes per volt. Fig. 5. Left: Overloaded power-amplifier
The total transconductance referred to output at 1000 cps. Right: output vs. inthe emitter of Q, is then 1.5 amperes per
put under the some conditions.
volt, resulting in a voltage gain of 12 to
lector
of Q, to the base of Q,. Shunt
an 8 -ohm load. Similarly local feedback
developed by the emitter current of Q1, capacitors provide phase lead in the
across a 1 -ohm resistor in series with the main feedback network to help stability.
Four 1.3 -volt flashlight -size mercury
emitter of Q10 (and the small base -toemitter voltage of Q1,) stabilizes the cells power Q Q10, and Q,,. To prevent
three -stage transconductance of Q,,, Q
and Q at 0.68 amperes per volt. Referred to the emitter of Q
also delivers 1.5 amperes per volt. A 500 -ohm Fig. 6. Power -amplifier square -wave readjustment in series with the emitter of
sponse
Qe permits precise matching of these
a
condition
during
the application of
transconductances.
power in which both output transistors
Because of the low voltage gain the
are conducting heavily a latching relay
normal tendency toward a simultaneous
Kl, modified for make before break opincrease in the two output -stage collecon the bias voltages before
tor currents with increased temperature eration, turns
the high voltages. The relay can be
is minimized. Residual drift is compensated to within ± 10 ma for ambient temperatures of 32° to 120° F by means of
diodes and a thermistor which vary the
J
Q
bias on Q, and Qe. These diodes also
form part of a network used to change
the bias in accordance with battery voltage variations so as to maintain constant
the output -stage no- signal collector current as either the + 22.5 volts or the
- 22.5 volts decreases to as low as 12
volts.
Drift of the output voltage due to unbalance in the collector currents of Q,,
and
is prevented by additional overall feedback amounting to 57 db at audio
frequencies and 87 db at d.c. This feedback from the output
to the base of
Q, holds the output signal at nearly the
base potential of the first stage. The base
potential is in turn determined by the
very small base -to-emitter voltage of Q,
plus that in Q both of which vary with
Q
J
AUDIO
At low frequencies, where the greatest
power output is needed to overcome
speaker-system inefficiency, the performance of this amplifier is outstanding. Figure 2 shows curves of total harmonic distortion versus power output to
an 8 -ohm load at 10,500, and 10,000 cps
when using a regulated power supply.
At 10 cps the distortion is less than 0.01
per cent at the full 20 watts output and
at 500 cps only 0.014 per cent.
Due to the limitation in the rate at
which the power transistor collector currents can be cut off the maximum power
output decreases above 10,000 cps. This
factor together with the reduction in
feedback for stability reasons to only 18
db at 20 kc results in a total harmonic
content between 0.5 and 2 per cent on
10,000 -cps signals up to 10 watts output.
Since less power output is needed at the
high frequencies in normal reproduction,
and the principal harmonic content is
beyond the range of audibility, the increased distortion is of no consequence.
Maximum power output at the clipping level as a function of frequency is
shown by the upper solid line in Fig. 4
when using a regulated supply. Slightly
less output, shown by the dotted curve, is
obtained when using battery power because the voltage decreases at high currents. A pair of 4000- microfarad energy
storage capacitors tends to hold up the
battery voltage during current peaks,
permitting sustained sinusoidal outputs
of 19 watts above 40 cps and instantaneous peaks of 42 watts when reproducing
music and speech.
When overloaded the amplifier clips
cleanly and synunrtrically as in Fig. 5
and recovers to its normal low distortion
state within 30 µsec after the input signal is reduced below the overload point.
The residual delay in the recovery seems
Battery7.
powered
control
unit has phono
preamplifier, four
Fig.
channel mixer,
and tone controls.
AUGUST, 1959
23
www.americanradiohistory.com
AmericanRadioHistory.Com
at the RADIO input, 10 mv
rms into 320 ohms for 10 cm/sec recorded velocity at the PHONO input, and
10 mv rms into 1000 ohms at the Mlorophone input. The Microphone input will
accommodate dynamic microphones having an impedance of 30 ohms or higher.
Full output from the power amplifier is
obtained when the master VOLUME control is turned 18 db below maximum.
Connections for the four inputs, TAPE
OUTPUT, main OUTPUT, and power amplifier remote control cable are on the side
of the control unit. An additional connector allows a check on the battery
condition without opening the case.
300 k ohms
Fig. 8. Inside the tone-control preamplifier.
to be inherent in feedback circuits that
saturate and is minimized by making the
high- frequency loop gain high.
At low levels the frequency response
shown by the lower curve in Fig. 4 is
flat within 1 db from 10 to 70,000 cps.
The corresponding square -wave response, Fig. 6, indicates low phase shift
and freedom from ringing.
Tone-Control Preamplifier
The control unit, Figs. 7 and 8, operates from six self contained 4 -volt mercury batteries having a life of 1000
hours. It provides complete facilities for
single -channel reproduction: a four
channel mixer for TAPE, RADIO, PHONO,
and dynamic Microphone; a master VOLUME control; BASS and TREBLE compensators; a MONITOR control for monitoring
the tape while recording'; an ON-OFF
switch, and ON -OFF push- buttons for remote control of the power amplifier. The
PHONO input has a low -noise preamplifier designed for ESL low-impedance
cartridges. When the tone controls are
set at their flat positions the output to
the power amplifier is equalized to complement the response of the speaker system while the output for tape recording
is flat. The tone controls operate on all
channels except MONITOR. The normal
signal level at the TAPE OUTPUT is 0.3
volts rms and at the main OUTPUT is 1
volt rms. Each output has 100 ohms internal impedance and is capable of feeding loads of 3300 ohms or higher through
as much as 1000 feet of cable. Noise and
distortion are extremely low.
Input levels are: 1 volt rms into 50 k
ohms at the TAPE input, 3 volts rms into
-
Feedback Circuitry
Three separate direct -coupled feedback amplifiers constitute the tone control preamplifier shown schematically in
Fig. 9. By powering each amplifier from
its own positive and negative 4-volt
batteries, decoupling problems and
power-line noises are eliminated. Each
amplifier has from 30 to 60 db of feedback around its output stage over the
range of 20 to 20,000 cps to hold its
distortion to a low value.
The first amplifier section is a three Q =,
transistor phono preamplifier,
and Q, providing gain and RIAA equalization for the magnetic pickup. Wide band low -leakage r.f:type transistors are
(Continued on page 58)
Q
DIO
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150K
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Fig. 9. Tone -control preamplifier schematic.
AUDIO
24
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
-
Rockbar introduces a remarkable new 4 -speed Collaro transcription stereo changer
The Constellation, Model TC -99. The TC -99 offers tested and proven professional turntable performance with the advantages of automatic operation truly a complete
record player for the connoisseur. Here are some of the features which make this the outstanding changer
on the market today Performance specifications exceed NARTB standards for wow, flutter and
rumble Extra-heavy, die cast non -magnetic turntable weighs 6%2 lbs. Extra -heavy duty precision- balanced and shielded four pole motor New two-piece stereo transcription type tone arm
Detachable five terminal plug-in head shell Each model is laboratory checked and comes with
its own lab specification sheet. Flutter is guaranteed not to exceed .04 %. Wow is guaranteed not
to exceed .15%. Rumble is guaranteed down -50 db (at 120 cps relative to 5 cm/sec at 1 KC). The
extra -heavy weight turntable is a truly unique feature in a changer. This extra weight is carefully distributed for flywheel effect and smooth, constant rotation. The non-magnetic turntable provides a reduction in
magnetic hum pick -up of 10 db compared with the usual steel turntable. The heavy duty four pole motor
is precision- balanced and screened with triple interleaved shields to provide an additional 25 db reduction
in magnetic hum pick -up. The rotor of the four pole motor is specially manufactured and after grinding,
is dynamically balanced to zero. While this is basically a turntable for transcription performance, a fully
automatic intermix changer, similar to the mechanism employed in the famous COLLARO CONTINENTAL, MODEL TSC -840, is an integral part of the unit. ADDITIONAL FEATURES New two -piece stereo
transcription type tone arm with detachable five terminal plug -in head shell. This new arm is spring
damped and dynamically counterbalanced to permit the last record to be played with the same low stylus
pressure as the first. Between the top and bottom of a stack of records there is a difference of less than a
gram in tracking pressure-compared with four to eight grams on conventional changers. Vertical and
horizontal friction are reduced to the lowest possible level. These qualities -found complete only in
Collaro transcription changers -insure better performance and longer life for your precious records and
expensive styli. The TC-99 handles 7", 10" and 12" records
any order. The changer is completely jam proof and will change or play records at all four speeds. The manual switch converts the changer into a
transcription type turntable providing transcription performance_ for the playing of a single long-play
stereo or monophonic record. The two -piece arm can then be set down to play portions out of rotation or
the entire record can be played singly and sequentially. The double muting switch provides absolute silence
for both stereo channels during the change cycle and the R/C network helps to squelch "pop," "clicks" and
other noises. The TC -99 comes complete with two audio cables ready to be plugged into your stereo system. It is pre -wired for easy installation styled in a handsome two-tone ebony color scheme to fit any
decor; tropicalizecl against adverse weather and humidity conditions. Long service life is assured by the
automatic disengagement of the idler wheel preventing development of bumps and wow. Price of the
TC -99 is $59.50, exclusive of the base. All prices are slightly higher in the West. For free colorful catalog
on the complete line of Collaro Stereo Changers write Rockbar Corporation, Dept. 100, Mamaroneck, N.Y.
-
:
:
-in
;
The last word in a Transcription Stereo Changer.. .
Collaro Constellation,
TC-99
RC12
www.americanradiohistory.com
AmericanRadioHistory.Com
Hi -Fi Speaker Enclosure
Damping Materials
JAMES A. HUFF, JR.`°
A report on a series of tests made to compare relative performance of three types of damping materials in speaker cabinets.
The action of a speaker is similar to
production of high fidelity equipment has a piston. Air entrapped in the enclosure
accentuated the need for more in- is actually compressed and expanded as
formation on speaker-enclosure damping the speaker cone moves in and out. As
materials. Cabinet damping techniques this expansion and compression of air
vary widely. Materials recommended for takes place, sound pressure is varied
this purpose range from brick and sand inside the cabinet.
This sound pressure is transmitted
to a wide variety of fabricated products
to .the cabinet walls. When they are
used in the building industry.
For the manufacturer who wishes to thin or unbraced, they act as diaphragms
select a damping material there is and transmit sound into the room. Cablimited information. On the other hand, inet radiation also causes dips and peaks
tone -conscious hi -fi enthusiasts, alert to in the speaker output and adds colorathe refinements possible in their sets, tion to the sound.
Application inside the cabinet of
are often frustrated in their attempts
damping materials with low sound to achieve cleaner sound.
Throughout the industry, millions of transmission properties minimizes the
dollars have been spent in laboratory diaphragm action of the cabinet walls.
research on amplifiers, preamps, turntables, pickups, speakers and enclosures. Resonances and Standing Waves
Results of this research have made top There are two types of cabinet resoquality components available to the con- nance that occur whenever a speaker is
sumer, each especially designed for the enclosed in a cabinet. They are fundahi -fi market.
mental resonance and spurious resoThe speaker system still remains,
nance.
however, the weak link in hi -fi installaFundamental resonance is determined
the
tions. This is due in large part to
by the compliance of the cabinet, tofact that damping materials inside the gether with the compliance of the
cabinet have been given too little atspeaker. The bigger the volume the
tention.
lower the fundamental resonant freA critical look at present damping quency for a given speaker.
This
reis
in
order.
materials therefore
Spurious resonances occur at freport is a step toward examining, com- quencies whose wavelengths are a multiparing, and developing data on three ple or submultiple of the cabinet dimendamping materials having good acous- sions.
tical properties.
Whenever sound waves are generated
within an enclosure they travel outward
Cabinets and Damping
from the source (the loudspeaker cone),
Sound from the back of a speaker strike a wall, and are reflected. This recone is 180 deg. out of phase with the flected or "bouncing" wave action consound from the front. Under certain tinues until the energy in the wave is
conditions of path length (front to dissipated and the wave dies out. The
back) and frequency they will cancel. time it takes for this sound energy to be
This cancellation causes dips and peaks expended depends on the absorption
in the speaker output. By mounting the properties of the reflecting walls.
speaker in a cabinet, however, the back
Hard surfaces, such as wood, absorb
wave is confined within the enclosure little energy and are highly reflective.
and cancellation cannot occur.
It takes a comparatively long time,
At the same time, enclosing the therefore, for sound waves generated inspeaker in a cabinet poses problems of side a wood cabinet to die out.
cabinet radiation, cabinet resonances
Sound waves built up inside a cabinet
and standing waves.
or enclosure in this manner are referred to as standing waves. If the
339 Twin Lane So., Wantagh, N.Y.
TREIRENIOLS GROWTH in the
length of these standing waves is a
multiple or sub-multiple of one of the
cabinet dimensions, resonances occur.
It follows that the presence of standing waves causes a varying acoustical
impedance or load to be presented to
the speaker. When this happens peaks
and dips in the speaker output result.
Many solutions have been offered to
correct these conditions. The damping
of cabinets or enclosures with an acoustical material has proved the most practical. Such a material should have two
properties-high absorption, and low
sound transmission.
Three materials recommended for
their sound- absorbing properties were
subjected to performance tests. Their
relative sound- absorption and sound transmission performances are compared in this report. The materials
tested were:
1. Audiofelt, wool felt, 3/8 -inch
thickness (non -woven)
2. Fibrous glass 1 -inch thickness
(non -woven batt)
3. Cellulose fiber 21/2 -inch thickness
(asphalt -impregnated sheet)
The equipment used for the tests consisted of :
Bozak 207 -A speaker system
Langevin 128 -A 20 -watt amplifier
Magnecorder Model PT6 -BA2HZ tape
recorder
Capps condenser microphones, Model
CM -2030C
RCA wideband oscilloscope, Model
WO-78A
General Radio Model 1302 -A audio
oscillator
Test Procedure
For all the tests the saine amplifier
and speaker were used. The speaker
cabinet was approximately 11 cubic
feet. The tests were made with the
cellulose, fibrous glass, and felt materials in that order. Constant input
power was maintained to the speaker
for all the tests.
Sound Absorption Tests: These tests
AUDIO
26
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AmericanRadioHistory.Com
AUGUST, 1959
Improve speaker
7
performance
Felt
Laboratory tests conclusively prove FELT is the
most effective damping material for hi-fi speaker
enclosures!
In recent tests made with the usual damping materials (fibrous glass
and cellulose fiber), FELT was scientifically proven to be the only
material really effective in the low- frequency range where troublesome cabinet resonances occur and where most of the power is
transmitted.
The use of FELT resulted in a smoother power output over the entire
frequency range from 50 to 15,000 cps, and acoustical power output
from the speaker was increased from 25 to 50 per cent in the lowand middle- frequency range.
Listening tests prove without doubt, that sound from a cabinet lined
with FELT has a cleaner sound with a much better balance between
the highs and lows. "HI -FI FELT" only $5.98 per sq. yd. (packaged)
Continental
BRAND
FELT
At better stores everywhere or write to :
CONTINENTAL FELT CO.,
22 West 15th Street, New York 11, N.Y.
"STUDIO QUALITY RECEPTION" for your Hi -Fi Room! Continental's
new DECOR-FELT WALL COVERING
with the quiet dimension for
distinctive interiors eliminates unpleasant sounds- enhances tonal quality -turns acoustical problems into beauty spots. FREE color swatch folder
on request!
-
AUDIO
AUGUST, 1959
-
27
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AmericanRadioHistory.Com
were made to determine which of the
three materials had the best sound
absorbing properties. The speaker cabinet was lined with each material. All
the inside surfaces were covered with
the exception of the front panel. A
microphone was placed inside the
speaker cabinet. This microphone was
used to measure the sound pressures for
selected frequencies between 50 and
15,000 cps. This is the range of frequencies encountered in hi -fi reproduction. Since damping materials are
used to reduce the sound pressure inside the cabinet, their effectiveness is
readily determined by measuring this
sound pressure. The lower the sound
pressure inside the cabinet the more
effective the damping material.
Sound Transmission Tests: These
tests were made to determine which of
(A)
(C)
(B)
Fig. 1. Oscilloscope traces made during the Sound Absorption Tests. (A), cellulose
material; (B), fibrous glass material; and (C), felt. The traces show sound pressures
inside the speaker cabinet for a frequency of 50 cps.
Summary of Results
the three materials at various frequen-
1 through 3 are photographs
of oscilloscope traces made during the
Sound Absorption tests. Figure 1 shows
the sound pressures inside the speaker
cabinet for a frequency of 50 cps, Fig.
2 the same data for 1000 cps, and Fig. 3
for 15,000 cps. In each case, (A) represents the cellulose material, (B) the
cies.
Figures
Figure 6 shows the results of the
Speaker Output Tests. The output of
the speaker, measured in decibels, is
plotted vs. frequency for felt, and the
three materials.
the three damping materials transmitted
the least sound. This property is important in order to prevent the sound
inside the cabinet from reaching the
Discussion
walls with sufficient amplitude to set
A good damping material has two
them vibrating. Cabinet vibration is
with
of
phase
it
is
out
since
undesirable
the front radiation from the speaker
and can cause a power loss of as much
as 50 per cent, which is especially
noticeable at the low frequencies. The
transmission tests were conducted by
placing each material between the
speaker and the microphone and recording the sound pressure drop in db.
The tests were made at selected frequencies between 50 and 15,000 cps.
(C)
Speaker Output Tests: For this series
(B)
(A)
of tests a second microphone was placed
cabinet at
inside
the
speaker
traces showing sound pressures
on the axis of the loudspeaker. This Fig. 2. Oscilloscope
1000 cps. (A), cellulose; (B), fibrous glass; and (C), felt.
microphone measured the output of the
speaker for selected frequencies between
50 and 15,000 cps. Since the same frefibrous glass material, and (C) the felt important properties-high absorption
and low sound transmission. High abquencies and same power input to the material.
Figure 4 shows the relative sound sorption is necessary to prevent the respeaker were used for all three materials, it was easy to see the effect the pressure in decibels vs. frequency for the flection of sound inside the cabinet. Low
different damping materials had on the three materials. The sound pressure was sound transmission is necessary to presound inside the
speaker output. By examining the curves measured inside the cabinet and the vent the undamped the cabinet walls
from reaching
plotted from these tests it was possible curves plotted from data gathered dur- cabinet
Tests. Figure with sufficient amplitude to cause them
to determine which damping material ing the Sound Absorption
Trans- to vibrate. If these two conditions are
of
the
Sound
the
results
5
shows
gave the smoothest output over the fremission Tests. The curves show the drop not met, standing waves result and
quency range and which gave the highin sound pressure, in decibels, through spurious cabinet resonances occur. When
est power output. All sound pressures
were measured in db. The data from
these tests were plotted and are shown
in the DATA section of this report. During the sound absorption tests, oscilloscope pictures were taken of the sound
waves inside the cabinet. These pictures
plainly show the differences between
the three materials.
Listening Tests: As each material
was tested, listening tests were made
to determine the differences in sound
(B)
(C)
(A)
caused by these materials. Various
cabinet at
the
speaker
inside
musical selections were played through Fig. 3. Oscilloscope traces showing sound pressures
15,000 cps. (A), cellulose; (B), fibrous glass; and (C), felt.
the system and recorded on tape.
AUDIO
28
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AmericanRadioHistory.Com
AUGUST, 1959
the all -new
VR -22
stir'
.5 mil diamond stylus. For pro
fessional -type tone arms, $27.95.
VR -225
stereo.
cartridge
.7 mil diamond stylus. For
record changer or turntable, $24.95.
VR -227
Now, outstanding in all four critical areas of stereo cartridge performance
Compliance- Tracks
precisely, not a trace of stiffness. Channel Separation -Up to 30 db for maximum stereo effect.
Nothing higher on the market! Response -Smooth and flat for superior sound from 20 to 20,000
cycles (VR -225), 20 to 17,000 cycles (VR -227). Virtually hum -free
currents. This is our masterpiece. We urge you to hear it.
GENERAL
-triple
shielded against stray
ELECTRIC
Audio Components Section, Auburn, N. Y.
AUDIO
AUGUST, 1959
29
www.americanradiohistory.com
AmericanRadioHistory.Com
10
1
`k
O
1
1
1
1
1
I
1
I
1
FIBROUS GLASS
- - --
`\....\
s -10
--
(I"
1
1
1
1
1
1
THICKNESS)
CELLULOSE (21/2" THICKNESS)
-
FELT (3/8" THICKNESS)
Fig. 4. Curves of
relative s o u n d
pressure vs. frequency as measured inside the
_.
o
e.
v/
o
-00
o
speaker
iO
cabinet.
-40
20
100
1000
FREQUENCY
IN
'
10000
]0000
CYCLES PER SECOND
this happens a general lack of clarity
in the sound results, and the power
output of the speaker is lowered.
An examination of Figs. 1 through 6
shows the superiority of felt over cellulose and fibrous glass in absorbing properties. Felt is particularly effective in
the low frequencies. Referring to Fig.
tain most of the power and any loss
in this range is very noticeable. Furthermore, most of the trouble from cabinet
resonances occurs in this range.
On an average, felt was found to be
50 per cent more effective in damping
throughout the entire frequency range
from 50 to 15,000 cps.
10
o
-10
Fig. 5. Curves of
sound
in
z
z -3o
O
-40
drop
-_,
20
-
---- --
pressure through
the three damp-
ing materials.
I"
FIBROUS GLASS
CELLULOSE (2
Y2
'
THICKNESS)
THICKNESS)
FELT (3/8" THICKNESS)
11
1
1
1
1
1
1
1
1
111111
1
.
20
WOO
100
FREQUENCY IN
10000
,0000
CYCLES PER SECOND
4, we see that in the low frequency range
from 50 to 300 cps, the sound pressure
inside the cabinet lined with felt was 3
to 6 db lower than for the other materials. This means that felt was 50 to 75
per cent more effective in damping the
low frequencies. This is an important
point, for the low frequencies con-
It should
pleasant "edge" or "sharpness."
be pointed out that a thick-
ness of only % in. was used for felt
against 21/2 in. for the cellulose and 1
in. for the fibrous glass materials.
During the transmission tests a
double th'ckness of felt was also tried.
It was found that the transmission loss
was doubled, making it far more effec-
10
o
z
n
0
2:
O
6
Curves
showing
relative
Fig.
20
r.
30
-40.-
-- -----
"
acoustic o u t p u t
from the three enclosures.
FIBROUS GLASS (1" THICKNESS)
CELLULOSE (21/2" THICKNESS)
FELT (3
I
I
I
'
.
.
I
I
I
I
4"
THICKNESS)
I
.
e
.
MD
e
1
1
1
.
.
.
.
1
1
1
1
.
10000
,000
tive over the entire range than either of
the other materials.
An examination of Fig. 5 shows the
sound loss through the three materials.
Fibrous glass was wholly ineffective,
having practically no transmission loss
below 500 cps, and only 3 db at the
higher frequencies. This meant that any
undamped sound inside the cabinet
would be transmitted to the cabinet
walls.
The cellulose material was effective
above 500 cps, but this is not as important as it would seem. If we refer
again to Fig. 4, we see that due to the
.high absorption of all the materials at
the higher frequencies there is very little
sound pressure inside the cabinet. Therefore, the real need is for low transmission and high absorption in the lotyfrequency range. Felt is 50 to 75 per
cent more effective in this range than
either of the other two materials.
The results from these tests would
indicate that the use of felt should accomplish two things with regard to the
sound output from the speaker : (1),
the speaker output in the low and middle frequencies should be higher, and
(2), speaker output should be smoother.
This is actually what happened as an
examination of the curves of Fig. 6 will
show. These curves were plotted for
specific frequencies, 50, 100, 300, 500,
1000, 3000, 5000, 10,000, and 15,000 cps.
The acoustical power output of the
speaker was smoother and was 25 to 50
per cent greater with the use of felt. The
fact that the use of felt causes the response to be smoother is very important,
particularly in the high-frequency range.
A lack of smoothness in this range
causes the sound to have a very un-
MOW
FREQUENCY IN CYCLES PER SECOND
Conclusion
Felt was found to be a superior dampmaterial. The possibilities for
further development work that would
lead to an ideal damping material are
ing
very exciting.
Felt was the only material really
effective in the low- frequency range
where troublesome cabinet resonances
occur and where most of the power is
transmitted.
The use of felt resulted in a smoother
power output over the entire frequency
range from 50 to 15,000 cps, and the
acoustical power output from the
speaker was increased from 25 to 50
per cent in the low- and middle -frequency range.
Listening tests confirmed the results
of the above. The sound from the cabinet lined with felt was a cleaner sound
with a much better balance between the
highs and lows.
AUDIO
30
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
Combining the performance of costly electrical crossover multi -way
speakers and the economy of single cone speakers, you have a wide
range of selection, ranging from a handy 61" two -way model up to
a 12v threeway model.
The PIONEER PIM -1ÓA, PIM -20A and PIM -25A speakers hove
two cones actuated by
coil and magnet assembly. Low frequency signals are reproduced by
the large outer cone, while high frequency signals ore reproduced by the
small inner
cone. The PIM -30A has two cones actuated by a single voice coil and magnetic
assembly for low frequency and mid -range reproduction, and an independent high
frequency tweeter unit for high frequency reproduction.
Due to the mechanical filters furnished on the large outer cone, the directional
characteristic is improved vastly in compared with the double -cone speakers mode
hitherto and intermodulation distortion in thus minimized and therefore,
smooth
overall response is provided at low cost.
a single voice
FUKUIN ELECTRIC, TOKYO, JAPAN
5
AUDIO
OTOWACHO 6- CHOME, BUNKYO -KU,
AUGUST, 1959
TOKYO.
31
www.americanradiohistory.com
AmericanRadioHistory.Com
What to Look for in
a
Tap e Recorder
HERMAN BURSTEIN
have
dealt with some basic matters that
the audiofan will wish to consider in
purchasing a tape machine : whether to
buy a transport only or a transport and
electronics; how many heads the machine
should have; what kind of record level
indicator is suitable for his purposes.
The present article deals with additional
factors, of varying degrees of importance, that play a part in a purchase decision. Some of these concern electrical
performance, some mechanical performTHE PRECEDING THREE ARTICLES
t
2S0 Twin Lane E, Wantagh, N. Y.
Fig. 2. A
stereo
tape machine utilizing a plug -in attachment for re-
cording second
channel. (Tand-
berg) Unit at the
left is the auxiliary recording amplifier for the second channel; without it, the machine
plays stereophonically and records
monophonically.
anee, and others operating convenience.
Probably no one machine contains all
the features that may be desired by all
audiofans. On the other hand, needs vary
from one tape recordist to another.
Through a preliminary familiarity with
the features available in one machine or
another, the audiofan is in a position to
choose that tape recorder which is most
likely to satisfy both his wants and his
budget.
Stereo Versus Mono
Fig. 1. A tape machine with provision for
stereo payback and monophonic record-
ing. (Norelco)
In view of the pace of stereo, the individual who purchases a tape machine for
serious music listening is well advised to
consider one equipped for stereo at least
in the playback mode. Of course it is
possible to modify a monophonic ma-
chine by replacing the mono playback
head with a stereo head, but this calls
for an additional playback amplifier,
raising two problems : (1) that of closely
matched equalization and amplification
facilities in the playback amplifier for
each channel; (2) that of a cable run to
the additional amplifier, with high frequency losses taking place if the cable is
too long, and with the possibility of hum
pickup if the cable is iníproperly routed.
A number of tape machines now provide for stereo playback but only mono
record, as illustrated in Fig. 1. If the
audiofan has any thoughts of eventually
wanting to record stereophonically, he
should inquire whether such a machine
has facilities for properly adding a record amplifier. The second channel reAUDIO
32
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AmericanRadioHistory.Com
AUGUST, 1959
AMPEX
960
RECORDER/ REPRODUCER
STEREOPHONIC
ABOVE --960 PORTABLE STEREO
RECORDER /REPRODUCER
Stereo
Portable
BELOW -MODEL 2560 PORTABLE
STEREO SYSTEM CONSISTING OF
960 AND PAIR OF 2010
A MPLI FIERSPEAKERS
PLUS!
-
Guiding the Ampex engineers who created the 960 was a dual objective
that of building a machine which was not only a superb example of
engineering skill, but one which would also offer its user
a range of capabilities far exceeding that of any other recorder made today.
The result was not merely an improved stereo recorder,
but an entirely new concept in home entertainment.
The STEREO 960 fits into family life in literally dozens of ways, contributing many
tangible benefits in musical, educational and recreational fun. You'll use it to keep up the
family correspondence by sending "letters in sound ", to tape stereo programs off the air,
to preserve your best monaural and stereo discs on tape, and to acquire new musical and language skills.
You'll have endless fun exploring the 960's many fascinating recording capabilities, including
sound -on- sound, echo chamber effects, and other advanced techniques.
AMPEX STEREO
SIGNATURE
OF
www.americanradiohistory.com
AmericanRadioHistory.Com
PERFECTION
IN
SOUND
-
Relax and enjoy the show
let your Ampex do the
narration! With the
commentary on tape, your
color slide shows are more
professional, more complete,
and more fun!
RECORDER /REPRODUCER
SPECIFICATIONS
The true values of a recorder are best assessed through careful evaluation of its performance specifications and operating features. It is worthwhile noting here that these specifications are based not on
Your favorite LP's and Stereo
Discs are at their exciting
best while they're new and
unscratched. That's when to
tape them on your Ampex,
and preserve their original
quality for keeps!
theoretical design parameters but on actual performance tests. They are specifications which the
recorder not only meets or exceeds today, but which years from now will still hold true.
The Ampex Model 960 Stereophonic Recorder Reproducer is capable of essentially distortionless
frequency response from 30 to 20,000 cycles per second at the operating speed of 7V2 inches per
second, and from 30 to 15,000 cycles per second at 334 inches per second. Its precision -engineered
timing accuracy is such that it offers perfection of pitch held to tolerances of less than one -third of a
half -tone. Playing times, using standard 1.002 "), long play (.0015 "), and extra -long play (.001") tapes
are
as
follows:
(a) 4 -Track
Stereo Tapes
33/4 ips - 2 hrs. 8 min.
hr 4 min.
71/2 ips
33/4 ips - 3 hrs. 12 min.
7' /z ips - hr 36 min.
33/4 ips - 4 hrs. 16 min.
71/2 ips - 2 hrs. 8 min.
200 foot reel
1
800 Foot reel
1
!400
fool reel
half -track
hrs. 8 min.
hr 4 min.
- 3 hrs. 12 min
71/2 ips
I hr 36 min.
33/4 ips - 4 hrs. 16 min
71/2 ips 2 hrs. 8 min.
ips
ips
33/4 ips
1
1
RECORD INPUTS: High impedance line inputs (radio TV phono,
When you tape it "off the
air" your only cost is for
blank tape. Yet your musical
repertoire can soon equal
that of all the stations
you hear!
(c) Monaural Tapes,
(b) 2 -Track
Stereo Tapes
33/4 ips hr. 4 min.
71/2 ips - 32 minutes
nutes
34/4 ips - I hr. 36 min.
71/2 ips - 48 minutes
33 ips - 2 hrs. 8 min.
71/2 ips hr. 4 min.
33.4
-
2
71/2
-
I
There's a real future in family
fun like this -with your
Ampex you can live such
happy moments over and
over again, with a quality so
lifelike you're almost literally
carried back.
auxiliary) 0.3V rms for program level;
high impedance microphone inputs
PLAYBACK OUTPUTS: Approximately 0.5V rms from cathode follower when playing program level tapes
PLAYBACK FREQUENCY RESPONSE: 30- 20,000 cps at 71/2 ips; 30. 15,000 cps at
Within +2 db 50- 15,000 cps at 71/2 ips, 55 db dynamic range
Within ±2 db 50- 10,000 cps at 33/4 ips, 50 db dynamic range
FLUTTER AND WOW: Under
0.2% rms at
71/2
ips; under 0.25% rms at
33/4
33/4
ips
ips
In the Ampex "Speech Testing
HEADS: Manufactured to the same standards of precision that exist in Ampex broadcast and recording
studio equipment. Surfaces are lapped to an optical flatness so precise that they reflect specified
wavelengths of light, resulting in uniform performance characteristics and greatly minimizing the
effects of head wear. Azimuth alignment of stereo head gaps in the same stack is held within 20
seconds of arc, equivalent to less than 10 millionths of an inch
a degree of precision achieved
through use of a unique process involving micro -accurate optical measurements within a controlled
environment. Head gap width is 90 millionths of an inch +5 millionths of an inch.
Game", you pit your wits
against the trigger -quick
memory of the Ampex
recorder /reproducer. You
can't win, but it's fun trying.
-
Letter- writing is no longer a
problem, with on Ampex
in the house
now it's a
family project. And even
more fun than sending letters
in sound is receiving them!
...
KEY TO THE
EXCITING
FUN FEATURES OF THE 960
--
THE AMPEX STEREO -GRAPH
Here's the simplest, quickest answer
to almost every question about how to
perform the operations illustrated at
right and numerous other recording
functions. The Ampex Stereo -Graph
shows you, quickly and clearly, the
proper dial settings to make for more
than a dozen of the most popular uses
for the 960
including sound -onsound, language and music instruction,
...
"letters in sound ", the
3" tape reel holds as much
For
as a 10 -page letter, mails
first class anywhere in the
United States for 8c.
and other special effects. A convenient
tape footage /playing time indicator is
included on the reverse side.
MODEL 2010
MATCHING
The Ampex, in private
rehearsal, can be a wonderful
AMPLIFIER -SPEAKER
confidence- builder for
people who normally develop
rubber knees when faced
with the prospect of
speaking before a group.
The Ampex Model 2010's ten -watt (20 watts peak) ampli-
fier section provides operating characteristics (unequalized)
flat within ' 0.1 db, with total harmonic distortion less
than 0.5 of %, throughout the maximum range of human
hearing ability, at rated output. Noise and hum ore 80 db
below rated output, and input sensitivity is 0.18V to
develop rated power.
The specially designed 8" speaker provides smooth, peak free response throughout a remarkably wide audio range.
Such superior design features as its massive die -cast frame
and edgewise -wound ribbon coil contribute effectively to
higher levels of performance than ever before achieved
with a speaker this size.
1
Learning to speak a new
language is made
immeasureably easier on
the Ampex; you can record
your own phrases side -by -side
with those of the instructor,
and play them back for
comparison at any time.
MODEL 960 DIMENSIONS: Portable cases 9" x 15" x 171/2". Unmounted recorder
13" x 15" x 616" depth below top plate, 1%" above. Recorder weight 36 lbs.,
speaker amplifier 31 lbs.
AMPEX
AUDIO.
INC.
SUNNYVALE.
CALIFORNIA
HANS
When you strike up the band
in stereo, you don't need
professional musicians to
make a professional
recording. Advanced
techniques are amazingly
easy on the Ampex.
cord amplifier should have the same
equalization and gain as for the other
channel, and-very important-there
should be means for synchronizing the
bias oscillators in the two amplifiers, if
separate oscillators are used, so that they
will operate at the same frequency. Bias
current in each channel will to some degree leak through to the other channel.
If the two currents are of different frequency, they will beat together, and the
resulting beat frequencies will appear on
the tape, causing birdies and other objectionable sounds. Figure 2 shows a
tape recorder designed to permit addition of a second record amplifier; in this
case the oscillator of the first channel
also serves the second channel.
Tape Speeds
For home purposes, in the past few
years the virtually standard speed compatible with high fidelity has been 7.5
ips, which permits frequency response to
about 15,000 cps and at the same time
allows satisfactorily low distortion and
a satisfactorily high signal -to -noise ratio.
The 3.75 -ips speed has also been widely
used, although not considered compatible
with high fidelity. The principle difficulty at the lower speed lay in high -frequency response. All other things remaining equal, the frequency response of
a tape machine varies directly with tape
speed. Thus a machine capable of maintaining flat response to, say, 12,000 cps
at 7.5 ips (response may be 3 to 6 db
down at 15,000 cps) will be able to maintain fiat response only to 6,000 cps at
3.75 ips.
The problem at 3.75 ips occurs in large
part in playback. being due to the fact
that treble response varies inversely with
width of the playback head gap. The recent introduction of heads with extremely narrow gaps -as fine as .00009"
-has made it possible to extend frequency response to about 15,000 cps at
3.75 ips so far as playback is concerned.
But there are also very serious recording
losses at high frequencies clue to bias
current and to the phenomenon known
as self-demagnetization (recorded frequencies on the tape are equivalent to
small bar magnets; the higher the frequency, the smaller is the equivalent
magnet and the greater is the tendency
of the opposite poles of each magnet to
cancel each other).
By using somewhat less bias current
than at 7.5 ips 1 which reduces treble
losses), by recording at somewhat lower
levels (which compensates for the
greater distortion because of reduced
bias), and by using somewhat more
treble boost in recording, it has been
found possible to put on the tape at 3.75
ips a signal with frequency response corresponding at least to minimum high fidelity standards and having acceptably
low distortion and acceptably high signal
AUDIO
to noise ratio. This does not mean that
3.75 -ips tapes are yet as good as 7.5 -ips
ones of recent vintage. However, they
are already as good as the 7.5 ips tapes
of several years ago, and it can be expected that technological progress will
bring further improvement.
Accordingly, the serious audiofan may
wish to include the 3.75 -ips speed and to
make sure that the machine he purchases
does all that is possible in the present
state of the art to achieve maximum performance at this speed. Specifically, he
will want a machine with a playback
bead that has a gap of .0001" or less,
and having the recording equalization
and bias current that allow frequency
response to extend to 10,000 cps and beyond. On the other hand, since equalization and bias current requirements will
he different at the 7.5 -ips speed, he will
want to make sure that performance at
this higher speed is not compromised by
failure of the machine to change the bias
and equalization when the tape speed is
switched to 7.5 ips.
The audiofan will probably find that
that 3.75 -ips speed is quite suitable for
various types of program material not
of the highest fidelity, such as old records
one wishes to copy (in fact, the loss of
the higher frequencies can be a distinct
blessing in this situation since these frequencies will consist more of noise than
music), AM station programs, etc. Or
there may be situations where one is
willing to exchange some sacrifice in
quality for the privilege of doubling the
recording time on a reel tape. Thus in
taping an opera or other lengthy work,
one can get from two to four hours of
time on a 7 -inch reel, using half -track
monophonic recording or quarter-track
stereo recording. Regular tape will yield
two hours, long -playing tape three hours,
and extra -long -playing tape four hours.
For non -high -fidelity applications,
such as recording speech, dance music
for parties, and so forth, the 1.875 -ips
speed is coming into increasing use. In
fact, this speed now enjoys about the
same status as 3.75 ips formerly occupied. A number of tape machines now
offer this speed along with a surprisingly
satisfactory quality for non -critical uses
where length of playing time is important. Thus on a 7 -inch reel of tape one
can record from four to eight hours of
material at 1.875 -ips, depending upon
whether one is using regular, long -playing, or extra -long -playing tape.
Frequency Response
At 7.5 ips, a modern tape recorder
should be able to cover the range of 40 to
15,000 cps, being no more than 3 or 4 db
down at either extreme and achieving
quite flat response-within ±1 db or ±2
db between 50 and 10,000 cps. Response
within ± 3 db may be considered satisfactory, but not of top quality. At 3.75
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Pre -Amplifiers
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FM-AM Tuners
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Record Changers
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Music
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Speakers
Speaker Enclosures
Equipment Cabinets
Finished and
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-
- - - -
AUGUST, 1959
35
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REAR
GAP (CLOSED)
LAMINATED CORE
I' .I.
.11111
WINDING
II
Alb
FRONT GAP (VASTLY
ENLARGED)
CONTACTS THE TAPE
\
WINDING
AN.
íF
Fig. 3. Tape head of laminated construc
tion.
ips, response should extend at least to
10,000 cps, remaining reasonably flat between 50 and 8000 cps. At 1.875 ips, response to about 5000 cps may he expected.
Distortion and Signal to Noise Ratio
The playback amplifier is generally
the dominant source of noise in a tape
reproducing system. The amount of signal produced by the tape playback head
is at the most a few millivolts in the
audio mid -range and is a fraction of a
millivolt at low frequencies. When this
weak signal undergoes the necessary amplification and equalization (bass boost),
the noise and hum of the first stage in
the playback amplifier and the hum
picked up by the head, are also greatly
magnified. The more signal on the tape
that is! the higher the recording level
the greater is the magnitude of the audio
signal relative to playback noise and
hum. In other words, the signal to noise
ratio is greater. Unfortunately, as the
recording level is increased, there is also
an increase in distortion due to the characteristics of the tape. In sum, then, distortion and signal -to -noise ratio go hand
in hand; the more distortion one is willing to tolerate in a tape system, the
higher is the feasible signal -to -noise
ratio, assuming that all else remains the
same.
It follows that one must define how
much distortion is acceptable. However,
this is not a straightforward problem. To
begin with, tape distortion is almost invariably stated in terms of harmonic
rather than intermodulation distortion,
because the amount appears respectably
low in terms of harmonic distortion but
tends to assume outlandish proportions
when stated as intermodulation distortion. Whether maximum harmonic distortion should he 1, 2, 3 per cent, or
possibly more is a viewpoint that varies
considerably among tape machine manufacturers.
Signal -to -noise ratio of the top quality
machines tends to be rated by their manufacturers on the basis of 1 or 2 per cent
maximum harmonic distortion. This may
correspond roughly to about 5 to 10 per
cent II. Many machines, however, state
performance in terms of 3 per cent harmonic distortion, and sonic even in ternis
of 5 per cent; these amounts may correspond to 30 per cent and more 1M.
Considering that the difference between
recording at a level that results in 1 per
cent harmonic distortion and recording
at a level productive of 5 per cent harmonic distortion represents an increase
of about 8 db in recording level, it can
he understood why some manufacturers
rate their machines on the basis of 5 per
cent. They are adding 8 db to the signal to -noise ratio they can claim for their
units.
The audiofan desiring truly clean,
silky recordings-assuming such program material is available to him -will
probably not want to operate his machine at levels that take him into 5 per
cent harmonic distortion. More likely, he
will want to stop at about the 1 or 2 per
cent level. Therefore, a tape recorder
should he rated for signal-to -noise ratio
in terms of a signal, in the range of 250
FRONT GAP
(CONTACTS THE
(TAPE)
CORE PIECE
CORE PIECE
WINDING
--
-
BACK GAP CLOSED
Fig. 4. Tape head of non -laminated con-
struction.
to 500 cps, recorded at a level producing
no more than 1 or 2 per cent harmonic
distortion. If the ratio is based on a
higher distortion figure, one can make a
rough adjustment by subtracting 2 db
for each 1 per cent of distortion above
1 per cent level.
Based on 2 per cent harmonic distortion, which is the NARTB (now NAB)
standard, a tape recorder may be considered excellent if it achieves a signal to -noise ratio of about 55 db, and very
good if the ratio is closer to 50 db. Below
50 db begins to get out of the category
of high fidelity. Less than 45 db tends to
be unsatisfactory. With a machine having a signal -to -noise ratio that approaches 55 db, one can make a clean
recording and play it back at life-like
levels, yet have virtually no discernible
background noise during quiet passages.
Such machines, unfortunately, are still
much more the exception than the rule
so far as home tape recorders are concerned. On the other hand, there are a
few, some at relatively moderate prices,
that are the equivalent of professional
machines in this respect.
Quality of Heads
Audiofans are wont to be very discriminating about the phono cartridges
they choose for their audio systems. In
similar fashion, there are quality differences among tape heads that deserve attention. Some of the factors involved in
head quality are as follows:
1. Gap Width. As pointed out before,
the narrower the gap, the better the high frequency response in playback. Most
playback heads encountered today have
gaps sufficiently narrow to permit relatively flat response throughout the audio
range at 7.5 ips and a close approximation to such response at 3.75 ips. The gap
should be .00025" or smaller for speeds
of 7.5 ips or higher. It should be .0001"
or smaller for 3.75 ips.
2. Gap Linearity. Recording of the
tape takes place at the trailing edge of
the record head gap (the last edge contacted by the moving tape). To achieve
a well- defined signal on the tape, it is
necessary that this gap edge be equally
well defined. It must be as perfectly
sharp and straight as possible. Sharpness
this case both edges
of the gap edge
also vital in playback. If the edges
are rounded, then the gap magnetically
behaves as though its physical width
were increased. Thus a head with a
.00025" gap and very linear edges may
provide better high-frequency response
than a .00015" head with a less well -defined gap. In a high -quality playback
head, the magnetic gap is about 10 per
cent wider than the physical gap.
3. Head Constriction. Heads are basically of two types, laminated and non laminated, as illustrated in Figs. 3 and
4. The laminated head tends to have
greater output because of its greater
volume of magnetic material. Moreover.
the laminations serve to reduce eddy current losses (by interrupting eddy current flow), which increase with frequency.
-Figure 5 shows another type of non laminated head, whose gap has considerably less depth than in Figs. 3 and 4.
This means that the gap wears more
-is
-in
of non -laminated
tape head.
Fig. 5. Another type
AUDIO
6
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
9=
quickly, with attendant loss of high frequency response.
4. Hum- Bucking Windings. Whereas
the heads in Figs. 3 and 5 each have two
sets of windings, the head in Fig. 4 has
only one winding. Two windings are desirable because this permits connecting
them in series so as to balance out hum
and at the same time increase voltage
output. The manner of connection is illustrated in Fig. 6. Hum polarity tends
to he the same at each output terminal,
so that there is little or no hum potential
between the terminals. On the other
hand, the signal polarity at one terminal
is positive when the other is negative.
5. Saturation. The core and design of
the record head must be such as to permit sufficient magnetic flux to be developed to magnetize the tape, but without
saturating the head and thereby causing
distortion. While tape heads are generally satisfactory in this respect, the
writer has come across instances where
the record head saturated before the tape
did.
H
I.
H.
H.
S.
H
S
-HUM POLARITY
=AUDIO SIGNAL POLARITY
Fig. 6. Connecting the dual windings of
a tape head in series for maximum voltage output and for hum cancellation.
Wow and Flutter
Wow refers to slow variations in
speed, below ten times per second, heard
as a quavering or "sourness" in the frequency being reproduced. Flutter refers
to rapid variations in speed, up to thousands of times per second, which tend to
be heard as extraneous sounds in the
nature of noise. That is, one hears a frequency corresponding to the rate of
fluctuation.
Professional performance calls for
wow and flutter not to exceed 0.2 per
cent, and preferably to be less than 0.1
per cent. This is not very easy to achieve,
particularly when tape speed is below 15
ips. One may say, then, that for home
purposes, about 0.25 per cent is the
maximum amount consistent with high fidelity performance.
The ear is a good instrument for cheek ing wow and flutter. By playing a test
tape having a recorded frequency of
about 3000 cycles (or by making such a
tape with the aid of an audio oscillator),
one can readily determine whether wow
and flutter are unduly offensive. Wow
AUDIO
Fig.
NARTB
Equalization.
7.
playback
>e
FREQUENCY
will be apparent as an unsteadiness in
the sound. Flutter will he noticeable as
imparting
the note.
a
grainy or noisy quality to
IN
Iaa
CYCLES PER SECOND
I_
MOM
diameter of the capstan may he out of
tolerance, resulting in excessive speed
error. Or there may be other misadjust-
ments.
The individual who pays the extra cost
Speed Accuracy
of a tape machine containing a synProfessional requirements are that chronous motor is entitled to a speed actape speed be correct within ±0.3 per curacy within 0.3 per cent. Should he
cent. Since there are 1800 seconds in find, through a test timing tape or use of
one half -hour (approximately the play- a tape stroboscope, that the error exing time for one track on a 7 -inch reel ceeds 0.3 per cent, he is entitled to have
of standard tape), a 0.3 per cent error this excessive deviation corrected by
translates into 5.4 seconds slow or fast whatever means are appropriate, includper half hour. Professional machines, ing replacement of the machine.
and sometimes the semi -professional ones
On the other hand, if the machine does
as well, generally achieve an accuracy of not have a synchronous motor, speed er0.2 per cent, which is 3.6 seconds slow or
rors up to 1 per cent should be expected
fast per half -hour.
and tolerated. Over 1 per cent may be
So long as a tape machine is employed considered excessive for a. high -quality
to play only tapes recorded on the same home machine with a non-synchronous
machine, the speed error is of no conse- motor.
quence, assuming the error remains the
In measuring speed accuracy, this
same over time. However, if commer- should be done at several portions of the
cially recorded tapes or other tapes made reel, because the error will tend to vary
on different machines are to be played, from beginning to end of a reel of tape.
speed errors appreciably greater than
While it is desirable for the individual
0.3 per cent, particularly those over 1
to measure speed accuracy (by means of
per cent, are apt to he noticed as signifi- a stroboscope or test tape), in the great
cant deviations from correct pitch.
majority of instances there is nothing
The better tape machines employ syn- he personally can do to correct the situachronous motors, whose speed is essen- tion. Whereas a fair number of phono
tially determined by the line frequency, turntables and even record changers pronamely 60 cps. But use of a synchronous vide the operator with means for readily
motor for driving the capstan does not adjusting speed, it is a rare tape rein itself guarantee accurate speed. The corder that makes such provision. Before
Fig.
8.
Playback
equalization
em-
ployed at 3.75
ips.
.o
Ne
FREQUENCY
,ewe
IN
CYCLES PER SECOND
AUGUST, 1959
37
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AmericanRadioHistory.Com
MICROPHONE
INPUT JACK
O
RECORD
MIC.
Im
PREAMP
AMPLIF
IER
RECORD
HEAD
HIGH LEVEL
INPUT JACK
When phone plug is nserted, the connection from
the microphone preamplifier to the following stage
is
interrupted.
Fig. 9. Tape machine permitting one to record from a microphone or a high -level
source, but not both at once.
o
PLAYBACK
HEAD
TAPE AMPLIFIER
VOLTAGE
AMPLIFIER
SPFAKER
POWER
AMPLIF
TAPE
IER
IN
MACHINE
OUTPUT TO EXTERNAL SPEAKER
OUTPUT TO EXTERNAL AMPLIFIER
o
Fig. 10. Tape machine with separate outputs for external speaker and external am-
obtained directly from a tuner, TV, or
the like. The other input is for microphone. In many cases these are alternative inputs, as illustrated in Fig. 9, so
that one can record from one input or
from the other, but not from both at
once. Insertion of a phone plug into the
high-level input jack disconnects the
microphone signal. In other instances, it
is possible to record from both sources
simultaneously. Too often, however, only
the high -level input has a gain control,
so that it is difficult to achieve satisfactory mixing. In the better machines,
there are individual gain controls for
each input.
The microphone input in the lower price machines is customarily intended
for a piezoelectric (ceramic or crystal)
microphone or for a high- impedance
magnetic microphone. If one intends to
use a crystal or ceramic microphone, it
is necessary to ascertain that the input
impedance of the tape recorder is sufficiently high to permit full bass response.
Typically, an input impedance of 5 megohms or more is required ; this depends
upon the particular microphone used.
Information on the necessary input impedance should he obtained from the
microphone manufacturer. If the input
impedance of one's tape recorder is less,
the necessary modification should be
made by a service technician.
A high -quality tape recorder (usually
the semi-professional and professional
ones) will provide an input for a low impedance microphone, which permits a
long run of cable to the tape recorder
without loss of high frequencies and
which is less sensitive to hum pickup
than the high impedance type.
plifier.
each speed because the recording losses
vary with tape speed. Therefore the tape
recorder should contain switching facilities to vary the record equalization
with speed. Some machines, however,
employ the same record equalization at
both speeds. The result is that frequency
terms of smoothness as
response
not as good at either
well as range
speed as it might be, because compromise
equalization is used; or else the result is
that, if good frequency response is maintained at 7.5 ips, then response is considerably short of as good as it might
Equalization
he at 3.75 ips because the other speed has
NARTB equalization (Fig. 7), or a been favored.
close approximation thereto, is considered virtually standard today for tape Inputs
recorders operating at 7.5 ips. AccordOutputs
Tape recorders customarily have two
ingly, the tape recorder should provide
Although a tape machine may contain
-level
sources,
high
for
is
One
'
nputs.
NARTB playback equalization within
such as the signal from a tape output its own power amplifier and speaker, it
2 db at 7.5 ips. Otherwise, when playprovide an output jack for
ing commercial recorded tapes, fre- jack of a control amplifier, or the signal should still
quency response may depart significantly from flat. Inasmuch as most
VOLTAGE
SPEAKER IN
AND
machines that depart from the NARTB
TAPE MACHINE
POWER
playback characteristic provide inadeAMPLIFIER
quate bass boost, the resultant response
PLAYBAC
HEAD
when playing a recorded tape will be a
OUTPUT JACK FOR
M1111140.
thin bass sound. These machines someEXTERNAL SPEAKER
in
boost
treble
considerable
times apply
by
for
is
called
none
playback, whereas
Connection to internal speaker is broken when
phone plug from external speaker is inserted
NARTB (except to compensate for head
deficiencies), so that shrillness is introspeaker
duced when playing a recorded tape.
ig. 11. Means for automatically disconnecting a tape machine's internal
when an external speaker is plugged in.
With respect to the 3.75 -ips speed, the
equalization question is not settled at the
present writing. For a time, equalization
RECORD AMPLIFIER
such as in Fig. 8 was employed. ReRECORD
cently, however, there has been a trend
the user seeks to tinker with the transport mechanism in order to speed it up
or slow it down, he should take into consideration that this attempt is likely to
backfire. He may improve speed accuracy, but at the same time he may cause
an increase in wow and flutter, which are
generally more deleterious to satisfactory musical reproduction than are
moderate speed errors. The user's best
recourse is to take a seriously inaccurate
machine back to the point of purchase.
-in
-is
K
/'
toward employing NARTB equalization
(Fig. 7) for 3.75 ips as well as for 7.5
and 15 ips.
Assuming that NARTB playback
equalization is employed at both 7.5 ips
and 3.75 ips, nevertheless, different record equalization will he required at
INPUT
0---
-
AMPLIFICATION
-+
EQUALIZATION
--
RECORD
HEAD
DRIVER
HEAD
MONITOR OUTPUT JACK
(FOR EARPHONES,
METER
OOSCILLOSCOPE, ETC.)
Fig. 12. Tape machine with a monitor output jack.
AUDIO
38
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AUGUST, 1959
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AUDIO
AUGUST, 1959
39
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IN
O
lower or other low-impedance circuit
(such as a plate follower) in the output
stage.
O-
OUT
Fig.
-TAPE MACHINE
TAPE OUTPUT
used
method of feeding
JACK
signals from
o'
TUNER
13. Most fre-
quently
high
CONTROL
POWER
AMPLIFIER
AMPLIFIER
fidelity
a
sys-
tem to a tope machine.
PHONO
SPEAKER
N
OUT
o
r o
TAPE
I TUNER
I
i
CONTROL
POWER
AMPLIFIER
AMPLIFIER
MACHINE
Fig.
14.
Seldom -
used method of
feeding a signal
from a high -fidelity system to a
tape machine.
PHONO
SPEAKER
TV
Tuner cable temporarily disconnected from control
amplifier to feed tuner signal to the Igoe recorder.
feeding an external audio system. Preferably, for minimum distortion, the signal should he taken from a point prior
to the power amplifier of the machine. In
some units, however, there is an output
jack designated for feeding either an
external speaker or an external amplifier; in th }s:ease the signal is taken after
the internfipower amplifier. The better
situation is where there are two output
jacks, one for feeding an external amplifier and the other for feeding an external speaker, as illustrated in Fig. 10.
To obtain as flat response as possible,
it is ordinarily desirable that the signal
at the output jack be taken from a point
prior to the machine's tone controls, if
any. In some machines, however, the tone
controls are employed as part of the
equalization circuit, and in this case one
would want the playback signal after
the tone controls. At the same time, it is
necessary to ascertain the position of
these controls that achieves flat response.
If the tape machine contains its own
power amplifier and speaker, means
should be provided for cutting off the internal speaker wheíu the signal is fed
to an external sound system. In some
cases this is done automatically when a
plug is inserted into the output jack, as
shown in Fig. 11.
Some tape recorders contain a monitor
jack, so that when recording one can
listen to the incoming signal with earphones, as shown in Fig. 12. While this
gives some evidence that the recording
signal is getting through, it is not positive proof that the signal is being satisfactorily recorded. Such proof is obtained only by using a machine with
separate record and playback heads,
which permits the signal being recorded
to be played back immediately and
checked. However, a monitoring jack
does have worthy uses. Thus if one is re-
cording directly from a tuner or phonograph, one can at least check the quality
of the incoming signal. Or one could attach an oscilloscope or meter (high impedance, to avoid loading effects) to
evaluate the nature of the signal with
respect to amplitude, transients, frequency response, and so on.
To permit a long cable rum from the
tape machine to the following equipment
without high -frequency loss, a low output impedance is desirable. It is for this
reason that the output jack in some machines is connected after rather than
before the power amplifier stage (we are
speaking, of course, of those units having their own power amplifier and
speaker). A preferable course is for the
machine to incorporate a cathode folTUNER
Input Sensitivity
When recording from a source other
than a microphone -FM tuner, AM
tuner, TV sound, phono pickup -most
audiofans will obtain the signal from a
control amplifier, as illustrated in Fig.
13, rather than by feeding the source
directly into the tape recorder, as shown
in Fig. 14 (where the source is a tuner).
In a number of control amplifiers, the
incoming signal is routed directly to the
tape output jack (for feeding a tape
recorder), without amplification or attenuation of the signal, as illustrated in
Fig. 15. Since high -level sources generally produce at least 0.5 volts on
peaks, it would appear that a tape recorder sensitivity-input signal required
to drive the machine to full permissible
recording level -of 0.5 volts is sufficient
for high -level signals. However, it is
advisable to allow for two contingencies:
(1) the occasional high -level source that
produces less than 0.5 volts; (2) the desirability of going above normal recording level, as for example on speech,
where distortion is less apparent than
on music. Accordingly, the high -level input sensitivity of a tape recorder should
be about 0.1 to 0.2 volts.
In some control amplifiers, as illustrated in Fig. 16, the incoming signal
first goes through an input level -set
control. Then it goes through a stage of
gain before reaching the tape output
jack, at which point it may be restored
to approximately its original level. However, there is no assurance that such
(Continued on page 95)
TAPE OUTPUT JACK
(FOR FEEDING SIGNALS
O
AUX O
MAGNETIC
PHONO
FOLLOWING STAGES OF
1
_
TAPEO
INPUT
JACKS
TO A TAPE RECORDER)
0
TVO
THE
SELECTOR SWITCH
PREAMP
Fig. 15. Method employed in some control amplifiers for
directly to a tape recorder.
INPUT
JACKS
CONTROL AMPLIFIER
SIGNAL SOURCE
feeding incoming signals
LEVEL SETS
AMPLIFICATION
STAGE
O
-0
---
TAPE
OUTPUT
JACK
FOLLOWING STAGES OF
THE CONTROL AMPLIFIER
LEVEL SET
SELECTOR
SWITCH
PREAMP
signals
Fig. 16. Method employed in some control amplifiers for feeding incoming
to a tape recorder.
AUDIO
40
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
(l
ouk ntuSiC S
IitP,VtitOhLi !
IF ITS WORTH LISTENING TO THE FIRST TIME...
IF YOU'D LIKE TO HEAR IT AGAIN... RECORD IT!
Viking equipment offers unmatched quality in the stereo recording
of AM FM and FM Multiplex programs and in the duplicating of stereo discs.
Once recorded, your tapes can be played as often as you wish
without deterioration. Your investment in Viking tape recording equipment
can be your most economical source of Hi -Fi reproduction.
You can expect performance in accordance with the following specifications: Frequency response 30 to 14,000 cycles,
db. Signal to noise
ratio 50 db minimum. Flutter and wow .2 %. Total harmonic and inter modulation distortion less than 2 %.
2
Most important, compare performance. Ask your high fidelity disa demonstration of Viking recording quality.
tributor for
:
Viking's Customer Service Department
provides a free planning service to
help you with integration of tape equipment with your music system.
-
11111b..
OF MINNEAPOLIS, INC.
9600 Aldrich Avenue South, Minneapolis 20, Mir. n.
AUDIO
AUGUST, 1959
41
www.americanradiohistory.com
AmericanRadioHistory.Com
Variable Electronic Crossover
and Biamplifier
GEORGE C.
The author describes
a
KANE'
combined variable electronic crossover
and a biamplifier that has a mid high- frequency power output
of 20 watts and a low- frequency power output of 50 watts.
AuncoPANS who build their
own hi -fi equipment, and some
who purchase kit -type components, soon realize that the cabinet space
allotted to the system becomes too small.
M
4NY
The author's system went through the
usual series of speaker additions and associated L -C crossover networks. The
frequency of crossover could not be
varied so there was always a question as
to whether the speaker performance
could be improved with a change in
crossover frequency.
Recently, a new component
Variable Electronic Crossover-appeared on
the market. The electronic crossover
seemed to have some desirable features
and some not so desirable. The good features are that it contains a method of
changing the crossover frequency, reduces intermodulation distortion, absorbs no audio power, and does not
affect speaker damping. Undesirable features are that it requires another amplifier (one for each channel), and if not
-a
".50 Queens Drive, Little Silver, N.
J.
properly designed and constructed it
can produce hum and noise. There are
other pro's and con's that will not be
taken up here.
There are two general types of electronic crossover units. One has a fixed
crossover frequency, the other type contains a method of varying the crossover
frequency. To the author, the type
having a variable crossover seemed most
desirable. The first model constructed
contained a switch that was used to
change capacitor values in the variable
portion of a low -pass and a high -pass
filter, resistor values remaining fixed.
An old amplifier was brought out of retirement and the system placed in operation. The speakers seemed to take on
a new brillance not heard before. Results were excellent until the crossover
frequency switch was changed to another
crossover frequency-the thud that came
from the speakers was powerful enough
to toss the speaker cones into the middle
of the living room! Another undesirable
feature was pointed out by the little
TI
Va
p1
V9
C33
T3
FI
R32
C22,C28,R1I,R13
cd; ow
3 (4
Fig. 1. The author's
VI
\
.
V2
C7,Cl2,
C
zCie
biamplifier, showing placement of major parts.
wife-she didn't want a chassis (elec-
tronic crossover) to remain on top of
a choice piece of furniture (no space in
the cabinet), nor did she approve of an
amplifier (additional amplifier for
treble) on the floor behind a chair.
Since the original space for the amplifier could not be enlarged, consolidation
of components was necessary if the electronic crossover was to be retained. After
many hours at a drawing board and
trying different arrangements of parts
on various shapes of chassis, the combined electronic crossover and biamplifier shown in Fig. 1 was constructed.
The complete schematic is shown in
Fig. 2.
Electronic Crossover Section
A block diagram of the variable electronic crossover portion of the biamplifier is shown in Fig. 3. The output of a
preamplifier feeds two level controls,
one for the high -frequency channel (for
the purpose of this article, the high -frequency channel is called the treble channel although it may contain frequencies
below several hundred cps), and one for
the low-frequency, or bass, channel. Each
channel is then coupled to a voltage amplifier where the program material is
amplified and passed on to a cathode
follower. So far, both channels are the
same with the exception of the coupling
capacitors (C,, C2, C,,, and C15i in Fig.
2), but here the similarity ends. Negative feedback is provided through resistors R5 and R55 to improve frequency
response and to reduce stage gain to
about four.
Cathode follower Vi,, feeds a high
pass filter, (B) in Fig. 4, consisting of
two R -C sections. The impedance ratio
of the first section to the second section
is 1 to 4. Therefore the slope of the curve
is approximately 8 db per octave. Cathode follower V,g feeds a low pass filter,
(A) in Fig. 4, which attenuates high
frequencies at the same 8 -db-per -octave
rate. The filters present curves that are
inversely symmetrical, (C) in Fig. 4.
When gain controls R, and RJ, are ad-
AUDIO
42
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
a new tweeter that solves at least
three of your speaker problems!
';",
.............................................!::::.
.e.e.e.e.e.e
..................e.......e.e.e.e.e................-:::::::::::;
.............................
::::::::::::::e-e.e.e..................-....::::;:
....."V...!
.................................................
................... ....................................
yy.
.
.....T1
..°¡.°:in.::i.+¡:¡'.'¡i:
:a..;¡:..:
.....
,
>r
°
.
J
.. ,Y....!..
JM..,..
.
......................................,!V..^
SOUTH AMERICAN TROUPIAL BIRD PHOTOGRAPHED
the ah!* electrostatic transducer
AT TREFFLH:H'S, NEW YORK
153/47r
---4
A Combination Mid -Range and Super Tweeter
The 'ah!', because of its revolutionary new construction gives clear,
O
parent response on all frequencies
transfrom 600 cps to beyond the limit of audibility
and has none of the limitations of tonal coloration
and
exaggerated
peaks found
in cone or piston type tweeters!
©
The 'ah!', because of its omni -directional characteristics, offers tremendous
advantages in your stereo system. The 'ah!' enables you to space out speakers
to achieve the dramatic effects associated
wide separation without the
disturbing "hole-in- the -middle" caused by with
the directional characteristics of
conventional speakers
or by single-ended, high distortion, limited range
electrostatic speakers.
elfT~
Mates easily and quickly to any speaker made.
Frequency Response: Full flat, lifelike midrange
plus UHF coverage -600 cps to past the limit of
audibility. Roll off 6 db /octave of speaker and
crossover network below 900 cps. Backwave
completely undamped.
Impedance: Designed to match 8 or 16 ohms
output of 15 to 50 watt amplifier.
Crossover: Self-contained R/C crossover net.
work; recommended crossover point between
650 to 850 cps. May be connected in parallel
directly across any low frequency woofer with.
out additional network.
Sound Dispersion: Full 180° coverage (front and
backwave) when speaker is mounted at least
6" from back wall.
Distortion: Practically unmeasurable. Radiation
area is 62 sq. inches.
Polarizing Voltage: Fused currentless 1000 volt
DC power supply. 110 volt AC power
line.
Hand rubbed genuine walnut cabinet, other fin.
ishes available on special order.
...
The 'ah!' electrostatic transducer is superior in quality
©
speakers selling
and performance to
for almost twice as much,
because of expert research
facilities and newly developed materials it is but,
offered
at
an
unprecedented low
price ... only $49.95.
-
/
Nothing else to buy R/C crossover network and
AC power supply are built in. 8 or 16 ohm L pad
may be added to attenuate tweeter, if desired.
-
An American -made speaker
patent
applied for by COSMOS INDUSTRIES.
EAST COAST
the 'ah!' electrostatic transducer can now be seen at WEST COAST
HUDSON RADIO
IFONARD RADIO
48 West 48th Street
69 Cortlandt Street
New York City
new York City
212 Fulton Street
New York City
35 William Street
Newark, New Jersey
AUDIO
GUARANTEED FOR FIVE FULL YEARS,
elements are practically indestructible.
NAM
FT RADIO
103 West 43rd Street
New York City
IN THE
MIDWEST
AT THISE
AMER
Voice & Vision Inc.
921 N. Rush Street
ChiGao 11, Illinois
Allied Radi. Corp.
100 N. Western Avenue
Chicago. Illinois
Volte & Vision Inc.
7055 W. North Avenue
Oak Park, Illinois
(lied Nigh Fidelity Inc.
2025 W. 95th Street
Chicago, Illinois
For complete information and
specifications write to:
See your local
NIOM FIOFtITY STORES
Allie
602
high -fidelity
dealer.
High Fidelity Stores
avis Street
(von ton, Illinois
\\
und
COSMOS INDUSTRIES, INC.
11
ee s Sotdevar
Isl-28
City 1, New York
AUGUST, 1959
-Long
anQd
43
www.americanradiohistory.com
AmericanRadioHistory.Com
clockwise position of the control adjusts
the filters to about 1200 cps. Types of
resistances required for the crossover
frequency control are given under "con-
The crossover frequency is changed
varying the crossover control which
has four variable resistances (R,,. R,, ,
R;7, : d R,o) combined into one eon trol. When the control is in the counterclockwise position (resistances at maximum) the filters are adjusted to a
crossover frequency of 100 cps. The full
;lusted so that the flat portions of the
curves are at the same level, the point
where each curve is down 3 db (half power point) is the crossover frequency.
At the 3 -db point, each filter is delivering half power and the two filters
together deliver full power resulting in
an overall curve that is fiat.
by
struction details."
Treble Amplifier
The output of the high -pass filter netR31
R34
+
C4
2W
22K
R20
5600 2W
C12
47 K
KT66
201450 V
CIO
TI
o
0
0.1
Q
TAW
OUTPJT
o
8
0.1
C11
0.1
RI8
4
1200
C8 `680
°
CROSSOVER
FREQUENCY
I
I
1_
KT66
_j
_
R63
R44
22 K
47 K
R56
2
20
C28
C22
20
4
O
,
I
20
V5B
C17=450V
C19
R46
r
Y
5600
1475
2
EL34
V7
BASS
475 V
C26
OUTPUT
.25
R61
16
I
V6A
L
25 K
R47
12
R50
R48
ñ
10 K
R49
100 K
8200
2200
V6B
R39
R62
2
C20
A
.043
C21
l
oe
73
5V
4
V8
.01
C25
390
R53
EL34
C29
1000
C24
+
50
680
^^LI
tlyfl9
Hy.
200mo
VI
.I
5
R66
300
C30
0.1
0.1
V3
V4
V5
V6
V7
V8
R67
20 W
C36
V?
A
110V 60
C35
COM
1000
Mee
+
40500 V
C32
+
C31
40
18 K
+
500 V
3DT475 V
PREAMP
30
o
o
475 V
1C34
o
.25
T4
o
110V
35 ma
R68
IOK
CRI
65 mo
R69
5000
R70
6800
°MATCHED PAIRS
WATT UNLESS OTHERWISE SHOWN
ALL RESISTORS
Fig. 2. Over-all schematic of the electronic- crossover
1
amplifier.
AUDIO
44
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
PROBLEM SOLVED
BY PILOT:
Develop a fine "bookshelf"
speaker system that gives
equal performance in vertical
or horizontal positions.
It
almost easy once Pilot engineers started to
it. As they saw it, the system should have five
speakers (you'd be surprised at how few others do),
a 12" woofer plus two mid -range and two treble speakers
angled for optimum dispersion. But then, if you mounted the enclosure in other than its prescribed position,
the tweeters and mid- ranges would be dispersing, yes,
but into the ceiling and floor! Pilot's answer: the
exclusive Acoustimatic Turret -with four speakers
two angle -mounted 6" mid -range and two angle -mounted
3" treble speakers. With a simple control at the rear
of the enclosure it takes only a few seconds to rotate
the turret so that these four speakers disperse the
sound horizontally, regardless of the position of the
enclosure. (Even the Pilot nameplate rotates so that
it looks at you right side up !) The four
in the
Pilot Acoustimatic Turret, plus the big speakers
12" heavy -duty
woofer with 1" cone excursion give you clean, solid,
well- defined bass, smooth response, and overall performance never before achieved ina "bookshelf" speaker.
was
work on
-
MOUNTS THREE WAYS
--
:1
= :" - ,
r
_
r
,
I
447'
._.
-'` --
,
,
1;
-!
PIL
PILOT PROUDLY PRESENTS THE PSV -1 SPEAKER SYSTEM
12 -inch Air -Flex heavy duty woofer, front mounted to seal
the opening of an air -tight, Orlon fiber filled enclosure.
Tweeters and mid -range units mounted to eliminate the
intervening ducts of conventional thick baffle boards, and
remove all possibility of distortion and tone coloration from
such ducts. Separate Presence and Brilliance controls supplied to match the PSV -1 to individual acoustical requirements. SPECIFICATIONS: Woofer -Pilot Model 53 Air -Flex
12 -inch low frequency driver. Frequency range 40 to 800
cycles. Free air resonance: 22 cycles. Mid -range -two Pilot
Model 40 6 -inch mid -frequency cone -type direct radiator
loudspeakers. Frequency range 800 to 8,003 cycles. Tweeters
-two Pilot Model 44 3 -inch cone -type direct radiator loudspeakers. Frequency range 8,000 to over 16,000 cycles.
Crossover network -6 db /octave, air -core inductance capacitance. Crossover frequencies: 800 cps and 8,000 cps. Impedance: 16 -ohms. Overall frequency response: 40 to 16,000
cycles. 45 pounds. Size 253/4" x 141/4" X 12" deep. Fully
finished on all four sides in a choice of hand- rubbed mahogany or walnut, as well as oiled walnut. $139.50.
PILOT RADIO CORP., 37 -0, 36th Street, Long Island City 1, N. Y.
Founded in 1919
AUDIO
AUGUST, 1959
45
www.americanradiohistory.com
AmericanRadioHistory.Com
The circuit of the bass amplifier is
similar to that of the treble amplifier.
V1B
VIA
GAIN
Tube V, is used as a voltage amplifier
TREBLE
CATHODE
VOLTAGE
AMP.
FILTER
and phase inverted which drives two
FOLLOWER
AMPLIFIER
C
EL -34 tubes also in push pull Ultra Linear operation. Fixed bias is obtained
INPUT
from a rectifier in the power supply.
FROM
The bass amplifier develops 50 watts at
PRE AMP
0.76 per cent intermodulation. Resistor
BASS
GAIN
TO
VARIABLE
RG2 serves two purposes : It provides a
V5A
V5B
BASS
HIGH PASS
VOLTAGE
CATHODE
test point for proper plate current (1.56
AMP.
FILTER
AMPLIFIER
FOLLOWER
volts) which in effect is added to the
fixed bias, and since R6, is unbypassed
it produces a small ampunt of current
Fig. 3. Block diagram of variable electronic crossover.
feedback. Any unbalance in grid signal
or a.c. plate current causes a negative
work is connected directly to the input 20 -watt amplifier seemed to be a good voltage across the resistor. The feedback
of the treble amplifier, Fig. 2. This par- companion to back up the bass ampli- voltage reduces distortion that may be
ticular amplifier circuit, which is es- fier which is rated at 50 watts.
Resistor R,,,
Tube V2 is a pentode- triode. The pent- caused by the unbalance.
sentially that of the Dynakits was used
provides the necessary feedback.
-gain
high
is
used
as
a
ode
A)
(section
because of its simplicity and excellent
performance. The treble amplifier con- voltage amplifier. It is directly con- Power Supply
tains only three tubes and a relatively nected to the triode (section B) which
The power supply furnishes 130 ma
small number of parts. Power output is is used as a cathodyne or split -load at 420 volts for the treble amplifier,
20 watts with slightly less than 1 per phase splitter. Grid return for V.4 is
140 ma at 450 volts for the bass amplicent total harmonic distortion. Inter - through part of the high -pass filter, R,r fier, 20 ma at 300 volts for a preampliof
the
phase
split
The
output
modulation distortion is 1.3 per cent at and R,3.
fier, and 30 to 50 volts bias for the
20 watts output and is under 0.5 per ter is connected to V, and V4 (KT -66's)
EL -34's.
which are operated in Ultra- Linear
cent at 10 watts.
Full-wave rectification with two
(Note: Since the photograph in Fig.1 push pull. Total plate current of 120 5V4GA tubes, each having its plates
was taken, transformer T, has been milliamperes (60 ma per tube) is ob- connected in parallel, (the 10 -ohm rechanged from a Linear Standard LS -63 tained by adjusting the slider on re- sistors, R73 -R76 balance current through
to an Aerosound TO -300. Plate -to -plate sistor RS0. Resistor RP7 is used to bal- the two halves) was used to obtain the
impedance of the LS-63 was found to ance plate currents. A balance is 280 ma required by the amplifiers. A
be too high for the KT -66 type tubes obtained when the voltage across re- separate 1 -to -1 transformer, T4 and a
is zero. Plate current half -wave rectifier CR, furnishes the
when operated in the Ultra -Linear con- sistors R,, and
is the correct value when the voltage
nection.)
30-to -50 volt negative bias. Capacitor
A few eyebrows may be raised when across each of these resistors is 1.5 volts.
Cr, filters the bias supply. The two
db
of
18
about
seeing a 20 -watt amplifier being used Resistor R,, provides
B -plus voltages are filtered through
for the "Treble" range. However, when negative feedback. Taps on the primary separate circuits. The filament circuit is
using a crossover frequency of 200 -300 winding of transformer T, provide the positively biased to about 40 volts by a
cps, some rather low frequencies must necessary screen feedback for Ultra - voltage divider of resistors R7, and R72.
Linear operation of the output tubes.
be amplified by the treble channel. A
TREBLE
TO
VARIABLE
HIGH PASS
R
C6
C5
R47
R46
R49
R48
C21
C20
OUT
IN
T
'
\
IN
OUT
T
(B)
(A) LOW PASS
+s
I
CP
5
5
PASS
II
Z
O
HIGH
-10
Q
s
`.a`
t
,r
d4Y,
4.P;1.
t
.(
?
`15^'
TC
z
15
20
/
e
``
ee
25
20
.RI
FREQUENCY IN
IOW
CYCLES PER SECOND
Fig. 4. Configuration of RC filter networks used in the biamplifier: (A), the low -pass
section, and (B), the high -pass section. (C), response curves of the two sections at
maximum and minimum crossover frequencies.
Construction Details
The amplifier is constructed on a
heavy-gauge steel chassis base 3 in. high
by 14 in. wide by 10 in. deep and has a
grille type metal cover. The chassis must
be made of heavy steel because two of
the transformers each weigh about 14
pounds. The completed amplifier weighs
48 pounds.
Location of parts (Figs. 1 and 5) is
very important. The power-supply components are mounted at one end of the
chassis, the treble amplifier in the middle
section, and the bass amplifier at the
other end as far away from transformer
T3 as possible. A steel shield is mounted
on the underside of the chassis to isolate
the external fields of transformer T4
and filter choke L,. The shield also provides valuable space for mounting parts
of the power supply. Tube shields are
used on the 12AU7's and the 6AN8's to
prevent hum pickup from the partially
shielded power transformer.
Filaments were wired by two sep-
arate pairs of twisted wires from the
power supply section, one pair supplying the power output tubes, and the
other supplying the small tubes. The
AUDIO
46
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
.
'::
_
a..
Win your next Rolls-Royce...
The superb $13,995.00 automobile illustrated will be awarded to the reader
of this message who listens to a Shure high fidelity Stereo Dynetic phonograph cartridge
demonstration and best describes its singular
sound re- creation qualities (in 25 words or less). No purchase is required.
If, however, you are the winner and have purchased a Shure cartridge
(our thinly disguised motive for sponsoring this competition) you may accept your
automobile at the Rolls -Royce factory. Travelling expenses for yourself and a friend
to the British Isles and return will be defrayed by
Shure Brothers, Inc., 222 Hartrey Avenue. Evanston. Ill.
Should you win (we don't expect an overabundance of entries, so your chances are rather
good) you'll probably never have to buy another automobile as long as you live.
Details and contest blanks available only at high fidelity dealers'
show rooms and salons. Contest ends August 31st, 1959.
SHURE
high {fidelity Stereo Dynetic phonograph cartridges , .
Unanimous choice of the critics.
Model M3D, $45.00 net; Model M7D, $24.00 net.
.
L
AUDIO
AUGUST, 1959
47
www.americanradiohistory.com
AmericanRadioHistory.Com
-4u
carries power to the preamplifier. These
leads were run separately because the
primary' current of transformer T3 is
about 2 amperes. Ground throughout the
amplifier is a #14 tinned bus wire
which is connected to the chassis near
the input jack. All electrolytic capacitors
are mounted on insulating wafers and
the shell connected to the ground bus
wire. Speaker connections, bias control
Rfei and preamplifier power socket are
mounted on the rear apron of the chassis.
An unusual feature of this amplifier is
that it does not contain a single half watt resistor! It is true that the current
in some circuits warrant the use of a
half-watt, or even a quarter-watt, resistor but this audiofan has encountered
several sad experiences with them.'
rvv
u.
rrc>ñáu
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rrrym -
uu
ñ
u
5K
539
V3
R3'
w
vs
cIF
538
C28
R61
u
C25
ve
530
va
V9
584
VIO
T6A
R66
568
C79
R67
Adjustments
c30
C3I
C12
C33
R69
R31
CRI
R71
Fig. 5. Underside of amplifier chassis showing parts placement.
filaments were wired first, keeping the
leads close to the chassis.
Because of the large number of parts
in the amplifier, terminal board construction was used where possible. Two
terminal boards are mounted along the
front apron of the chassis. These boards
mount most of the parts required in the
input circuits and the electronic crossover networks. Parts associated with the
crossover frequency control are mounted
on the boards as close to the control as
possible. This allows short leads to the
cathode followers and to the grid of
the 6AN8's where hunt is likely to be
picked up. Two other terminal hoards
moult parts associated with the bass
and treble amplifiers. Coupling capacitors were put in last. Terminal board
construction makes removal of parts
easy, does not clutter the socket pins,
and if properly assembled actually reduces capacitance between parts and
chassis. The hoards were assembled on
the bench, then mounted on the chassis
and wiring completed.
The crossover frequency control is assembled by using one IRC "PQ" control
and three "M" sections all having a
linear taper. The control consists of one
25 -k "M" section IRC (M11 -120), two
100 -k "M" sections (M11-128) and a
25K "PQ" standard control (PQ11120).
(standard control) is the basic
control and is next to the front apron.
Instructions for adding the "M" sections to the "PQ" control are packed
with the control. Particular attention
must be given to wiring this control
since with clockwise rotation of the
shaft, resistance must decrease thereby
increasing the crossover frequency.
Capacitor Cs and C6 in the high -pass
R
filter and capacitors Ct6 and C2, in the
low -pass filter are selected values that
are within 1 per cent of desired value.
C6 was made up by paralleling .02-µf
and .004-sf units then measuring the
combination on a capacity bridge. Cro
is an .0470 unit that actually measured
the desired value of .043µf. Resistors
R,o, R12i R46, and R48, although standard values, were measured and selected
to be within 1 per cent of the desired
value. (The author's parts dealer loaned
a handful of capacitors and resistors so
the correct values could he selected, allowing return of the parts that could
not be used, my thanks to him.) Resistor
pairs such as R., and X22, Rt7 and R68,
R69 and RG0i and It, ?2 and Ras were
matched to within 1 per cent. Such exactness may not be necessary but on an
overload test, it's nice to see clipping at
both grids of each power amplifier take
place at exactly the sanie level.
Some preamplifiers have the 117-volt
power switch leads within the cable that
Fig.
with
crossover
set
1957.
Response
6.
of the two sections of the biam-
plifier
The only adjustments required are
bias for the EL.34's and balancing the
KT -66's. Proper bias (and correct plate
current) for the EL -34's is obtained by
adjusting R69 until a voltage of 1.56
volts is measured across R64. The correct balance and plate current for the
KT -66's is obtained as follows: Connect
a low -range voltmeter across resistors
R69 and Rss (pins 8 of Va and V4) and
adjust resistor R27 for zero voltage. The
voltmeter is now connected across Rae
(or R33) and the slider of resistor Rso
adjusted until an indication of 1.5 volts
is obtained on the meter. The balance
adjustment should be checked by repeating the zero -voltage measurement
previously described.
Several "tests" were made on the overall amplifier such as power output and
frequency runs at different crossover
frequencies. Figure 6 shows the results
of one "run" and indicates the over -all
response at an output of 10 watts. Calibration figures on the frequency control
(Fig. 1) are approximate only, since
in operation the exact value does not
mean much.
(Continued on page 83)
One experience similar to that explained by Walter Richer, in "The sad tale
of a half -watt resistor," Avaao, December,
the
°
5
2
lo
cps.
g
Q
control
for 350
Ó
3
ó
S
? -20
Z
O
O -a5
á -30
LI
Z
O
to
s -10
CROSSOVER FREQUENCY= 350
WATTS IN 16 OHMS
KO
FREQUENCY
laW
IN
CYCLES PER
AUDIO
48
www.americanradiohistory.com
AmericanRadioHistory.Com
CPS
SECOND
AUGUST, 1959
Years Ahead
New Bogen stereo receiver is years
ahead in price and in performance
NO ONE BUT BOGEN,
builder of over one
million high- fidelity and sound distribution components, could have
engineered this new high -fidelity
stereo receiver, the SRB 20. A superb
all -in -one stereo instrument, it's a
highly sensitive FM -AM stereo tuner,
it's a versatile stereo audio control
center, it's a magnificent 20 watt (10
per channel) stereo amplifier, and it's yours for only $199.50
-a price you'd expect to pay for a comparable tuner alone!
BOGEN'S ENGINEERING STAFF,
fir(
ihdirffir
largest
of any sound -equipment maker, designed each circuit stage of the SRB
20 as an individual unit. By concentrating on each stage separately,
they can pack more value, more clean
performance in less space than is
otherwise possible. The separate
stages are then carefully, logically
arranged in an overall circuit of proven superiority. This new
Bogen concept eliminates wiring clutter, prevents hum and
distortion, provides savings which are passed on to you.
Bogen's engineering excellence, crystallized during 25 years
of building specialized sound systems for schools, theatres,
industrial plants and offices, is yours to enjoy in the new
SRB 20. Put it in a cabinet or on your bookshelf (it fits
easily). Ask your Bogen dealer to show it to you today.
BOGEN
Selector, FM Tuning. AM Tuning. Separate Bass
and Treble for each channel (lock for simultaneous control
of both). Volume for each channel (correct imbalance, then
lock for simultaneous control). Separate On -Off Power. FM
On -Off and AFC. AM On -Off. Multiplex.
CONTROLS:
-Grue, 4,o4uutcC, -t,o_akj..
to
Send for illustrated booklet, "Understanding High Fidelity."
64 -page explanation of hi -fi and stereo. Enclose 25c please.
nocENmtEsro co., Dept. A89, P. 0. Box 500, Paramus, N. J.
AUDIO
AUGUST, 1959
wuteyC, btoz.eo
HIGH FlDEIJrY
A
division of the Siegler Corporation
49
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Hi -Fi for Lo -Do
S.
G. LUCAS*
While most of us would prefer a factory -built cabinet, the lack of "dough" may make it
necessary that we "do" it ourselves. And if you don't have a power saw, it seems likely that
there is a lot of the "do" required to turn out this professional -type speaker enclosure.
WILLING to gamble less than
and about 10 to 12 hours
work for the actual living presence
of Bach, Beethoven, Brubeck, or Goodman via this back -loading folded horn
RE YOU
$25
for your listening pleasure?
This horn is designed for use with
woofers having resonances of about 55
cps but will work very satisfactorily
with much lower resonances and slightly
higher resonances. The theoretical cutoff
frequency is 40 cps but good performance will prevail down to 30 cps.
The cabinet is basically the Jensen
hyperbolic -exImperial reproducer
ponential design (covered by U.S. Pat.
2,338,262) -to be used as a free- standing type for corner or sidewall placement. I plan on installing the Jensen
KT -31 speaker kit, but any combination
-a
employing a 15 -in. woofer or a 2 -/or away assembly-such as the ElectroVoice Model 15 TRX; the University
Model 315 -C; the James B. Lansing
Model D130, etc. -can be mounted into
this folded horn.
In Figs. 1 and 2-on two 4 ft. x 8 ft.
plywood sheets -are shown the lay-outs
of the various panels that are needed
to construct this speaker cabinet. Below are listed the measurements of these
panels, plus the necessary lumber needed
for the bracing and the base.
An important point to remember in
building your cabinet is that all joints
must be accurately fitted and that it
must be made as rigid as possible to ob"
322 Park Avenue, New Castle, Pa.
3/4
TABLE I
-inch plywood
x31
22'/2
piece
Bottom
x 32'h
x 41'/4
x 49'/4
x 31
24
32'/z
17'/2
4 3/e
Top
Front
Back
Part A
x31
23'/e
15'/z
Part
11 3/4
x 31
x 12'/4
x 31
163/4
x
4
Center Shelf
Lower Shelf
125/16x 31
l0 5/s x 49'/4
pieces
Lumber
1'/z
piece
1/2
1
x2'/
x
x
1
x
pieces
1
3/4
x
25/a
'/2
X
1/2
X
3%
1
1
Part
41'/4
x
x
x
x
x
2'/z
1%
B
Part C
Part D
E
Sides
29
40
64'/2
Top Stiffener
Back Stiffener
761/2
481/2
Cleats
Cleats
Base
48'/2
Posts
All dimensions in inches
tain the best results. Except for such
parts as the base, posts, cleats, and
stiffening members, 3/4 -inch plywood is
used throughout. All joints should be
adequately glued and screwed to maintain rigidity.
The following construction procedure
is suggested: Begin by cutting out the
bottom and the front panel and he sure
that these first cuts are square to insure
a tight fit. The centerline of the speaker
opening is 113% in. from the bottom
edge and located on the vertical axis.
This opening may be cut to accommodate either a 12 or 15 in. woofer or
your present tri- or co -axial speaker.
Upon checking the list of materials, you
will note that the bottom panel is 3%
in. smaller all around than the top -so
be sure you pick the correct one to
start your construction. Next, take the
corner posts and cut two sides of each
with a notch 1/4 in. deep and % in.
wide, with the upper edge of the notch
8 in. down
from the top of the post.
Glue and screw these corner posts to
the front panel-but be sure and mount
them 3/4 in. in from the side edge and
3/4 in. up from the bottom of the front
panel in order to leave room for later
fastening the bottom and side panels.
Figure 3 shows how Part A-4% x 31
attached to the notched corner posts
and the front panel. I glued and screwed
these panels together and with the use
of clamps to hold them firm, then let
-is
(left). Layout of one of the plywood sheets is the
initial step in the actual construction. Fig. 2 (below). Layout of the second sheet to make sure you get all the parts
out of the two pieces of plywood.
Fig.
1
E
SIDE
SIDE
CENTER
SHELF
LOWER
C
SHELF
BACK
4 x 8
fr. PLYWOOD
AUDIO
50
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AUGUST, 1959
PRESENTING THE JBL RANGER -MINIGON
The new 1BL Linear'Efficiency Speaker, with its small enclosed-airvolume
require
ments, permits the use of radial refraction in an acoustical enclosure measuring just
32" wide, 15'A" deep, 12 %" high. The same method of projecting a broad stereo
field that originated with the fabulous JBL Paragon and was popularized with the JBL
Metregon is used in the Minigon. One Minigon gives you the highest fidelity monaural
reproduction ever provided by a minimum size enclosure. Two will give you enviable
stereo, integrated by the curved refracting panels. Usually placed end to end, Minigons
may be separated a reasonable distance without disturbing the stereo field. Your
choice of louvered wood or fabric grilles. Hangers for wall mounting are built in.
New JBL Dale Enclosure, Model C49. for
JBL Linear. Efficiency drivers measures
23,4"
a 11% " a 12" high, is delightful in
its simplicity. refreshing in its restrained
use of interest-arousing design details.
New JBL Madison Enclosure. Model C48,
23% "x 13i "x IIr
high. reflects the
influence of Danish design. Finished on four
sides and front, the Madison may be used
in either vertical or horizontal position.
/
NEW
EW
®LSV`i,f1NS
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Ul.à Vrri'SD®11
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Wtr
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/"
N
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Il
U
V
S
FOR S.VLALL
ENCLOSURES
PRESENTING THE JBL LINEAR -EFFICIENCY SPEAKER
You see an all new precision transducer
that could only be a product of James B
Lansing Sound, Inc. The company which brings you the best speakers for horn enclosures and the best units for reflex enclosures now offers the finest infinite baffle type
transduces. Under intensive development for a year and a half, design judgment and
engineerirg decisions were recurrently confirmed by analog computer.
You will hear
big, deep, accurate bass from these instruments. Application of new principles of
cone suspension permits unusually long linear excursion. Relatively high efficiency
with its attendant precision transient response, clean reproduction, least dynamic
range is achieved by use of large voice coils, precisioninstrument tolerances, ad
vanced magnetic circuitry -all typical of JBL transducers.
Illustrated above is the JBL Model LE10.
the super 10" Linear Efficiency Low
Frequency Driver. To the left are the new
LX3 Dividing Network and the new JBL
d
Model LE30 High Frequency Driver. To
ar left is the new LE8, the super 8"
LineaEfficiency Loudspeaker
which gives a flatness of response
from 30 to 15.000 cycles that is
the
extended range
without precedent in
Write for a complete description of these new units and the name
of the Authorized JBL Signature Audio Specialist in your community.
a
unit of this size.
JAMES B. LANSING SOUND, INC. / 3249 CASITAS AVENUE, LOS ANGELES 39
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_
Fig. 3. The two notched corner posts are
attached to the front panel, and the base
is attached next. Casein glue and plenty
of wood screws ensure a solid cabinet.
Fig. 4. Installing the center shelf. Note
have been atthat two pieces of 1 x
tached to the shelf before mounting on
the front panel.
Fig. 5. Making ready for the installation
of Part B. Note the use of temporary
braces along the sides to keep the center
shelf in the correct position.
them set over -night.
Figure 4 shows the installation of the
center shelf. First cut this panel
113/4 x 31-and two pieces of the 1
in. x 1 in. lumber-one 31 ins. long and
the other 28 ins. long. Glue and screw
the 1 x 1 x 31 cleat to the rear, lower
edge of the center shelf. Next, cut 11/2
in. notches in the forward edge of this
panel to fit around the corner posts. At
this point, it is necessary to plane the
rear edge of Part A and the rear edge
of the center shelf approximately 20
deg. to insure a tight fit of the network
panel, which is fastened later. Mount
the center shelf 203/4 in. down from the
upper surface of Part A. As can he
seen in Fig. 5, I had nailed some tem-
porary braces to the ends of the center
shelf and the corner posts to position
these pieces securely until ready for the
tween the lower shelf and the corner
posts. Also shown is the speaker com-
-
Part B and one side installed;
lower shelf in place with small stiffening
member between it and bottom panel.
Fig. 6.
Also shown are
2
4
base members.
1
next step.
Cut Part B-231/8 x 31 -with a 12 in.
square opening cut in the center. Bevel
the top and bottom edges of this panel
to form a level plane with the upper
surface of Part A and the lower surface of the center shelf. Now lay the
cabinet assembly face down and glue
and screw Part B into position. At this
point it is best to add a side panel to
give additional support to the bottom.
If your speakers have any Tone or Balance Controls it is necessary to cut the
needed holes in the side panel before
mounting. Also, don't forget to bevel
the rear edge of the sides at 45 degrees
to make a smooth fit with Part E.
The above steps are shown in Fig. 6,
along with the lower shelf being added.
this
panel -12 5/16 x 31-and
Cut
slightly bevel the rear edge approximately 6 deg. to insure a tight fit with
Part C. Take Part D-4 x 121/4 -and
bevel it so that it is 4 in. at one end and
23/4 in. high at the other end. Glue and
screw Part D to the center of the lower
shelf. Then mount this assembled lower
shelf on to the bottom panel so that
the front edge of this assembly is 23/4
in. away from the inner surface of the
front panel and with the slant pointing
down toward the front. Along at this
time, you can cut two pieces of
2x4x163/4 and one piece 2 x 4 x 31
with the ends mitered, for use as a base.
Mount these pieces to the bottom as
shown in Fig. 6-the piece running
across the back edge is just a temporary
brace -which is removed later when the
casters are added.
Figure 7 shows how the various panels
were glued previous to adding the remaining side. Note the clearance he-
partment panel, Part C -151/2 x 31with an access opening of 12 x 17 cut in
the center. After this panel has been
glued and screwed to the center and
lower shelf, the other side can be
mounted.
Figure 8 shows a rear view of the
cabinet with Parts E mounted. Remember to bevel the rear edges of Parts E
at 45 deg. At this point it is necessary
to cut two rabbets 1 x 3 x 481/2 beveled
45 deg. at one edge -these can be seen
mounted at the rear of the inside of Part
E, so that the 45 -deg. bevel is such that
it will form a 90 deg. corner in which
the hack panel will fit.
Fig. 7. The structure progresses -part C,
with the large rectangular speaker-access
opening, has been installed. Note space
between lower shelf and corner posts.
AUDIO
52
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AUGUST, 1959
NOW, FROM GENERAL ELECTRIC'S NEW
55
2%
6L6-GC..
WATTS...with only
distortion without feedback*
Power for orchestral climaxes with full concert -hall brilliance
...
yet
mellow in tone, undistorted! You can build this high speaker power into
your new equipment at a cost one-third less than the cost of other tubes
with comparable performance!
With 30 watts plate dissipation, 5 watts screen, General Electric's
6L6 -GC beam pentode can take peak power demands in stride. This is a
new tube throughout, designed to handle easily the speaker requirements
of the finest audio systems. Type 6L6 -GC has, among other features:
Special 5 -layer bonded -metal plate, developed by General Electric for improved heat conduction and radiation.
New large heat radiator on control grid, to minimize grid emission.
Redesigned screen grid, for higher dissipation.
New protective slots on micas, to reduce high -voltage interelement leakage.
New- design bulb, to radiate heat more efficiently.
* Two 6L6 -GC tubes push -pull, Class
AB1 service,
Key design -max ratings, per tube, of
the new General Electric 6L6 -GC are:
Top power output-low distortion -completely new design -economy!
Four important advantages to you of General Electric's 6L6 -GC. Ask any
G -E Receiving Tube Department office below for further information!
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(N.Y.C.) Wisconsin 74065, 6, 7, 8
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SPring 71600
with 450 v on the plate.
Plate voltage
Plate dissipation
Screen voltage
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Cathode current
ELECTRIC
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30
w
450 v
transformer taps)
5
w
110 ma
Ft»gress Is Our Most Important Product
GENERAL
500 v
2.211.101
Fig. 8. The remaining side and parts E
are now mounted in place, resulting in
this appearance.
-
The top of the cabinet can now be
attached. Add a stiffening member
11/2 x 21/2 x 29 across the middle of the
under side of the top. At the same time,
-1
x 1 x 15-beveled at 45 deg.
a cleat
at each end mounted at the rear of the
top panel 3/4 in. in from the edge -to
provide a screwing surface for the removable back panel.
As shown in Fig. 9, it is wise to
caulk all joints with a material such as
linoleum cement or any compound which
will not become brittle with age. It is
very important that all enclosure joints
should be air -tight and that is why a
liberal use of glue, wood screws and a
caulking compound should be used. The
best test for adequate rigidity is to
thump the center of all panels with a
clenched fist; a vibrating panel will
quickly reveal its presence by the hollow,
drummy sound indicating additional
bracing is needed.
Check Fig. 8-after installing your
speaker to the opening, it is necessary to
drill a small hole in the center shelf to
pass the lead up to the network compartment. Cut a panel-14 x 19 -as a
cover to the opening of the lower compartment and fasten with 11/2 -in. wood
screws on approximately 6 in. centers.
Next, cut a panel 14 in. square. Mount
all your network units on this panel,
drill a small hole in this panel as an
opening for the leads, and then fasten
securely to the 12 x 12 opening. Remember that any small holes drilled for
insertion of leads, should be made airtight with the application of a plastic
wood cement.
If you have a midrange and/or super tweeters, they are to be mounted in the
upper compartment on Part A and any
controls can now be affixed.
After all speakers, networks, and
controls have been mounted, the back
panel can be attached. To the vertical
center -line of the back, a stiffening member -11/2 x 21/2 x 40- should be fastened.
One small hole should be drilled in the
back panel through which the input
lead can he fixed. The removable back
can now be placed into position and
screwed securely.
Figure 10 shows the completed cabinet with no speakers, networks, or leads
attached. Be sure to putty in all the
countersunk screw holes.
addition to the liberal use of
casein glue, as shown here, it is desirable
to caulk all joints with a non -hardening
compound, such as linoleum cement.
Fig. 9. In
Figure 11 shows grill cloth secured
to the upper speaker compartment, and
with the excess grill cloth temporarily
mounted on the front panel. Due to the
size and weight of this cabinet, it was
felt necessary to mount wheels to facilitate ease of handling.
At your local hobby shop or wallpaper dealer, it is possible to buy decal
veneers, such as "Contact" to dress up
this cabinet -the final appearance is unlimited, and the more experienced constructor may take the trouble to veneer
the entire unit in a hardwood finish.
.
Fig. 10 (left). Cabinet is com-
plete except for trim, finishing,
and installation of speaker
and network components. At
this point it should be thoroughly solid and non -resonant.
11 (right). Grille cloth installed in upper section and
on front panel. A "picture
frame" type of moulding will
cover edges of grille cloth.
Cabinet may be painted, veneered, covered with "Contact" decal, or simply left as
shown, depending on the degree of personal freedom enjoyed by the builder.
Fig.
AUDIO
54
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AUGUST, 1959
FOR
A
EVERY MUSIC LOVER
Whether your requirements are modest or magnificent,
there is a fine -music Bozak Speaker System to satisfy
every individual need.
For Limited Space: The new Bozak "Spinets," quality
two- and three -way Systems in compact, functional enclosures measuring only 141/2" x 231/s" x 111/2", that
outperform any speakers near their size and price.
For Built-ins: Panel- mounted and wired two- and three way Systems for convenient installation where you want
in wall, bookcase, or well -made furniture.
them
For the Hobbyist: The easily assembled, acoustically
superior infinite -baffle E -300 Kit enclosure, with
Bozak's one line of one quality components: the popular
B-207A coaxial, the outstanding B-199A woofer, the
unique B -209 midrange, the sweet -natural B -200X
tweeter, distortion -free crossover networks-and, soon
to be announced, the multi -purpose 8" aùxiliary speaker.
For Decor: The industry's widest selection of customcrafted fine furniture enclosures in Provincial, Urban
and Contemporary styling with matching equipment
or unfinished for
choice of fine finishes
cabinets
special individual requirements.
For Stereo: The original and incomparable single cabinet dual- matched System -the Bozak B -304 Stereo
Fantasy. Or any pair of Bozak Systems.
For the Connoisseur: Supreme in realism of music
and sound reproduction, the magnificent B-310A and
B-400 Systems.
see a
Reward your appreciation of fine music
Bozak Franchised Dealer for The Very Best in Sound.
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CONNECTICUT
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Errors and Mistakes of Engineers
ALBERT WOODRUFF GRAY
Architects, engineers, and consultants can not usually be held liable
for failures in their work -they must exercise due diligence like physicians and lawyers, but successful results are not necessarily guaranteed.
ago by a New
England court was outlined the rule
that governs the liability of an engineer or any other professional worker
in his performance of services.
"What then is the contract of the professional man with his employer in regard to his qualifications and conduct,"
queried that court. "And here it may be
laid down broadly, that without a special contract for that purpose he is never
a warrantor nor insurer. He never stipulates for success at all events and he is
never to he tried by the event.
"By our law a person who offers his
services to the community generally or
to any individual for employment in any
professional capacity as a person of skill,
contracts with his employer that he possesses that reasonable degree of learning,
skill, and experience which is ordinarily
possessed by the professors of the same
art or science and which is ordinarily regarded by the community and by those
conversant with that employment, as
necessary and sufficient to qualify him
to engage in such business. "'
Even earlier than this pronouncement
by that New Hampshire court is an
English case in which it was asserted,
"every person who enters into a learned
profession undertakes to bring to the
exercise of it a reasonable degree of care
and skill.
"He does not, if he is an attorney,
undertake at all events to gain the cause
nor does a surgeon undertake that he will
perform a cure. Nor does the latter
undertake to use the highest possible degree of skill, as there may be persons of
higher education and greater advantages
than himself, but he undertakes to bring
a fair, reasonable, and competent degree
of. skill. "2
In the circumstances surrounding a
lawsuit in New York State the humanity
and justice of this old common law rule
became apparent. There an engineer
had written to a company, "I am to act
as consulting engineer in your company
and to assume entire responsibility for
the design and construction, devoting as
OVER A HUNDRED 1V-1128
112-20 72nd Drive, Forest Hills, N. Y.
'Leighton v. Sargent, 27 N.H. 460, De-
cember, 1853
' Lanphier
February
v.
Phipos, 173 Eng. Rep. 581,
16, 1838
much time to this work as may be required. In consideration of being retained I agree not to engage in consulting work for clients in similar or
competitive lines of work."
Five months later the engineer was requested to resign. This he did with the
agreement that he would be given two
months salary in place of the usual notice. When the company failed to pay
this advance, suit was brought by the
engineer for the amount he claimed as
due under his employment contract.
As a counterclaim the company demanded $10,000 for expenses it had incurred which would have been avoided,
the company claimed, if the engineer had
properly performed his work as a consulting engineer.
"It would, I think, be a violent construction of this contract," said the court
in refusing to recognize any liability as
resting on the engineer under this charge
of his employer, "to hold that this engineer intended thereby to guarantee the
sufficiency of the plant which was to be
erected under his care. 1 think a fair interpretation of this contract would hold
the engineer to an obligation to assume
full charge of the construction of the
work and to use his best endeavor to accomplish that purpose. "a
Charges of Negligence
A very similar situation had been before the Florida courts the year before,
but in that instance the charges of negligence and lack of skill had been made
against architects instead of engineers.
There as in the New York decision, the
errors or mistakes of the architect in
this instance, or of the engineer in the
former action, afforded no grounds for
the claim of negligence in the performance of the services.
"The architect's undertaking," said
the Florida court, does not imply or
guarantee a perfect plan or satisfactory
result and there was no evidence sufficient to support a verdict of the existence of a specific promise or guarantee."
To this statement was added an outline
of the legal obligations of a. professional
worker. "The law requires only the exercise of ordinary skill and care in the
rsulkley v. Kaolin Products Co., 187
A.D.103, New York, March 21, 1919
light of the present knowledge. If the
plans and specifications were in fact
justified by the common knowledge upon
such matters at the time and met the
judgment of approval of those men ordinarily skilled and experienced in their
conclusion, the architect has complied
with his contract"*
This charity bestowed by the courts
on the honest mistakes of engineers and
other professional workers in the performance of their undertakings was extended by a court in the District of Columbia a few years ago to relieving an
engineer of consequential damages when
the correction of the mistake was timely
made.
Consulting engineers had been employed to prepare plans and specifications and on the basis of those plans,
contracts had been made for the performance of construction work. in the
specifications was discovered later a
mathematical error and corrected plans
were immediately prepared. By the court
in this instance there was charged
against the engineers only the additional
cost resulting from the mistake.
"The engineers," said the court, "contracted to furnish plans. They did not
contract to install the system or guarantee that the system would be installed
for any specified sum. Through negligence they failed to furnish the proper
plans but when such negligence was discovered they supplied supplemental
plans which together with the original
plans filled their contract obligation.
"Had the original plans been free of
error the cost would have been $183.30
less than in the use of the original plans.
Such amount places the owner in the
same position it would have been in if
the error had not been committed. A
larger sum would permit the owner to
profit by the engineer's mistake."5
This feature of the obligations of en-
gineers, carried a. step further, appeared
in a recent South Carolina controversy
in which engineers had obviously failed
to exercise the care and skill demanded
(Continued on page 102)
4
Bayshore Development Co.
2d 387, District of Columbia,
www.americanradiohistory.com
AmericanRadioHistory.Com
Bonfoey,
January
Atl.
31,
1951
AUDIO
56
V.
March 20, 1918
' Henry J.Florida,
Robb. Inc. v. Urdahl, 78
78 So. 507,
AUGUST, 1959
precise
Brings The Luxury Of Complete Stereo
Within Reach Of Everyone!
JtkfELtJt&
MARK XXIV
The Ultra -New Complete
STEREO AMPLIFICATION SYSTEM
Not since the advent of Stereo has any unit had such dramatic impact on the world of high fidelity.
Now, for the first time, a complete stereo system which includes dual amplifiers and pre -amplifiers in a single corn pact unit
with sufficient power to equal custom sound
reproduction
PLUS every important luxury feature found
in amplifiers sold at twice the price.
And, best of all, the Ultra -new INTEGRA Mark XXIV will equal
any stereo amplifier in advanced circuitry, engineering.
...
...
beauty of design, quality of manufacture
performance.
.
.
and superb
.
Waiting for Multiplex? The INTEGRA Mark XXIV is ready now
to accept Precise Development's accessory MULTIPLECTOR
which places Multiplex right where it belongs
inside the
amplifier! You'll be able to receive Multiplex programs with
no additional equipment other than your own AM Tuner, FM
-
Tuner or TV.
iQ
A DRAMATIC LINE -UP OF FEATURES:
Two Individual Amplifiers and Pre -Amplitiers in a Single
Compact Unit
20 Watts RMS Power in Each Channel (40
Watts Peak)
40 Watts RMS Power Combined for Monophonic Listening (80 Watts Peak)
Ready to Accept Internal Accessory MULTIPLECTCR for Immediate Reception
of Multiplexed Programs When Used With Your Own AM or
FM Tuner or TV Set
Separate Push -Pull Amplification Circuits Using 4 Tubes
Exclusive Voltage Regulating Fixed
Bias Supply Provides 5 Times Greater Efficiency and Virtually Eliminates Distortion
High Inverse Feedback Circuit Yields Flat Response from 18 to 20,000 CPS (I db at
75,000 CPS
IM Distortion Less Than .6% at Normal Listening Level
Total Harmonic Distortion Less than .2% at
Normal Listening Level
Separate Treble Controls for
Each Channel
Separate Bass Controls for Each Channel
Separate Volume Controls for Each Channel
Master
Loudness -Control Provides Gain and Attenuation for Both
Channels Simultaneously
Separate Panel Illumination
Switch
Contour Switch with Provision for Normal Listen Ing,-10 and -20
Slide Switch Affords Stereo, Monophonic
or Multiplex Listening Plus Mute Position
Slide Switch
for Normal Stereo Listening or Reversal of Stereo Channels
Selector Control has Positions for Phono, Tuner
Tuner Plus TV (for Special TV -Radio Stereo Broadcasts) TV
and Tape
Built-in Speaker Phasing
Variable Hum Balance Control
Inputs for 2 Tuners (Can be Operated Simultaneously for Stereo Broadcast Reception)
Dual Tape
Inputs
Dual TV Inputs
Inputs for Magnetic, Ceramic
and Crystal Cartridges
Dual Tape Outputs
Isolated
Heavy -duty AC Power Transformer
AC Convenience Outlet
Luxurious White and Gold Contrasting Front Panel
Handsome Cabinet
Tube Complement: Four 6805
(EL84); one 6AC4 (EZ81); one 12AU7 (ECC82); three 12AX7
(ECC83)r one Germanium Diode; one Neon Regulator
Precise Development Corp. Dept.
A -8
Ide, Long Island, N.Y.
Please send me information about
O
Equipment.
High Fidelity
Name
Address
City
Zone
State
MY DEALER WOULD LIKE INFORMATION TOO1
He is
Address
City
AUDIO
Zone
State
AM -FM TUNER
Extraordinary New
superb AM and FM tuner providing maG:hed performance and great beauty. Coupled with variable
automatic frequency control and metered output, it
brings in the weakest stations and provides razorsharp selectivity. Distinctive white and gold front
panel styling.
A
-
-
88 to 108 MC
AM
500 to 1600 KC
Output Tuning Meter
Cathode Folower Output
AC Convenience Outlet
Phono, FM, AM,
Switch
Inputs for Phono and TV
Foster -Seeley Discriminator
Flywheel Tuning
Two Limiters
Ferri -Loop
3-Gang
Variable
Condenser
Logging Scale.
Complete with Case
FM
$9995
TV
Ready For
Listening
5QlQ,a4 40-WATT
MONOPHONIC AMPLIFIER
Superb New
superb 40 -watt amplifier which supports a symorchestra with live, crisp, brilliant, distortion -free reproduction.
A
phony
24 Positions of Equalization
DC on Input Tube Filaments
Volume
Control
Loudness Control
my Full Output
5
Rumble Filter
Muting Switch
AC Convenience Outlet
Output Meter Reads
Power Output in Watts, Tape Output in Volts
Separate and Independent Tape Output Level Potentiometer
Cathode Follower Tape
Internal Grid Bias, Grid Balance and Hum Balancing Controls
Output
Output Selector for Speakers of Different Impedance
A -AB -B
Speaker Selector
Special Patent -pending Output Transformer
10
Tubes
Fused Power Supply . Rich White and Gold Front Panel
precise
$8995
Ready For
Listening
Complete
with Case
DEVELOPMENT CORP.
High Fidelity Division
OCEANSIDE, LONG ISLAND, NEW YORK
AUGUST, 1959
57
www.americanradiohistory.com
AmericanRadioHistory.Com
TRANSISTOR MUSIC SYSTEM USING DIRECT COUPLING
(from page 24)
used in the common -emitter connection.
Low -noise operation of Q a PNP type,
results from operating its collector at
only 0.25 volt and 35 pa. Using two PNP
stages followed by an NPN stage allows
the collector operating point of Q, to be
near ground potential which is convenient for the feedback connection to
Q,.
Unity d.c. feedback from the collector
of Q, to the base of Q, establishes a
high degree of temperature stability for
all three stages over the range of 32 to
125° F. At audio frequencies the input
and feedback networks tailor the response to the RIAA curve. A s- section
RC low -pass filter at the input flattens
the phono pickup peak in the 10 to 20 kc
region and at the same time prevents
rectification of local radio station carriers, a serious problem in many loca-
tions.
Following the phono preamplifier four
channels are mixed at the input of the
four transistor tone control section Q4,
Qs, Q6 and Q,. Each input has an r.f.
filter. This amplifier is similar to the
phono preamplifier except for the addition of an emitter follower Q,. Again
direct coupling and feedback are used to
temperature- stabilize the four transistors at once, determine the gain characteristics, and provide BASS and TREBLE
control action.
Stabilization of the feedback at high
frequencies is accomplished as in the
power amplifier by means of local loops
through small capacitors. In the tone
control section there is a stabilizing capacitor from the emitter of Q, to the
base of Q67 from the emitter of Q, to the
base of Q4, and from the emitter of Q,
to the base of Q. A 100 -ohm isolating
resistor in series with the TAPE OUTPUT
jack prevents the phase lag due to line
capacitance from causing instability.
for a greater range of bass boost than
attenuation and a greater range of treble
attenuation than boost.
When the tone controls are set at their
fiat positions the response is flat within
0.1 db from 10 cps to 100 kc as shown
by the lower curve, Fig. 11. As a result
of the gradual attenuation above 100 kc
the square-wave response, Fig. 12, is
excellent and exhibits no high -frequency
ringing. The phono input is RIAA compensated within 1 db from 30 to 10,000
cps. Its response curve, Fig. 13, was
measured at the TAPE OUTPUT with an
ESL C60 pickup playing an RCA No.
12 -5-49 test record.
Equalization for the speaker system,
measured at the main OUTPUT with the
tone controls at their flat positions, is
Fig. 12. Square -wave response at the
tape output at the flat setting of the tone
controls.
Both the TAPE OUTPUT signal from the
tone -control amplifier and the MONITOR
playback signal from the tape recorder
are mixed at the input of a similar four stage output amplifier
Q Q,0, and
Q,,. This section equalizes the speaker
response at low and high frequencies by
means of selective feedback.
Q
10.000.,
d
10 L
SPEAKER
EQUALIZATION
0
F OM TAPE INPUT TO MAIN OUTPUT
TONE CONTROLS FLAT
VOLTAGE GA N
4
VOLTAG
GAIN FROM
TAPE
INPUT
TAPE OUTPUT
TONE CONTROLS FLAT
P
-let
''.....\
loo
10
to
1000
FREOUENCV
IM
100K
CYCLES PER RECORD
IN
Fig. 11. Response at the main output and the tape output at the flat setting of the
tone controls.
at 20 cps and 13 db at 20 kc. This
response, shown by the upper curve in
Fig. 11, was determined primarily by
extensive listening tests using the response curves of the woofer and tweeter
measured by a close microphone as
guides.
As a result of the high feedback factor
22 db
Performance
Figure 10 shows the response from
the TAPE input to the TAPE OUTPUT. The
tone -control action and the final component values were determined by listening tests on a wide variety of program
material. These tests indicated the need
Fig. 10 (left). Bass and treble controls balance the response
without losing extreme low and high frequencies. Fig. 13
(below). Phono preamplifier and ESL -C60 pickup response.
"
a
II
1
1
RESPONSE TO RIAA INPUT WITH ESL CARTRIDGE
MEASURED AT TAPE OUTPUT
TONE CONTROLS FLAT
.10
0
10
ae
1000
FREQUENCY
IN
0x000
10000
00
Ioo
FREQUENCY
CYCLES PER SECOND
www.americanradiohistory.com
AmericanRadioHistory.Com
X0°°0
CYCLES PER SECOND
AUDIO
58
1000o
loop
IN
AUGUST, 1959
The world's
most sensitive
FM TUNER
Nao And designed for a long future!
I
AGAINI Year after year, tuner after tuner, there is only one best -THE FISHER. Today,
the leader is the FM -100, latest in a series of FISHER FM tuners now used by radio stations, the Satellite
Tracking Project of Ohio State University and by many government agencies. The reason is simple
these tuners meet the exacting standards of performance and reliability required by professional users.
And where standards are concerned, the audio enthusiast is, in his own right, a professional. He desires
maximum sensitivity for optimum reception of stations near and far. FM-100 SENSITIVITY is 0.8 microvolts
for 20 db of quieting
The audio enthusiast wants an FM tuner that permits simple adaptation to
stereo. THE FM-100 IS CUSTOM-DESIGNED FOR STEREO. It has space directly on its own chassis for installation of a multiplex adaptor. Moreover, it includes feed -through facilities for FM -FM and FM -AM stereo
as well. The audio enthusiast expects maximum fidelity. THE FM-100 OFFERS FOUR WIDE-BAND IF STAGES,
uniform frequency response (20 to 20,000 cps) and less than 0.5% harmonic distortion.
The audio
enthusiast wants an FM tuner that eliminates noise when tuning between stations. THE FM-100 EXCLUSIVE
INTERSTATION NOISE SILENCER automatically eliminates noise, side -band response and unwanted weak
and noisy signals. For the audio enthusiast who buys the best at the outset, there is only one truly logical
choice -IT IS THE FISHER FM -100 TUNER.
$159.50 Cabinet, $15.95
FISHER DOES IT
-
!
Slightly Higher in the Far West.
WRITE TODAY FOR COMPLETE DESCRIPTIVE LITERATURE
FISHER RADIO CORPORATION
21 -29 44th DRIVE
LONG ISLAND CITY 1, N. Y.
Export: Morhan Exporting Corp., 458 Broadway, New York 13, N. Y.
AUDIO
AUGUST, 1959
59
www.americanradiohistory.com
AmericanRadioHistory.Com
USED BY
PROFESSIONALS:
410
¡-""`
or
'
Fig.
,J
.1
-10
15.
System
acoustic response
with doors open.
A
%A
i
I.
,rrr
o
IN
"0"
BIA RECORDS
from a low -impedance source, is -73 to
- 79 db depending upon the control
settings. Since each input will handle 10
db more than its rating, signal -to -noise
ratios as high as 83 to 89 db can be
attained. When the master VOLUME control is turned to zero the output noise
COLUMBIA
DECCA RECORDS
PICTURES
each section of the tone-control preamplifier, harmonic distortion is very
low. A 1 -volt rms signal at the TAPE OUTPUT, which is 10 db above the normal
level, has less than 0.05 per cent total
harmonic distortion from 20 to 10,000
cps at any control setting. The MAIN
COLUM-
CAPITOL RECORDS
CYCLES PER SECOND
il:
CBS
RADIOCBS TELEVISION
V
'WFREOUENCY
AUANGEL RECORDS
TION
BEL DIO FIDELITY RECORDS
TONE RECORDING STUDIOS
CBS LABORATORIES
11
20
ALTEC LANSING CORPORA-
DEUTSCHE GRAMOPHON
GESELLSCHAFT LONDON
RECORDS* MGM STUDIOS
NATIONAL BROADCASTING CO.
RADIO
RECORDERS U.S. ARMY U.S.
MARINE CORPS U.S. NAVY
UNITED
U.S. COAST GUARD
VOICE OF
NATIONS RADIO
RCA VICTOR RECORDS
AMERICA
WARNER BROS.
WESTMINSTER RECORDS
Fig.
runniammilowLINR9
Ifill11111111111 .1111111111
IOW
INFREQUENCY
IN
1
0000
Microphone at 2
feet on center.
decreases to below
audibility at
Fig.
iMIr1121111.lwr
fIN11! I'11RII
'III19JY1Il IGIhI
10
1
foot
from the speaker.
At the phono input the noise is remarkably low, about - 74 db referred to
a peak velocity of 10 cm /sec at 400 cps.
The absolute level is less than 0.15 ttv
referred to the input when based on the
50 -cps gain.
..rl111111113111MM1
l'II
17.
System
acoustic response
with doors as in
Micro14.
Fig.
phone at 2 feet on
center.
20
20
ROW
100
FREQUENCY
SOLD ONLY BY
SELECTED DEALERS,
INCLUDING:
AUDIO- ACOUSTIC EQUIP. CO.,
DALLAS
D & N DISTRIBUTING CO.,
NASHVILLE
:
+10
o
System
CYCLES PER SECOND
volt rms from 20
to 10,000 cps. This level is 8 db above
the 0.4 volts needed to drive the power
amplifier to 20 watts output. Limiting
at higher output signals is symmetrical
when the load is 3300 ohms.
Noise referred to either the TAPE,
RADIO, or Microphone input, when fed
output also delivers
1
16.
acoustic response
with doors open.
HARVEY RADIO CO., INC.,
NEW YORK
HIGH FIDELITY HOUSE,
BALTIMORE
MAGNETIC RECORDERS,
SAN FRANCISCO
MAGNETIC SERVICE CORP.,
COLUMBUS
NEWARK ELECTRIC, CHICAGO
RADIO SHACK, BOSTON
SANDERS & ASSOCIATES,
SANTA FE
STEINBERG'S, CINCINNATI
STUDIO SUPPLY CO.,
LOS ANGELES
20TH CENTURY SALES CO.,
SPOKANE
U.S. RECORDING,
WASHINGTON, D.C.
VIDEON, INC., HIALEAH
W & W DISTRIBUTING CO.,
MEMPHIS
EXCLUSIVE SALES &
SERVICING AGENTS
IN THE U.S. AND
CANADA:
I
IN
CYCLES PER SECOND
AUDIO
60
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
IT'S WHAT'S ßIGHT HERE THAT'S ALWAYS COUNTED!
M-49b
\
NEUMANN
CONTINUOUSLY
ELECTRONICALLY
VARIABLE DIRECTIONAL
PATTERN MICROPHONE
SYSTEM
0l411.11
_
KM-54a
NEUMANN HYPER -CARDIOID
MINIATURE MICROPHONE,
DESIGNED WITH TV AND FILM
IN MINO
U-47 (U-48)
NEUMANN "STUDIO STANDARD"
MICROPHONE SYSTEM
KM-56
NEUMANN MINIATURE
CONDENSER MICROPHONE SYSTEM
COMPLETE TECHNICAL SPECIFICATIONS WILL BE PROMPTLY FURNISHED UPON
PROFESSIONAL REQUEST.
otham
2
AUDIO
/''ludio sales
West 46th Street, N. Y. 36, N.
Y.
co.
COlumbus
5
inc.
-4111
AUGUST, 1959
61
www.americanradiohistory.com
AmericanRadioHistory.Com
Speaker System
Developed and
Guild- erafted
by
Philips
of the
Netherlands
...the
0P ee
new line
rig strramel
Construction
5-way
of
binding
posts
LOUDSPEAKERS
featuring new magnets
Ticona I.7
alloy
magnet
of úMOo RIcia
e
(30% more powerful than alnico)
Standard E.I.A.
ounting kolas
This new line of 5" to 12" loudspeakers is designed
to match the quality requirements of the discriminating music lover
at a surprisingly moderate price.
The world's greatest buys on the basis of listening
quality, the T-7 series incorporates voice coil magnets
of Ticonal -7 steel, the most powerful of modern magnet alloys, for maximum efficiency and damping
dual cones for wide frequency response
constant
impedance resulting in an extremely straight response
curve
longer effective air-gaps and extra high flux
density to provide exceptional transient response and
to eliminate ringing and overshoot.
...
Ao-s277Y
...
...
...
A63600M
hove
(nns)
Model
AD-2690M
Sin
(inlalut,
Frs,eear,
tilìnerirl 9.141 flue
real al 40D cps (Mannllil
Response
Audi,Mita
his)
Mel
90.52776
12-
20
50
6%
12e.000
25.15.000
572.50
991.42779
12-
20
10
7%
00000
]5.11.000
2000
A0.4571M
1-
6
0
lo%
50.300
50.20.000
36.00
90.750065
0-
6
10
6%
26.200
75.10.000
9.90
AD.0500M
5'
3
5
4%
26.200
]0.10.000
a.24
A04600M
640-
6
9
5.5%
26.200
70.11.00
7.0S
AD.2600M
6.09
6
0
15%
15200
70.16.000
6.75
"'eke 'EXHIBITION'
SPEAKER ENCLOSURES
Available In three sizes in hand -rubbed Mahogany, Walnut,
Blond or Cherry finishes. -The "Rembrandt," (26" x 2142"
x 1746" deep) Walnut or Cherry $99.50; Blond $94.95; Ma.
hogany $91.00. The "Van Gogh," (232/4" x 132/6" x 115/4"
deep') Walnut or Cherry $59.95; Blond $55.50; Mahogany
$51.00. The "Vermeer," (1842 x 12" x 8- 15/16" deep')
Walnut or Cherry $35.00; Blond $33 25 Mahogany $31.00.
May be placed horizontally or vertically.
...also new
from
Are/CO
The "HAGUE "; Completely integrated quality speaker sys-
tem.Two high -efficiency
T -7 loudspeakers in an acoustically
matched enclosure. Designed for optimum dispersion
maximum efficiency
.
extremely wide- range, flat response. 26" x 2142 x 1746" deep. Walnut or Cherry
$159.95; Blond $154.95; Mahogany $149.95.
...
For further descriptive literature write to:
NORTH AMERICAN PHILIPS CO., INC.
High Fidelity Products Division, Dept. 3A8
230 Dully Avenue, Hicksville, L. I., N.Y.
To produce a smooth musical sound
the speaker system incorporates its own
reverberation chamber. Two hinged doors
forming an adjustable triangular chamber in front of the closed box speaker
enclosure, Fig. 14, reflect the sound
numerous times in a random manner.
Their effect in listening is rather similar
to placing the speaker system in a live
listening room.
The enclosure itself is a 2.3 -cubic -foot
closed box or infinite baffle completely
filled with sound absorbing material. It
contains a Lansing Model D130 15 -inch
woofer and a Jensen Model RP-103
horn -type tweeter. An earlier enclosure
design used a ducted bass -reflex port.
The tweeter and several convex sound
reflectors were built into the port which
then acted as a reverberation chamber
for the tweeter. Changing to a closed
box and re- equalizing has permitted extension of the bass range of the entire
music system from 80 cps down to 20
cps. The larger reverberation chamber
formed by the doors produced reverberation for both the woofer and the tweeter,
resulting in a smoother sounding crossover.
Contrary to the present trend toward
inefficient woofers in which the middle range efficiency has been lowered to
match that of the bass range, this system
uses a woofer having a 4 -inch voice coil
which makes one of the most efficient
motors obtainable. As a result of the
high efficiency the bass response falls off
in a nonresonant manner which can be
equalized by the relatively simple RC
feedback network in the output amplifier
of the control unit. Flattening the response by means of electrical equalization instead of mechanical produces a
wider bass range and up to 10 db more
acoustic power output on program material having moderate bass energy con-
tent.
A single 10 -µf nonpolarized electrolytic capacitor in series with the tweeter
comprises the crossover network. The
average impedance of the system is
about 10 ohms.
Curves of the equalized speaker response, made outdoors with a very close
microphone are shown in Fig. 15. For
these measurements the speaker system
was placed face up on the ground with
the doors folded back against the sides.
A calibrated Altec type 21 -C microphone
was placed 1/2 inch from the grill cloth
i11 front of the woofer to measure the
solid curve and 4 inches from the grill
cloth on the axis of the tweeter to measure the dashed curve. The remarkably
flat response of the woofer and speaker
equalizer within ±2 db from 25 to 1000
cps indicates that the motion of the cone
AUDIO
62
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
14. Closed -box speaker system.
Doors form reverberation chamber.
Fig.
is well controlled in this region. Although
the system could have been equalized
for flatter response above 5000 cps, listening tests indicated that further high frequency compensation was undesirable
even on live program material.
When the microphone is moved to a
distance of 2 feet on the axis of the
speaker system, the measured frequency
response, Fig. 16, is entirely different.
This curve was measured by an equalized
Western Electric type 640AA microphone in the Harvard anechoic chamber.
A high -pass filter in the measuring systan attenuated frequencies below 50 cps.
A peak at 4000 cps in the tweeter response, Fig. 15, has now become a valley
due to cancellation from the woofer. At
50 cps the response is down nearly 10 db
from that at 500 cps. Listening tests
indicated that increasing the bass compensation to flatten this curve made the
system sound boomy in most locations.
The compensation which produced flat
response with the close microphone, Fig.
15, seemed to be optimum.
As would be expected, partially closing the doors in front of the enclosure
as in Fig. 14 produced multiple reflections which resulted in a great many
peaks and valleys in the response, Fig.
17. Surprisingly the musical quality with
this jagged curve is much smoother than
that with the doors open.
The foregoing techniques have produced a compact music system having
both high performance and ear appeal.
REFERENCE
I3urwen, Richard S., "Portable transistor
music system" Journal of the Audio Engineering Society, Vol. 6, No. 1, January
1958, pp 10-18.
AUDIO
PACO is the kit division of PRECISION Apparatus Co.,
Inc., world famous manufacturers of laboratory electronic
instruments for over a quarter century. The new Model
is the first of a series of component high fidelity kits
A new SA-40
from PACO...engineered for utmost performance and lastvalueing
designed for maximum eye -appeal.
40 -watt
Whether you're an experienced audiophile or a newcomer
stereo to the thrill of high fidelity, the factors you must consider
choosing the amplifier you need are:
preamp -amplifier inPOWER,
DISTORTION, FLEXIBILITY and VALUE.
in kit form The PACO SA -40 offers you greater reserve power capacity
than
other preamp -amplifier in its category. Its excepfor only tionalany
circuit design assures highly stable performance with
extremely
low distortion. Step -by -step assembly instructions
$79.95 and giant -size
wiring diagrams are so clearly detailed and
by simple that the technical difference between expert and
novice disappears. And...the SA-40 provides maximum
flexibility in any stereophonic high fidelity system...present
lt-tS
or contemplated.
For those interested in engineering details, some of the
also
more important technical specifications are listed below:
available
Ca
factory wired
for $129.95
Ask your own
Audio -Radio -TV
Serviceman about
PACO and PRECISION
products. He'll tell you that
they always live up to their
specs. That's why we can
say that the PACO SA-40
is the last preamp-amplifier
you'll ever have to buy
Available at leading electronic
parts distributors and
wherever good sound is sold.
For complete information
write to:
POWER OUTPUT:
Steady State Power Output: 20 watts per channel,
40 watts total.
Music Waveform Power Output: 25 watts per channel,
50 watts total.
Peak Power Output: 40 watts per channel,
80 watts total.
RESPONSE: 30 cps to 90 Kc, ± 1.0 db.
DISTORTION:
Harmonic: Less than .2% at 20 watts per channel output.
Less than .1% at 10 watts per channel output.
Intermodulation: Less than 1% at full rated output.
FRONT PANEL CONTROLS AND SWITCHES: 14 controls
including separate bass and treble controls for complete
flexibility with any monophonic or stereo program source.
INPUTS: 14 total; 3 dual high -level and 4 dual low -level.
OUTPUTS: Dual tape outputs. separate preamp output as
well as standard dual speaker outputs.
HUM AND NOISE LEVEL:
High Level Input: 80 db below rated output.
Low Level Input:
70 db below rated output.
Tape Input:
65 db below rated output.
SPEAKER CONNECTIONS: 4, 8, 16. 32 ohms.
SENSITIVITY FOR RATED OUTPUT:
Aux Input: .75 V Phono 1: (Magnetic) 5 Mv.
Tuner: .75 V Phono 2: (Magnetic) 5 Mv.orCeramic.3V
INVERSE FEEDBACK: 25 db
DAMPING FACTOR: 22
Electronics Co., Inc.
70 -31 84th Street
Glendale 27, L. I., N.
A Division of
Y.
PRECISION
Apparatus Company, Inc.
Export:
Morhan Exporting Corp.
458 Broadway
N. Y. 13, N. Y., U.S.A.
Canada:
Atlas Radio Corp., Ltd.
50 Wingold Ave.
Toronto 19, Ontario
BASS TONE CONTROL RANGE: ±15 db at 50 cps.
TREBLE TONE CONTROL RANGE: ± 15 db at 10 Kc.
RUMBLE FILTER: 6 db per octave below 50 cps.
EQUALIZATION: Phono: "RIAA "; "EUR ";
Tepe: 344 and 754 ips, NARTB
TAPE OUTPUT LEVEL: 2 volts per channel.
POWER SUPPLY: Silicon diode, low impedance for minimum
distortion on extended high level passages.
EXTERNAL DESIGN: Gold and satin black hooded case, with
panel Illumination and satin gold panel.
DIMENSIONS: 153/4" wide x 113" deep x 5%" high
Model SA-40: Complete with case and step -by -step
assembly- operating manual
Kit Net Price $ 79.95
Model SA-40W: Factory Wired
Net Price $129.95
COMING SOON
-
MODEL ST-45
AM /FM STEREO TUNER KIT
matching companion
for the SA -40
AUGUST, 1959
63
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AUDIO
TAKE TWO MINUTES
DISCOVER THE
TO
SOUND BEYOND
CONVENTIONAL STEREO!
(Reading time: 2 minutes)
...
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cally illustrated by its space- saving size.
The entire system blends beautifully with
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Weathers TRIOPHONIC STEREO is
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Here's what the "Home Testing Laboratory" of MUSIC, U.S.A. recently
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"As we walked into the room, we were
directional hideaway bass.
immediately conscious that we had entered
This was the same
a new realm of sound':
kind of bass quality we'd heard before in
live performance, but never through playback reproducers -especially through
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The wonderful practicality of Weathers
TRIOPHONIC STEREO is dramati-
Write to Dept. A for FREE booklet on the full TRIOPHONIC story.
size full range stereo speakers and a non-
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SE -66
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THE SOUND OF TOMORROW, TODAY!
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WEATHERS INDUSTRIES, 66
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(front page 16)
TO BELIEVE IT!
Gloucester Pike, Barrington, N.J.
Division of Advonce Industries
Emport. Joseph Plasencia, Inc, 401 Broadway, New York 13, N. Y.
2. CARTRIDGES
In the general enthusiasm for our developing stereo equipment this last spring I
was given so many new stereo cartridges
to try out that I ended up more confused
than enlightened. Since my "testing" is
always strictly practical use and ear-listening, the thing to do was to put these cartridges to work and see what happened. I
hooked them all up into my interchangeable
plug-in (four -wire) system, tried a couple
in a changer, as well as in a manual turntable set -up, and went about my business
of playing records by the dozens -and listening, not to the cartridge but to the
music. That's what counts, after all.
I'm going to have to beg off any detailed
report on each one of these numerous excellent stereo cartridges; there were too
many for my ears. I'll offer a few generalizations, though, plus a few side -comments
on one or the other, and hope that the
persevering cartridge makers will forgive
me for having only one set of ears.
GE
General Electric is one up on me-the
company has brought out a new stereo
cartridge, the VR -22 type, before I so
much as got around to discussing the first
one. I haven't seen the new model but I
gather it is an outgrowth of the earlier
design rather than a wholly new departure
in cartridge construction -so perhaps my
remarks herewith will apply to the whole
present GE stereo lino of cartridges.
What I have to say is simple enough.
The GE magnetic cartridge has from the
beginning been aimed at a very specific
place in the phonograph world and has been
tailored with exquisite care to fit its basic
simple, efficient, mass -produced
purpose
cartridge that in volume production can
give a maximum value at a minimum price.
It takes a very large company to swing
a project of that sort and GE has the size
and the umph to do it. But as we all know,
the larger a mass- production project gets,
the more crucially important are the exact
details of the manufacturing process. Such
a product is 90 per cent designed around
production -quick, simple manufacturing.
The most minute details, even down to the
diamond point itself, must be planned for
volume operation. The tiniest miscalculation, from this special viewpoint, can spell
disaster on a relatively huge scale.
It has been GE's purpose and GE's accomplishment through these years to
achieve maximum cartridge value in these
very special ternis, as I see it. The intention is utterly different from that of a
cartridge such as, say, the Grado, which is
deliberately designed for top excellence on
an individual basis, virtually hand -made.
These differences in emphasis are little
known to the general public but every manufacturer knows them all too well. The very
first consideration in every piece of manufacturing design must be to choose the
-a
AUDIO
64
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AmericanRadioHistory.Com
AUGUST, 1959
exact area of contemplated production and
shoot precisely for it, down to the last
screw and wire and hunk of solder
any.
With this prelude, it seems to me that
we can look at the GE cartridge and see
precisely where it stands -today as in the
past. There was much initial criticism of
the GE stereo on the glaringly obvious
ground that the stereo model used basically
the same two coils as the mono version
before it and thereby sacrificed the obviously valuable hum- bucking qualities of
the double -coil arrangement.
Does anybody think GE didn't know
this? Don't be silly. Of course the GE design people knew all about it (or they
wouldn't deserve a grade -school diploma in
elementary science). But the likely alternative, a double -double -coil design, four coils
and dual hum -bucking, was one of those
fatal traps that GE unerringly avoided. In
the GE -type operation, this was just plain
out of the question. The added cost would
simply kill the basic concept of the cartridge, which is a simple product to sell at
a fabulously low price in huge volume.
Perhaps you'll remember the Model T
Ford and the old Ford idea that the $300
auto could be painted "any color so long
as it was black." Without implying any
direct comparison between GE and Ford
T, I suggest that the old Ford concept was
just as delicately calculated as the new GE
cartridge concept and that, in the old days,
the addition of rainbow colors to the
model T would have been basically just as
costly, as prohibitively uneconomical in
the manufacturing, as the use of double
coils in the original GE stereo model. After
all, how much Ford do you buy now for
$300 -or $600, taking account of the dollar's change?
Moreover, I suspect, and believe, that
GE did sonic marvelously careful calculating on this hum problem. It was a risk, a
neatly calculated one. I think I can get
away with saying that the first GE stereo
cartridge did, indeed, as I used it myself,
pick up stray bum noticeably more easily
than other cartridges, in the very same situations. Just move a hefty motor or a
sizeable transformer somewhere near that
cartridge and the hum rises up as clearly
as you please. No two ways about it, the
cartridge obviously was susceptible
susceptible -to a good deal of hum pickup.
But liete does it work out in. practice?
That is the real question.
It works out generally as GE must have
predicted- pretty darned well. As I reconstruct it, this must have been the sort of
canny thinking that went on chez GE.
1. The cartridge picks up hum, but in
most situations it won't pick up enough to
bother the average GE user, in all his
-if
-is
m
AMPEX
351
/
STEREOPHONIC
THE STANDARD THAT SAVES DOLLARS
Since its introduction, the Ampex 351 Series has been acknowledged as the standard of excellence in professional recorders for
the broadcast industry. Broadcasters -and other users with
highly critical recording requirements, such as recording studios
and educational institutions -will find that the purchase of an
Ampex 351 is further justified by these important facts:
The recognized precision and engineering skill which go into
each Ampex 351 guarantees unsurpassed durability and reliability
for a long, dependable life. As a result... on a cost- per-operatinghour basis. Ampex is the most economical of any recorder made.
PERFORMANCE SPECIFICATIONS
Note: As professional equipment, the Ampex 351 specifications listed are
accurate measurements required by NAB standards and do not incorporate
any exaggerated sales claims. These are the guaranteed minimum performance
specifications the customer can expect in long -ronge operation.
Frequency Response:
15 ips
71&
Flutter and Wow:
Timing Accuracy:
Starting Time
Stopping Time:
:
Models:
-
AUDIO
ips
±2db
±4db
30 to 15,000 cps
30 to 15,000 cps
± 2db 40 to 10,000 cps
15ips -well below 0.15% RMS
7h ips -well below 0.2% RMS
Within ±0.2°/0 ( ±3.6
sec. in a 30 min. recording)
Full speed in less than 1 /10 sec.
At 15 ips, tape moves less than 2" after pressing
"Stop" button.
Half track, full track,
2 track stereo (separate erase
to each track). Console, portable and rack mount.
FULL REMOTE CONTROL
The Ampex 351 Series can be operated in
the relay -solenoid tape motion control unit
for Start, Stop, Fast Forward, Rewind and
Record modes from any remote location.
:iIlionns.
2. The phonograph makers who install
GE cartridges themselves at the factorya major intention of such a cartridgewill be able to solve the hum problem reasonably well in advance of sale.
3. Most home listeners are conditioned,
and accept, a certain minimal hung. Them's
treasonable words, I admit, and they are
MONOPHONIC
There are 185 Ampex dealers to serve you. Check the
Recording Equipment listing in the yellow pages of
metropolitan area directories, or write Dept. 304 for
the name of your neorest dealer.
934 CHARTER STREET
REDWOOD CITY, CALIFORNIA
Offices and representatives in principal cities throughout the world.
AN PIEX
CORPORATION
professional
products
d i rision
..
.,
r
AUGUST, 1959
.
65
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DYNAKITS
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most high quality preamplifiers.
Only $12.95* net.
* PM -2S Panel mount kit provides
integrated handsome appearance
plus mounting facility -$5.95 net.
* CM -2S Cabinet Set includes
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$17.95* net.
cabinet.
Available from leading Hi -Fi dealers everywhere.
Descriptive brochure available on request.
Slightly higher in West
DYNACO INC.
617 N. 41st St., Phila. 4, Pa., U.S.A.
mine, not authorized by GE. It's just what
I think GE must have thought, in its private calculations. But the premise is valid,
if unpalatable. People do accept hum, because they've always had a good bit of it
around. I am astonished again and again
at the hum level in various commercial
phonographs-some of them right on the
dealer's floor. (One was set up for demonstration ill the main central office of a
huge national electric company. The company engineers with me at the time hastily
disclaimed responsibility ; it wasn't their
department.)
4. This is a really solid premise: There
may be practical hum problems here and
there, but technological progress in other
components will work to GE's advantage
and can be relied upon ahead of time.
GE could realistically count on steady
improvement in the radiation of hum from
motors and transformers, in all the minutely ingenious ways that good design
engineers can apply their skill to the
steady bettering of a manufactured product. Time, definitely, would favor GE.
5. And meanwhile, GE itself would work
on improvements of its basic design, via
experience and experiment, improvements
that could further whittle down the calculated risk without tossing out the basic
cartridge concept.
That's it, folks, I'm all for GE, then,
and in fact while I was away I hooked up
my original and early GE stereo cartridge
in a Glaser -Steers changer for my relatives
who took over my house for some weeks. It
sounded just fine and there wasn't a trace
of hum to be heard. Well, almost not a
trace.
Stereotwin
Only one mild and still unsolved problem with this useful German cartridge import. The rugged stylus assembly is of the
type where the stylus arm is set in a protective shell, a kind of half- circle, an open
tube extending out beyond the diamond tip.
This is fine insurance against the frighteningly -easy bending of the stylus that can
so quickly occur in these ultra -compliant
days. The fact that the whole assembly
pulls out of the cartridge is additional insurance-in case the stylus is forcibly
hooked into some unyielding surface such
as a turntable mat. The thing just yanks
out, and remains undamaged, compliance or
no.
My trouble with the Stereotwin was
simply in the fact that the half -tube protecting shell is small, and close to the
stylus itself. There is very little leeway for
play, either sidewise or vertically. Now I
don't mean to imply that the stylus can't
move the full width and depth of a stereo
groove -of course it can. But as we all
know, arm pull tends to displace a stereo
stylus to one side, even with the best of
care in the equipment. And, more vital,
variations in the stylus force applied
from above displace the point rather largely
in the vertical sense. Everything's fine when
the record is perfectly flat, the table precisely flat, too, the arm utterly free to move
sidewise with no measurable friction and
the point pressure exactly regulated to an
unchanging and rock -solid 3 or 4 grams.
But how often, my friends, do we achieve
this ideal in practice t
I found that my Stereotwin would produce clear musical sound at fantastically
low stylus forces-but thanks to the many
complications we run into the total armand- record assembly, at these delicate pressures it often skipped grooves, or repeated
grooves. Not the cartridge's fault, basically, but-shall I say -the situation. Especially in changers.
But when I increased the stylus force a
bit, the Stereotwin's stylus hit bottom
(top, more correctly) and buzzed against
its protecting shell.
The leeway, in my particular model,
between a pressure so light as to skip
grooves and so heavy as to cause stylus
bottoming on the shell, was uncomfortably
close. With a larger protective shell, the
stylus would have more room for displacement and could take a slightly greater distortion without hitting the shell -at a
greater risk of damage.
I would not want to apply my particular
experience to all Stereotwin cartridges
since my stylus may have been bent or loose
or something else, and I understand that
the newer version -the 210 -has this
trouble corrected. But the general principle is an interesting one, and I refer you as
a comparison to the Shure stereo cartridges,
which have a similar protecting half -tube
construction that is, however, larger and
further away from the stylus itself. Also to
the Stereodyne, from Dynakit. But -the
pay-off is that both of these cartridges
have suffered damage under the Canby program of Rough Treatment.
The Shure M3D, my most -used cartridge,
developed a permanent list to one side
after a few months -and I won't try to
tell you how I did it ; I don't know. But list
it did. However, the stylus tip did not hit
the protecting shell at any point. And
thanks to the great compliance and the
traction arrangement, like an old -fashioned trolley car pole on its wire, the
Shure stylus tends to straighten out in the
playing and tracks more or less where it
ought to, in spite of the list that shows up
when you look at it. The sound, to the best
of my knowledge, is unaffected.
My Stereodyne cartridge from Denmark
had an even larger protective shell around
the point-so large that the complaint bar
in that one was bent really haywire in my
first weeks of testing, to the point where I
did not care to use it on my good records.
My assisting engineer tried to straighten
it out and broke the thing off in the
process.
However, don't draw conclusions from
this experience since there have been
changes in this Stereodyne stylus since I
got my early model. No point in judging a
stylus via an assembly that is no longer in
production. I'll tell you later about the rest
of the Danish Stereodyne, which looks like
a rocket about to take off at a tangent, and
is an excellent and reasonably priced cartridge, one of the nicest I've tried.
AUDIO
66
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AUGUST, 1959
PRODUCT PREVIEW
A look into the future at the products you will find on dealers' shelves
during the coming months -some brand new, some being items introduced within the past few months, and some continuing their year- afteryear of success derived from reliable performance and user satisfaction.
to be an expanded NEW PROD section for this month completely exceeded
our expectations as to size. And while the sixteen pages originally intended to include all of this
material is well filled up, with more than nine columns
of runover commencing on page 105, we still have not
covered the entire field. The entire group of phonograph pickups and arms has been held over to provide
for another section in the September issue -not, perhaps, as large as this one, but in the same general style
and completeness.
On the subject of completeness, it is obvious that
every product of every manufacturer cannot be pictured and described
would more than cover all the
pages of this relatively large issue and still have plenty
left over. We have tried to cover some products from
each manufacturer-choosing those the manufacturer
himself wished to stress, or in some cases, just using
our own judgement as to the most important items. In
addition to the products pictured and described, several other items have been listed following many of the
descriptions, which makes this section one of the most
complete ever carried in a monthly magazine.
We have departed from our usual custom of not
WHAT STARTED OUT
listing prices in NEW
UCTS
PRODUCTS items because this
more in the nature of a catalog.
You will be able to use in it planning additions to your
present system or for planning a complete new system
for yourself or for someone else. We believe you will
find it useful as a reference all through the next year.
Since this is a catalog-type presentation, it must be
remembered that the statements made about the various products are not the result of our own testing, but
are the specifications as furnished by the manufacturer. And if you find some manufacturer not represented here although you know he makes products in
the specific categories, you may assume either (1) that
we may possibly have mislaid the material sent to us
for this section, in which case it will appear next
month, or (2) the manufacturer did not send us the
information requested, or (3)- perish forbid-we
overlooked that manufacturer completely when we sent
PRODUCT PREVIEW is
-it
out the requests for information.
We are sincerely grateful for the co-operation given
us by all the manufacturers represented. Without their
concerted help we could not have prepared this material. We trust you will find it interesting and informative throughout the year.
AMPLIFIERS and PREAMPLIFIERS
ACROSOUND
Ultra- Linear 60-Watt Power Amplifier KU.
The Ultra -Linear II meets the performance
specifications of the most demanding professional application or the most discriminating
music lover.
Embodying
the well -known
patented Ultra Linear circuit, it delivers full
output with less than 1.0 intermodulation at
any standard combination of test frequencies.
For either low- or high -power operation. the
Ultra -Linear II is unexcelled. Aero Products,
369 Shure Lane, Philadelphia 28, Pa. User
net price, $79.50. Assembled, $109.50.
Stereo 20 Self- powered 20 -w ampi. Kit $44.50.
Stereo 20A Satellite 20 -w ampi. Kit
$29.50
Stereo 20-20 36 -w stereo ampi. Kit
$69.50
ALTEC
work for "three -channel" stereo. Circuitry Includes feedback -type equalization plus feedback around all tubes for minimum distortion.
All low -level tubes have d.c. on heaters. Fourteen Inputs include two each for magnetic
cartridge, ceramic cartridge, tape head, tape
recorder, tuner, microphone, and multiplex.
Frequency response is 20 to 20,000 cps +1.0
db at 25 -watts output 10 to 30,000 cps +0.5
db at 10 watts. Harmonic distortion is -less
than LO per cent. Tone controls are ganged
and provide 14 db of boost or cut at 50 and
10,000 cps. Rumble filter attenuates at the
;
Stereo Amplifier -Preamplifier. This latest
addition to the Altec-Lansing line of high
fidelity equipment, Model 353 -A, is a complete amplifying system, embodying two 25watt stereo channels which may be combined
for 50 -watt monophonic operation when desired. Among its features is a matrixing net-
CONTENTS
Harmonic distortion is less than 1.0 per cent
at any frequency between 20 and 20,000 cps
at output within 1.0 db of 60 watts. Frequency response is within 1.0 db from 18 to
30,000 cps at full output. Square -wave response is entirely without distortion for all
practical purposes from 20 to 20,000 cps, with
no overshoot or ringing. Rise time of wave is
1.5 microseconds. Damping factor is variable
from 0.5 to 10. Damping control may be
switched out to provide a fixed damping
factor of 15. Hum is 90 db below 60 watts.
AUDIO
w
Amplifiers and Preamplifiers
AM, FM, and Stereo Tuners
67
Loudspeakers
Record Changers
74
79
Phono Turntables
81
Tape Equipment
Tape
Accessories
Miscellanous
71
82
110
111
AUGUST, 1959
rate of 12 db /octave below 30 cps. Silicon
rectifiers are used in power supply. Engineered
to the professional standards of other AltecLansing equipment, the 353 -A meets every
criterion of the most discerning music lover.
Altec Lansing Corporaton, 1515 S. ]Blanchester
Ave., Anaheim, Calif. User net price, $199.50.
355A "Quartet" 20 w mono ampi
$111.00
350A 100 w mono ampi
171,00
440c Mono preamp
147.00
345 60 w stereo ampi
270.00
445A Stereo preamp
189.00
67
www.americanradiohistory.com
AmericanRadioHistory.Com
ARKAY
Stereo Preamplifier- Amplificr Kit. A complete audio control center which offers exceptional performance, the Arkay CS -28
matches advanced engineering with excellence
of design which won the Fashion Foundation's coveted Gold Medal award. Identical
14 -watt
28 -watts
amplifiers may easily be converted to
for monophonic operation. Reverse-
stereo switch Interchanges channels when
desired. Balance control compensates each
channel for speaker systems and room acoustics. Gain control operates both channels
simultaneously. All of the front -end facilities,
including tone controls, are available at the
dual preamp output connectors. For tape
recording loudness and tone controls are bypassed by means of a panel- mounted switch.
Frequency response Is 20 to 20,000 cps within
+ 1.0 db. Intermodulation and harmonic distortion are under 1.0 per cent at rated output. Tone controls afford 16 db boost and
cut at 50 and 10,000 cps, respectively. Hum
and noise level is down 70 db at low-level
input. Radio Kits, Inc., 88-06 Van Wyck
Expressway, Jamaica 18, N. Y. User net
price, in kit form, $64.95 ; fully wired, $99.95.
49.95
Ampl- preamp
FL-30
36.95
20w stet ampl -preamp
CS -12
49.95
ampi
SPA -36 40w stet
BELL
tying system providing two 30 -watt channels
for stereo use, or 60 watts of output for monophonic operation. Harmonic distortion is under
1.0 per cent at full output. Frequency response
is 20 to 20,000 cps within 0.5 db. Featuring
many engineering refinements, the DB230A
has a six- position selector control for handling
inputs for tape. phono cartridge, tuner, or
other auxiliary equipment. The unit has volume, bass and treble controls and two hi -lo
filter switches. Special features are the Bogen
"Speaker Phasing Switch," which eliminates
the "hole-In- the -middle" effect that sometimes
occurs in stereo reproduction, a loudness contour selector for levelling out frequency response at low volume, and a control for balancing the two channels plus a channel -reverse
switch. Bogen- Presto Company, a Division of
The Siegler Corporation, Paramus, N. J. User
net price, $189.50.
D B212
$119.95
24w Stereo ampi
DE
Fifty-Watt
WALD
Stereo
Although
Amplifier.
modest in cost, the Model N -2200 "Classic"
embodies a complete stereo control system
and two power output channels with a combined continuous-power rating of 50 watts.
Included among features are separate equalization, selector, and mode controls offering
the user full flexibility of operation. Tape monitoring and tape -output jacks permit
output. Hum and noise level is more than 90
db below 35 watts. The use of prewired printed
circuitry, detailed step -by -step instructions
and pictorial diagrams, enables even the
novice kit builder to construct this amplifier
with complete confidence. Average construe-
tion time is about five hours. Dynaco Inc., 817
N. 41st St., Philadelphia 4, Pa. User net
price, including protective cover. $99.95.
$69.75
Mk II 50 w ampi kit
84.95
Mk Ill 60 w ampi kit
59.95
Mk IV 40 w ampi kit
34.95
Preamp kit, mono
12.95
Stereo control kit
8.95
Preamp power supply kit
EICO
Low -Coat Stereo Amplifier Kit. This new
Eico amplifier brings full stereo performance
to even the most budget -minded music lover.
It is engineered to provide true bi -fi quality
nt power levels which are adequate for driving high -efficiency speakers to concert volume.
The input selection, mode of operation. tone
and level controls insure complete flexibility
of operation. The AF -4 employs a moderate
single- ganged tone control so that available
gain. released by this type of control. is converted into distortion -reducing negative feed-
Stereo Amplifier. Developed for stereo from
input to output, the Bell "Carillon" Model
6060 is conservatively rated at 30 -watts output for each channel, with 60 watts of mono-
phonic power available when needed. Frequency response is stated by the manufacturer
to be 15 to 30,000 cps ± 1.0 db. Hum level is
71 db below rated output. All operating controls of the 6060 are conveniently located
across the front panel. Bass controls permit
15 db rise and 18 db droop at 50 cps ; treble
controls afford 9 db rise and 18 db droop at
10,000 cps. Also located on the front panel
are four lever-type switches which provide
high- and low -frequency filter cut-off (to
eliminate hiss and rumble), stereo function
control, and speaker selection for stereo in
more than one room. A separate balance control adjusts the volume level between two
stereo speakers. Continuously -variable loudness control compensates for bass and treble
at low listening levels. Dial frame is extruded
aluminum, while the panel has all the lettering etched for clarity. Vinyl tan cover is
set off by the perforated thermal duct which
provides ventilation. Bell Sound Division,
Thompson Ramo Wooldridge Inc., 555 Marion
Road, Columbus 7, Ohio. User net price,
$219.95.
$ 69.95
2212 "Pacemaker" 14w ster ampi
99.95
20w stet ampi
"
2221
55.00
10w ampi
"
2215
BOGEN- PRESTO
Stereo Amplifier-Preamplifier. The new
Bogen Model DB230A is a stereophonic ampli-
-
direct tape recording with complete control
of volume and tone. Individual bass and treble
controls are included for each channel. Sixteen
input jacks mounted in the rear of the amplifier are isolated from each other so that
any or all of them may be used at any time
without interference or signal loss. Output
circuitry utilizes four EL -86 tubes, with resultant intermodulation being well under 1.0
per cent at full output. De Wald Radio Division of United Scientific Laboratories, Inc.,
33-15 37th Ave., Long Island City, N. Y.
User net price, housed in an attractive black
picture -frame case with brushed -brass face
plate, $189.95.
N -1200B 30w comp stet ampi
S
99.95
back. The problem of distortion, created where
available gain is expended on severe bass and
treble boost, is thereby avoided. The feedback
level around each power amplifier is 27 db.
which results in intermodulation and harmonic distortion figures, taken at average
listening levels, which fall well within high fidelity standards. Front panel controls are:
input selector, mode, level, tone, and on -off.
Five pairs of inputs are provided for lowand high -gain program sources. A serviceselector switch permits parallel or separate
operation of the power amplifiers for stereo
or monophonic use, respectively. Exact engineering specifications were not available at
press time. Electronic Instrument Co., Inc.,
33-00 Northern Blvd., Long Island City 1,
N. Y. User net price, in kit form, $38.95 ;
factory wired, $64.95.
HF81 stet preamp -ampi
DYNAKIT
kit, $69.95 wired, $109.95
;
"Stereo 70" Power Amplifier Kit. This amplifier kit is designed to meet the needs of the
discriminating listener for a moderate -power
high- performance power amplifier. Engineered
for both stereophonic and monophonic operation, the Stereo 70 incorporates two 35-watt
channels which can be paralleled by means of
a convenient switch to provide 70 watts of
single-channel output. The high power capability and low internal impedance of the
amplifiers provide excellent damping for all
types of high fidelity speaker systems, including the low-efficiency types, without need
for individual adjustments. Frequency response
is + 0.5 db from 10 to 40,000 cps power response-20 to 20,000 cps without exceeding
1.0 per cent distortion within 1.0 db of 35
watts. Sensitivity is 1.3 volts rms for 35 watts
;
HF85 stet preamp
HF30 pwr ampi
.. kit, $39.95; wired, $64.95
....
FISHER
Stereo Master Audio Control. There is no
more versatile preamplifier- control unit than
the Fisher Model 400-CA. Capable of remote
operation when used with the Fisher RK -1
remote control unit, it contains 16 input jacks
for any combination of stereo or monophonic
application. Four output jacks are provided
and a total of 11 controls -including bass and
treble controls to provide independent regulation of each channel, or ganged control of
both channels-provide a shading of adjustment to satisfy the most demanding music
lover. Frequency response is uniform from 20
AUDIO
68
www.americanradiohistory.com
AmericanRadioHistory.Com
kit, $39.95; wired. $62.95
AUGUST, 1959
to 25,000 cps. Distortion is less than 0.15 per
cent for 2 volta output; less than 0.3 per
cent for 5 volts output. Hum and noise level
is down 65 db for 10 -mv low -level input and 2
volts output. Crosstalk between channels is
down more than 65 db. Cathode -follower re-
corder output, and low- impedance output to
amplifier-speaker system, permit output cable
length of 100 ft. without impairment of signal. D.c. is used on all heaters. Four switched
auxiliary a.c. receptacles on rear apron furnish
up to 650 watts for associated equipment. The
400 -CA will meet every demand of the most
discriminating connoisseu r. Fisher Radio
Corporation, 21 -21 44th Drive, Long Island
City 1, N.Y. User net price, $174.50.
101A 40w ster preamp -ampl
30C
ream
400CA ster preamp
SA -300 60w ster pwr amp'
194.50
174.50
169.50
GENERAL ELECTRIC
"Stereo Ciaaeic" Amplifier. The G -E Model
MS -2000 is an integrated unit combining a
high -quality stereo preamplifier with matching
power amplifiers on a single compact chassis.
Notwithstanding its moderate price, it leaves
nothing to be desired in audio performance.
Power output is 28 watts. 14 watts per channel In stereo operation. Frequency response is
20 to 20.000 cps ±0,5 db at rated output;
distortion is below 1.0 per cent. Hum and
quency response is 20 to 20,000 cps ± LO db ;
15 to 35.000 cps +1.5 db. A complete complement of controls -including remote balance
control on 20 -ft. extension -permits every
desired stereo function. Construction is greatly
simplified through use of printed circuit
control, permits variation of input to stereo
speakers. Push-button switches are used for
rumble and scratch filters, to disable loudness
control compensation, and for switching power
on and off. Tone controls provide 15 db of
boost or cut nt 50 and 10,000 cps. The 28PG
is fused and contains two convenience outlets.
Moderate in price, it offers an unexcelled
combination of fine performance at moderate
cost. Precision Electronics, Inc., 9101 King
St., Franklin Park, Ill.
GROMMES
Twenty -Eight Watt Stereo Amplifier. The
new Grommes Model 28PG is complete In
every respect, incorporating a full set of
ganged controls, two preamplifiers, and two
14 -watt power amplifiers that may be switched
to 28 watts of monophonic power when not
using stereo sources. Low-heat silicon rectifiers are used in the power supply. Frequency
response is within ± 0.5 db from 20 to 20,000
cps. Harmonic distortion is less than 1.0 and
intermodulation is under 2.0 per cent at full
rated output. Ten inputs accommodate virtually any type of signal source. Along with all
conventional adjustments, a channel- balance
AUDIO
;
WA -P2 preamp, mono
EA -2
12w ampi
W -7M 55w ampi
$ 19.75
28 »5
54.95
HARMAN -KARDON
KNIGHT-KIT
Stereo Amplifier-Preamplifier. The "Ballad"
Model A230 is a new stereo amplifier incorporating dual preamplifiers and dual 15-watt
power amplifiers on n single strikingly handsome chassis. It operates under the most conservative conditions, including self -bias of the
output tubes, assuring long trouble -free performance. The power amplifiers have instantaneous recovery time, resulting in clean and
faithful transient response. Among features
of the Ballad are friction -clutch tone controls
which adjust bass and treble separately for
Knight -Kit 40-Watt Stereo Amplifier. Both
economy and impressive performance are combined In the Knight -Kit 40 -watt stereo amplifier, a complete preamplifier and power
amplifier on a single chassis. Two 20 -watt
channels may be paralleled for monophonic
operation when desired. Frequency response
is 15 to 35.000 cps ± LO db
each channel and lock automatically to provide the convenience of ganged operation.
An exclusive speaker selector permits the operation of a third speaker as a "center channel" in a stereo system, and it also permits a remote speaker to be used monophonically at the same time. All are selectable
by front panel switches. Additional features
include illuminated push -button on /off switch
which permits the amplifier to be switched on
or off without disturbing control settings;
special tape outputs unaffected by loudness
:
noise level is down 55 db and 73 db on lowand high -gain inputs, respectively. Channel
separation Is better than 40 db over the entire
frequency range. Full -wave selenium rectifier
reduces heat. Front panel controls include
rumble filter and continuously- variable loudness contour adjustment. Tone controls are
of the variable turnover Baxandall type. The
MS -2000 is compact for all its power output,
measuring 5y."I1 x 15 "w x 12 "d (less knobs).
The cabinet is finished in leather -grain gray
vinyl. Front panel Is finished in darker gray
with satin silver trim. General Electric Company, Audio Components Products Section,
West Genesee St, Auburn, N.Y. User net
price, $129.95.
MS -4000 40 w ster ampi
$179.95
RG -1000 Remote stereo control
14.95
boards. Heath Company, Benton Harbor,
Mich. User net price, SP -2 Stereo Preamplifier,
$56.95 ;
SP -1
Monophonic
Preamplifier,
$37.95 C -SP -1 Conversion Kit, $21.95.
and tone controls ; speaker phasing switch;
contour switch balance control mode switch ;
function selector switch ; rumble filter ; impedance selector switch. Frequency response
is stated by the manufacturer to be 15 to
70,000 cps ± 1.0 db nt normal listening level.
Harmonic distortion is less than 1.0 per cent
nt full rated output. Harman-Kardon, Inc.,
520 Main St., Westbury, N. Y. User net price,
less enclosure, $109.95.
A220 "Lute" 20w ster amp!
79.95
;
;
HEATHKIT
Mono- Stereo Preamplifier Kit. This kit is
intended for those who wish to build a top quality monophonic preamplifier now, with an
eye toward converting to stereo in the future.
It is available in three distinct kits. It may
be purchased as Model SP -2, a complete versatile stereo preamplifier ; or as Model SP -1, a
at 10 watts output. In addition to offering all conventional
functions for 2-channel stereo, this unit provides a unique third, or "center channel"
output which permits feeding full-range program material to a center speaker for elimination of the "hole-in-the-middle" effect, or
for feeding an extension speaker for monophonic listening. Bass and treble controls offer
15 -db boost and droop at 20 and 20,000 cps,
respectively. Among other advanced features
are printed circuitry plus printed-circuit
switches for ease of assembly ; dual -concentric
clutch -type tone controls for individual or
simultaneous adjustment of the two channels,
and switch -controlled Fletcher -Munson -type
loudness control. Harmonic distortion is less
than 0.5 per cent at rated output. Allied
Radio Corporation, 100 N. Western Ave.,
Chicago 80, Ill. User net price (approximate),
$80.00.
20w stereo ampi
60w stereo pwr amp!
Stereo preamp
$44.50
84.50
62.50
LEAK
Newly-Styled "Point One" Stereo Preamp.
Impressive new styling enhances the appearance of the latest version of the well-known
Leak "Point One" stereo preamplifier. Decorator- designed, the new front panel offers
changeable color panels for both faceplate
and knobs, enabling the user to match the
decor of any room. The new escutcheon plate
is interchangeable with the present one, permitting present owners the option of inez-
high- quality monophonic preamplifier, which
may be converted to stereo bg means of the
Model CSP -1 conversion kit. To make the
conversion, no rewiring is required to the already existing monophonic channel. The conversion kit is simply wired and plugged into
the SP -1 chassis, which is designed to accept
the additional equipment. The control shafts
plug directly through the channel A control
knobs, allowing concentric operation of channel A and channel B controls. Six inputs are
provided for each channel -tape, magnetic
phono, microphone, and three auxiliary. Fre-
AUGUST, 1959
69
www.americanradiohistory.com
AmericanRadioHistory.Com
pensive conversion to the new styling. The
"Point One" includes provisions for playing
stereo, stereo reverse, left channel only, right
channel only, and monophonically. There are
five dual inputs for virtually any type of
stereo or monophonic source, including microphone. Bass and treble controls permit boost
and cut of 16 db at 30 and 15,000 cps, respectively. All controls are of the dual -ganged
type, operative on both channels simultaneously. Distortion is less than 0.1 per cent
for 1.25 -volt output. A balance control allows
for a great difference in sensitivity between
speakers. This new unit has been expressly
matched to all Leak power amplifiers. British
Industries Corporation, 80 Shore Rond. Port
Washington, N. Y. User net price, less cabinet,
$109.50.
$189.00
Ster 50 ster ampi
149.00
Ster 20 ster ampi
right speaker only; left channel on both speakers, and right channel on both speakers. For
monophonic operation, the C-20 internally
parallels and decouples a stereo pion cartridge to provide best possible reproduction
from monophonic records. A 2- position high frequency cut -off control (9 and 5 kc) is provided for suppressing hiss. Rumble filter rejects low- frequency noise. Treble control provides 13 db boost and 18 db attenuation at
20,000 cps; bass control provides 16 db boost
and 20 db attenuation at 20 cps. FletcherMunson -type "aural compensation" control is
continuously variable. The C -20 matches its
impressive performance with handsome appearance. McIntosh Laboratory, Inc., 4
Chambers St.. Binghamton, N.Y. User net
price, $225.00.
MC -30 30 w amplifier
MC -60 60 w amplifier
$143.30
198.50
MARANTZ
PACO
Stereo Console. The Mnrantz Model 7 is a
self -powered stereo preamplifier- control unit
which features n high order of versatility.
together with remarkable ease of operation.
It will deliver unexcelled performance when
used with either stereo or monophonic program sources. Typical of the quality inherent
in this unit is the volume control. Especially
developed for Mnrnntz. each control is individually tested for 2 -db tracking at any
point of rotation down to 65 db attenuation:
total range is 90 db. Separate step -type feedback tone controls with identical curves are
Sterco Preaunp-Amplifier Kit. The Paco
Model SA -40 consists of two 20 -watt amplifiers. each with its own preamplifier- control
system. on a single chassis. It is mounted
in an attractive gold and satin black case.
with satin gold panel to blend harmoniously
with all decors. The amplifiers deliver a true
20 watts output per channel due largely to
a well -regulated low -impedance power supply.
There is no clipping even on sustained high level passages. Distortion is kept to a minimum because of the unique main feedback
circuit which eliminates phase-shifting com-
incorporated in each channel. The steps are
in increments of 3.0 db at 50 cps and 21/2 db
nt 10.000 cps; both controls are removed
from the circuit in flat position. A full -range
balance control permits complete cut -off of
either speaker. Frequency response is 20 to
20,000 cps ± 0.5 db. Intermodulation and
harmonic distortion are reduced to negligibility. Hum is far below thermal noise. Nine
pairs of inputs and three pairs of outputs are
mounted on rear panel. The Model 7, while
not inexpensive, offers a measure of performance well in keeping with its price. Maranta
Company. 25 -14 Broadway, Long Island City
6, N. Y. User net price, less cabinet, $249.00;
cabinet, in mahogany, walnut or blond, $24.00.
1
2
5
$153.00
219.00
mono Audio Consolette
40w pwr ampi
30w pwr ampi
eiec x -over
4U 00
McINTOSH
as
Sterco Preamplifier -Control. Designated new
the Model C-20 Stereo Compensator, this
the
for
McIntosh development is designed
music lover who insists on the nearest possible
approach to perfection. Full stereo flexibility
is provided plus bult -in protection for the
-Freuser's investment in monophonic records.
quency response is 20 to 20,000 cps + 0.5"db.
rated outDistortion is under 0.2 per cent at
High put over the entire frequency range.
level-input hum and noise level is 85 db below
mode
-position
Six
volts.
2.5
rated output of
selector includes: stereo; stereo reverse; left
on
channel
right
only
channel on left speaker
;
1.11111111M
ponents. In addition to all the standard controls and switches the Model SA -40 includes:
two dual phono inputs to permit the use of
both record changer and manual turntable,
special switching which affords selection of
additional speaker systems anywhere in the
home, and Balance -Right and Balance -Left
test selector for a simplified aural check on
the balance of Iwo speakers for best stereo
results. Frequency response measured at 1.0
watt steady -state output is 30 to 90,000 cps
+ LO db. Intermodulation and harmonic distortion are less than 1.0 per cent and 0.2
per cent, respectively, nt full rated output.
The SA -40 is supplied with step -by -step assenility instructions and giant -size wiring
diagrams to ensure easy and successful assembly. PACO Electronics Company, Inc.,
70 -31 84th St., Glendale 27, N. Y. User net
price, in kit form, $79.95 ; factory wired,
$129.95.
PILOT
Introduced by
Pilot as being "as professional as a stereophonic preamplifier can be," the Model 216-A
offers virtually every facility which could be
desired for comprehensive audio control. Two
illuminated VU meters incorporated for InStereo Preamplifier -Control.
Channel A and high frequencies to Channel
13 for monophonic bi- amplifier use. Frequency
response is 20 to 20,000 ±1.0 db. Harmonic
distortion is 0.2 per cent below maximum
sensitivity. Audio output is 1.0 volt. Hum and
noise level is down 80 db. Professional in
both design and performance, the 216-A will
enhance the potential of any home music
system. Pilot Radio Corporntion, 37 -04 36th
St., Long Island City 1. N. Y. User net price,
complete with enclosure, $199.50.
240
245 -A
232
260
SP2I0
$129.50
199.50
89.50
139.50
89.50
30w ster preamp -ampi
40w ster preamp -ampi
40w basic ster ampi
70w basic ster ampi
ster preamp
PRECISE
Stereo Amplifier-Preamplifier. Containing
two individual amplifiers and preamplifiers on
a single compact chassis, the Integra Mark
XXIV affords stereo users two audio channels.
each with a continuous power rating of 20
watts. When desired the two channels may be
combined for monophonic operation with a
40 -watt power rating. Although low in Cost,
the Integra offers many features of higher priced amplifiers. Frequency response Is
stated by the manufacturer to be fiat from 18
to 20,000 cps, with harmonic distortion and
interntodulation less than 0.4 per cent and
0.6 per cent, respectively, at normal listening
levels. Separate boss, treble, and volume controls are supplied for each channel. A master
loudness operates on both channels simultaneously. A three -position contour switch
permits adjustment to room acoustics. Channel reversal is accomplished by means of a
panel -mounted slide switch. The Integra is
handsomely finished with a white and gold
contrasting front panel. Precise Development
Corporation, 2 Neil Court, Oceanside, N.Y.
User net price, $99.95.
SARGENT -RAYM ENT
Stereo l'rcatnplificr- Aoepliler. Developed for
use in advanced music systems, the S-R
Model 1717 meets professional standards
throughout. It is a combination on a single
chassis of two preamplifiers, including tone
controls, with a stereo power amplifier, each
channel of which is rated at 20 watts. All
controls are of the dual ganged type, affording
ease and accuracy of stereo tuning. A stereo
balance control provides equal volume from
both channels at any point in the listening
room. Type 7189 tubes are used in a highefficiency push -pull output circuit, delivering
less than 1.5 per cent Intermodulation and
less than 0.5 per cent harmonic distortion at
rated output. Bass and treble controls afford
up to 15 db boost at 40 and 10,000 cps,
respectively, with less than 1.0 db rise at mid frequency. Carbon -deposited resistors are
used in the preamp for minimum noise. Frequency response is within ± 1.0 db from 20 to
15,000 cps through the entire system with
tone controls set flat. A separate audio output is supplied from each channel for tape
recording. An 8- position selector switch con-
dicating tape recording output level, or for
visually balancing the channels of a stereophonic music system. Exclusive Trolok tone
controls permit treble and bass adjustment
for each channel separately, or ganging for
simultaneous adjustment. Fourteen inputs include two each for phono record changer,
phono turntable, tape head, microphone, FMAM, multiplex, tape recorder. Loudness contour control applies Fletcher- Munson compensation to both channels simultaneously.
Electronic crostover feeds low frequencies to
AUDIO
70
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
trola inputs and equalization for various
types of recordings. Sargent -Rayment Company, 4926 E. 12th St.. Oakland 1, Calif.
User net price, including attractive metal
housing, $189.60.
matched by its flexibility of operation, containing, as it does, control for most every
conceivable stereo or monophonic function.
Il. H. Scott, Inc., 111 Powder Mill Rond,
Maynard, Mass. User net price, $199.95.
SR -570
99D
222
70w basic ampi
ster preamp
-5100 100w ster basic ampi
119.50
163.50
183.60
SR2000
SR
250
130
135
H. H. SCOTT
Stereo Amplifier. The Scott Model 299 is a
complete stereo amplifier- control center. It
is conservatively rated at 40 watts and includes two complete channels with dual preamplifiers and dual 20 watt power sections.
III
Among its advanced stereophonic features is
a third -channel output for eliminating the
"hole-in- the -middle" effect. Separate bass and
treble controls are provided for each channel
to permit compensation for differences in
speaker characteristics. Low -level stereo cartridge inputs have 3.0-mv sensitivity for accommodation of pickups with very low output. Phase -reversal switch corrects for reversed phasing on improperly made tapes and
recordings. In addition to its function as a
stereo amplifier, the 299 can also be used as
an electronic crossover. Special balancing
circuit permits quick and accurate channel
balance. Preamplifier tubes have d.c. on filaments to minimize hum. Frequency response
of the 299 is stated by the manufacturer to
be virtually flat from 20 to 30,000 cps. Inter modulation and harmonic distortion are less
than 0.3 per cent and 0.8 per cent, respectively. Hum is stnted to he 80 db below rated
output. Technical excellence of the 299 is
22w comp amp!
24w comp ster ampi
40w pwr ampi
Ster preamp
Stereo - Daptor
$109.95
139.95
119.95
169.95
24.95
SHERWOOD
Stereo Amplifier -Preamplifier. The new
Sherwood Model S -5000 incorporates two
channels with a continuous power handling
capacity of 20 watts each. It permits either
20- watt -stereo, or 40- watt-monophonic operation with only one set of basic coordinated
controls, yet offers every important control
feature essential to both stereo and monophonic operation. These include 10 two channel controls, stereo normal/reverse
switch, phase inversion switch, and dual amplifier monophonic operation with either set
of input sources. All controls normally operate both channels simultaneously. In addition,
the bass and treble controls feature frictionlocked shafts which allow the adjustment of
each channel separately when desired. Also
provided is operation of a stereo phono cartridge playing n monophonic record with
vertical rumble and noise components balanced out. Frequency response of the S-5000
within ± 0.5 db. Harmonic
distortion and intermodulation are 0.5 and 1.5
per cent, respectively, at full rated output.
Styling and front-panel size are identical
with that of other Sherwood amplifiers and
the S-2000 FM -AM tuner (see Tuners on page
74). Sherwood Electronics Laboratories, Inc.,
is 20 to 20,000 cps
4300 N. California Ave., Chicago 18, 111. User
net price, less case, $189.50.
5 -1060
60w comp ampi
$149.50
S- 100011 36w comp ampi
109.50
S -4400
36w add -on basic ampi, ster
preamp
159.50
STROMBERG-CARLSON
Stereo Control Amplifier. The StrombergCarlson Model ASR -433 is n completely versatile antpli''er which can be used for stereo or
monophonic reproduction, or as an electronic
crossover for monophonic operation with a
tweeter and woofer. Each of its two chan-
nels has a continuous power rating of 12
watts with frequency range of 20 to 20,000
cps within ± 1.0 db. Intermodulation and
harmonic distortion are both under 1.0 per
cent. The exclusive Stromberg- Carlson "output balance signal" permits balancing of the
two channels by a signal tone. Each channel
has its own set of controls- loudness /volume,
bass and treble-plus a master gain control
which affects both channels simultaneously.
Full -frequency feedback provides minimum
distortion at all frequency levels. D.c. is
superimposed on all preamp filaments, bringing hurls and noise level down 63 db. Matching impressive performance with distinctive
appearance, Stromberg- Carlson amplifiers are
designed by Joseph Federico, one of the country's leading designers. Stromberg-Carlson,
Special Products Division, 1400 N. Goodman
St., Rochester 3, N.Y. User net price, $129.95.
ASR-333
ASR-444
ASR-434
ASR-422
24w ster ampi
60w ster ampi
ster preamp
40w ster pwr ampi
$
99.95
169.95
99.95
99.95
TUNERS
ARKAY
Van Wyck Expressway. Jamaica 18, N.Y.
User net price, $49.95 fully wired, $74.50.
;
Stereo -Binaural
ALTEC
AM-FM Tuner. Employing a fully shielded
extra large tuning capacitor directly mounted
to the chassis for perfect grounding, the carefully designed circuit layout and complete
isolation between transformers and power
mains in the 300A tuner reduce coupling to a
point that easily exceeds FCC radiation requirements. The FM section employs a Foster Seeley discriminator. "cascode" low -noise ri.
stage, triode low -noise mixer, n.f.c., and two
limiters. AM section lies three 1.f. trans-
Taner Kit. The Arkay
Model ST -11 is designed for simultaneous
reception of FM and AM broadcasts, or for
monophonic reception of either. In effect it
is two distinct self -powered tuners mounted
on a single chassis. Sensitivity on FM is 4.0
microvolts for 20 -db quieting. Three wide band high -gain i.f. stages and Foster- Seeley
discriminator assure excellent selectivity.
Image rejection is 30 db minimum. FM frequency response is 20 to 20,000 cps within
0.5 db, with distortion less than 1.0 per cent.
Variable n.f.c. adds to flexibility of FM tuning. Hum level is down 05 db. AM section
AM -5
FM -6a
HFT -7
FM -8
AM tuner
FM tuner
FM -AM tuner
FM tuner
$
29.95
25.75
32.00
39.95
BELL
AM-FM Stereo Tuner. One of the newest additions to the Bell line is the Model 3070 AMFM stereo tuner which matches in styling the
stereo amplifier of the sane company. This
unit features
automatic frequency control,
logging scale. multiplex output, and a stereo
selector switch which feeds either AM or FM
monophonic signal through both channels of
the stereo amplifier. or feeds both simultaneously to separate channels for stereo. FM
ecii,i
formers for flat pass bond, and sensitivity is
3 microvolts on an outside antenna and 50
microvolts with the built -in Ferrite loopstick.
Distortion is less than 1.5 per cent at 30 Per
cent modulation on AM and less than 1 per
cent at 100 per cent modulation on FM.
Cathode follower output. Altec Division, Ling Altec, 1515 S. Manchester Ave., Anaheim,
California. User net price, less cabinet, $199.50.
307A FM tuner
$96.00
AUDIO
features variable-bandwidth
1.f. stages, with
frequency response of 20 to 8500 cps in broadband position. Image rejection is 30 db minimum. A 10 -kc. whistle filter eliminates inter station interference. Features common to both
sections are adjustable grin control, flywheel
tuning, and edge -lighted 0-100 logging scale.
The advanced engineering features contained
in the ST -11 provide the custom builder a
stereo tuner of excellent sensitivity and flexibility of operation. Radio Kits, Inc., 88-06
AUGUST, 1959
Iia> a ,rm1Init ,d r; mir r olis for 20
db of aiuict ing, and image rejection is 28 db.
Hum and noise are 50 db below 100 per cent
modulator. The AM section furnishes a 0.1volt output signal from a 20- microvolt input
signal. while both channels give a 2.5-volt output at 100 per cent modulation at usual input
signal levels. Cabinet has unusually low silhouette, being only 43¢ in. high by 16 in. wide
and 11% in, deep. Bell Sound Division, Thompson Ramo Wooldridge Inc., 555 Marion Rd.,
Columbus 7. Ohio. User net price, $139.95.
2216 "Pacemaker" FM tar
$ 69.95
2222
"
AM -FM ster tnr
109.95
71
www.americanradiohistory.com
AmericanRadioHistory.Com
BOGEN- PRESTO
Budget-Priced Sterco Receiver. The BogenPresto "Challenger" Model RC412 is an
FM -AM stereophonic receiver with a dual
6- watts -per -channel amplifier which delivers
12 watts in monophonic operation. Frequency
response is 30 to 15,000 cps. Inputs are provided for magnetic and crystal phonograph
distant stations. A high Q filter eliminates
10-kc whistle while reducing response by no
more than 3.0 db at 9000 cps. A full -wave
rectifier and heavy filtering provides n stable
hum-free supply. R.f. and i.f. coils are supplied
pre-aligned so that no test instruments are
needed for satisfactory operation of the completed kit. Additional features Include slide rule dial. flywheen tuning, auxiliary output
for recording. and front -panel volume control.
Image rejection is 58 db. Precision tuning is
achieved by a traveling eye indicator which
contracts into an "exclamation point" at the
exact center of each broadcast channel. The
HFT94 is also available completely wired,
ready for installation. Electronic Instrument
Co., Inc., 33 -00 Northern Blvd., Long Island
City 1, N. Y. User net price, $39.95; fully
wired, $65.95.
HFT -90 FM tuner .. kit, $39.95; wired $65.95
HFT -92 AM -FM tuner kit, $59.95; wired, $94.95
cartridges, tape recorder, and auxiliary equipment. The receiver has built -in antennas for
foth FM and AM, as well as a connection for
outside antenna. A multiplex switch Is also
provided. Hum and noise level is down 58 db
on FM, 48 db on AM, and 45 db on all other
inputs. Distortion is 1.5 per cent on FM, 3.0
per cent on AM, and less than 1.0 per cent
ou phono and tape channels. Audio sensitivity
is 4.0 my for magnetic cartridge and tape
operation. Dimensions are 16'F- "w x 12% "d x
51/2 "h. Bogen -Presto Company, a Division of
The Siegler Corporation, Paramus, N. J. User
net price, less enclosure, $169.50; enclosure,
Basic
FM tuner
T661 Basic AM -FM tuner
ST662 AM -FM Stereo tuner
DE
WALD
Sterco Tuner. Modest price and good per-
3M microvolts for 20 -db quieting. Frequency
response is 20 to 20,000 cps and hum level is
stated as being 70 db below 1.0 volt. Response
of a.f.c. is +0.8 megacycles at 100 microvolts.
Output jacks include AM, AM -FM monophonic,
FM stereo, AM tape. FM tape, and multiplex.
The tuner is cased in an attractive black
picture-frame housing with brushed -brass face
plate. De Wald Radio Division of United
Scientific Laboratories, Inc., 35 -15 37th Ave.,
Long Island City 1. N.Y. User net price, including cabinet, $99.95.
EICO
Wide-Range AM Tuner Kit. The new Model
HFT94 is a basic AM tuner designed primarily
for high fidelity application. It matches in
size and appearance the EICO HFT90 FM
tuner. the two tuners making excellent companion units for stereo operation. The HFT94
offers a choice of wide bandpass to 14.000 cps
for high fidelity operation, or narrow bandbass
to 7000 cps when the objective is to receive
and reduced noise. General Electric Company,
Specialty Electronic Components Departtnent,
Utica, New York. User net price, $129.95.
GROM M ES
FM-AM Sterco Tuner. Matching the new
Grommet; "Premiere" series of amplifiers in
appearance, the new Model 103GT stereo tuner
features FM sensitivity of better than LO
microvolt for 20 -db quieting. The FM section
has grounded -grid input, tuned cascode r.f.
FISHER
$115.00
139.50
189.50
formance are combined in the De Wald Model
N- 1000 -B "Ambassador" FM -AM stereo tuner.
Included in the circuitry are eight tubes plus
diode detector and rectifier, with four stages
of i.f., including discriminator. Sensitivity is
interference suppression. Tuning meter indicates center- channel tuning on FM and peak
of AM signal, and there is no audible drift.
Circuit employs r.f. amplifier stage in both
AM and FM channels for increased sensitivity
Super- Sensitive FM Tuner. Introduced by
the manufacturer as the most sensitive FM
tuner In the world, the Fisher FM -100 requires only 0.4 microvolt for 20 db quieting
with a 72 -ohm antenna. Frequency response
Is 20 to 20,000 cps ± 0.5 db, with a 60-db
signal-to -noise ratio for 100- microvolt input,
and distortion is less than 0.5 per cent at full
modulation. The wide -band ratio detector,
$8.50.
FM51
200 microvolts /meter provide a 20 -db signalto -noise ratio. FM frequency response falls
within + 2 db of fiat from 20 to 15,000 cps,
while AM response is down 25 db at 10 ke for
using a matched pair of germanium diodes,
offers completely linear and distortion -free
operation entirely free of hum. Instantaneous acting dual dynamic limiter stages are highly
effective on any signal. whether strong or
weak, eliminating ignition interference and
other noise elements. A Multiplex Separation
control is included on the front panel, plus
Main and MPX channel positions on the selector switch. while power and electrical
connections and apace bave been provided for
simple plug-in installation of the Fisher
MPX-20 multiplex adaptor when desired. The
i.f. stages are flat- topped, with an unusually
wide band for maximum fidelity and minimum distortion, plus steep skirts to eliminate
adjacent- and second -channel interference.
Included in the circuitry of the FM -100 are
mixer-oscillator, the Fisher
a dual- triode
Micrognp cascode r.f. stage, four wide -band
Lt. stages, and a wide -band ratio detector.
Four controls on the FM -100 include Tuning,
Selector Switch, Muting Control, and Multiplex Separation. Fisher Radio Corporation,
21 -21 44th Drive, Long Island City 1, N.Y.
User net price, less cabinet, $159.50.
AM -FM ster tnr, preamp, and
600
20w ampl
$349.50
GENERAL ELECTRIC
AM -FM Tuner. Model FA -11 is a new unit
which features high sensitivity, precision tuning. and an unusually low hunt and noise level.
It is equipped with an FM multiplex jack for
reception of multiplexed programs when used
with an adapter. FM sensitivity is 5.0 microvolts for 30 db quieting. and AM signals of
stage, automatic frequency control. dual limiters, and broad -band Foster -Seeley discriminator. Matched crystal diodes are used for
detector. The AM section has variable i.f.
selectivity, infinite- impedance detector, and
10 -kc whistle filter. FM frequency response
is 20 to 20,000 cps ±0.5 db ; AM response is
20 to 7500 cps ±3.0 db in broad -band position.
Tuning meter, flywheel tuning, and slide -rule
scale simplify station selection. Output is provided for FM multiplex. FM distortion is reduced to negligibility at 100 per cent modulation. Push-button switches control tuning
meter, AM bandwidth, a.f.c. input, and power
off-on. Precision Electronics, Inc., 9101 King
St., Franklin Park, Ill. User net price. $201.95.
HARMAN -KARDON
FM -AM Stereo Tuner. Engineered as a companion piece to the H -K "Ballad" Model A230
stereo amplifier. the "Sonnet" Model T230
tuner incorporates separate AM and FM sections for receiving stereo broadcasts. A jack
in the rear makes it readily adaptable for
multiplex reception. The Sonnet employs a
consisting of
new low -noise front end
r.f. amplifier,
grounded-grid cathode -fed
and
r.f.
interstage,
double-tuned overcoupled
low -noise grid -fed triode mixer, followed by
transitionally- coupled i.f. stages. It uses an
Armstrong circuit with pentode limiter, wide band Foster -Seeley discriminator, and automatic frequency control. The AM circuit is a
superheterodyne with a.v.c. and a built -in
ferrite loopstick antenna. FM sensitivity is
3.5 microvolts for 20 db quieting; 7.0 microvolts for 30 db quieting. FM frequency response is 30 to 15,000 cps ± 0.75 db. Intermodulation is under 3.0 per cent at 100 per
cent modulation. Harman-Kardon, Inc., 520
Main St., Westbury, N.Y. User net price, with
enclosure, $114.95.
$114.95
T224 "Duet" AM -FM ster tnr
TA230 "Festival" AM -FM ster tnr, pre 259.95
amp -ampi
HEATHKIT
FM -AM Stereo Tuner Kit. Outstanding features in both circuitry and styling in the PT-1,
a 16-tube deluxe FM -AM combination, include:
AUDIO
72
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AmericanRadioHistory.Com
AUGUST, 1959
for FM -AM stereo
broadcasts. A cathode -follower multiplex output is provided for use when this form of
transmission becomes available in the listener's locality. An exclusive dynamic- sidebandcan he used simultaneously
regulation circuit controls incoming signal to
reduce distortion of very weak or over -modulated signals on FM. FM sensitivity is 2.5
microvolts for 20 -db quieting ; 4.0 microvolts
for 30 -db quieting. Circuit includes limiter detector with dual limiters, tuned r.f. amplifier, and switched automatic frequency conthree circuit boards for easy construction and
high stability ; wired, prealigned 3 -tube FM
tuning unit tuning meter a.f.c. with on -off
switch, and flywheel tuning. FM and AM
circuits are separate and individually tuned.
Cathode-follower outputs with individual
level controls are provided for both sections.
Other features include variable AM bandwidth. 10-kc whistle filter, tuned -cascode FM
front end, FM n.g.c. and amplified a.v.c. for
AM. Unique i.f. limiter design automatically
provides the number of limiting and l.f.
stages required for non -flutter reception of
weak or strong stations. Depending on signal
strength anywhere from one to four limiters
or i.f.'s are automatically. provided. FM
sensitivity is 2.0 microvolts for 20 -db quieting. Harmonic distortion is less than 1.0 per
cent. Frequency response is 20 to 20,000 cps
±2 db on FM. A jack is provided for use of n
multiplex converter without changing existing circuitry. The tuner is housed in a vinyl clad steel cabinet finished in black with gold
trim. Heath Company, Benton Harbor, Mich.
User net price, $89.95.
BC -1A AM tuner
$ 26.95
;
;
trol. FM frequency response is 20 to 20,000
cps ± 0.5 db. AM sensitivity is 5.0 microvolts
for 20 db signal -to -noise ratio. and frequency
response is essentially fiat from 50 to 7000
cps. Three -position variable- bandwidth i.f. is
employed in the AM section. A separate
cathode -ray tuning indicator is incorporated
for each tuner. Handsome in appearance, the
KN -125 will lend distinction to any surroundings. Allied Radio Corporation, 100 N. Western Ave., Chicago 80, 111. User net price,
$139.95.
LEAK
FM Tuner. The new "Trough Line II" tuner
matches in appearance the newly -styled Leak
"Point One" stereo preamplifier. Sensitivity
of L5 microvolts for 20 -db quieting makes
practical the reception of FM stations on
KARG
7'weive- Channel FM Tuner. Although similar basically to earlier versions of the Tunematic FM tuner, the new XT series embodies
a number of notable improvements. Up to 12
channels may be had in the new models, each
channel individually controlled by a precise
quartz crystal ground to military specifications. In effect, the Tunematic is a group of
fixed -frequency tuners mounted on a single
chassis. Other refinements in the newly -designed chassis include a volume control com-
considerable distances. Cathode- follower output delivers 1.0 volt and facilitates the use of
long output leads with negligible high frequency
attenuation. Automatic frequency
control is included in the circuitry for drift free tuning. A magic eye assures tuning
accuracy. Controls include on-off switch. a.f.c.
off-on, tuning, and local -distance. Chassis
dimensions
are
10t,ß "w x 7% "d x 33/4 "h.
British Industries Corporation. 80 Shore
Road, Port Washington, N.Y. User net price,
less cabinet, $129.00.
PI LOT
Stereo FM -AM Tuner. The Pilot Model 680
is a deluxe unit built to professional specifi-
cations, and which offers unsurpassed reception, even In difficult fringe areas. Its independent AM and FM sections may be used
individually for monophonic reception, or
simultaneously for stereo broadcasts. With an
external multiplex demodulator the 680 will
provide FM- multiplex reception. The FM
tuner section features 1- microvolt sensitivity
for 20 -db quieting. Freedom from drift is
assured by means of a temperature- compensated oscillator. Wide -hand detector (1000 kc
wide) makes tuning non- critical. Interstation
noise suppression (muting) is equipped with
control for defeat when desired. Audio output
Is constant and independent of signal level.
The AM section of the 680 has sensitivity of
2.0 microvolts /meter. It employs a germanium
diode detector for lowest possible distortion.
Featured is a high -gain pentode r.f. amplifier,
two steep -skirted i.f. stages with front -panel
band -width control, and a 10 -kc whistle filter.
A rejection trap is incorporated for i.f. interference. Separate precision tuning meters are
provided for FM and AM. Built -in ferrite core
antenna. Dual cathode followers permit long
output cables without signal loss. The 680 is
an impressive instrument in all respects. Pilot
Radio Corporation, 37-06 36th St., Long
Island City 1. N.Y. User net price, complete
with enclosure, $219.50.
690-A AM -FM ster tun, stet preamp .. $289.50
590
AM -FM ster tun, ster preamp .. 239.50
PRECISE
FM-AM Tuner. Despite its low cost, the
"Perfecta" is a tuner of distinctive appearance and excellent performance. Among its
features is a tuning meter which assures accuracy of station selection. Circuitry includes
McINTOSH
bined with power switch on the front panel,
and the use of silicon diodes to replace the
tube rectifier with the accompanying advantages of cooler operation and indefinite life.
Frequency response of the XT series is stated
to be 15 to 30.000 cps ± 0.5 db from antenna
to cathode -follower output. Intermodulntion
Is 0.5 per cent maximum at 100 per cent
modulation- The dial of each Tunematic is
custom tailored for the area in which it is to
be used. If the user moves, crystals can be
exchanged to cover his new location at no
extra cost. Karg Laboratories. Inc., South
Norwalk, Conn. User net price, including
ventilated metal cabinet, $199.50.
FM -AM Tenter. Developed for the connoisseur, the MR -55A tuner sets high standards in
distortion -free FM -AM reception. The FM
section has a sensitivity of 3.0 microvolts at
100 per cent modulation for less than 3.0 per
cent total distortion, using IHFM measurement standards. Distortion -free a.f.c. is completely variable. Hum is 70 db below full signal. Capture ratio is 1.0 to 0.8. Frequency response is 20 to 20.000 cps +3.0 db. I.f, bandwidth is 200 kc, flat on top. Silence between
stations while tuning is achieved by means of
cng^. $99.95.
SARGENT-RAYMENT
KNIGHT
FM -AM Stereo Tuner.
KN -125 incorporates two
a single compact chassis.
used individually for AM
AUDIO
The Knight Model
sensitive tuners on
The tuners can be
or FM reception, or
power transformer. with full -wave rectification. Output is of the cathode- follower type.
Included in the circuit are two limiters, a
Foster -Seeley discriminator, and a three -gang
tuning capacitor. A logging scale and flywheel
tuning assure precision tuning on both FM
and AM. Panel- mounted function switch affords selection of phono. FM, Alf, or TV.
Variable a.f.c. eliminates drift effect on FM.
Precise Development Corporation,
2
Neil
Court. Oceanside, N. Y. User net price, less
a
Stereo FM -AM Tuner. Strictly deluxe in
every- respect, the SR -1000 offers every feature
which could be desired in an instrument of
this type. Sensitivity of 0.85 microvolts for
20 -db quieting on FM is achieved by means of
McIntosh "Ultrasonic" muting circuit. AM
section features 3- position i.f. bandwidth control, with frequency ranges to 9500, 6500, and
2000 cps. Exceptionally strong a.v.c. assures
less than 4.0 db audio output change with
variation in input from 10 to 100,000 microvolts. Sensitivity selector has three positions.
1Vhistle filter has 70 -db rejecton at 10,000 cps.
Two tuning meters are incorporated in the
MR -55A, one each for FM and AM. McIntosh
Laboratory, Inc., 4 Chambers St., Binghamton, N.Y. User net price, $225.00.
AUGUST, 1959
73
www.americanradiohistory.com
AmericanRadioHistory.Com
advanced circuitry and use of a gold -plated
frame -grid cascode tube. Minimum AM distortion is assured through use of the wellknown S -R 2 -tube detector system. Two independently operated tuning indicators are
incorporated. FM frequency response is 18 to
22,000 cps ± 1.0 db. Distortion is less than
0.5 per cent at 100 per cent modulation. Drift
is negligible after 10 -sec. warmup period. The
S -R loopstick, said to be the largest produced
commercially, assures optimum AM signal -tonoise ratio. Variable band -width i.f. permits
wide-range reception on AM, also excellent
selectivity for distant stations. Whistle filter
gives 65 -db attenuation at 10 kc with no effect
at 8.5 kc. Cathode follower outputs are used
for both AM and FM. Sargent -Rayment Company, 4926 E. 12th St., Oakland 1, Calif. User
net price, $184.50.
SR -380 AM -FM tun, ster preamp .... $199.20
response from cross modulation by strong
local signals makes possible the use of this
tuner in any location, even close to FM transmitters. The AM section of the 330 -D contains n 3- position adjustable i1. bandwidth
wide- range, normal, and distant. A 10 -kc
whistle filter minimizes interstation interference. Low -impedance outputs permit installation of the tuner at any practical distance from the amplifier without signal deterioration. Separate outputs are incorporated
for tape recorder and for multiplex. Notwithstanding its compactness, the 330 -D is an
excellent performer in every respect. H. H.
Scott, Inc., 111 Powder Mill Road, Maynard,
Mass. User net price, $224.95.
$174.95
310C FM tuner
124.95
3110 FM tuner
139.95
320 AM -FM tuner
H. H. SCOTT
FM-AM Tuner. Featured in the Model S2000 II tuner is one of the most sensitive FM
circuits ever developed, permitting 20 db
quieting with only 0.95 microvolt signal input ; 3.6 tnicrovolts affords n signal -to -noise
ratio of 50 db. This unusual sensitivity makes
FM reception practical beyond 100 miles. In
addition, highly stable coil design, delayed
automatic gain control, and Foster- Seeley
type discriminator preceded by three limiters,
assure a minimum of distortion even with
modulation over 100 per cent. The AM section of the S -2000 II features a selection of
either a 15-kc wide "hi -fl" bandpass or a
FM -AM Stereo Tuner. The wide -range AM
section of the Model 330 -D tuner, plus n highly
sensitive, drift -free, wide-band FM section
make it an excellent choice for the reception
-
SHERWOOD
sharply selective 5 -kc bandwidth for listening
to weaker stations without noise and interference. A high -Q filter traps out 10 -ke inter-
of AM-FM stereophonic broadcasts. FM sensitivity is 1.0 microvolt for 20 -db quieting with
matched 72 -ohm antenna. Illuminated tuning
and signal -strength meter for both FM and
AM permits precision tuning of very weak
stations. Automatic gain control affords low
capture ratio, assuring rejection of interference practically as strong as the station
being received 80-db rejection of spurious
;
station whistle while reducing audio response
less than 3 db at 8 kc. A built -in ferrite -rod
antenna is pivot- mounted and may be oriented
for best reception of distant stations. FM
frequency response is 20 to 20,000 cps within
± 0.5 db. A multiplex output jack is provided
for connection to a multiplex adapter. Sherwood Electronics Laboratories, Inc., 4300 N.
California Ave., Chicago 18, III. User net
price, less case, $145.50.
105.50
5- 300011 FM tnr
STROMBERG-CARLSON
FM-AM 7'uncr. Engineered for easy, accurate tuning. the Stromberg- Carlson Model SR440 also features high sensitivity to provide
outstanding FM perfortnnnce in fringe areas
and to permit reception of distant AM stations. FM sensitivity is 0.9 microvolt for 20 -db
quieting. Wide peak -to -peak separation (550
kc), a long linear slope (350 kc) of the balanced-ratio FM detector, and low-noise
golden -grid cascode front end result in high
signal, low noise, and exceptionally stable
output. Improved temperature- controlled circuitry eliminates drift for all practical purposes. Frequency range on FM is 20 to 20,000
un AM it is _o io 7000 in broad band wid.h position. FM i.f. bandwidth is 20(1 kc;
AM is 15 kc b "ond. 8 kc sharp. The tuner is
well within FCC requirements for spurious
radiation. Distinctively styled with white
face plate and hu niched brass escutcheon and
knobs, the SR -440 matches its impressive performance with hand'ome appearance. Special
Products Division. Stromberg- Carlson, 1400
N. Goodman St., Rochester 3, N.P. User net
price, $159.95.
LOUDSPEAKERS
ACOUSTIC RESEARCH
"Acoustic- Suspension" Speaker
System. Selling for less than a hundred dollars, the AR -2 speaker system uses the ARpatented acoustic- suspension principle, in
which a small enclosure is accompanied by unproved rather than compromised reproduction
quality. In this design the speaker (woofer)
cone is mounted on very free suspensions, so
compliant that they are unable to provide the
elastic restoring force normally required of
Low-Cost
watts. Acoustic Research, Inc., 24 Thorndike
St.. Cambridge 41, Mass. User net price, in
mahogany or birch. $96.00 utility, unfinished
pine, $89.00; walnut or cherry, $102.00;
korina, $111.00.
AR -1 full -range spkr system, mah ... $185.00
145.00
AR-1W woofer only, mah
216.00
AR -3 full -range spkr system, mah
;
ALTEC
Economy Speaker System. The Monterey Jr.
is a compact moderately- priced system whose
quality of reproduction equals that of some
systems costing considerably more. A small
ruggedly -built bass reflex enclosure houses an
Altec 402A 8 -in. "controlled- linear-excursion"
speaker and the newly -designed 2000A direct radiator cone tweeter. Frequency range of
the Monterey Jr. is stated by the manufacturer to be 20 to 18,000 cps. and power rating
is 15 watts. Impedance is 16 ohms. A single
Monterey Jr. is excellent for monophonic
listen;ng, while two make an ideal medium pr'ced stereo system. It can be flush -mounted
in a wall or ceiling, or used in a console as an
integral part of a music system. Dimensions
them. The missing elasticity is then reintroduced by the pneumatic spring formed by the
air within the cabinet. The cone literally rides
on air instead of on mechanical springs. The
small enclosure size is necessary for optimum
performance. The AR -2 is a 3- speaker system
comprising a single woofer and two 5 -In.
tweeters. Frequency response is more than
adequate to cover the entire range of musical
instruments. Horizontal dispersion is 90 deg.
Dimensions of the AR-2 system are 131 "h x
1156"d x 24 "l. Recommended for use with
amplifiers having power output of 20 to 40
are 111/4"h x 23 "w x 1134"d. User net price,
in walnut. blond or mahogany, $79.50 unfin;
ished,
7003
830A
832A
833A
605A
$69.50.
"Melodist" system
"Laguna" corner spkr system
"Ccrena" corner spkr system
"Verde" spkr system
Duplex 15" loudspeaker
$126.00
599.00
399.00
309.00
177.00
AUDAX
Multi- Speaker Systems. Designed by George
Nelson. one of the country's leading furniture
and industrial designers. the new Audax
speaker series brings a distinctive blend of
beauty and functionalism to component high
fidelity. "The idea behind the Audax speaker
systems was to make them interesting, exciting furniture pieces. beautiful in appearance
as well as sound." said Mr. Nelson. The
Audax cabinets are finished on all four sides,
to be used as wall units or free standing. Each
model Ices detachable legs and a new type of
speaker grille, a three -dimensional "acoustical
screen" which can be removed easily for
cleaning. Model CA -80 contains two 8-in.
extended -range speakers. Model CA -100 has
AUDIO
74
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
two 10 -in.
Both units
ance. Both
ment, and
woofers, plus two cone tweeters.
are identical in external appearare intended for bookshelf placealso may be used as floor units.
Both systems use Audax "Pernfiex" speakers,
a patented new design with many innovations, giving a sound quality which is smooth
and natural. Audax, Inc.. Division of Rek -OKut Company, Inc., 38 -19 108th St.. Corona
68. N.Y. User net price for the CA-80 is
$99.95; for the CA -100. $139.95.
three drivers to provide a measure of performance which is hardly believable in a system of such compact size. The diffraction
horn employed on the tweeter makes the
Esquire 200 ideal for use in pairs for full range stereophonic reproduction. Supplied in
AUDIO -TECH
Wide -Range speaker System. Although extremely compact. the Audio -Tech Model 1[íE12
has a frequency range of 37 to 20,000 cps.
BRADFORD
Containing a 12 -in. woofer and a 3 -in. cone type tweeter, it incorporates a special calibrated level control for high -frequency balance. Colored binding posts permit easy determination of polarity for connection in
stereo music systems. The speakers are fused
to prevent damage from accidental overload.
Enclosures are made from selected walnut,
mahogany and fraitwood, with a handsome,
hand -rubbed nil finish. Audio -Tech Laboratories, 3420 Newkirk Ave., Brooklyn 3, N.Y.
User net price. $99.50.
BOZAK
Small Speaker System. The Spinet, a new,
small speaker system has been introduced by
Bozak to meet the needs of listeners who have
a pronounced space problem. Measuring a
compact 140,4 "b x 23',4 "w x 111/2"d, it has a
Compact Wide -Range Speaker Enclosure. The
Bradford enclosure. made in four sizes for 8-,
10-, 12 -, and 15 -in. speakers, is only two inches
larger titan the speaker it contains. Its construction is based on n variable-damping
principle, in which speaker damping is varied
automatically by a pressure relief valve in the
rear of the cabinet. Operation of the valve is
coordinated with cone excursion. In reality,
it is an "acoustic spring" acting uniformly
over the entire rear surface of the cone.
Boontiness and the effects of cabinet resonance
are virtually eliminated. The Bradford enclosure will enable the user to realize the potential of most any speaker with which It is used.
Bradford Audio Corp., 27 E. 38th St., New
York 16. N.Y. Prices of the Bradford enclosure range from $39.50 to $69.50, depending
on size and finish.
2 -126 Spkr system, mah
$250.00
4 -12B Spkr system, mah
525.00
COSMOS'
hand- rubbed hardwood veneers, it will add
distinction to even the most tasteful surroundings. Available in walnut, mahogany,
or limed oak. Electro- Voice, Inc., Buchanan,
Mich. User net price, $111.00.
Thirty -Inch Woofer. This is the world's first
mass-produced 30 -in. loudspeaker. Engineered
expressly for use in the well -known E-V
"Patrician" 700, the Model 30W is also highly
recommended for use in any custom installation of exceptional quality. The speaker
frame is a massive one -piece rigid casting
which supports a true piston formation cone.
"AH!"
Electrostatic
Mid -Range
Speaker /Super
Tweeter. Frequency range of the "eh !" extends from 600 cps to well beyond the limits
of audibility. It mates easily and quickly with
any woofer or full -range speaker to provide
extended high- frequency response. Two push-
pull capacitor elements give direct radiation
over a full 120 -deg. arc. Polarizing voltage is
supplied by a built -in fused 1000-volt power
supply which consumes practically no current
and may be left permanently connected to a
117 -volt 60- cycle line. Crossover network is
self-contained. Recommended crossover frequency is 650 to 850 elm. The "ah !" may be
paralleled across any conventional woofer
without additional network. Two "all "s may
1w used in conjunction with n single woofer
for One Were., reproduction. Supplied in cabinet with hand -rubbed walnut finish. Other
finishes available on special order. Cosmos
Industries, 31-28 Queens Blvd., Long Island
The cone in itself is revolutionary, being a
one -piece molding of polystyrene foam manufactured by a newly -developed injection -forming process. The 30W is capable of reproducing boss tones in the range of 18 cps with
earth -shaking reality. While these tones do
not exist in pure form in commercially recorded music, there are undertones and
sub -harmonics in this area which add distinctly to realism in reproduction. ElectraVoice. Inc., Buchanan, Mich. User net price,
$139.00.
FRAZIER
!
naturalness of response in bass, mid -range
and treble which is compatible with the larger
Bozak speaker systems. The Spinet is available in two models the two -way B-500 system, and the three -way B-502 system. Both
models utilize the same finely- constructed,
integrated components found in larger Bozak
systems, and upon which the Bozak "Systematic Growth" idea is based. This latter enables users to start with a modest installation. and then to "build" on it as they desire,
without having to replace initial components.
The Spinet is available finished in mahogany,
blond, walnut. or ebony, or unfinished for
those who wish to match the cabinet to an
existing decor. R. T. Bozak Sales Company,
Darien, Conn. User net price B -500, $134.50;
B-502. $209.50.
:
AUDIO
City
1,
N.Y.
Compact Two-Way Speaker System. The
Monte Carlo. the newest and smallest Frazier
two-way speaker system. is made to order for
stereo. Measuring only 15%"w x 10%"h x
115ín "d, its size permits its use as n bookcase type speaker, and it is the most economical of
all Frazier models for starting a stereo sya-
ELECTRO -VOICE
Ultra- Compact Spro her- System. Economy is
preserved without any sacrifice of performance
or appearance in the E-V "Esquire" Model
200. The latest addition to the broad E -V line
of ultra- compact systems. it is a full 3-way
system using specially designed and coordinated components. Bass is delivered from a
highly-compliant 12 -1n. woofer with a long throw voice coil. An S -in. cone driver is incorporated for smooth mid- range, and the
E -V Sonophase -throat-design tweeter handles
the very highs. The acoustically- correct enclosure is coordinated in design with the
AUGUST, 1959
75
www.americanradiohistory.com
AmericanRadioHistory.Com
tem. It employa a modified Helmholtz -radiator
principle, and has a frequency range from
below 70 to 15,000 cps. Power handling capacity is 12 watts continuous. Tweeters are
mounted for right and left placement for
stereo. The cabinet is equipped with two
concealed plastic feet and is finished in hand rubbed natural walnut. The Monte Carlo is
shipped two to the carton, matched for stereo.
International Electronics Corporation. 2649
Brenner Drive, Dallas 20. Tex. User net
price, the pair, $99.50.
$125.00
Cortez 2 -way spkr sys
59.50
Scotsman 2 -way spkr sys
79.50
Del Mar 2 spkr sys
GENERAL ELECTRIC
members are heavy castings. Manufactured in
England. Goodmans speakers are distributed
in the United States by Rockbar Corporation.
Mamaroneck, N.Y. User net price, Model 575
with 50 -watt power handling capacity,
$232.50; Model 355, saune but with 40 -watt
power handling capacity. $196.50.
15" 3 -way spkr
615
755
15" woofer
H750 "Midax" mid -range driver
$147.00
78.00
58.50
HARTLEY
Compact Full -Range Speaker System. The
Hartley "Capri" comprises a full -range full size speaker mounted in a handsome natural
wood cabinet which measures 24 "w x 131/2"h x
12 "d. The grill is made of bamboo, adding a
Two -Way Speaker System. Engineered
for high -quality sound reproduction in a limited space, the Model G -501 is a new, comG -E
pact speaker system announced only recently
by General Electric's audio components section. Termed a "stereo- compact" system, the
G -501 will deliver excellent audio performance, yet is only 22 "w x 13"h x 9 "d, true
bookshelf dimensions. The new unit is based
on GE's extended -bass design, and has a
woofer, tweeter, and electrical crossover network all housed in a dramatically styled enclosure. The G -501 presents a departure from
previous G -E speaker systems, blending rich
wood finishes, new grill patterns, and greater
use of metal trini. User net price, $85.00.
GOODMANS
Four -Way Speaker System. Built to a standard of high quality without compromise, the
new Goodmans "Tetraxiom" is a unitized 4way speaker featuring the "Rigidflex" cone,
a flexible free -floating cone rim and rigid
cone center to provide pure piston action.
The Tetraxioms have high power capacity
and smooth response from 20 to 20,000 cps.
with usable response to 35,000 cps, according
to the manufacturer. They are composed of
four independent, concentrically-placed radiators, each of which is designed for maximum
performance and efficiency within its portion
of the spectrum. In addition to the Rigidflex
woofer, the Tetraxiom contains a rear- driven
"Midax" mid -range radiator, and two pressure- driven horn -londed high -frequency "Trebax" tweeters which are angled to the polar
axis for wide dispersion of the highs. Because
of the massive nature of these speakers, and
the need for absolute rigidity, all structural
note of distinction to the appearance. The
driver has n "polymerized" cone developed by
Hartley engineers for rigidity and extreme
lightness. Audible response extends from
30 to beyond 16.000 cps. The Capri cabinet is
filled with 35 linear feet of absorbent material to form in effect a "tunnel" 10 feet
long. Hartley Products Company. Inc.. 521 E.
162nd St., New York 51, N.Y. User net price,
$120.00.
$ 72.50
217 full -range spkr
217 -Duo enclosure
146.00
JANSZEN
Wide -Range Speaker System. The Z -400,
an inexpensive wide -range speaker system,
marks the first time that the well -known
.iansZen electrostatic tweeter has been available in a compact, shelf -mounted enclosure.
In the Z -400 the JansZen is acoustically
paired with the Model 350 11 -in. dynamic
woofer. The high -compliance cone of the 350
is specially treated to provide low- frequency
reproduction which perfectly complements the
JansZen tweeter. The Z -400 is stated to cover
the range from 30 to beyond 30.000 cps with
exceptional uniformity and low distortion.
Tweeter and woofer are integrally mounted
in a totally- enclosed Fibreglas -filled enclosure
which may be placed vertically or horizontally
as desired. A built -in power supply and high pass filter furnish power for the two push pull electrostatic elements, and eliminate the
external crossover networks and
attenuators. The Z -400 measures 15 "h X
26 "w x 13tf "d, and is available in walnut,
need for
mahogany
ISOPHON
Three -Channel Four- Speaker System. Made
in Western Germany by a foremost manufacturer of speakers and speaker systems, the
Isophon III is a superb instrument utilizing
a woofer. a mid -range compression type driver,
and two tweeters. Matched through a universal transformer and special divider network, this combination assures utmost compensation and tonal balance at all intensity
levels and uniformity of response over the
frequency range of 30 to 17,000 cps. The
and birch
finishes.
Neshaminy
Electronic Corporation, Neshaminy, Pa. User
net price, $134.50.
JENSEN
Speaker System. The new
Jensen "Galaxy II" speaker system achieves
wide panoramic stereo sound with two tiny
satellites and a single small bookshelf -size
unit. The latter, which is called the "bass
center" speaker, may be placed on floor or
shelf wherever convenience and decor dictate.
Finish on all four sides allows vertical or
horizontal positioning. The Jensen "Flexair"
high -compliance woofer has unusually low
resonance and is capable of total motion of
sÿ in.. providing clean bass as low as 3G cps.
The small satellite units handle midrange and
high frequencies. Their placement is not critical so long as they are placed to the left and
right of the center unit. They may be spaced
as much as 20 feet apart and still provide
stereo sound with excellent spacial center -fill.
The Galaxy II system provides the equivalent
of two complete 3 -way speaker systems with
the added feature of a "derived third channel"
for eliminating the "hole-in- the-middle" effect.
The Flexair woofer is driven by two voice
coils, one for each channel of the stereo system. Frequency range of the complete system
Is 36 to 14.000 cps and power rating 25 watts.
Jensen Manufacturing Company, 6601 S. Laramie Ave., Chicago 38, III. User net price, in
"Satellite"
Stem-co
handsome hand- crafted cabinet is designed on
the distributed -port principle. The 25 -watt
woofer has n frequency range of 30 to 8000
eps. The mid -range unit corers 1000 to 10,000
rya. while the tweeters extend from 4000 to
17.000 cps. Enclosures are available in either
light Isophon Arizona finish or in dark English mahogany. Isophon Speaker Division,
Arnhold Ceramics, Inc., 1 E. 57th St., New
York 22, N.Y. User net price, $295.00.
$169.50
IV
3 -way, 4 spkr sys
102.50
P38 15" woofer
49.45
P37 12" woofer
8.15
P16 6" mid -range spkr
7.15
P6
21/z" tweeter
AUDIO
76
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AUGUST, 1959
walnut, tawny ash or mahogany, $109.00; the
same assembly is available unfinished in kit
form, $92.50.
SS -100 Stereo -Director 3 -way system
DS -100 Dual Stereo 3 -way system
.
CN -100 12" 3 -way system
P12 -NF 12" Flexair woofer, low res
$179.95
369.50
149.50
42.00
-
KLH
size suitable for the average living room. The
Paragon measures 8' 10" in length
the
smaller Metregon
similar type of cabinetis 6'2"; and two Minigons measure 5' 4" in
length, with a height of 12h" and a depth
of 15% ". Two styles are available, louvered
LAFAYETTE
-a
Bookshelf Speaker Enclosure. This cabinet
is engineered to obtain optimum performance
from any 12-in. wide -range speaker or 12-in:
woofer -tweeter combination with no loss in
speaker efficiency. Although the design is
basically that of the family of "reflexed" or
;
(as shown) or with grille cloth. Both are
designed to accommodate the Linear Efficiency speakers, with either the 8" model
being used alone, or with a 10" cone (LE10)
used in conjunction with an LE30 high frequency driver and an LX3 dividing network
system designated S -5. James B. Lansing
Sound, Inc., 3249 Casitas Ave., Los Angeles
39, Calif. User net prices Minigon enclosure
alone, $120.00; with LES speaker installed,
(D46LE8) $177.00; with S5 system installed
(D46S5), $243.00.
LE10 10 -in. I.f. driver
$52.80
Model Seven Speaker System. This is the
newest in the KLII line of integrated speaker
systems. Enclosed in a sealed cabinet matched
to their acoustic requirements are a 12 -in
acoustic -suspension woofer and two newly-
-a
:
LE30 High -frequency
LX3 Dividing network
driver
52.80
I7.40
NORELCO
Speaker Series. Illustrated is Model AD5277M, the most powerful in the new T -7
series of twin -cone speakers manufactured by
Philips of The Netherlands, and featuring
Ticonal 7, a high- coercivity alloy which provides the highest possible concentration of
flux densities in the voice -coil air gap. Weight
for weight. Ticonal 7 is said to be about 30
per cent more powerful than any of the conventional magnet materials used in speaker
construction. Voice -coil impedance of the new
T-7 speakers is held constant throughout the
"ported" enclosures, there are two unique
departures. These are an elliptical port and a
triangular-shaped diffracting ring mounted
on the front of the baffle board. These features
serve to broaden the frequency response, improve transient response, and create a "lens"
effect, changing relative particle velocities
and, consequently, phase relationships so as
to produce a smooth transition from front
to rear radiation. Lafayette Radio, 165 -08
Liberty Ave.. Jamaica 33, N.Y. User net price,
designed director -radiator tweeters. A built -In
L -C crossover network contains a 3-position
switch for increasing or decreasing high frequency level by 3.0 db. Enclosure volume
is 2.6 cu. ft. Full -range frequency response
of the Model Seven permits reproduction of
the entire musical spectrum with a degree of
realism which is unsurpassed. Power handling
capacity is 75 watts of program material.
Impedance is 8 ohms. Dimensions are 261/4"11
x21 % "wx11?{, "d. KLH Research and Development Corporation, 30 Cross St., Cambridge 39, Mass. User net price, walnut ana
oiled- walnut finish, $203.00; unfinished walnut, $198.00; mahogany and korina, $196.00;
unfinished birch, $189.00.
FOUR 2 -way spkr sys, mah
$209.00
SIX
2 -way spkr sys, mah
$32.50.
JAMES B. LANSING
"Linear Efficiency" Speakers. The Lansing
Model LES is n remarkable new full -range
transducer of unicue design. Engineered
specifically for small enclosu.es or infinite
baffle mounting, the performance of the LES
in an enclosure of only 1 cu. ft. is outstanding. Smallest of the new JBL "Linear Efficiency" components, the LES delivers full
bass by means of its exceptionally long linear
119.00
KINGDOM LORENZ
Wide -Naupe 12 -in. Speaker. Although modestly priced, the Kingdom Lorenz Model S1288 offers no compromise In impressive performance. When properly housed it has a
travel. It will produce high sound intensity
in a large room when driven by only 1.0 watt
of amplifier power. Voice -coil diameter is 2-in.
and free -air cone resonance is 37 cps. Power
handling capacity is 20 watts continuous. For
excellence of performance in n compact enclosure. the LES is unsurpassed. James B.
Lansing Sound. Inc.. 3249 Casitas Ave.. Los
Angeles C9. Calif. User net price. $57.00.
frequency range of 18 to 1:-..000 cps because
of dual -cone construction. Fully tropicalized
for operation In any climate, it is built on a
non -resonant
cast -aluminum
girder -constructed frame. Twin voice coils have impedance of 4, 8, or 16 ohms one coil may be
connected to each of two stereo amplifiers to
provide a common woofer for the two channels. Magnet assembly weight is 61.5 oz.
Power rating is 30 watts peak. Kingdom
Products, Ltd., 514 Broadway, New York 12,
N.Y. User net price, $44.50.
Omega -1 sys w /12" woofer, 2 tw
$109.50
Kai Audette sys w /8" spkr, tw
49.50
Audette Sr. sys w /8" woofer, tw
69.50
"Minigon" Loudspeaker Housing. One of
several types of cab:nets designed to match
the Linear Efficiency components, the JBLRanger Mingon serves as an ideal unit for
monophonic reproduction. and when placed
end -to -end as a pair brings the principle of the
well -known JBL- Ranger Paragon down to a
entire frequency range by means of a copper
ring fitted into the air gap. The ring acts as
a shorted turn which induces a current opposite in polarity to that flowing through the
voice coil, which reduces that current, thereby
lowering the impedance to its proper level.
The resonant frequency of the T -7 speakers is
very low, resulting in an extremely straight
response curve in the bass region. In addition to the cone for low and middle notes,
the speakers are equipped with a high -note
cone which extends the upper frequency
range. Model AD -5277M is a 12 -in. speaker
with a frequency range of 35 to 18,000 cps
and 20 -watt continuous power handling capacity when properly housed. Cone resonance
is 35 cps. High Fidelity Products Division,
North American Philips Company, Inc., Hicksville, N. Y. User net price, $72.50
Integrated spkr sys
$150 -160
1
2 End for 8" spkrs
3
50-60
End for 8" spkrs
31 -35
RJ
RJ /Wharfedale Speaker System. Combining
the RJ /8 enclosure with the Wharfedale Super
8 /FS /AL speaker, this compact assembly Is
;
S888
8" wide -range spkr
AUDIO
AUGUST, 1959
21.50
ideally suited for stereo music systems. The
EJ enclosure, when it was introduced six
years ago, established an entire class of products. Tite RJ is distinguished from all other
small -size speaker enclosures by a unique internal design, which is covered by two U.S.
77
DUAL
Deluxe Changer -Turntable. The United
Audio DUAL -1006 is a precision -built machine
in all respects. It will track and operate automatically with stylus force as low as 1.5
grams. Operating at all four standard speeds,
It in.,,rparates a motor of unusually high
MIRACORD
GLASER -STEERS
Stereo Record Changer. The GS Seventy completely
Seven is precision -engineered,
automatic in operation, and offers new features and refinements which enhance the enjoyment of stereo records. at the same time
allowing enjoyment of monophonic records to
the utmost. Stylus force is variable over a
wide range with easily accessible vernier adjustment. Variation of stylus force between
first and last record on n stack is less than
0.9 grain. The damped. acoustically isolated
tone arm is not resonant within the audio
power, assuring Constancy of speed under any
normal load condition. Field coils are tropical ized, and thorough shielding prevents hum.
The lightweight tone arm is of one -piece construction and is equipped to accommodate interchangeable cartridges by means of a lock ing -key snap-in arrangement. Direct set of
ball bearings in both axes insures freedom of
lateral and vertical motion. Finger -tip stylus force adjustment is mounted directly on the
tone arm assembly. Patented roller-feeler
guide in the tone -arm head permits the 1006
to operate automatically and intermix, regardless of record size. Fast change -cycle time
is constant irrespective of operating speed. A
stereo -mono switch introduces a phase- cancelling feedback circuit to remove vertical signal
when stereo cartridge is used to play monophonic records. Notwithstanding its many
features, the DUAL 1006 is simple to operate,
only three push buttons being used to govern
start, stop, reject, and repeat functions. A
muting switch assures silence during changing cycle. United Audio Products, 202 E. 19th
St., New York 3, N. Y. User net price, $69.95.
GARRARD
Model RC88 Record Changer. The precision
watch -like construction of this 4 -speed auto-
mattc and manual record player suits it for
association with the finest of high-fidelity
components. Rumble is so low that it approaches the minimum standards for in a professional turntable. All levers are machined to
close tolerances and are fully adjustable; easy
and inexpensive to service. Heavy steel table
minimizes wow and reduces possibility of hum
pickup when using magnetic cartridge. A
4-pole shaded "induction- surge" motor further
reduces the chance of hum pickup and assures
constancy of speed with vibration eliminated
for all practical purposes. Interchangeable
plug-in pickup shells accommodate all standard cartridges. Stylus pressure adjustment is
easily accessible from top side of mounting
board. Manual play, with tone aria disengaged
from changer mechanism, is accomplished by
means of a switch arm returns to rest after
each playing. Muting switch eliminates noise
through speaker during changing cycle. An
aluminum true -tangent tone arm provides
rigidity, low resonance, low mass, aand light
weight. The RC88 is an excellent changer,
worthy in all respects of its reputation.
Garrard Sales Corporation, 80 Shore Road,
Port Washington, N. Y. User net price, leas
cartridge but with two universal plug -in
shells, $54.50.
;
80
range, and moves both laterally and vertically on pin -point bearings. Rumble, wow, and
flutter have been reduced to insignificance by
improved motor design. As in earlier Seventy
Seven models, the turntable pauses during a
change cycle, and resumes motion only after
the stylus has been lowered to the next record,
to reduce stylus and record- surface wear. The
idler disengages automatically in "off" position to prevent wow caused by flat spots. A
dual -channel muting switch and R -C network
maintain silence for both stereo channels during record change and at shut -off. Glaser Steers Corporation, 155 Oraton St., Newark,
N. J. User net price. less cartridge, with two
cartridge shells, $59.50.
GSC
cover for
GS -77
9.75
LESA
Four -Speed Record Changer. Fully automatic, the new Lesa Model CD2 /21 record
changer has only two controls for all operating cycles, speed selection, start, stop, reject.
Up to eight records of any size may be played
with automatic intermix. For manual operation, the record balance is simply moved to
its side position. When operated manually,
the tone arm is returned to rest automatically
after each record. A built -in click suppressor
Automatic Record Changer. Equally suitable for stereo or monophonic application, the
new Miracord Model XS -200 is an automatic
turntable when its manual spindle is in position, and a fully automatic intermixing
changer when the Miracord "Magic Wand"
spindle is used. Irrespective of whether it
is used as a single- record player or as a
changer, the unit is push- button controlled
with no need for ever touching the tone arm.
Every function -Stop, Repeat, Filter, Pause,
Start-Is controlled by push bottons. The jam proof arm returns to rest after each record.
A 41/2-lb. cast turntable assures constant
speed with minimum flutter and wow. Hum is
reduced to negligibility regardless of the type
of cartridge employed. A 4 -speed player, the
XS-200 is equipped with a heavy -duty 4-pole
motor which is spring -suspended to minimize
vibration. All adjustments can be made without tools. Precision -built by ELAC in Western
Germany, Miracord products are distributed
exclusively in the United States by Audio gersh Corporation, 514 Broadway, New York
12, N. Y. User net price, less cartridge, $67.50.
XM5 -210 man player w/4 -pole motor $ 4750
THORENS
Record Changer. The Thorens Model CD43NS combines speed accuracy, silence, and a
unique combination of operating features. It
is wired for stereo. A three -speed machine, it
is equipped with a "fine- tuning" knob for
exact pitch adjustment. Incorporated is a
Mir
pause and reject control permitting immediate
record reject plus adjustable pauses between
records. The machine plays 12 -, 10 -, and 7 -in.
records, automatically intermixing 12- and
10 -in. records when desired. Control is included for manual operation. A rugged 4-pole
direct-drive motor is equipped with mechanical
filter to reduce rumble content. The changer
automatically shuts off after the last record
in a stack has been played. Operates on 50or 60 -cycle a.c., any voltage from 100 to 250
volts. Thorens, New Hyde Park, N. Y. User
net price, $79.95.
75.00
TD -184 4-sp semi auto player
eliminates switching noises by means of an
R -C network. A 4 -pole, carefully balanced,
heavy -duty motor drives the CD2 /21's turntable which has an exceptionally high moment
of inertia. The tone -arm mechanism is jam proof, the arm capable of being moved or
handled at any time without damage to the
mechanism. The record changing cycle time
of 6 seconds is the same for all record sizes
and speeds. Pre-wired for both monophonic
and stereo operation, the Lesa changer is
equipped with a universal plug -in shell which
accommodates all standard cartridges. Electrophono & Parts Corporation, 530 Canal St.,
New York 13, N. Y. User net price, $39.95.
4V3 /I1 4 -sp man rec player
$
TD -I34
4-sp manual
LOOK
$ 59.95
player
FOR THIS SECTION
NEXT MONTH
PHONO PICKUPS AND ARMS,
Miscellaneous Accessories
2325
AUDIO
AUGUST, 1959
PHONO TURNTABLES
ARGONNE
REK -O -KUT
Hysteresis Turn table. Employing a true
hysteresis motor. this new single -speed turntable will maintain a constant 33%-rpm
speed irrespective of normal load or line voltage fluctuation.. The 12-in. 4t,ß -lb. die cast riot -weighted aluminum table turns on a
Hysteresis -Motor Turntable Kit. Meeting
professional standards throughout, the Model
K -33 -H turntable kit can be assembled in 30
minutes or less. using only simple tools. A
single -speed unit (3:t';, rpm), it features a
high -efficiency I,y,t,re.is synchronous motor
with a pressure lubricating system. Handsome
black, whit,, and chrome styling. Garrard
Sales Corporation, 80 Shore Road. Port Washington, N. Y. User net price, $59.50.
GRAY
precision ball bearing and is engaged by means
of an oversize heavy -duty idler wheel. Wow
and flutter components are less than 0.2 per
cent, and signal -to -noise ratio is better than
45 db, The unit is supplied with a heavy
rubber turntable mat and mounting template.
Dimensions are 13%" x 14%" x 6% ". Argonne
Electronics Mfg. Corp., 165 -11 South Road,
Jamaica 33, N. Y.
Precision-Built Turntable. Developed to defeat the rumble problem which came with the
introduction of stereo records, the Gray 33 -H
incorporates an unusual bearing-shaft assembly which reduces vertical motion to negligibility. Wow and flutter are well within
NARTB specifications for professional equipment. A unique motor suspension virtually
CONNOISSEUR
Transcription Turntable. Built throughout
to professional standards. the Connoisseur
Type B turntable is a three -speed machine
suitable for playing both monophonic and
stereo recordings. The full 12 -in. table is lathe turned and manufactured of non- ferrous material. Underneath the table a large stroboscope disc is fitted, this being viewed through
a reflecting mirror with a built -in light source.
Speed change is arranged mechanically and
eliminates vibration. A single -speed (33%
rpm) machine, the 33 -H is driven by a hysteresis synchronous motor through a stretch belt
drive which further reduces vibration caused
by mechanical coupling. Gray Manufacturing
Company, Inc., High Fidelity Division, 16
Arbor St., Hartford, Conn. User net price,
$79.95. The Gray HSK -33 turntable kit contains the same engineering features as the
33 -H except for smaller mounting plate. Assembly time is 25 minutes. User net price,
$49.50.
built to Rek- O -Kut's exacting specifications.
Noise level is 52 below average recording level.
The crown -spindle belt drive uses a custom made endless -woven fabric belt with thickness
held to +0.001 in. An adjustment is supplied
for belt Tension. A built -in strobe disc permits
constant speed check. The solid cast -aluminum
turntable is lathe -turned, and tapered for
easy disc handling. The entire assembly is
finished in silver-tone aluminum. Where economy must be observed. the K -33 -H presents
an ideal means of possessing a high quality
turntable at modest cost. Rek -O -Kut Company,
Inc., 38 -19 108th St., Corona 68, N. Y. User
net price, $49.95.
N -33H 33 1/3 w /hys sync motor ..
$ 69.95
K -33
331/3 w/4 -pole motor (kit)
39.95
B -12H 3 -sp w /hys sync motor
129.95
B -12
3 -sp w/4 -pole motor
84.95
H. H. SCOTT
Stroboscopic Turntable. Developed primarily
to meet the demanding requirements of stereo,
the Type 710 -A turntable employs a radically
new design which isolates the table proper
from all extraneous mechanical vibration. It
features push -button selection of 33%-, 45 -,
or 78 -rpm operating speed. Each speed has
its own vernier adjustment and may be varied
PICKERING
permits a four per cent variation on all operating speeds. All revolving shafts are precision ground and lapped to mirror finish.
Bearings are made adjustable so that full
servicing can be performed throughout the
machine's life. The synchronous motor is
dynamically balanced and resiliently mounted,
making it virtually vibrationless. Rumble is
stated to be down 50 db, and wow is less than
0.15 per cent at rated speed. Manufactured
by A. R. Sugden and Company of Brighouse,
Yorkshire, Eng., the Connoisseur Type B
turntable is distributed exclusively in the
United States by Ercona Corporation. 16 W.
46th St., New York 36, N. Y. User net price,
$119.50.
"Gyropoise" Turntable. Engineered specifically for microgroove records -both monophonic and stereophonic -the Gyropoise 800
Stereotable is a single -speed machine operating at 33% rpm. It embodies a unique method
of magnetic suspension, on which patents are
pending, which eliminates vertical rumble to
the point that it becomes inconsequential in
the playing of stereo records. Vertical period
of spring suspension is below 5 cps compound
vertical rumble attenuation is 12 db /octave
below resonance noise is 65 db below reference level speed accuracy is +0.2 per cent
total variation. Pickering & Company, Inc.,
Plainview, N. Y. User net price, chassis only,
$59.95. Model 800CB, complete base, in mahogany, walnut or blond, $15.00.
;
;
;
GARRARD
Deluxe Manual Record Player. The Garrard
4HF constitutes a 12-in. turntable
complete with transcription -type arm mounted
on a single unit plate. It is fully wired for
stereo or monophonic operation. Although
modest in price, the 4HF affords most of the
features usually expected only in equipment
considerably higher in cost. Variable speed
adjustment is available on each of the four
standard operating speeds. Automatic start stop is built into the tone arm rest. A newly designed center spindle housing is equipped
Model
AUDIO
per cent to match pitch of accompanying
musical instruments. A built -in expanded -scale
optical stroboscope permits exact speed adjustment even while a record is being played.
Motor rumble is more than 60 db below recording level, and wow and flutter are less than 0.1
per cent of rated speed. Precision nylon helical drive gear and steel worm are housed in
permanently oil-filled transmission. A special
clutch permits cueing. H. H. Scott, Inc., 111
Powder Mill Road, Maynard, Mass. User net
price, $129.95.
± 5.0
THORENS
Transcription Turntable. Engineered for
the finest music systems, the Thorens Model
TD -124 is a four-speed machine featuring a
full 12 -inch, 11%-pound table for lowest wow
and flutter. The main table is made of cast
AUGUST, 1959
81
www.americanradiohistory.com
AmericanRadioHistory.Com
and easily accessible levelling screws. The
precision 4 -pole motor is equipped with a
compliant belt-plus -idler arrangement which
provides excellent motor vibration isolation.
The TD-124 operates on 50 or 60 -cycle n.c.
nt any voltage from 100 to 250 volts. Thorens,
New Hyde Park, N. Y. User net price, $99.75.
TDK -101
331/3
rpm kit
47.50
WEATHERS
iron to provide shielding against hum pickup.
cover table made of aluminum, plus an
A
attractive rubber mat, mitigates the attrac-
tion of magnetic pickups. Precision- machined,
the morons Roto-Drive is adjustable ± 3.0 per
cent for exact musical pitch. A built -in illuminated strobe allows setting to exact speed
while record is playing. Easy levelling is accomplished by means of a built -in level-bubble
LightrrcighI Turn fabla. Engineered especially for modern phonograph pickups having
wide -range response and low tracking force,
this turntable is manufactured of light aluminum and is suspended on a hearing assembly
of unique design to offer a nilnhnum of friction. The table is driven by a 12-pole synchronous motor of very small size but of
adequate torque to drive the machine at exact
speed regardless of line- voltage variation or
normal variations in load. Noise level is 25
db less than the noise recorded on high
quality phonograph records. Rumble and
acoustic feedback are eliminated for all practical purposes. The table is a single -speed
3354. -rpm machine, however additional speeds
may be obtained by means of the Weathers
Type P -620 Electronic Speed Control which
has been designed for broadcast station use.
Rumble is down 70 db, flutter is 0.1. per cent,
and wow is 0.15 per cent. Weathers Industries, 66 E. Gloucester Pike, Barrington, N. J.
User net price, ML -1 Turntable, $59.95.
$111.75
K601 33 1/3 rpm rec player
KL-I
34.50
Same as ML -1 in kit
TAPE EQUIPMENT
AMERICAN CONCERTONE
Professional Stereo Tape Recorder. A machine of advanced design, the Concertone
Mark VII records and plays back 2 -track stereo
and monophonic tapes; the Mark VII-F in
addition will play back 4 -track stereo and
monophonic tapes. Featured in the Mark VII
series is a direct -drive capstan motor and
4-pole induction -type reeling motors. Manu-
factoring tolerances are stated by the manufacturer to be within two millionths of an
inch. Push -button controls are solenoid -operated. Automatic reel -end cut -off switch prevents tape runaway. Self- energizing brakes
assure smooth operation without tape stretch.
Dual inputs are supplied for microphones and
auxiliary devices. Four separate level controls
and master gain control permit mixing of all
inputs. Frequency response is 30 to 17,000 cps
+2.0 db at 755 ips. All standard reel sizes up
to 10%-in. can be accommodated. Lightweight
for easy portability, the Mark VII weighs
only 39 lbs. in portable carrying case, including record and playback preamplifiers. American Electronics, Inc., Audio Division, 9449 W.
Jefferson Blvd., Culver City, Calif. User net
price, Mark VII in portable carrying case,
$940.00; Mark VII -F, $895.00.
. $1050.00
Mk. X -3 Bdcst Rcdr, Stet rec /pb
X -1
Bdcst Rcdr,
Y2
tr. mono rec /pb
270 Spkr /amplifier, in case
965.00
188.00
quency range at 3% ips is 30 to 15,000 cps.
Its precision -engineered timing accuracy is
such that it offers perfection of pitch held
to tolerances of one -third of a half -tone.
Flutter and wow content is under 0.2 per
cent rms at 7% ips; under 0.25 per cent nt
3% ips. Dynamic range is 55 db and 50 db at
the higher and lower speeds, respectively.
High- impedance inputs are provided for
microphones and high -level program sources.
Cathode -follower output is approximately 0.5
volt. Azimuth alignment of stereo head gaps
in the same stack is within 20 seconde of an
arc, equivalent to less than 10 millionths of
an inch. The appearance of the 960, in a
distinctive gray portable carrying case, is
well in keeping with its impressive performance. Ampex Audio, Inc., Sunnyvale,
Calif. User net price, $650.00.
Matching Amplifler- Hpeaker. Engineered for
use with the Model 960 recorder is the Model
2010 amplifier -speaker. Matching the 960 in
size and appearance, the 2010 amplifier section provides operating characteristics flat
within ±1.0 db, with total harmonic distortion less than 0.5 per cent, throughout the
maximum range of human hearing. The specially-designed 8-in. speaker provides smooth
peak-free response throughout n remarkably
wide audio range. User net price, each (two
required for stereo playback), $199.50.
AMPEX
Home Tape Recorder. Although it is classified primarily as a home -type instrument, the
Ampex Model 960 meets professional recording standards throughout. It is a highly
versatile stereo machine capable of almost
any desired mode of operation. Capable of
recording and playing back half -track monophonic tape and two -track stereo tape, it will
also play back four-track tape when desired.
The 960 will record a frequency range of 30
to 20,000 cps with distortion reduced to
negligibility at 7% ips operating speed; tre-
BELL
Cartridge Player-Recorder. Bell "Stereo Pak" tape -cartridge players and recorders
have been designed to accommodate the new
RCA -type stereo tape cartridge. Using the 4track cartridge at a speed of 3% ips, the user
can obtain up to a full hour of stereo sound
on 600 ft. of 1.0 -mil tape. Use of moving
parts in the Stereo -Pak has been kept to an
absolute minimum to insure dependable and
trouble -free operation. Only two mechanical
controls govern all operating functions. Wow
and flutter content is under 0.25 per cent.
Playback frequency response is stated by the
manufacturer to be 50 to 15,000 cps. This
unusual response figure for 3% -ips operation
is achieved by means of a head gap width of
only 90 millionths of an inch. The Stereo -Pak
preamplifier equalization circuits are especially engineered to take maximum advan-
tage of the head characteristics. All models
of the Stereo-Pak incorporate a completely
transistorized stereo record -'playback preamplifier with exceptionally low hum and
noise. Illustrated is Model 405, which includes
built in 14 -watt (7.0 watts on each channel)
stereo power amplifier. An accessory speaker
system, Model 450, is available as a matching
accessory. Bell Sound Division, Thompson
Ramo Wooldridge Inc., 555 Marion Road,
Columbus, Ohio. User net price, $299.95 ;
Accessory speaker system, per pair, $49.95.
$109.95
T210 mono rec /pb
119.95
T211 mono pb, 1 tr ster pb
129.95
7212 mono rec /pb, y tr ster pb
7213 mono rec/pb, IY2 tr ster rec /pb 149.95
E.M.I.
Battery -Operated
lightweight portable
the reproduction of
comparable to that
www.americanradiohistory.com
AmericanRadioHistory.Com
This
Recorder.
;
AUDIO
82
Tape
recorder makes possible
sound with a fidelity
of professional studio
equipment. Weighing only 14% lbs., including
batteries. and measuring only 14" x 8" x 7 ",
the E.M.I. Series L-2 uses standard 5 -in.
reels of quarter -inch tape and requires no
external power source. It is available in
three models : 3% fps for 30 minutes 7%
ips for 15 minutes, and 15 ips for 7% min (Continuerl on page 105)
AUGUST, 1959
New H.H. Scott
Stereo Amplifier has
CROSSOVER
features never before
offered at $139."55'
AND
BIAMPLIFIER
(front page 48)
Operation
Selection of the best crossover frequency is done by listening tests only.
The gain controls should be adjusted
for best balance of treble to bass. These
controls should be readjusted each time
the crossover frequency control changed.
It is best to adjust the gain controls to
a high level, and eut the input signals
by turning down the level controls in
the preamplifier. The author recorded
all settings of the gain controls for each
setting on the crossover frequency control so that previous listening tests
could be duplicated for comparison.
A few words about the speakers used
with this amplifier. The author's speaker
system includes four speakers. A good
quality 15 -inch woofer in a back -loaded
folded horn is directly connected to the
bass amplifier. The middle- and upper frequency speakers include two 8 -inch
speakers mounted in the upper section
of the same cabinet. Within the same
compartment as the 8 -inch speakers is
a horn type tweeter with a 3000 cycle
L -C high pass filter. This arrangement
is connected directly to the treble ampli-
The new H.H. Scott 24 watt stereophonic amplifier, Model 222,
puts top quality within the reach of all. This new amplifier has many
features never before available for less than $200. It is backed by
H.H. Scott's fine reputation. Check the features below and you'll
see why you should build your new stereo system around th#+
H.H. Scott Model 222.
fier.
Building the amplifier described in
this article was quite a job. However,
results have shown that it was well worth
while. Until somthing new comes along,
I think this is it !-and the little wife
hopes so.
PARTS LIST
All resistors are
specified.
Rn R,,
R,, RH,
R,, R.
R
Ru Ras
Rs, Ras
R,,
R,,
R,1
R
Ra, R,, R,,,
R,,, Ru
R,,,
R,,, R,,
R,,, R,,
R,,,
R,,, Rs,
R,,, R,, Re,
R,,, Rar
R,,
R
R
watt unless otherwise
500 k -ohm pot, linear
220 k ohms
2200 ohms
39 k ohms
2.2 megohms
470 k ohms
1500 ohms
22 k ohms
2200 ohms, 1%
25 k -ohm pot (see text)
8200 ohms, 1%
100 k -ohm pot (see text)
you
choose
between
RIAA compensation for
monophonic and stereo
records; NARTB, for
switch positions for accurate balancing, for playing
stereo, reverse stereo
and for using monoSpecial
phonic records with
your stereo pickup.
;
Effective scratch filter
improves performance
on older worn records
and improves reception on noisy radio
broadcasts.
This position lets you
play
a
monophonic
source such as an FM
tuner or a tape re.
corder through both
Exclusive center-
/
tape
tortion
Separate
Bass
and
Treble
controls
on
each channel let you
adjust for differences
in room acoustics and
different speaker systems.
power
stages and
speakers.
270 k ohms
680 ohms
47 ohms
1200 ohms
R,,, R,s
R,s
Rr» R+ri Rsr, R,e
BIG, Rrc
Rn
Rm, Rrs,
Ru, AN
AUDIO
trol adjusts for different speaker efficiencies and brings
channel volumes into
balance quickly and
easily.
Master volume control
adjusts volume of both
channels simultaneously. Also functions as
automatic loudness
control whenever desired.
channel output lets you
use your present amp.
liter for 3-channel
stereo or for driving
extension
speakers.
Separate stereo tape recorder outputs.
SPECIFICATIONS: Dual 12 watt channels 0.3% IM dis; frequency response 20 to 30,000 cps; ex-
0.8% harmonic distortion
tremely low hum level
(-
80db); DC operated preamplifiers heaters; Inputs for
stereo or monophonic recorders, tuners, phono cartridges and tape heads.
Phono sensitivity 3 mv. Sub -sonic rumble filter prevents overload from noisy
changers or turntables.
Price $139.95
H.H. SCOTT INC.
Dept. A.B. 111 Powdermill Road, Maynard, Mass.
Export: Telesco International Corp., 36 W. 40th St., N.Y.C.
Insist on genuine H. H. Scott components.
*West of Rockies $149.45. Accessory case entra.
1.2 megohms
47 k ohms
47 k ohms (matched
SEND NOW FOR
FREE HI -FI GUIDE
AND CATALOG
100 k ohms
100 ohms
100 -ohm, 4 -watt
1000 ohms
Rush me complete details on your new Model 222 and
your complete 1959 Hi Fi Guide and Catalog. Dept. A -8
Name
Address
City
pairs)
R,,, Rr,
Channel balance con-
10kohms
R
Rro,
1
Equalization switch lets
pot
AUGUST, 1959
www.americanradiohistory.com
AmericanRadioHistory.Com
State
Dr. Kenneth Eldredge. noted Electronic Consultant and
Research Director. puts SARGENT- RAYMENT equipment
through an intensive series of performance tests in one of
the West Coast's most advanced electronic laboratories.
From
`
minals ..
s
e
SARGENT - RAYMENT has the
LOWEST COMBINED DISTORTION
of any stereo system available today,
at any price
It is easy to claim superiority -difficult to prove it. But there is
one proof that passes every test -the proof of performance. This
is what SARGENT - RAYMENT has to offer, and is why
SARGENT- RAYMENT components are fast becoming
the stereo standard of comparison. To engineer and music lover
alike, SARGENT - RAYMENT Stereo offers performance all
out of proportion to its price. Judge it yourself, with the one test
that's undisputable-your own ears. Hear it at your
Component Hi -Fi Dealer's today.
SARGENT
CO.
RAYMENT
.4926 East 12th Street,
Oakland
1,
California
HI-F1's BEST GUARANTEE
-R Stereo Reproducers are backed
by the industry's best Guarantee...
S
15
MONTHS
Please send FREE 12 -page technical brochure
describing S -R Stereo Reproducers.
Name
Address
& State
City
AUDIO
84
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
TB'
f
0.5%
R47
aN
o
x
V
z
U O_
2f
ON
aN
o
40
20
60
80 100%
AM distortion of special
S -R two -tube detector
1%
0.8%
0.4%
O
I%
0.8%
0.6%
0.4%
0.2%
0
40 5OWATTS
WATTS OUTPUT
Amplifier output with
R57
R22
R54
R24
R55
R23
R51
R26
R52
R25
R60
132
R59
R33
j
R18
C8
Fig. 7. Layout of components on the resistor mounting boards, and the indicated
sections of the crossover- frequency control.
all tubes
being driven within recommended
operating voltages
300 ohms, 20 watts,
R,,, Rc,
0.2%
Tone control, high voltage -lowdistortion cathode follower output
I.M. DISTORTION VS
R21
0.6%
IV
2v 3v 4V 5V
IM. DISTORTION VS VOLTAGE OUTPUT
30
R58
C24
O
20
TB3
R53
PERCENTAGE OF MODULATION
l
TB4
I
0.5% ¢O
R,,,
R,2,
adjustable
R
5600 ohms, 2 watts
R.
25 ohms (matched)
22 k ohms, 2 watts
1000 ohms
100 k ohms (matched)
R,,, R4,
R
R,,, Rc,
R
R, R.
R
R,o
12 ohms, 1%
18 k ohms, 2 watts
10 k ohms, 2 watts
RG,
R
C,,
C,
C,,
5000-ohm pot, 4-watts
6800 ohms, 2 watts
100 k ohms, 2 watts
C
.05
.03
10
C4
µf, 600 volts
µf, 600 volts
µf, 475 volts,
electrolytic
C,
C,
Ca C,e, C,,,
Cs, C,4
C.
electrolytic
µµf, 400 volts
680
µf, 600 volts
40 µf, 150 volts,
OA
C,,,
C.
Cu,
C
.25 µf, 600 volts
.0431.4f, 600 volts, 1%
.01 µf, 500 volts, 1 %,
C.
20
C.
C
390 µµf, 1000 volts,
ceramic
.25 µf, 600 volts
(matched)
50 pf, 50 volts,
C
40
Ceo
C
electrolytic
mica
µf, 475 volts,
electrolytic
Photo at left and curves above refer to
SARGENT -RAYMENT SR -1000 AM -FM
Stereo Tuner ($184.50). SR -1000 Master
Stereo Preamplifier ($163.50), and SR5100 dual 50 -watt Stereo Power Amplifier ($183.60). These and other S -R
stereo equipment fully described in free
-page brochure available through
coupon at left.
C.
C,,,
C
, C.
, C.
C,,,
F,
F,
AUDIO
C
L,
T,
4 -]Ty.
T,
Ultra-Linear output,
electrolytic
µf, 500 volts,
electrolytic
30
pf, 475 volts,
electrolytic
0.1 ltf, 600 volts, bathtub
2 x 0.1
5 amperes,
3AG
1/ ampere,
3AG
Littelfuse
Littelf use
AUGUST, 1959
choke, 200 ma
Ultra -Linear output,
Acrosound TO -300
Dynaco A -430
Thordarson 221/35
117-v primary to 117-v
secondary, 35 ma
T,
T4
Selenium rectifier,
Federal 1002A, 65 ma
12AU7 tube
6AN8 tube
KTGG tube
EL34 tube
5V4GA tube
Phone jack, Amplienol
CR,
1r r,
P P,V,
1'
P
F F,F
J,
80 -C
0.1 µf, 600 volts, 1%
.024 µf, 600 volts, 1%
20 µf, 450 volts
C
C C, C,,, C,,,
Cn,
12
CC
CKC
KC
IX
IO
Ce
ll
R49
100
FM distortion through entire
audio band at full modulation
0
Te
f
FREQUENCY IN CYCLES PER SECOND
0
Ce
R13
o
CO
1112
RI
2F
TECHN ICAL DATA
Power output:
Treble channel
Bass channel
Power input
20 watts
50 watts
222 watts,
117v
Input voltage for 12 watts output,
crossover at 500 cps
Treble channel ... 0.7 volts
Bass channel
0.9 volts
Hum:
Treble channel ... 95 db below
20 watts
Bass channel
80 db below
50 watts
Crossover data:
Frequency range
100 to 1,200
....
....
.
cycles
8 db (approx./
per octive
Note: Test equipment was not available for
intermodulation tests.
Total harmonic distortion was less
than 2%. However this was for the
Attenuation
entire system (using
a
Test Record).
85
www.americanradiohistory.com
AmericanRadioHistory.Com
is his first big band date in more than a den
ade, and the major role he assumes in the
music for television's "M Squad." Although he
andl/Nitat.
CHARLES A. ROBERTSON*
STEREOPHONIC
George Gershwin At The Piano
20th Fox SFX3013
Piano Roll Discoveries
RCA Victor LSP2058
When entertainment in many homes centered on the player piano, Aeolian Duo -Art
'was one of the most famous imprints of the
time, claiming the same respect as trade
mames on high quality audio components enjoy today. Where the ordinary pianola clattered away with unvarying clangor, unless
the operator was a skilled manipulator of
Thoth foot -pump and pedale, the Duo -Art was
fed nuances of phrasing and dynamic shading
from a series of holes along the sides of the
roll. The company staged blindfold tests during the Twenties that were forerunners of
the current "Live vs. Recorded" concerts.
Among the pianists it employed was the
youthful George Gershwin, who made rolls
for a decade, beginning in 1915, and near the
close of the period cut his own reading of the
complete Rhapsody in Blue, a performance reclaimed on both these discs by the latest
stereo techniques.
By delving also into the archives of a
sister subsidiary, 20th Century -Fox gives the
fullest portrait of the composer at the keyboard yet unveiled, presenting him at four
stages in his career. First there is the journeyman pianist of 1920, relaying the songs
of others in true piano -roll style, as exemplified by Left AU Alone Again Blues, Grieving
For You, Pm A Lonesome Little Raindrop,
and Just Snap Your Fingers At Care. Five
years later, just before his writing activities
limited his professional appearances, he is
playing his own compositions in the Rhapsody,
and That Certain Feeling. Then in 1929, via
Fox Movietone News and the transfer from
optical sound film to magnetic tape, he is
heard directing a rehearsal of "Strike Up The
Band," leaving his post at the piano momentarily to engage in banter with the comedy
team of Clark and McCollough. Finally in
1931, the newsreel cameras pick him up
again at the opening of the Manhattan Theatre, an occasion enlivened by his impromptu
variations on I Got Rhythm.
Because the familiar strains of the Rhapsody in Blue, as orchestrated by Ferde Grofe,
have filled the channels of mass communication for so long, many listeners have lost an
early enthusiasm for the work. An opportunity
to hear the composer's original piano version
is likely to stir their interest anew. Perhaps
it will even convince Ira Gershwin and the
Gershwin Estate, whose approval 'was needed
for these recordings, that a modern orchestration is in order. A commission to Robert
Prince, Gil Evans, Johnny Mandel, or even
Leonard Bernstein could do much to prevent
it from becoming a period piece.
Both projects were carried out at RCA Victor studios and an impressive list of engineers
was involved. William Jordan and Douglas
Williams were from 20th Fox, and Lou Layton, Michael Crawford and Paul Hoffman represented Victor. Alphonso D'Artega made sure
the Imperial- Industrial electric reproducing
732 The Parkway, MamaroneokkN. Y.
piano performed on schedule. Either is to be
preferred in stereo, but those who want both
may be satisfied to take one in monophonic
form.
Among a sampling of other piano -roll specialists, Victor includes, in addition to Gershwin's major opus, his version of Whose Baby
Are Your A second look at the label may be
required to convince you that the question
comes from Jerome Kern. A younger generation, fresh in the knowledge that Thelonious
Monk sometimes lampoons Zez Confrey, can
learn the rest of the story as related on
Stumbling, a piece of his own devising, and
The Sheik of Araby. For those who do remember, the rewind and flapping noise at the end
of a roll are retained.
Other composers playing their own works
are Felix Arndt on Nola, Lee S. Roberts and
Max Kortlander with Smiles, and Fats Waller
on Squeeze Me. Of most worth to jazz students
is the daddy of them all, James P. Johnson,
stating J Ain't Givin' Nothin' Away, and Victor can do no better than locate enough of
the rolls he and Waller cut to make up a sequel.
Bauduc -Nappy LaMare: Two -beat
Capitol ST1198
Generation
Ruby Braff: Easy Now
RCA Victor LSP1966
When played in tandem, these albums comprise a pleasant sector in jazz chronology and
are planned with some thought for the advantages of stereo placement. In fact, the Bob
Crosby alumni based on the West Coast go
outside their own little group to Jack Marshall for arrangements. He provides a chase
between two trumpets on Coffee House Rag,
and shifts the players about to suit his fancy
before each number. His other work on this
label indicates that he bas made quite a study
of the problem. Guitarist Nappy LaMare sings
on Papa's Gone, Good Bye, and Ray Bauduc
is as sharp a drummer as ever. Gene Bolen's
clarinet is pure New Orleans on My inspiration, and Jackie Coon alternates on trumpet
and mellophone. Among the dozen tunes are
Smokey Mary, and De Paris' Martinique.
Ruby Braff, heading two casts, affords protracted examples of trumpet interplay. On six
tunes with a sextet, his respondent is Roy
Eldridge, who sends back rapierlike sallies on
This Is My Lucky Day, and Someday You'll
Be Sorry. By switching in midstream to flugelhorn, he gives a firm underpinning to Braff's
lyric sentiments. In an octet, with the added
Ray
voices of Vic Dickenson, trombone, and Bob
Wilber, tenor sax, Braff meets Emmett Berry,
playing one original as well as My Walking
Stick, and Willow Weep For Me. The horns
blend admirably in stereo on each occasion.
The Music From M Squad
RCA Victor LSP2062
Benny Carter: Aspects
United Artists UAS5017
With the halfway mark passed, it seems
more than certain that this year will be remembered for the resurgence of Benny Carter
in all his many capacities. One Contemporary
album is behind him, and a second will unite
him with Earl Hines. Also on the credit side
shares the writing about equally with Johnny
Williams and Stanley Wilson, the musical director, his alto sax weaves assuredly through
solos on nearly every number and is especially
compelling on A Lady Sings The Blues. Considered as jazz, the score is the most mer¡tons to emerge from the private -eye dramas.
Recorded by Al Schmitt at RCA Victor's new
Music Center of the World, the sound strikes
a happy medium between that of most recording studios and the larger movie sound
stages.
Carter salutes the months of the year on
his big band session, composing four originals
to fill out the requisite amount. The personnel
lists the familiar names of Hollywood studio
musicians, including Shorty Sherock. Pete
Candoli, Buddy Collette, Barney Kessel, and
Shelly Manne. Here his characteristic setting
for the entire sax section, balanced admirably
in stereo, is as rewarding as the featured solos. Ideal for dancing, it offers a pleasant
change from most West Coast units.
Bill Evans: Everybody Digs Bill Evans
Riverside Stereo RLP 129
All the elements which make Bill Evans a
musician's pianist are winningly exhibited on
1
his second album. Gifted with a fine and sensitive ear for melody, he combines a concise,
impeccable touch with an unfailing sense of
rhythm. On Peace Piece, a long original solo
excursion, he passes around a set of variations in the impressionistic style first brought
to jazz piano in the compositions of Biz
Beiderbecke. In other hands, a notable exception being Jess Stacy, this approach is
often refined into amorphous wandering that
bears little relation to jazz or Debussy, from
whom it stems. Evans restores its masculine
vigor, renewing it through a telling use of
modern phrasing. Also unaccompanied are
Lucky To Be Me, and a brief Epilogue.
Otherwise, his companions are Sam Jones,
bass, and drummer Philly Joe Jones, who
curbs any tendencies to become overpretty on
Night and Day, Tenderly, and Young and
Foolish. The trio is joined effectively in stereo.
Appleyard
Audio Fidelity AFSD5901
The Vibe Sound Of Peter
Terry Gibbs: More Vibes On Velvet
Mercury 5R80027
The amount of straight melody coaxed
from the vibraphone in these two efforts is
enough to please the most demanding must hear- the -tune auditor. Both musicians have
good reasons for not breaking into fervid but
lese lyrical embellishments. Since arriving
from Canada in 1954, Peter Appleyard has
gained a working acquaintance with the preferences of club patrons on this side of the
border. His first LP for local consumption is
based on a knowledge of what the more lucrative segment of his audience demands.
Briefly, it is the Jonah Jones formula of
singing lines and a personal touch. He fills
the prescription on Avalon, Just in Time, and
'S Wonderful. Centered between bass and
drums in stereo, the vibes are crystal clear.
"It's very hard to play straight melody on
vibes," is the way Terry Gibbs notes his sentiments, "You keep wanting to play little figures and things around the tune and It's
really tough to stay on the melody." Among
his inducements are five new ballads, set to
lyrics by his wife. He wrote four himself, and
delivers them in slow, persuasive tempos. His
tones are equally subdued on Moonlight Serenade, Blues In The Night, and Steve Allen's
Impossible. Rich saxes, arranged by Manny
Alban], surround the vibes in stereo.
Clark Terry: Top And Bottom Brass
Riverside Stereo RLP1137
Noting that the relationship between the
trumpet and tuba is actually the same as that
of violin and double bass, Don Butterfield prefers to regard his tuba as a "contra -base
trumpet." A member of the orchestra at Radio
City Music Hall, he met Clark Terry when
the Ellington trumpet man did a guest appearance on stage. Together they worked out
the idea of combining the two instrumente in
a unique front line, enriching it further with
AUDIO
86
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AUGUST, 1959
the original and positive sound reproduction techniques
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Listen to the mellow trumpet and
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of Dixieland recordings
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AFLP 1868 /AFSD 5868
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Jo Basile and his accordion are
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with the artistry of Leon Berry
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AUGUST, 1959
HEAR the
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available in stereophonic high fidelity
These recordings reproduce it proper
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The
TH
MONOPHONICALLY AND STERE)PHONICALLY
87
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the full voice of Terry's flugelhorn. He also
utilizes his trumpet mouthpiece, in a lighthearted recasting of the unbridled jungle
sounds of the wa -wa mute, on an original
blues. Following this example, Butterfield removes his tubo completely from a subsidiary
wounded
role, permitting it to charge like
rhino through a longer blues.
Besides engaging in sprightly collaboration
on My Heart Belongs To Daddy. they investigate march and waltz tempos. In evading the
tuba, bassist Sam Jones' work is cut out for
him, and Jimmy Jones, piano. with drummer
Art Taylor completes the quintet. Butterfield
states that his tuba, in the title tune, picks
up a unison B flat from Terry and descends
through its register to pedal B fiat, the last
black note on the piano keyboard. Quite a test
for your equipment, as well as for everyone
concerned in the processing, particularly Jack
Matthews, of Components Corp., who made
the stereo master.
three
elegantly
styled
ultra
Leon Bibb: Folk Songs
Vanguard VSD2012
Jimmie Driftwood: The Wilderness Road
RCA Victor LSP1994
If these were jazz artists it would be impossible to cover them tinder the same heading. Fortunately, the collector of folk songs
seeks broad experience and is catholic in his
approach, qualities some jazz enthusiasts
might well adopt. As the folk contingent is
already hot on their trail, these new discoveries are grouped together because their
first LPs belong in any collection. Experienced
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in Broadway musicals, Leon Bibb is a polished
performer and brings the dramatic intensity
of a Harry Belafonte to his material. It includes songs from prisons and chain gangs,
blues and love songs. He also is benefited by
the accomplished assistance of Fred Hellerman and Milt Okun, who frame his voice
with a guitar, harmonica or choral group,
depending upon the nature of his role. The
stereo recording is splendid.
Jimmie Driftwood was introduced to n
New York audience at an Alan Lomax concert in Carnegie Hall, and his national fame
rests on The Battle Of New Orleans, the hit
song he revised from a 140 -year -old version.
Of the dozen songs gathered here. all are
charming hits of Americana and carry an appeal not dictated by hit- parade requirements.
Some may end up there. however, notably
Four Little Girls in Boston, and the tale of
Peter Francisco, the Paul Bunyan of the
Revolutionary War. Besides accompanying
himself on guitar. Driftwood interjects solos
on the "Pickin' Bow," which is held to the
mouth and played with a pick. sounding like
an oversize Jew's harp. The woodsy effect is
enhanced by a Nashville recording which
seems to have hint sing through a hollow log.
Stereo enlarges the log and nothing could remove the hard -cider twang from his voice.
Highlights Of Vortex
Folkways Stereo FSS6301
The music of Vortex, described as a new
kind of theatre, was composed for a series
of sound experiments at San Francisco's
Morrison Planetarium, where the audience is
surrounded by a circle of thirty -eight speak-
ers. An added sound source is two speakers
in the center of the domed auditorium, and
a control panel channels the taped compositions to any combination required. or
selects them in series for rotational playback. This electronic music differs from its
parent Musique Concrete, a recent import
from Europe. in that it is meant to be combined with visual effects. The auditory treats
on each program are accompanied by moving
patterns and flashing colors obtained front
the planetariun's intricate lighting system
and a battery of Vortex projectors. Its dissemination throughout the globe is now in
the hands of the Audio -Visual Research
Foundation.
Of necessity, its composers are wizards
with a tape recorder, and two have close
associations with the jazz world. William
Loughborough, creator of the "boo Lam" and
other percussion instruments, has toured
with Chet Baker to demonstrate his inventions. His polyrhythmic study, For the Big
Horn, had its initial playback through an
exponential loudspeaker which he built with
AUDIO'
88
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AUGUST, 1959
mouth twelve -feet in diameter. Henry
Jacobs, originator of the project with Jordan
Bellson, is known In another Incarnation for
his research into the weird life of Shorty
a
I'etterstein for World -Pacific. His works included are a film sound track, two mood
pieces, and a study in amplified Haitian
drums and Indian tabla.
An employee of the Ampex Corporation.
Gordon Longfellow gives the name of one
of its prize products to Three Fifty Dash
Two, creating echoed rhythms from the
sounds of a musical saw, electric mixer, engine noises, pots and pans. He also extracts
mammoth reverberations from plucked piano
strings in a three -part suite. David Talcott,
a staff member at radio station KPFA in
Berkeley, conducts four experiments using
delay loops and the human voice.
To be believed, it must be heard, regardless of the visual attractions present at the
time. The stereo effect is contrived without
strict adherence to the position of the sounds
as originally generated. Listen carefully and
your ears will be alerted to some of the
stereo tricks engineers can play on ordinary
everyday nwsie.
Folkways FA2476
Heard briefly in the first volume of Samuel
Charters' "Music of New Orleans," Snooks
Eaglin now has an album of his own, through
the courtesy of Dr. Harry Oster, of Louisiana
State University, who recorded him on home
grounds in March, 1958. A minstrel walking the streets of the city today. he became blind at the age of two and taught himself to play a guitar received on his sixth
birthday. After revealing that most of his
songs were learned from the radio and recordings, the notes pose a question as to
how many other folk artists obtained supposedly "authentic" material in the same way.
It is pointed out that these sources, the bane
of believers in the oral heritage of songs
passed from singer to singer, need not always
carry a commercial stigma. True enough in
this case, which is no valid test of the theory,
ns Eaglin Is a natural blues singer and goes
direct to the heart of n song to make it his
own. He restores basic emotions and pares
away nonessentials. Someone should send him
a Ray Charles album.
He simulates the traditional solo breaks on
High Society. playing without n pick, and
his one original is n sriking instrumental
blues. Choosing from his vast repertoire, he
selects both old and new, proving at twenty two that street singers are not a thing of
the past. For a field recording, the sound 1s
better than usual.
Blues In The Mississippi Night
United Artists UAL4027
Lil Armstrong: Satchmo And Me
Riverside RLP12 -120
Two valuable additions to the spoken
documentation of the music which coursed
along the Mississippi River in the first part
of this century are made on these recordings.
Amateur tape recordists should take hope
on learning that seventeen years have passed
since Alnn Lomax set up his portable disc
machine and encouraged three unidentified
blues artists to tell their stories. Aside from
the primitive sound, about the only point to
be regretted is that it took so long to reveal
his interview formula. A model of its kind,
it places Lomax in the background, interrupting the flow of experiences only with
short musical examples and casual prods
from the leader of the group. Although he
might find a trio willing to speak with equal
frankness today, the responses would be different and carry less import. Essential to a
study of the blues and Southern folk mords,
the text is transcribed in full on an enclosed
folder and will form part of a book Lomax
writing.
LiI Armstrong's tale of life in Chicago with
her noted husband during the Twenties deserves a place besde his autobiography. It
is jam packed with personal memories, from
her first meeting the shy youth who was
King Oliver's new trumpet player to the final
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breakup of their marriage. Her enthusiasm
for the subject is only slightly dampened by
an interrogator who seems to have just met
her at the studio. How much more ground
would be covered were she allowed to cut
up old times with someone like Luis Russell
and Buster Bailey Lomax shows how to
avoid the formality of questions and answers.
In the next installment, Riverside should put
Louis in a room with Milt Gabler and Joe
Glaser.
!
Art Blakey: Holiday For Skins, Vol.
Hi -Fi Cuban Drums
1
Blue Note 4004
Capitol T10141
A campaign to educate the populace about
drums is continued by Art Blakey, who conducts his annual seminar with wonted gusto.
His elucidators include a septet of AfroCuban percussionists, headed by Sabu and arrayed to furnish a background of contrasting
rhythms for challenging statements front
three jazz drummers. In addition to the
leader, they are Art Taylor and Philly Joe
.tones, whose ceremonial chanting prepares
for the bacchannalian rites of The Feast.
Atmospheric passages are supplied by Donald
Byrd, trumpet, and Ray Bryant, piano,
while Wendell Marshall is a steadying influence on bass. The first of two volumes produced in an all -night session, it provides an
exciting sequel to last year's "Orgy in
Rhythm." which will be among Blue Note's
initial stereo releases. This latest Installment
should follow shortly.
Blakey is interested in telling a story and
takes his material from a number of sources,
drawing greatly on the three years he spent
Ill Africa. He will find his language spoken
by the corps of drummers assembled in Havana, where they were recorded for Capitol
by Ramon S. Sahat. Some were brought in
from the hills to demonstrate the wild
rhythms of native dances. before ballroom
polish was applied. Assorted gourds are
struck, scraped and shaken, along with various discarded agricultural implements. The
deep bass sounds come from the marimboola,
made of metal straps cut from the mainsprings of broken, hand -wound phonographs.
And you can't hardly get those kind anymore!
Al Hirt: Swingin' Dixie
Audio Fidelity AFLP1878
It forced to trim his rampant lines to fit
hand arrangements, Al Hirt would be a carbon copy of Harry James. As it is, he combines the swing trumpet style with the
brashness of a Wild Bill Davidson, resulting
in n fiery and unquenchable combustion. Not
a thought in a carload, apparently. and this
is the way many individuals prefer their
Dixieland. Hal Cooper, his clarinetist, is
known from early Dukes of Dixieland recordings. Bob Havens, trombone. and Paul Edwards, drums. played in the band of the
late George Girard. Bob Coquille, bass, and
Ronnie Dupont, piano, are simply natives of
New Orleans.
Hirt's recent departure from the Crescent
City for the rarified atmosphere of the
Palmer House is commemorated on Chicano.
The dozen tunes on his second album are
all tried anti true, from Darktown Strutter's
Ball to Song of the Wanderer. Included is
Harry James' Feet Draggin' Blues, and a
robust Battle Hymn of the Republic.
Ray Bryant: Alone With The Blues
New Jazz 8213
Ramsey Lewis: Down To Earth
Mercury MG36150
pianist worthy of the name can
neglect the blues, although record executives
usually feel no such obligation. Given the
opportunity to express himself at will and
unaccompanied, Ray Bryant reaches back to
basic principles on five striking originals.
Organized in a variety of shades and colors,
they incorporate the plaint of early blues
singers, the spiritual release of gospel song,
and the glad, swinging approach of the stride
pianists. Bryant started as a bass player and
his left hand is strongly developed. He uses
it in a distinctive manner that avoids the
limitations of period or style. The blues
No jazz
feeling is also projected on Lover Man, and
a restful Rockin' Chair.
The Ramsey Lewis trio, once billed as "The
Gentle -men of Jazz," steps out in a new
guise, distinguished mainly for an improvised
blues lasting five minutes. Here the group's
former restraint disappears completely, but
the controlled teamwork remains. Falling
somewhere in between this performance and
the soft -sell are tasteful investigations of
Green8leeves, Dark Eves, and Come Back to
Sorrento.
Humphrey Lyttelton:
www.americanradiohistory.com
AmericanRadioHistory.Com
Play As I Please
London 113101
Dizzy Reece: Blues In Trinity
Blue Note 4006
Unless employed in the section of a big
band, most British trumpet players hew close
to traditional lines. Those who try to branch
out into other styles are apt to find their
following falling away and dates hard to find.
Because of his stature as a pioneer in the
New Orleans revival, Humphrey Lyttelton
has negotiated the transition to mainstream
jazz with fair success, fronting a septet in
his own London Club. Fresh from twomonths of concerts behind Jimmy Rushing, it
Is steeped in the blues for this session and
develops three original themes with a vigor
matched by few studio groups in this country.
Kathleen Stobart, n blue -eyed blonde lady
on tenor sax, is guest soloist on Johnny
Hodges' Going Out the Back 1Van. For one
set, it is augmented to thirteen pieces by
Don Rendell's group featuring Ronnie Ross.
A Paseo band. outfitted with marimba,
bongos and timbales for the Spanish tinge
on La Paloma. almost finds the leader returning to his Hot Five period.
Dizzy Reece, on arriving in 1948 from
Kingston, Jamaica, started from scratch and
now enjoys considerable respect among the
home guard and visiting American musicians
as a modern stylist. When engagements were
slim, he would slip over to the Continent and
won many fans in Paris. where this recording was made last year. As the title implies. it is most notable for his warm exposition of original blues themes. His work
is remarkably free from traces of other
trumpet men. possibly because he learned a
great deal from an association with Don
Byes, the expatriate tenor sexist with whom
he traveled about Europe. Two tourists,
Donald Byrd and Art Taylor, join in, and
Tubby Hayes makes an eloquent tenor -sax
solo of Round About Midnight.
Both leaders score one point over traditionalist compatriots whose best efforts
always belie the place of origin. In their
case, it is almost impossible to tell.
Hampton Hawes: Four!
Contemporary C3553
Roy Haynes: We Three
New Jazz 8210
Technique, as applied to a jazz pianist, is
a word to be weighed carefully in the balance, an axiom well illustrated in the careers
of Hampton Hawes and Phineas Newborn.
The son of a preacher, Hawes grew up on
church music and the blues, first broadening
his style to include Charlie Parker's conception of time. Since then, a slow process
of absorbing ideas and new material was
guided by his aversion to "technique that
sounds like technique." But there was always
enough for what he wanted to say, especially
on his blues originals, one of which is featured here. Topping a set of standards is
Parker's Yardbird Suite. Red Mitchell records
his first bowed bass solo on Bow Jest, abetted
by Barney Kessel, guitar, and drummer
Shelly Manne.
Newborn's debut drew acclaim for the brillance of his playing, and he has suffered from
it ever since. The need to live up to his
notices has hindered his growth, although
some mentioned his lack of maturity. Now,
in an effort to play less and say more, he
assumes a secondary billing to Roy Haynes,
a drummer who spent five years backing
Sarah Vaughn. The pianist comes to grips
with blues on After Hours, where his soul searching choruses make this his most interesting LP. He includes two Ray Bryant
tunes, and one original. With Paul Chambers on bass. Haynes lends encouragement or
trims sails to suit prevailing winds.
AUDIO
90
I
AUGUST, 1959
Barney Kessel: Some Like It Hot
Contemporary M3565
As the only new tune in this album bears
the film title, Barney Kessel needs little
prompting from the score to revisit prohibition days. Both he and Shelly Manne
helped record the sound track, however, and
the perils thrust on Pearl White must seem
mild after a vision of two Chicago musicians
harried by gangsters and Marilyn Monroe.
Out of sympathy, they are impelled to adopt
the free and easy manner of the Windy City
and blow modern breezes through old favorites. Manne pummels a suitcase a la Josh
Billings, while Kessel switches to unamplifled guitar on Sweet Sue. Joe Gordon, a
former Gillespie trumpet man, finds cadenzas
missed by Clyde McCoy on Sugar Blues. Besides playing alto and tenor sax, Art Pepper
explores the lower register of the clarinet
on I Wanne Be Loved By You. Pianist Jimmy
Bowles and bassist Monty Budwig strengthen
the septet's allout choruses on By the Beautiful Sea, and Rennin' Wild.
Kessel has the added support of Jack Marshall on rhythm guitar, and they combine in
duets on Stairway to the Stare, and I'm
Thru With Love. There is enough of a hint
of what to anticipate in stereo here to advise waiting for it. On two numbers, Kessel
uses a bass guitar, with a range as deep as
a bass violin, and believes this to be the
first time it was recorded as n solo voice.
An interesting sound, and the way his deft
fingers keep it from conflicting with the bass
is another reason for his top rating as a
Underside of superstructure.
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hysteresis belt drive
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Theodore Bikel
and
Geula Gill:
Folk
Songs From Just About Everywhere
Elektra 161
Mexico!
Capitol T10205
Where folk singers once remained close to
their national heritage, the modern professional is becoming more and more a cosmopolite. Tours embracing several foreign
lands make it impossible for concert artists
to resist adding to their repertoire, and those
staying at home follow their example by
means of recordings. Since leaving her native
Israel, Geula Gill traveled in South America
and Theodore Bikel has been just about everywhere else. They unite in the songs of eleven
nations, sung in ten languages other than
English. As might be expected, they are most
comfortable with Hebrew music and tend
to select material of a similar nature, no
matter what the origin. Dov Seltzer and
Fred Hellerman helped plan trips to Bolivia,
Roumania, Brazil, Persia and Argentina,
while Billy Paler assists on banjo.
William Clauson's first album was recorded in New Zealand in English, and his
second in Stockholm in Swedish, Norwegian
and Danish. When at home, the big, blond
Swedish -American lives in California, relatively close to the source of the dozen songs
which take him south of the Rio Grande to
a studio in Mexico City. He sings them in
Spanish with El Mariachi Mexico, giving the
willing little band of mariachis a cheerful
guitar lead. He prefers a livelier beat than
is usual, imparting a new zest to Veracruz,
Guadata jara, and .ifalaguetia.
William Clauson: Clauson
In
Djamal Asian: Lebanon
20th Fox 3001
An Evening In Beirut
Capitol T10189
After being introduced to the seductive
music of the Middle East by Mohammed ElBakkar, those adventurous souls whose appetite for strange sounds remains unappeased
will welcome the opportunity for further
indulgence. An accomplished oudist, Djamal
Asian is gifted with a romantic voice which
transcends language barriers. As a composer,
he shows a knowledge of Western rhythms,
sometimes incorporating them in tunes meant
for the younger set. And his six years at the
Conservatory of Music of the University of
Cairo enables him to give an authentic pulse
to the singing and handclapping of a twenty seven voice chorus under Edouard Ghazal.
Since arriving on these shores, he has appeared in concert at the Library of Con (Continued on page 104)
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AUGUST, 1959
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I'YE DONE
console
marantz
$249
24
Consumer Net
Cabinet
Slightly higher in West
In pre -amplifiers and power amplifiers, Marantz has set today's highest
standard of quality.
Consider the Marantz Stereo Console.
Here is the essence of uncomplicated, beautiful styling. So simple to
use, even the most non -technical
person can easily achieve matchless
reproduction quality. Yet, this fine
instrument offers an order of versatility that pleases the most discriminating professional users. Carefully
planned circuitry and wiring layout
result in unsurpassed freedom from
distortion, hum and noise.
Dedication to quality in every detail
is the reason why the Marantz 30watt power amplifier, too, is in a
class by itself. The Marantz circuit
permits this superb amplifier to recover instantaneously from sharp.
to effortlessly
musical transients
to
drive loudspeakers of all types
consistently outperform amplifiers of
considerably higher ratings.
both stereophonic and monophonic programs, Marantz is your
assurance of long, carefree operation
and unprecedented performance.
For
30 -WATT AMPLIFIER
Net
7.50
Grill
$147
Slightly higher
ln
West
* Selected for demonstration
American Natl. Exhibition
at the
in Moscow
CO MP
25 -li
BROADWAY,
A
NY
LONG ISLAND CITY 6, N. Y.
]MY
BEST
-bUt I just couldn't
review any records for you this month.
The reasons are interesting.
If you have read AUDIO, ETC. in this
issue, you will know what happened upon
my arrival here in lovely Tennessee, where
the temperature ranges around 5 degrees
lower than that of New York City, given
a good hot spell. It wasn't the heat that got
me but the liveness.
I brought down with me something like
500 LP records, mostly stereo, including all
the recent ones I could lay a hand on; I
toted along two complete stereo systems
four speakers-just to be sure I could play
them. And yet in the first nine days here, I
got to play just one-half a record.
Now I understand. What I should have
done was bring (a) maybe 20 records and
one "hi-fi" and (b) I should have hired me
a trailer and filled it up to the brim with
every rug, blanket, pillow, mattress and
other sound- deadening device I could locate, plus any extra rolls of cotton batting,
quilting, insulation, and what -not that
could be commandeered for the occasion.
Then, perhaps, I could have furnished
you'all with a few nice, authoritative record
reviews, out of a reconditioned and sound deadened Southern classroom.
Nope, (this is written later than AUDIO,
ETC.)
didn't get to use that goh'geoua
big fraternity house room, the only available one in this town that has really
proper living room acoustics. Instead, I
went around the campus searching for
something else-and was I amazed. One
place after another I tried -front halls,
lounges, coffee rooms, class rooms, pool
rooms, play rooms, common rooms-and not
a single one of them had so much as a
stitch of soft material in them. Seems to be
a policy of the University of the South,
which might just have something to do
with that old Suthunn problem, dampness
and mildew.
What I must point out to you is simply
that under really poor listening room conditions, record listening is just plain impossible. Even with the fanciest hi -fi equipment on the market.
I will review you any good LP record at
all on a portable table -top "hi -fi ", if you
will give me a good listening room for it.
And I'll stand back of my opinion, against
all comers. But in a bare class room, a
swimming -pool -style lecture hall, you could
not drag me into writing three words about
any recording, no matter how superduper
the hi-fi. And so-on principle, I give you
no reviews this month. Take a month off,
everybody, for silent contemplation, upon
the importance of the listening room.
P.S. I have finally found a nice old band
practice room and fixed it up tolerably well
-just tolerably. It was entirely bare, as
usual ; but the floor was of wood, not tile,
and the walls were wallboard, painted
-
-I
white. Live as all get -out but not as live as
my earlier concrete class room nightmare.
I spent two days in search of rugs. There
weren't any. Finally I got into the store
rooms of two college dormitories, closed for
the summer, and came forth with about six
floor-rags of the rubber -backed type, in all
states of discolor. (One of them stank so
badly I had to wash it in the shower room
with Cheer,* to cheer it up.) I also snitched
Plug.
a big green square of the same, clean and
about 10 by 12, from a private bed room,
took all my car blankets along-and managed to dampen down that band room so
that it is now merely very live. Not violently live. And I'm playing records again.
if
While I'm at it, I'll present some cogent
rules for listening -room acoustics.
1. The right acoustics (and the right
room configuration, for stereo) are more
important than any other factor in record
listening -more important than all the fi
in the whole chain of sound reproduction.
Flout this law at your own risk.
2. There is a fairly wide tolerable area
in which we can enjoy recorded sound,
ranging from fairly live to fairly dead
(with other more complex factors such as
room size and shape put aside for the
moment). But beyond this area -much too
live or much too dead -listening progresses
from difficult to impossible. The sound message simply is not adequately received
by the brain.
3. Stereo reproduction greatly extends
this range of tolerance in the dead direction-indeed, almost to extreme deadness
in the listening acoustics. The deader the
room, the greater the audible difference
between mono and stereo sound. This is a
major virtue of stereo.
In the direction of too much liveness,
stereo simply merges with mono sound into
an unintelligible jumble.
4. A vital point: within the tolerance
area of listening liveness, we are able to
learn, after long familiarity, to ignore the
listening effect of our own rooms in favor
of the objective effect of the recorded
sound. We hear the record; we close our
ears to the room. This is a major factor in
good listening and accounts for our general
agreement, such as it is, concerning the
qualities of this or that recording.
But -in a new, a strange listening place,
we must begin all over again and re- educate
our ears to the new sound, before we can
hear our records as before. (Note that the
same principle also applies to new reproduc-
ing equipment, notably the loudspeaker.)
5. In a new or unfamiliar listening place,
those records which compensate for the existing conditions will sound best. Thus in
an abnormally live room, your deadest
recordings will sound fine, but the records
with larger built-in liveness will be a
AUDIO
92
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AmericanRadioHistory.Com
AUGUST, 1959
i
AT
M
LAST!
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AFTER
LONG
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IRTE D ELI VERY
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Radio Shack's new 1960 catalog, GUIDE TO ELECTRONIC
BUYING creates a new standard in electronic catalogs.
It's big
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AUDIO
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CORPORA /ON
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RADIO SHACK CORPORATION, Dept. 8H
730 Commonwealth Ave., Boston 17, Mass.
Please send me the following:
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ELECTROSTAT -3
7 lbs.
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230,240 Crown St., New Haven 10, Conn.
AUGUST, 1959
-
C.O.D.
Name
Address
City
zane
Stat.
93
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AmericanRadioHistory.Com
leading audio magazines say
.. .
FINEST QUALITY
AMPLIFIER CAN BE
ASSEMBLED BY YOU
IN A fEW HOURS!
Acrosound Ultra -Linear Il Amplifier Kits have
astounded leading electronic exponents with
their ease of construction and high quality perno
formance. Quick and simple to assemble
experience necessary. Lowers cost because you
do it yourself! Follow the choice of experts
enjoy the ultimate in stereo sound, in your
home now in a matter of hours!
...
-
jumble. Similarly, in a dead room your
very live recordings will come out on top.
But, again, long familiarity with the
listening room will tend to cancel out these
effects.
Keep this in mind when entertaining
friends who don't know your listening
room, or in giving lectures and record demonstrations in strange places. Suit the record to the listening room -in reverse.
6. An excellent objective test for room
liveness is the sound of a close -to recorded
speaking voice. In a good room it will
sound natural, unforced, realistic. In an
overly -live room, the vocal sound has a
tell -tale hollow, metallic quality (which
seems to be in the recording, of course). In
a dead room, the recorded voice will seem
startingly close to you, the sibilants much
too distinct, the over -all sound rather bossy.
7. A final, and to me inexplicable, rule:
a. In an ultra -live room, reproduced
music seems drastically to lack highs; the
middle range is pipey, metallic, hollow, the
bass is hugely exaggerated. (Cf. AUDIO,
ETC.)
b. In an ultra-dead room, oppositely, the
highs seem strident and Missy, the bass is
unimpressive in effect, though present.
You figure that one out for me.
.
NEW LITERATURE
ACROSOUND ULTRA -LINEAR II
AMPLIFIER
$7950
KIT
e7
watts rated continuous
"With an output of 60
of less than 1 per
quality
power at an IM distortion
tfoperration
Thesentire construction
two hours by the most
require more than
_cent,
inexperienced."
December 1958 -AUDIO
"As a result of careful
the U -Ill goes together predesign planning,
two hours. It represents in something under
a superb blend
constructional ease and
of
guaranteed to delight thesuperior performance,
most hard -to- please
fanatic and the most
dedicated music
listener."
HIGH FIDELITY MAGAZINE
December 1958
simple since a
"The construction is extremely
entire circuit
printed board of basically theleft to the conreally
is furnished. All that is
the transformstructor is the wiring of both
the front
amplifier kit that
panel. Athnewo60 -watmounted
circuit with exemploys an unusual feedback
The total time required
ceptional stability
21h hours."
to build the kit is approximately
ers
...
RADIO
It
TV NEWS
"The steps are few and the
booklet and accompanying pictorial are
clear and easy to
follow
. Test results
In the last and
most important test, the amplifier
sounded
clean and performed beautifully
at all volume
.
levels."
POPULAR ELECTRONICS
March 1959
Write today for FREE descriptive literature on all Acrosound Amplifier Kits.
ACRO PRODUCTS COMPANY
369 Shurs Lane, Phila. 28, Pa.
ACRO
... THE FIRST NAME
Circle 94A
IN AUDIO
Valor Instrumenta, Inc., 13214 Crenshaw
Blvd., Gardena, Calif., will mail free a 4page pamphlet which discusses the maximum power dissipation in transistors.
Methods of determining the maximum
power which may be dissipated by a transistor and the effects of maximum power
dissipation on circuit considerations are
illustrated. Factors to consider in arriving
at an allowable collector dissipation such
as thermal runaway are also explained.
This is an excellent treatise for the audio
design engineer.
8-1
Electro-Voice, Lao., Buchanan, Mich., has
Just released Catalog 120A, a descriptive
new guide to Electro-Voice professional
microphones. This complete catalog con-
tains the photograph, response curve, polar
pattern, wiring diagram, dimensions, and
complete specifications for each microphone. A copy of this informative booklet
should join the technical library of every
broadcast station, motion picture studio,
and recording studio in the country. It
will be mailed upon written request, or
may be obtained from E -V distributors.
K -a
Unimaz Switch Division, The W. L. Maxon Corporation, Ives Road, Wallingford,
Conn., presents detailed information on the
expanded line of Unimax snap- action precision switches in its new 28 -page Catalog
No. 359. Convenient pictorial index shows
where to find dimensional drawings, descriptions, force and movement specification tables, and electrical ratings for each
Unimax switch listed. Data on bases, terminals, circuit arrangements, and NEMA
standard definitions of sensitive switch
terms are also included. Requests for
copies should be directed to the attention
of Mr. J. Martinez.
H -3
Ohmite Manufacturing Company, 8630
Howard St., Skokie, Ill., has done the elec-
tronics industry a distinct favor with the
publication of its new Catalog No. 30. Corn plete in every respect, well planned and
clearly printed, this catalog should be in
the hands of every person engaged in the
purchase of electronic gear on a professional scale. Design and production engineers alike will find this comprehensive
listing of Ohmite products to be of great
value in their work. Available on written
8-4
request.
GRADO
...
a
takes pride in announcing
new Custom Series Stereo
Cartridge. The Grado "Custom" was designed for the
selective audiophile who desires excellent reproduction
at a moderate cost. With its
excellent tracking ability and
extremely low distortion, the
new Custom Stereo Cartridge
becomes a perfect companion to the widely acclaimed
Grado "Master" Stereo Cartridge. Because of small moving masses and low tracking
forces, stylus wear is virtually
nonexistent. Grado Laboratories now guarantees all of
the stereo diamond stylii for
a period of 5 years from date
of manufacture.
A greatly improved Grado
Tone Arm is now available. It
is dynamically balanced and
features a new micrometer
tracking force adjustment.
Stylus force accuracy of
tenths of grams may now be
achieved with complete simplicity. Also new is a stainless
steel arm rest lock. All present
Grado Tone Arms can be
modified.
Master Stereo Cartridge
549.50
532.50
Custom Stereo Cartridge
Micrometer Stereo Tone Arm 529.95
.
For
www.americanradiohistory.com
AmericanRadioHistory.Com
.
.
.
further details write to:
GRADO LABORATORIES,
INC.
4614 7th Avenue
Brooklyn 20, New York
ExportSimontrice,
25
warren
St., N.Y.C.
Circle 94B
AUDIO
94
.
AUGUST, 1959
TAPE GUIDE
l
(from page -fu)
restoration will be complete. Therefore
it is all the more desirable in this situation that the tape recorder be capable
of being driven by a signal well below
0.5 volts.
The sensitivity required for microphones depends a great deal on the type
of microphone used. Of the two types
most apt to be used by the home record-
ist- piezoelectric and magnetic microphones-the latter generally produce
considerably less signal. At ordinary
speaking levels a few feet distant, the
magnetic microphone may produce about
2 or 3 millivolts at average levels and
perhaps 10 to 15 millivolts on peaks. Allowing for a reasonable reserve of gain,
an input sensitivity of about 2 millivolts
is desirable.
Output Level
If the tape machine (that is, the signal from the tape amplifier) is played
back through a high -fidelity system, most
often it will be fed to the control amplifier, which generally can he driven to
the desired level (enough to drive the
power amplifier and speaker in turn) by
signals of about 0.1 to 0.5 volts, depend-
ing upon the particular control amplifier. Allowing for a reasonable reserve,
it may be said that an output of 1 volt
from the tape machine should be sufficient in virtually all situations. One volt
should also be enough to drive a power
amplifier directly, as is sometimes done,
because most power amplifiers can be
driven to full or very high output by 1
volt or less.
(If the playback signal is taken directly from the tape head, then one must
look to the control amplifier rather than
to the tape machine to assure there is
sufficient gain. On signal peaks at 1000
cps, the tape head will produce roughly
5 millivolts or less on a half -track tape;
and correspondingly less on a quarter track tape. Thus at 1000 cycles the control amplifier should be capable of being
driven to about 1 volt for a signal of
about 2 millivolts from a tape head.)
Adjustment Facilities
Every tape recorder should have
means for readily adjusting the azimuth
of the heads, so that the gaps are perpendicular to the length of the tape.
This is commonly achieved by locating a
spring under one or more of the head
mounting screws, so that tightening or
loosening the screws slightly will tilt the
head about its vertical axis.
Adjustments for equalization, bias
current, and calibration of the record level meter are seldom found in machines
of the home type, but are generally in-
AUDIO
i
HOW
DID
PU
HIGHER
FIDELITY
INTO
THE
HARTLEY
CAPRI ?
*it's polymerized.
...
The all new Hartley Capri
the FIRST and ONLY shelf speaker system with
Hartley's famous POLYMERIZED cone
combines a newly engineered Hartley Luth Speaker with revolutionary POLYMER CHEMISTRY
to provide a high
fidelity "break through" that you can actually HEAR. Your
music achieves
optimum fidelity -free of fuzziness and cone "break up" caused by
conventional
paper cones.
The Polymerized cone makes the Capri virtually "weather- proof"
the first
shelf speaker that gives year -round quality performance-even under the
most
extreme humidity or temperature changes.
Capri cabinetry matches its advanced electronic
It is decorator styled
for shelf or console use (24" x 131" x 12"), anddesign.
rigidly constructed of solid
%" oil -finished walnut. Its exclusive all- bamboo grille with
special acoustical
weave liberates every note undistorted. Only the Hartley
utilizes 85' of
acoustic material to permit pure response down to 30 cps.Capri
features combine to give you truly higher fidelity response. All these exclusive
Audition this handsome compact speaker at
your franchised Hartley Dealer today. Hear
for yourself how chemists put higher fidelity
into the new Hartley Capri, only 3120.00
Fully guaranteed for five years.
Write for complete FREE information and
specifications on the entire House of Hartley
line of stereophonic and monophonic speakers
and enclosures, and the name and address of
your nearest Hartley Franchised Dealer.
...
...
-
artley
products company
521 East 162nd St., New York 51, N. Y.
"Over 25 years of Electronic Development for Better Listening."
Dept. A -8,
Export: Teltech International Corp., 431 5th Ave., New York 16, N.
Y.
AUGUST, 1959
95
www.americanradiohistory.com
AmericanRadioHistory.Com
corporated in the better grade machines
associated with semi -professional and
professional use. If a tape recorder is
to be capable of consistently providing
high -grade performance, then the following adjustments should he available.
1. Playback Equalization. At 15 and
7.5 ips (and perhaps at 3.75 ips as well),
equalization of the playback amplifier
should conform to the standard curve,
which is NARTB at present. Equalization can be checked and adjusted on the
basis of a series of frequencies fed into
the amplifier from an audio oscillator or
by playing a test tape. Some tape ma -'
chines include compensation for treble
losses due to the playback head. Many
or most playback heads used today have
gaps sufficiently fine so that treble losses
at 7.5 ips and higher speeds are negligible. On the other hand, as a playback
head wears, its gap tends to widen and
treble response to deteriorate. Thus an
adjustment for frequency response at
the very high end-above 10,000 cps or
so-can prove useful. However,. such
equalization has limits. For one thing,
after the gap widens to a certain extent,
the drop in high -frequency response becomes too sharp to compensate satisfactorily. For another, excessive high -frequency boost in playback accentuates
noise of the playback amplifier.
2. Record Equalization. Once play-
A NEW STANDARD OF VALUE
IN
HIGH
FIDELITY
SPEAKER SYSTEMS
The ME -12
Speaker System
for Stereo or
Monophonic
Use
$99.50
Setting the Pace in Quality, Integrity, Value
Out of the laboratory comes a truly remarkable new Speaker System
that defies comparison in quality performance at a low price. The
AUDIO -TECH ME -12 easily outperforms units twice its size and price.
Designed by Joseph Giovanelli to meet the exacting requirements of
stereo and monophonic sound reproduction, the ME-1 2 produces startling
results. Just read the features below:
40 to 20,000 cps
Entire system possesses superior transient response
full load input capacity-30 watts 12" extra- heavy -duty woofer with
High quality
Gauss
12,500
magnet
(32
oz.),
2" voice coil -permanent
tweeter balance control with calibrated scale for
3" cone tweeter
laboratory pre- tested
fused to prevent overload
accurate resetting
and inspected.
CABINET: Infinite baffle sloped front hand rubbed oil finish in natural
walnut, mahogany, or fruitwood 24" h. x 12" d. x 14" w.
2 -YEAR GUARANTEE AGAINST DEFECTIVE MATERIALS AND /OR WORKMANSHIP.
ch
Laboratories
Department A, 3420 Newkirk Ave., Brooklyn 3, N. Y.
INgersoll 9 -7134
hack equalization is adjusted to conform
to the standard curve, then equalization
of the record amplifier-in particular,
treble boost- should be capable of adjustment to yield relatively fiat response
on a record- playback basis. Some machines incorporate two adjustments; one
determines the maximum amount of
treble boost, and the other the point at
which treble boost commences. This permits very accurate shaping of the recording characteristic.
3. Bias Current. As pointed out earlier, the amount of bias current fed to
the record head governs the amount of
recorded distortion. Up to a point, an
increase in bias reduces distortion. Before this point is reached, however, bias
current causes severe high-frequency
losses in recording. At 15 ips, one can
usually adjust bias for minimum distortion-without seriously affecting treble
response, because the high -frequency
losses become very severe above the
audio range. But at 7.5 ips and lower
speeds, these losses are severe within
the audio range. Therefore at 7.5 ips and
lower speeds, the bias setting is critical,
being less than that which produces minimum distortion. One must make sacrifices both in distortion and in frequency
response, and the problem is to find the
optimum amount of bias that does not
unduly sacrifice one performance characteristic for the sake of the other. Therefore the ability to adjust bias to the
optimum level is important for the person desiring the best possible results. A
previous article pointed out that tape
machines which use a meter as a record level indicator generally employ a
switching arrangement so that the meter
can be used to check whether bias is
correct. Inasmuch as the proper amount
of bias current will vary with tape speed,
and even with brand or type of tape, it
is desirable that the bias control be
fairly accessible.
4. Record -Level Indicator Calibration.
A high -quality machine will permit one
to adjust the amount of signal fed to the
record -level indicator so that it accurately indicates when the amount of
signal fed to the tape produces a given
amount of distortion-2% or 3% harmonic distortion usually being considered the maximum permissible amount.
Bias Frequency
In order to avoid discernible heats between the bias frequency and harmonics
of the audio frequencies, the bias frequency should be about four to five times
the highest audio frequency, namely between 60,000 and 75,000 cps. While
75,000 cps or higher is even more desirable, a limit is set by the fact that
capacitive losses in the record and erase
heads increase with frequency. Accordingly, the bias oscillator has to work
AUDIO
96
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
proportionately harder as bias frequency
increases, which raises the problem of
distortion in the bias waveform and attendant noise. Hence 75,000 cps or so is
a practical. maximum for the bias frequency. A frequency much below 60,000
cps is open to serious question as to its
compatibility with high -fidelity per-
formance.
A -B Switching
In a machine having separate record
and playback heads, it is highly desirable
that there be an A -B switching facility,
as illustrated in Fig. 17, to permit comparison between the incoming signal and
the signal recorded on the tape. Specifically, the output jack of the tape machine and the monitor jack should be
switched between the incoming signal
and the playback signal. Comparison between the two signals can then he made
by earphones connected to the monitor
jack or by means of a sound system fed
from the output jack.
Record Interlock
One of the catastrophes that occasionally befalls the tape recordist is that of
inadvertently erasing part or all of a
valued tape because the machine is accidentally set in the record instead of
playback mode. To minimize this danger,
most tape machines provide a safety interlock that prevents putting the machine into record position unless one
simultaneously actuates a special record
button or lever. This button or lever
should automatically disengage when the
machine is put into any other mode of
operation. To further minimize the danger of accidental erasure, some tape recorders have a warning light that goes
on when the machine is in the record
mode.
Automatic Equalization Change
It is desirable that the record equalization, and if necessary the playback
equalization, be automatically changed
when going from one tape speed to another.
TD -124
WHAT MAKES THE TD's
STO PS?
...finer for stereo...finer for mono
If you move in circles where component
hi -fi is a by -word, you've no doubt heard
about the Thorens TD-124 transcription
turntable and its fabulous performance.
But for late-corners we'd like to point up
just
a few of the really big features (nontechnical readers may skip remarks in
parentheses): Extra heavy table for constant speed (10 lb rim -concentrated table
insures low wow and flutter; higher moment of inertia than any similar table).
Exact speed ( +3% adjustment on all
speeds -162/3, 331/3, 45, 78 -with built in illuminated strobe for setting after
stylus is on record). Easy on records
(unique two-table design permits starts
after you've placed stylus, permits 2/3
rev. starts, makes cueing easy).
Extremely low rumble (mirror -finish main bearing, nylon- seated ball -thrust -bearing
reduce both vertical and horizontal rum ble to a new low, so important for stereo).
2 -way motor rumble reduction (both
an extra -large idler and an ultra-compliant belt -drive keep motor vibration and
speed variations from table). Driving
parts electronically balanced. No costly
base necessary (only $9.00). 50/60 cycles, 100/250 volt operation.
These are just a few of the TD -124's
features. Ask your dealer to tell you the
whole story on the fabulous TD -124.
Now two budget-priced
TD
Number of Motors
The transport has three basic mechanical functions so far as the record
and playback modes are concerned: (1)
-
TD-134
TD -124 but you save two ways: (1) they come
already equipped with stereo -wired professional
arm without overhang making them ideal
changer replacements. (2) Some TD features
have been eliminated to save you money. But
they still top the performance of every similar
turntable and player on the market. TO-184
has semi -automatic operation. TD -134 is man.
ually operated. Precision metal stroboscope
(50/60 cycles) furnished with each unit.
100/250 volt operation. Wooden base only $6.00.
RECORD
AMPLIFIER
TD-184
$75.00 net
o
PLAYBACK
HEAD
OUTPUT
JACK
*Mks
Write Dept. A -8 for catalog on complete Thorens Hi -Fi line
PLAYBACK
AMPLIFIER
A
-B
SWITCH
SWISS MADE
MONITOR
JACK
PRODUCTS
HI -Fl COMPONENTS
SPRING- POWERED
LIGHTERS
SHAVERS
MUSIC BOXES
Fig. 17. A -B switching arrangement.
AUDIO
4 -speed
$60.00 net
RECORD
HEAD
o
turntables
turntables have same basic
adjustable -speed precision -drive as famous
These
INPUT
$99.75 net
NEW HYDE PARK, NEW YORK
AUGUST, 1959
97
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Tape Handling
To turn the takeup reel in a given direction; (2) to cause the supply reel to
tend to turn in the opposite direction so
as to provide back tension on the tape;
(3) to drive the capstan, which in conjunction with the pressure roller grips
the tape and pays it out at a prescribed
rate of speed. As a general rule, the
best performance-most accurate speed
and least wow and flutter-is achieved
by transports having a separate motor
for each function. On the other hand,,
there are a few single -motor transports
that through excellent design and construction achieve results about as good.
The speed, ease, and smoothness of
tape handling are among the factors to
be considered in acquiring a tape recorder. Starts and stops should be fast,
but accomplished with sufficient smoothness to avoid breaking or stretching the
tape. While some professional machines
can come up to operating speed or to
a full stop in as little as 0.1 second, as
much as 1 second is usually adequate for
home purposes.
A transport should be able to wind a
1200 -foot reel of tape in either direction
in about 60 to 90 seconds; semi-professional and professional units require as
little as 30 seconds. Smoothness of winding is of greater importance than speed,
however, so one should not be overly
distressed about a slow- winding machine
provided that it winds uniformly. The
slower the winding speed, the less the
tendency to stretch the tape or generate
stresses that can result in distortion.
Some tape recordists, where utmost
quality is sought, have been known to
rewind a tape at operating speed by
reversing the reels and putting the machine in the playback mode. If the winding speed varies according to the tape
speed setting (7.5 ips, 3.75 ips, etc.), it
may be advisable to rewind the tape in
the slowest available speed.
Tape Lift
To minimize head wear, which is due
to abrasive action of the tape against
the heads, it is desirable that the tape
be automatically spaced away from the
for the /1 man in 7
who can ` separate
the wheat from the chaff
u H E 2 u NI v E R SA
$29995
plus Fed. Ezc. Ta.
AUDIO
Complete
UHER
UNIVERSAL
with
AUTOMATIC
Remote Control
Microphone.
Carrying Case,
CONTINUOUS
PLAYBACK
Empty Reel and
Dust Cover
TAPE RECORDER
SLIDE
MODULATION
7
CONTROLS
TRANSISTOR
DYNAMIC MICROPHONE
HYSTERESIS SYNCHRONOUS MOTOR
UP TO 8 HOURS RECORDING
your place
in
seconds
4
AUTOMATIC
different signals simultaneously
5
INPUTS
3 TAPE
SPEEDS
15/16"
from
SEPARATE RECORDING AND PLAYBACK VOLUME
TIME
AUTOMATIC REWIND
AUTOMATIC COUNTER
40.16,000 CPS, Sig. to Noise Ratio 45 dbs, Wow and Flutter
WORKS ON ANY POWER SUPPLY ANYWHERE
MUSIC, for DICTATION.
PROJECTOR SYNCHRONIZED
- takes
Self- contained SPEAKER SYSTEM and TAPE DECK Operation
Push Button JAM PROOF Keyboard
REMOTE CONTROL
MIXER
CONVERTIBLE
- at
the flick of
a
CONTROLS
- to
find
- .3%
button - for
+
or
Precision Engineered by Craftsmen of West Germany
where the tape recorder originated
For Your Nearest Franchised Dealer, Write
WARREN WEISS, sole U. S. Agent,
Dept.
c/o
A
Loading
Loading of the tape machine should
be a simple, rapid procedure, without
the tape having to be threaded through
SELLS FOR
ACTIVATED
heads during rapid wind or rewind. In
some machines, this spacing is deliberately kept small to permit a slight
amount of signal pickup (chiefly low
frequencies) to facilitate locating a desired passage on the tape.
TRANS -WORLD ELECTRONICS, Inc.
1650 Broadway, New York 19. New York
a complex system of guides, rollers, and
so on. Most transports today feature
"in- line" loading, where the tape is
merely dropped in a straight or slightly
curved slot and thereby properly engages the driving mechanism, heads, and
so on. There are times when the operator
will have to reload as rapidly as possible
-for example, when taping a program
off the air -and facile loading can then
be a most important asset of a tape
machine.
The purchaser will want to check that
the tape path is such as not to skew the
tape, but allow it to wind from one reel
onto the other without scraping the top
or bottom of either reel (assuming the
reels are not warped). If the path causes
the tape to skew, not only is there a
disturbing noise as the tape scrapes the
reel, but the azimuth relationship between the tape and heads may be affected.
Tape Index
To facilitate location of a passage on
a tape, a tape index of some sort is desirable. Most transports at least provide
markings under the reel to indicate
elapsed time or remaining time at a
given speed. In addition, a number incorporate a mechanical counter of one
type or another. Some employ a clock type dial and revolving hand. Others
use rotating numbered discs.
AUDIO
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AUGUST, 1959
_
Editing Facilities
The serious recordist may be concerned with editing problems, where it is
necessary to make splices at a given note
or syllable. In this case, it is important
to the recordist that the machine provide
easy access to the tape when it is in front
of the heads, so that he can mark the
exact point on the tape where a splice
is to be made.
044,d.
re'
4L4A S.,1:1-Pi
r
.........,.z
11
Controls
Push -button controls- either mechani-
cal or employing solenoids-are found
in many tape recorders, both of the home
ir!rti
type and of professional grade. While
they offer operating convenience compared with transports manually actuated
by levers, on the other hand the more
complex the mechanism the greater is
the possibility of malfunction. Moreover,
there is less "feel" to a machine with
push- button control, and tape breakage
or spillage may occur if the push- button
mechanism functions improperly.
Æ
BOOK REVIEW
KKp
'[.(L.rf
&la:44 z.g
-
-
-
AUDIO
Otite,"
Ua-a,-
;14, Mad;
Q.ri .
C-/.4'
F
e 4e,;(4!t ,
..
.lebee"if,14! 14 drG1^-
-...
/`
:.._
.
, ..
ty 74. mid a..4.4.ae
$19.95.
measurements, installation techniques,
and general information. The obviously
added -on last chapter, about disc stereo,
is the only one not fully up to date.
The book is presented as a series of
questions, with the text comprising the
answers to them. This makes for an unusual style, but it appears to be as effective as the more common style, and at
least more informal and therefore more
readable.
Some 240 pages are devoted to test
equipment and audio measurements
sections which in themselves would make
a valuable and much-needed book if they
were available alone. About 170 pages
cover optical film recording and motion
picture projection equipment rather
more than seems necessary since a relatively small number of people actually
work at it. However, much of the basic
audio engineering came from the motion
picture studios, and the author has been
in that line of work for most of the thirty
years that this reviewer has known him.
Practically every subject we have looked
up has been covered in this cyclopedia
which is more than can usually be said
about most cyclopedia-and on those subjects with which we are familiar it appears that the information is adequate,
correct, and well presented. We know of
no other single source of so much audio
information.
-CGMcP
(/'
fl
The Audio Cyclopedia, by Howard M.
Tremaine. 1280 pages, 6" x 9", 354 halftone illustrations, 1300 line drawings.
Indianapolis: Howard W. Sams & Co.
The first complete audio handbook has
finally made its appearance. Said to have
been eight years in preparation-which
we can well believe -and two years of
editing, The Audio Cyclopedia brings more
than a wealth of information between its
covers. Its 26 sections begin with the
basic principles of sound and continue
through acoustics, constant speed devices,
components used in studio -type systems,
amplifiers, disc recording and reproducing, magnetic and optical recording, motion picture projection equipment, loudspeakers, power supplies, test equipment,
ism
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AUGUST, 1959
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99
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HAROLD LAWRENCE
Lofty Music in Paris
To the crew about to undertake a recording of the St. Sulpice crgan, the most formidable impression made by this sprawling 18th century church is that of stairs.
Stairs in front of the center portals, spiral
stairs winding up toward the organ loft,
perilously narrow wooden stairs going to
the platform above the mightly instrument, and more stairs to the uppermost
ramp of the interior of the church. The
longest continuous stairway is the spiral
one; taken at too fast a clip, this corkscrew -like ascent can set your head spinning by the time you reach the landing,
and, if the steep climb does not make you
dizzy, the view from the balcony down the
full length of the church (some 400 feet)
will do the job. From here, powerful Dela-
sor, Charles -Marie Widor, held the post for
no less than 64 years and, quite naturally,
the little room is a tribute to his memory:
there is an oil portrait of the late master
as well as other memorabilia including his
desk, furniture, and manuscripts. In its
simplicity and lonely setting it has a
strangely moving effect on the observer.
Above the organ loft, through another
locked door, we reached as far as stairs
could bring us, namely, to the upper ramp
of the interior. After looking over the array of pewter -toned pipes from our vantage point, we calculated what the most
practical microphone position would be;
then we examined the walls of the church
to locate a good rope -tying spot. (The rail-
ing along the ramp is precariously shaky.)
Much to our delight, the 18th- century architects had thoughtfully included a pair of
are replacements for wartime casualties). built -in iron rings in the walls on both
sides of the organ. We therefore strung
The beauty of the proportions of the interior conveys a sense of repose and bal- our rope and pulleys through the rings.
Now that we had decided on an over-all
ance that is in marked contrast to the "exuberant decorative art of the lateral chap- microphone setup, the next plan of action
was
to locate the monitor room. This
els, with their globe "clouds," cherubs,
and concealed lighting. There is even a.. proved to be a more difficult undertaking.
pair of gigantic Venetian shells in the In terms of access to the console, there
was, of course, the organist's study behind
aisles which are used as holy water vessels.
the organ loft; but this was rejected beAll these stairs are located in the south
cause of the size: it was large enough to
tower of the church, the focal point of the
preparatory work involved in the record- accommodate the three speakers, all right,
but no personnel. The sacristan then suging. In the manner of an army about to
gested the ground floor chapel of the south
storm the heights of a medieval fortress,
tower which is in use only once a week.
the first order of the day was to explore
But that would have made it necessary for
the tower from ground to turret in order
M. Dupré to climb the equivalent of seven
to discover the most convenient and shortstories in order to go from console to moniest route for the audio cables. This, of
tor room each time he wanted to hear a
course, was dictated by the placement of
playback. At this point, Minard recalled
the microphones and the disposition of the
playback room. Our guide for the investi- that there was a chapel (now abandoned)
gation, M. Minard, the sacristan, brought not far from the organ loft, on a slightly
with him a large batch of keys with which higher level. Up we went again. Opening
a door behind the organ pipes, we ascended
to open the numerous doors, gates and partitions as we proceeded mole -like through a narrow wooden staircase, pushed open a
the dimly -lit passageways. Illumination was trap door, climbed a few stairs, and there
we were. Nothing remained of the chapel
provided by means of a series of buttons
except a statue of the Madonna. The rest
found at regular intervals along the way.
of the long room contained chunks of
By pressing one of these, electric bulbs
light up throughout the tower. An auto- crumbling masonry, an oil canvas lying
matic timing device turns off all the lights beneath a pile of broken straw chairs,
several empty beer bottles, and some 1937
every minute or so, however, and you are
then thrown into a dungeon-black darkness. newspapers. Apparently the chapel had
been used as a recreation room for conA stranger in the tower, not knowing where
the next light button was located, would struction workers during a period of
have to grope forward cautiously, and church repairs. We learned later that stusearch along the walls with his hands for dents' mass was celebrated here many
the button. At moments like these, it was years ago. When we told Dupré that we
as our
reassuring to have Minard with us; he were going to utilize the old chapel
playback room, he told us that he atwould tell us to "freeze' while he clattered
We
as
a
boy.
Sunday
mass
there
tended
on confidently to the next button.
he
Scores of steps later we found ourselves invited him to look in and seeforwhether
him, and
thought it would be suitable
in a corridor leading to the organ loft. We
-the
another
door
lie
directed
us
toward
passed a row of bellow -pedals, a carry -over
wrong door. Re had forgotten the way
from pre -automation days when the organ
over the years. Entering the chapel with
drew its breath from foot -operated bellows.
us, he paused an looked at the ruined inTo the right, a legend engraved in the wall
terior with tears welling up in his eyes:
listed the registration-stop pedigree of this
he said, "Just think, it's been 50
mighty instrument, the largest on the Con- "Tien,"
since I last set foot in this place!"
tinent. At the end of the corridor is the years
decided to use one end of the
It
was
organist's study, now occupied by Marcel
chapel as the playback area since it was
Dupré who holds the coveted position of
or less separated from the main part
organist of St. Sulpice. Dupré's predeces- more
of the room. The lack of furniture and ilwas dealt with in a crude but
Y.
lumination
11,
N.
New
York
'.66 W. Ninth St.,
croix frescoes look down upon noble columns bathed in a topaz-,colored light (the
temporary yellow stained -glass windows
D41
AUDIO
100
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AUGUST, 1959
effective manner: two battered chairs
placed at a wide interval supported a long
wooden lank, nail -studded and bristling
with splinters; this constituted the work-
table for the A. & R. department. For
light, a dormant electrical outlet was discovered and put into service by an enterprising engineer. The chapel, incidentally,
became the assembly point for the monitor, microphone and intercom cables which
had been hauled up the façade of the
church from the recording truck below.
The object of all this activity was to
capture on magnetic tape the sound of a
renowned instrument performed by an artist who is thoroughly familiar with all its
resources and capabilities. Of the latter,
the St. Sulpice organ is richly endowed.
Built by Cavaillé -Col during the last century, it is a product of the golden age of
French organ building. As in the churches
of Sacré -Coeur and Ste. Clothilde, Cavaillé -Col achieved here a remarkable degree of purity of timbre. While his St.
Sulpice organ is admirably suited to the
fullblown Romantic works of Widor, it
nevertheless does justice to Bach and
Couperin because the contrapuntal voices
are projected without blurring or rumbling.
The first test recordings were made before midnight early last June. The church
was empty and the old district of St.
Sulpice was as quiet as a provincial village
at night except for the distant bustle of
nearby Boulevards Raspail and St. Germain. Suddenly, the sound of this glorious
instrument rolled into the star-filled Parisian night and echoed through the Place
St. Sulpice and the streets leading into the
square. Transfixed by the music, a lone
bicyclist stopped to listen. It seemed as
if the whole qunnier joined with him. A
COMING HI -FI SHOWS
Sept. 11- 13- Milwaukee, Pfister Hotel.
(Rigo)
Sept. 18- 20-Chicago, 8th Annual High
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Palmer House, (International Sight and
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Sept. 25- 27-Rochester, N. Y., Sheraton
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Oct. 5-10-New York, High Fïdelity Music
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*Diagonal measurer
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Nov.
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Nov. 13- 15-Portland, Ore., New Heath man Hotel. (Rigo)
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AUDIO
Write for name of dealer nearest you.
PEEta700
Crafted by Conrac, Inc.
AUGUST, 1959
CUSTOM TELEVISION
Dept. M
Glendora, California
101
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DUAL CONCENTRIC SPEAKERS
EXCELLENT IN MONOPHONIC
'TAM N OY'
SUPERB IN STEREO
BELVEDERE
Advocating now, as in the past, that the enclosure is an integral part of
the speaker system, Tannoy has designed two new enclosures for use
in stereo reproduction. Due to the inherent quality of the Dual Concentric speakers to provide fundamental response at the low end of the
spectrum, and an ingenious loading device in the enclosure design, it
is now possible to present a system of small physical dimensions and yet
still maintain the extended frequency response of 30 to 20,000 cycles for
which the Tannoy Dual Concentrics are famous. These systems provide
absolute minimum harmonic and intermodulation distortion, excellent
transients, and in addition, an integrated sound source so necessary for
good stereophonic reproduction.
For the 12" Dual Concentric (or the 12" Direct Radiator) there
is the 'BELVEDERE'. Designed for vertical or horizontal positioning, its external dimensions are 26" x 18" x 12 ".
The 'BELVEDERE SENIOR' houses the 15" or 12" 'MONITOR' Dual Cencentric. It is a compact 31 '/," x 23%" x 16",
and is of solid %a" construction.
Both cabinets are acoustically corrected, and handsomely finished
in either walnut or mahogany.
1
$203.00
Deal Concentric
$144.00
'BELVEDERE' with 12" Direct Radiator
'BELVEDERE' only
$ 65.00
'BELVEDERE SENIOR' with 12" Dual Concentric .... $223.00
'BELVEDERE SENIOR' with 12" Direct Radiator .... $164.00
Price's: 'BELVEDERE' with 12"
BELVEDERE
SENIOR
'BELVEDERE SENIOR' with 15" Dual Concentric
'BELVEDERE SENIOR' only
(Slightly higher In the 11'e4
....
$264.00
S
95.00
I
ENGINEERS' ERRORS
(from page 56)
by the law. In a suit against engineers
a judgment was recovered against them
which they appealed. In affirming that
judgment the South Carolina court
stated a rule of law that is fundamental
in the determination of the liability of
engineers for mistakes of this character.
"It seems to he well settled," said that
court, "that where a person holds himself out as specially qualified to perform
work of a particular character, there is
an implied warranty that the work 'which
he undertakes shall he of proper workmanship and reasonable fitness for its
intended use and if a party furnishes
specifications and plans for a contractor
to follow, he thereby warrants their
sufficiency for the purpose in view.
Recently in Virginia the defense to
a suit for the foreclosure of a mechanic's
lien for architect's services involved the
sanie principles of law applicable to the
services of engineers. By the owner it
was contended that the work had been
faulty and the cause of a loss.
"
WRITE FOR DETAILS
TANNOY (CANADA) LTD.,
36 WELLINGTON ST. EAST, TORONTO, ONT.
Circle 102A
TANNOY (AMERICA) LTD.,
BOX 177, EAST NORWICH, L. I., N. T.
Obligations Limited
There the Virginia court outlined the
extent of these obligations imposed by
the law on engineers, architects and
other professional workers. "The owner
earnestly argues," said that court, "that
it has suffered great loss as the result
of the defects due to the failure of the
architect to execute proper and sufficient
plans and specifications.
"The architect in the preparation of
plans and drawings owes to his employer
the duty to exercise his skill and ability,
his judgment and taste, reasonably and
without neglect. In his contract of employment he implies that he possesses
the necessary competency and ability to
enable him 'to furnish plans and specifications with a reasonable degree of technical skill.
"He must possess and exercise the care
of those ordinarily skilled in the business
and in the absence of a special agreement, he is not liable for fault in construction resulting from defects in the
plans, because he does not imply or
guarantee a perfect plan or a satisfac-
tory result."'
CONNOISSEUR MODEL B
TRANSCRIPTION TURNTABLE
MADE IN ENGLAND
Be sure and see (and hear) the new
Connoisseur Stereo Arm and Pickup with
sensational features. One demonstration and
you will be convinced.
ERCONA CORPORATION
(Electronic Division)
New York 36, N. Y.
16 W. 46 Street, Dept. 42
Circle 1026
A decision frequently adopted by the
courts as an authority in these controversies involving the liability arising
from the performance of services by engineers and other professional workers
was rendered by the Maine Supreme
Court in the last decade of the past
S.E.2d 885,
o Hill v. Polar Pantries, 64
South Carolina, April 30, 1951
Surf Realty Corp. c. Standing, 78
S.E. 2d 901, Virginia November 30, 1953
AUDIO
102
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
century. There suit had been brought for
professional services and the defense
interposed was that the services were not
of benefit to the owner although no imputation was made of either negligence
or bad faith in the performance of the
work.
Granting a new trial to this professional worker who had been met with an
adverse decision in the lower court, this
appellate court said of the law governing engineering and other professional
workers,
"The responsibility is essentially the
same as that which rests upon the lawyer
to his client, or upon a physician to his
patient or which rests upon anyone to
another where such person pretends to
possess some skill and ability in some
special employment and offers his services to the public on account of his fitness
to act in the line of business for which he
may be employed.
"The undertaking of an architect implies that he possesses skill and ability
sufficient to enable him to perform the
required services at least ordinarily and
reasonably well and that he will exercise
and apply in the given case his skill and
ability, his judgment and taste, reasonably and without neglect."
To this rule however the court set out
an all important exception. "But the
undertaking," said the court, "does not
imply or warrant a satisfactory result. It
will be enough that any failure shall not
be by the fault of the architect. There is
no implied promise that miscalculations
may not occur.
"An error of judgment is not necessarily evidence of a want of skill or care,
for miscalculations are incident to all
the business of life." To this is added an
outline of the duties of the professional
worker and the principle of law govering all professional services of this
character.
"Those who employ hint have a right
to his best judgment, to his skill, to his
advice, to consultations with him and to
his absolute fidelity and good faith and
when he has contributed these things to
the person who employes him, his duty
has been fulfilled."8
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- - - - - - -
Amplifiers
Pre -Amplifiers
FM-AM Tuners
Turntables
Phono
Record Changers
Microphones
Cartridges
Music Control Centers Speakers
Speaker Enclosures
Equipment Cabinets Finished
and Assembled or Do -It-Yourself Kits
THREE FULL DAYS OF CONTINUOUS DEMONSTRATIONS
FRIDAY, SATURDAY, AND SUNDAY
FROM
1
P.M. to 10 P.M. FOR EACH SHOW
RICO HIGH FIDELITY MUSIC SHOWS, Fall 1959
11 -12 -13
Milwaukee
September
Guarantee
Rochester, New York
September 25- 26-27
In another instance involving this
same feature, the obligations and liabilities of engineers and other professional
workers, a New England court a hundred years ago said of the rule of law at
that time which still subsists,
"The professional man contracts that
he will use reasonable and ordinary care
and diligence in the exertion of his skill
and the application of his knowledge to
Buffalo, New York
October 30-31 Nov.
Seattle
November 6-7-8
New Washington Hotel
Portland
November 13 -14-15
New Heathman Hotel
Philadelphia
November 20 -21 -22
Benjamin Franklin Hotel
"Ordinary Care and Diligence," not a
°
Coomba v. Beede, 36
May 7, 1896
AUDIO
Atl. 104, Maine,
Pfister Hotel
Sheraton Hotel
1
Statler Hotel
ADMISSION 75t
RIGO ENTERPRISES, INC. 500
AUGUST, 1959
N. Dearborn, Chicago 10, III.
103
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WHERE
THERE'S
accomplish the purpose for which he
is employed.
"He does not undertake for extraordinary care of extraordinary diligence
any more than for uncommon skill. The
general rule is well settled that the contractor for services to be performed for
another, agrees to exert such care and
skill as men of common care and common prudence usually exert in their own
business or in a similar kind. He agrees
to be responsible for the want of such
care and attention and he stipulates
that in no event, without an express contract for that purpose, for any greater
liability."9
A FINE
TAPE
RECORDER...
there's
°
Leighton v. Sargent, 27 N.H. 460, De-
cember, 1853
FITTITE___
note to
BELL
JAll
(from page 91)
owners
gress and the United Nations. His first recording Is well executed, with an assist from
several of El-Bakkar's musicians, and should
win him many friends.
On n visit to the night clubs of Lebanon's
capitol city. the women take over. Of the
seven vocalists heard during the evening,
only one is a man and he has a female accomplice. The tour, recorded on the spot, is
a lively one and encompasses an engaging
variety of style and accompaniments. Again a
Western influence crops up, but is soon subdued in a welter of Oriental melodies.
To insure optimum recording quality
with your excellent machine, the
recommended tape is Irish #211.. .
and for uninterrupted recording,
irish #724 with its 6 lb. tensile strength
gives you one lull hour at 71/2 i.p.s.
Send for technical bulletin.
ORR INDUSTRIES INC.
Opelika, Alabama
Circle 104A
COVER PHOTO
JUST WHAT IT TAKES
TO MAKE THE SHOW...
The installation shown on the front cover
of this issue is obviously designed to be
"lived with." Not garish in appearance, but
simply neat and efficient throughout, it incorporates a Fisher 90X FM tuner with
space provided for a multiplex adapter, a
Fisher 400 stereo preamplifier, two Leak
L50 -plue 50 -watt amplifiera, two Bozak 305
speaker systems in custom enclosures, a
Garrard RC98 record changer with a Pickering 371D cartridge, and an Andrea TV set.
There is a KLH Model Six as an auxiliary
speaker on the adjacent sun porch with a
volume control at the listening position.
-
EASY TO OPERATE
THE EASY TO READ
STUDIOSOUND S -301 -R PROGRAM EQUALIZER
Assure the success of your shows or recording sessions with the always decheck these top performance StudioSound specifications:
pendable S -301 -R
...
LOW- FREQUENCY EQUALIZATION: 12 db in 2 db steps at 100 cps & 40 cps
(shelving Characteristic).
HIGH- FREQUENCY EQUALIZATION: 12 db in 2 db steps at 3, 5, 7, 10 and
15 kc. (shelving characteristic).
HIGH AND LOW FREQUENCY ATTENUATION: 16 db in 2 db steps.
This star performer has built -in flexibility, it's available complete on one panel
or in money saving kit form.
Other fine StudioSound components vital to a good show are: StudioSound Filters,
Pads and Networks. Special components made to order. For further information
contact:
STUDIO SUPPLY CO.
711 So. Victory Blvd.
Burbank, California
Box Z -8 -59
Circle 104B
The heat duct along the back of the
cabinetry acts as a chimney and there are
aluminum deflectors to conduct heat to back
and up. Slots are located on the toe plate
below the cabinets for ventilation when the
doors are closed. The grill cloth below the
controls provides ventilation for the power
amplifiers, and is removable for servicing.
The room is fully carpeted and has one
fully draped wall in addition to a partially
draped wall opposite the unit. One wall,
adjacent to the record cabinet of the unit,
is walnut paneled.
AUDIO
104
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AUGUST, 1959
PRODUCT REVIEW
(¡rolll pall,
-
utes. Frequency response at 15 fps in within
db of the level rat 1000 cps. between 50
and 7000 ceps, and within ±:l db from 7000 to
cps.
10,01111
The signal -to -noise ratio is
better than 45 db unweighted at 1000 cps.
Separate recording and playback heads and
±2
BIG SOUND from
SMALL enclosure!
the NEW
%lea a14"
RAZI£R
TRUE BOOKCASE SIZE
PAIRED FOR STEREO AT $99.50
TWO -WAY SYSTEM
(each enclosure has a separate
woofer and a tweeter)
NATURAL WOOD FINISH
HIGH EFFICIENCY
(not printed wood graining)
(no more than 10 watts per channel
required for concert hall volume)
amplifiers are provided to facilitate monitoring and instantaneous playback. Manufactured by Electrical & Musical Industries. Ltd..
of Engluant. the E. M.1. portable recorder is
distributed in the United States by Ercona
Corporation, 10 W. 46th St., New York 36,
N.Y, Yser net price. $395.00-
MAGNECORD
Stereo ayne-cordellr. The Series 100 Mng-
necordette is a portable professional -type
tape recorder which both records and plays
back in -line stereo. A two -speed machine,
operating at 71.. and 3% fps, it is HMO capable of standard monophonic recording and
playback when desired. Separate VU meters
and gain controls are Incorporated for each
channel, as well as n finster gain control
which operates on both channels simultaneously. Frequency response IS 40 to 15.000 cps
+2.0 dl at 71_ ips: 50 to 751111 +2 db at 3%
ips. Inputs are provided for hero high-impe-
The
dance microphones, nl SO for auxiliary devices
such as tuners. phono cartridges. etc. Twomotor drive system hohl,. flutter and wow to
less than 0.3 per cent. Noise level is down
more than 48 db. Binaural monitoring is
accomplished by means of a panel- mounted
phone Jack. Playback outputs are cathode
followers which deliver 1.0 volt from normal
output level. This is truly a tine instrument
for the serious hobbyisr who demands n high
measure of audio quality as well as dependa-
%/f.a
CT/!4
is truly the best value in small
loudspeakers in America today ... performance from
below 70 cycles to 15,000 cycles; Power handling capacity
is 12 watts continuous, impedance, 8 ohms. Small enough to
fit in your bookcase! Only 101/2" high, i57/ß" long, i17/" deep;
the Monte Carlo 3/4" cabinet is hand -rubbed Walnut
finish in natural wood, and is equipped with four
concealed plastic feet. Tweeters are mounted for right
and left placement. Only $99.50 per pair ... hear the
Frazier Monte Carlo at your dealer's ... you will
be amazed at the performance!
Backed by the
Reputation
hility of perro rata uve. Magnecord Incision,
Midwestern Instruments, Inc., 41St St. and
Sheridan Road. MISS. I MN. Yser net price,
in portable carrying cane. $449.95.
PT6 -6A
PT6 -61
/I
2sp, full
/2tr, rec /pb,
rec pb ampl, port
AUDIO
port $405.00
295.00
Send for
Bulletin
tr;tir
for Quality
RAZ£R
DB 69
AUGUST, 1959
INTERNATIONAL ELECTRONICS CORPORATION
2649 BRENNER DRIVE
DALLAS 20, TEXAS
105
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2
NOW
SAVE HALF
ASSEMBLE -IT-YOURSELF
9chdét ELECTRONIC
NO SPECIAL
SKILLS
PAY KIT -BY -KIT
ORGANS
Now you can afford an electronic organ. Whether you choose
the full Concert model or the smaller Consolette, you have an organ
equal to any made by the foremost manufacturers. In addition, you save
the cost because you assemble it yourself ...and you enjoy the
over
thrill of achievement. Too, you purchase each kit only when you are ready for it.
s
2
2
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W-`.`
*
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tt
*
different MODELS
different SIZES
different PRICES
MAGNEMITE
,
CONSOLETTE
MODEL
CONCERT
MODEL
FULL SIZE PIPEORGAN MANUALS,
122 KEYS
OCCUPIES 3'5" x 4'7" FLOOR SPACE
COUPLERS
32 BASSSPEDÁ
TWO
S
ASSEMBLED CONSOLE
CONFORMS TO AMERICAN GUILD OF
ORGANISTS SPECIFICATIONS FOR PIPE
ORGANS
COMPLETE STEP-BY-STEP INSTRUCTIONS
**
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OCCUPIES ONLY 2' x 3'2" FLOOR SPACE
TWO
PIPE-ORGAN MANUALS,
122FUKLYSIZE
ABOVE -KEYBOARD TABS
22 STOPS
13 HEEL -AND-TOE BASS PEDALS
7 FULL OCTAVES OF TONE (DOWN TO 32
CPS)
BUILT-IN SPEAKERS OPTIONAL
ASSEMBLED CONSOLE
COMPLETE STEP-BY-STEP INSTRUCTIONS
-
LP RECORD DEMONSTRATING BOTH MODELS
AVAILABLE FOR $2, REFUNDABLE UPON PURCHASE
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NEW 1959 EDITION OF 16 PAGE ILLUSTRATED BOOKLET ON REQUEST
Write Now
The
SCHOBER
-
See
ORGAN
What Fine Instruments You Get At Such Great Savings
Corporation
NEW YORK 24, N. Y.
2248 -K BROADWAY
*- Designed by
SCHOBER KITS ALL OVER THE WORLD
Richard H. Dorf.
Circle 106A
NOW ..enjoy your H/-f/ OUTDOORS
PATIO, GARDEN, TERRACE, PORCH
with the new WT -6
ATLAS
HI -FI
COAX -PROJECTOR
all- weather construction...install it, forget W...
or take it with you wherever you listen.
True HIGH FIDELITY TWO -WAY system -not
just a "compromise" of two horns coupled to
a single diaphragm. The WT-6 comprises a
weather -proof cone type driver (with 6-inch
throat) coupled to its individual woofer horn;
a separate pressure -type driver loaded to its
separate tweeter horn. The built -in crossover
v-
y
/1
"'GOP'
t
A
electronic filter supplements the electromechanical frequency -limiting characteristics
of the 2 individual reproducers
providing
-
for smooth frequency division as each
speaker functions within its engineered
range of frequencies.
All.weather
high efficiency
compact
.
for all indoor and outdoor uses .
universally adjustable "U" -type rugged steel
mounting
. finished in high temperature
baked modern beige enamel.
net
POWER RATING 15 watts continuous
$34.50
FREQ. RESP. 140-15,000 cps
IMPEDANCE 8 ohms. DISPERSION 120°
DIMENSIONS bell opening 15 ", overall depth 12"
See the WT-6 at your local distributor. Send for catalog A-8
...
...
Ito ttery- Opernteft Spring -Motor Tope Recorder. Accuracy and simplicity of operation
are stressed in the design of the VU Magnemite portable tape recorder. Professional performance is provided by the Incorporation of
a VU meter to act as n recording and output level indicator and "A" and "13" battery
voltmeter. Special ballistic characteristics
are incorporated In the meter to ensure
avoidance of overloud of peak signals. Shunting of the output signal during recording is
avoided by employing an isolating amplifier.
The VU model is similar to other 3Ingnemites
in general characteristics. It is available with
operating speeds ranging from 15/16 to 15
fps. Frequency ranges run from 300-2500 cps
to 50- 15,000 cps. depending on operating
speed. At 15 ips the machine meets primary
NARTB standards. Because this recorder is
primarily n professional instrument, available
for n wide range of specific uses calling for
various accessories. it is suggested that interested readers get in touch with the manufacturer for exact price Information. Amplifier Corp. of America, 398 Broadway. New
York 13. N.T. User net price, 7% -ips twin track model, $365.00.
NEWCOMB
Stereo Tope Recorder. The Newcomb Model
SM -310 is n rugged. simple. foolproof instrument with the precision and dependability
required by the professional. combined with
the straightforward operation desired by the
serious amateur. Transport control is centered in a "joy stick" with completely logical
positioning -fast forward 13600 feet in two
minutes). right : rewind. left : record or playback. down. Partial stick movement gives
slower reel speed. An edit position permits
turning reels by hand. The SM -310 is a twospeed (7s and 3% ips), two -channel machine
for either stereophonic or half -track monophonic recording as well as playback. Two
inputs with mixing controls are provided for
each channel, also two illuminated VU meters.
Handles reels of any size up to 10s/- 1n., including NARTB hubs. Tape drive is by means
of n single powerful fully -synchronous cool running motor. Frequency response is 30 to
15.000 cps ± 2M db at 7% ips; less than 0.25
per cent at 3% ips. Equalization is NARTB
standard. Output is approximately 1.3 volts
from cathode follower, each channel. The
SM -310 is an ideal instrument for the individual who Is deep in the art of tape recording. Newcomb Audio Products Co.. 6824 Lexington Ave.. Hollywood 38. Calif. User net
price. including case, $499.50.
N -64c Uni -dir dyn mic, w /cord. plug .. $60.00
N -36c Slim omni -dir dyn mic, w /cord, plug
51.60
.
ATLAS SOUND
CORP.
Brooklyn 1B, N. Y.
1449 39th St.,
Circle 106
B
AUDIO
106
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AUGUST, 1959
NORELCO
Stereo Tape Recorder. Engineered and manufactured by Philips of The Netherlands, the
new Continental "400" features halt -track
stereo playback and quarter -track stereo and
New
monophonic record
and
the Ultimate
STEREO CARTRIDGE
for
tape
-7 %, 3% and 1% fps
versatility, and simple piano -key controls for ease of operation. It is fully compatible with conventional recorded tapes. The
unit comprises a tape -drive mechanism, two
preamplifiers with controls, two 4 -watt power
economy, three speeds
PROFESSIONAL 55
playback
-for
amplifiers, and a Norelco wide -range speaker,
all housed in a high -fashion portable carry-
NEW SOUND
EXCITEMENT
FOR THE HI-FI
STEREO AGE!
LOUDSPEAKERS
Never before so many quality features in
loudspeakers -yet priced for the modest
budget! Dual cones for breathtaking wide
range performance! Twin voice coils in 12"
loudspeakers, with flexible impedances of
4, 8, or 16 ohms, enabling you to select
the impedance you require! Non-resonant
cast aluminum girder constructed frames!
Fully tropicalized for finest operation in any
climate. For stereo or monaural -singly or
in matched pairs.
COLUMBIA
Professional 55 ...
Cost $28.95
This new transparent cartridge is
the professional's version of the
popular Columbia CD. A high -compliance model with excellent transient response, it uses a .5 -mil diamond stylus and is designed for
transcription turntables. Comes
complete with 4 miniaturized plug in equalizing networks for low- and
high -level inputs.
CURVES, FACTS AND FIGURES PROVE IT
log case. Also furnished is a Norelco dynamic
stereo (dual element) microphone. Only a
second speaker is needed for stereo playback.
Dubbing facilities permit recording sound on
sound. The Continental 400 has inputs for
recording from microphone, tuners, and
phonograph, with facilities for mixing the
microphone input with either of the other two.
output jack for monitoring with stereo
headphones is also provided. Special Philips
magnetic heads with a gap of only 0.00015 in.
make possible extended high- frequency response even at lower recording speeds. Frequency ranges at the various speeds are: 7%
Ips -50 to 18,000 cps; 3ÿ¡ fps -60 to 14,000
cps ; 1' ips-60 to 7000 cps. Noise level is
down 55 db, and flutter and wow are less
than 0.3 per cent. High Fidelity Products
Division. North American Philips Company,
Inc., Hicksville, N.Y. User net price, $399.50.
HEAVY DUIY
CAST ALUMINUM I.
u.,
CONSTRUCTION
MAGNET ASSEMBLY,
WEIGHT SI 5 07
An
ROBERTS
Monophonic Tape Recorder. The new Roberta
Model 191 is a full -track monophonic recorder
of special interest to radio and TV stations.
sound engineers and recording studios. A twospeed recorder, it meets professional specifications, having a frequency range of 40 to 15,000
epa ±2.0 db at 7% ips, and 40 to 9500 cps
4. 8 AND 16 OHM
IMPEDANCES
TWIN VOICE COILS
DUAL CONES
NEW! LORENZ S -1288
Value-packed basic 12" loudspeaker of advanced
design, with dual cones and twin anice coils.
Choice of Impedances of 4, 8, or 16 ohms on
one speaker)
Frequency
response: 18 to
15,000 cps. Magnetic assembly weight 61.5
oz. Power rating: 30 watts peak.
$44.50
I
NEW! LORENZ S -1288 IC
A complete system in one convenient
unit! Brilliant full range diaxial for the
most critical connoisseur. Consists of
Lorenz S -1288 plus twin tweeters on
rigid metal bracket and high pass crossover Dual cones and twin voice coils
18.18,009 cps
35 watts peak
4,
8 or 16 ohms
$67.50
NEW! LORENZ S -888
wonderfully adaptable to single or multiple use. Dual cones
for thrilling broad sound response, cast
aluminum girder frame
30.14,500 cps
18 watts peak
8 ohms
$21.50
A wide range speaker
Ask for Bulletin
E -331. Check the
Professional 55's superiority in:
linearity
separation .. needle
point impedance
low mass
freedom from hum and distortion
... output level... and ruggedness.
...
...
,
...
AM
NEW! LORENZ S -388
The perfect match mate for Lorenz 12"
or
tweeter
8" speakers. Armored horn -type 21/2
with plastic cone for efficient 120 degree
YOUR OWN EARS PROVE IT
Better still. Your own ears will convince you the Professional 55 is
your best investment. Ask to see
and hear it at your distributor's
today!
CBS ELECTRONICS
A Division of
Columbia Broadcasting System, Inc.
Danvers, Massachusetts
Distributed in Canada by
CANADIAN GENERAL ELECTRIC CO., LTD., TORONTO
Circle 107A
AUDIO
high -frequency sound dispersion. Extends
the range of any system!
2,000.18,000
cps
20 watts peak
5.5 ohms
$8.50
HP -1 HIGH PASS CROSSOVER
Crosses over at 2,000
at rate of 3 db
+3.0 db at 3% ips. Flutter and wow content per octave-feeds highs cps.
to tweeters, lows to
is less than 0.2 per cent rms. Noise is 55 db woofer. Extends speaker system range to
below recorded zero level. The hysteresis - limit of audibility. For use with 2 or 3 way
$4.95
synchronous drive motor is belt- coupled to a systems.
speed -stabilized
flywheel /capstan assembly.
At
High
Fidelity
Dealers
Everywhere.
The amplifier features professional-type terFREE Cetalea -Write Dept. A-8,
minal board wiring and has (I watts output
for feeding the built -in playback speaker. High PRODUCTS. Ltd.
impedance prealnp output is also supplied for
314 'roadway, Now Te,Y I2. N. T. WOnh 4.0,00
feeding external equipment. Equalization is
GWYN. O. S. 0161IbaI,. Io, LONIS HIRN rld,I.I Load.p,L,r
based on EARTH standards. VU meter is
Circle 1078
NO
,
AUGUST, 1959
107
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Bound Volume of AUDIO Magazine
IMPORTANT
ANNOUNCEMENT
January- December 1957
AUDIO durably preserved in a handsome binding for
quick, easy reference at all times. Only a limited number available -so,
be sure to order your copy now!
A full year of
No. 122 1957 Bound Volume of AUDIO $10 Postpaid.
SHIPPED SAME DAY WE RECEIVE ORDER!
(U. S. DELIVERY ONLY)
ND9ooK
Of
SO
enient service to AUDIO
renders. Order your books
rely by mail -save time and
travel, we pay the postage.
'NA 40
T
HANDBOOK OF SOUND REPRODUCTION
by Edgar M. Villchur
Right up to date, a complete course on sound reproduction.
Covers everything from the basic elements to individual
chapters of each of the important components of a high fidelity
system. $6.50 Postpaid.
Q
NEIV!
Jo. 120
THE 4th AUDIO ANTHOLOGY
$2.95 Postpaid
No. 112
This is the biggest Audio Anthology ever!
TAPE RECORDERS AND TAPE RECORDING
by Harold D. Weiler
A complete book on home recording by the author of
Nigh Fidelity Simplified. Easy to read and learn the
2.ontains a wealth of essential high fidelity
:now -how in 144 pages of complete arti:les by world-famous authors.
techniques required for professional results with home
recorders. Covers room acoustics, microphone techniques, sound effects, editing and splicing, etc. Invaluable to recording enthusiasts.
Paper Cover $2.95 Postpaid.
No. 115
McPROUD HIGH FIDELITY OMNIBOOK
Prepared and edited by C. G. McProud,
publisher of Audio and noted authority
and pioneer in the field of high fidelity.
Contains a wealth of ideas, how to's,
what to's and when to's, written so
plainly that both engineer and layman
can appreciate its valuable context.
Covers planning, problems with decoration, cabinets and building hi -fi furniture. A perfect guide. $2.50 Postpaid.
NEID!
No. 119
HIGH FIDELITY AND THE MUSIC LOVER
by Edward Tatnall Canby
An up -to -the- minute guide that shows you how to get the
best out of your hi -fi records and tape recorder. Mr. Canby
discusses in detail the speaker, the amplifier, the radio tuner,
the record player and the tape recorder. He shows you how
to save time and money, and get the hi -fi equipment that suits
your particular, needs. Illustrated with line drawings. $4.95
'are an rr;,air
ol
HI-Fl
No. 118
NEW! How -to Book on Hi -Fi Repair
-FI-Volume
CARE AND REPAIR OF HI
by Leonard Feldman
AUDIO Bookshelf
RADIO MAGAZINES, INC., Dept. A
P.O. Box 629, Mineola, New York
Please send me the books I have circled below. I am enclosing the
full remittance of
$
(No. C.O.D.)
Latest information on hi -fi components for efficient repair and maintenance. Complete, down -to -earth information that is not punctuated with complicated mathematics. Helpful to the hi -fi enthusiast,
technician or engineer, this first volume includes many important
features: Example schematics with tube layouts, descriptive illustrations and hook up diagrams, buyers' guide. 156 pages profusely
illustrated. $2.50 Postpaid.
All U.S.A. and CANADIAN orders shipped postpaid. Add 50e for Foreign orders
(sent at buyer's risk).
119,
120,
122
118,
115,
BOOKS:
112,
110,
NAME
ADDRESS
CITY
I
ZONE_$TATE_
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calibrated from -10 to +3 db. Interlocking
controls prevent accidental erasure of recorded
tapes. Notwithstanding the fact that it is a
complete record /playback system, the 191
measures only 15%"h x 141 "w x 91/4"d, and
weighs but 28 lbs. Roberts Electronics, Inc.,
1041 N. Sycamore St.. Los Angeles 38, Calif.
User net price, $325.00.
SUPERSCOPE
Stereo Recorder -Playback System. Everything required for stereo recording and playback. including two VU meters and two power
amplifiers, is incorporated in the Sony "Sterecorder." A precision -built instrument in all
respects, it incorporates a hysteresis- synchronous drive motor and affords instant selection
of 71- and 3% -ips drive speeds. Frequency respouse is 50 to 15.000 cps + 2.0 db at 7%
ips; 30 to 12.000 cps at 3%, ips. Flutter and
wow components are less than 0.2 per cent
ization) is 30 to 20,000 cps at 7% ips ; 30
to 16,000 at 3% ips, and 30 to 8000 cps at
1% fps. Flutter and wow are 0.1, 0.2, and
0.25 per cent at the three respective speeds.
A powerful motor of the capacitor -starting
type assures uniform speed over a range of
line voltages from 90 to 135 volts. The erase
head is selective and may be used to erase
any one of the four tracks individually. An
automatic tape -stop switch stops tape with
metallized leader at end of reel. Tandberg of
America, Inc., S Third Ave., Pelham, New
York. User net price, as shown but with
second -channel recording amplifier mounted
In an auxiliary matching mini -case, $489.50.
TELECTRO
Series 900 Tape Decks and TRY-Il Record/
Play Amplifier. The Series 900 offers a variety
of facilities in a simple tape -transport mechanism without electronic equipment. For
those who wish a complete recording system,
including record and play amplifiers and the
necessary bias oscillators. the Telectro line
includes the Model TRY -11 record/play pre amplifier, which provides for recording from
low -level microphone input or from a high level source such as a tuner, and in the play
mode has an output of approximately 5.0
volts. Controls on the TRP-11 include n record /play selector, equalization switch, noise
balance, and gain control. Recording level is
shown by n VU meter. The tape transport
itself is available in five forms, depending on
the head complement. Model 900 -1 is equipped
for monophonic recording and playback and
for 2- or 4 -track stereo playback 900 -2 has
three heads-monophonic erase and play /record heads, and a 4 -track .stereo head which
may be used as a monitor during monophonic
recording, or for playing back both 2- and
;
and 0.3 per cent at the higher and lower
speeds. respectively. Stacked high-frequency
erase head erases both channels when recording stereo, or one channel (half track) when
recording monophonically. Individual level
control is afforded for each channel, plus
master gain control for simultaneous adjustment. Automatic head -demagnetizing circuit
prevents residual magnetism, with resultant
minimum tape hiss. Automatic tape lifters
protect recording heads and tape during fast
forward and rewind. Designed for both custom installation and portable use, the Sterecorder will satisfy the most fastidious user.
Superscope, Inc., Sun Valley, Calif. User net
price, $395.00. Note: A wide range of accessories is available for use with the Sterecorder, and it is suggested that those interested
in purchasing one write for descriptive
material.
TANDBERG
Stereo Record -Playback System. Notwithstanding its compactness, the Tandberg Model
5 -2 performs virtually every task which could
be expected of a modern tape recorder. A 3speed machine (7., 3% and 1% ips), it has
facilities for 4 -track stereo and monophonic
recording and playback, playback of 2 -track
stereo, and playback of half -track and quarter track monophonic tape. The unique 4-track
in -line precision laminar head has double
mu -metal shielding to give crosstalk rejection
of 60 db. Frequency response (NARTB equal-
optimist?
4 -track
stereo tapes ; 900 -3 has two heads,
stereo erase and 4-track record /play ; 900 -4
is equipped only for playback, and has a single
4 -track head which will play mono and stereo
tapes; 900-5 has three stereo bends, making
it possible to monitor a tape during recording.
All models are for 3-speed operation-7%,
3% and 1?i, ips. Flutter and wow content is
less than 0.25 per cent. Signal-to -noise ratio
is better than 50 db when used with the
TRP -11. Speed accuracy is within NARTB
standards. The mechanism employs a single
motor with belt drive to the reel hubs and
to the capstan. the latter having a large flywheel for speed stability. Transport controls
are push- button operated. They include: stop,
rewind. wind, play, and pause. The TRP -11
incorporates n VII meter. Frequency response
is 50 to 15,000 cps +3.0 db. Inputs are supplied for a low -level microphone and high level tuner, with maximum recording level
sensitivity of 0.002 volt. Telectrosonic Corporation, 35-18 37th St.. Long Island City, N. Y.
User net price : Model 900-1 tape transport,
$89.95 ; 900-2, $104.00 900 -3. $101.00 ; 900-4,
$89.95 ; 900 -5. $126.25. Model TRP -11 recordplay preamplifier, $65.00.
That's putting it mildly. If you really
want to cook with gas on your next
P.A. installation, choose from the University range. Then you'll be sure of
getting the most economical speaker
for the right amount of power, the
right coverage, the right frequency
response. The world's most compre-
hensive range of P.A. speakers is
described in University's new product
catalog. It's FREE. Also, invest $1 in
the all -new 64 -page University Tech nilog, the authoritative reference
book for planning public address
speaker installations. See your local
distributor, or write to Desk R-4,
University Loudspeakers, Inc., 80 So.
Kensico Ave., White Plains, N. Y.
;
UH ER
Multi -use Tape Recorder. A compact and
ideal tape recorder for most tape applications
excepting those where a maximum frequency
range is required for high fidelity uses, the
Uher Universal offers facilities not duplicated
with most other machines. With three tape
speeds
%, 13k, and 15/16 ips-the Uher is
-3
AUDIO
AUGUST, 1959
THE WORLD'S MOST COMPLETE RANGE
RADIAL
HIGH FIDELITY WEATHERPROOF
WIDE -ANGLE
DIRECTIONAL
SUPER -POWER
PAGING
SUBMERGENCE -PROOF
EXPLOSIONPROOF
.
TALK -BACK
109
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4iM4p
'-
SAVE
and edit functions, while the outer ring controls fast- forward and rewind. Universal head mounting bracket on all decks comprising the
Series 85 permits changing or adding to head
complement at will. All models are equipped
with long-wearing laminated heads, tape lifters, non -resonant pressure pads, and automatic tape run -out switch. The transport may
-
114
\>
horizontally or vertically. Frequency response is 30 to 14,000 cps ± 3.0 db.
Signal -to -noise ratio is better than 55 db.
Flutter is less than 0.2 per cent at 7% ips.
Front panel speed change, 3% and 7% fps.
The RP62C record /playback preamplifier is
engineered to match the operating characteristics of the Series 85 deck. Bias oscillators
may he synchronized for stereo recording.
be operated
25%
This
is
our
GROUP SUBSCRIPTION PLAN
Now you, your friends and co- workers
can save $1.00 on each subscription
to AUDIO. If you send 6 or more subscriptions for the U.S., Possessions and
Canada, they will cost each subscriber
$3.00 each, 1/4 less than the regular
one year subscription price. Present
subscriptions may be renewed or extended as part of a group. Remittance
to accompany orders.
AUDIO
is still the only publication
devoted entirely to
Audio
Broadcasting equipment
Acoustics
Home music systems
Recording
PA systems
Record Revues
I
Please
sufficiently flexible to serve as a dictating
machine at the lowest and as a conventional
music recorder at the highest. where the frequency range is said to be 40 to 16,000 cps.
Remote-control unit and Synchro -Akustomat
device for actuating an automatic slide
changer by means of a recorded tone signal
are available accessories. and the unit is
provided in a travel -style case which accommodates microphone, cables, and tape supply.
Hysteresis synchronous motor, self- contained
speaker system, separate recording and playback volume controls, and many other useful
and desirable features. Made in Western
Germany, the Uher is distributed in the U.S.
solely by Warren Weiss, c/o Trans -World
Electronics, Inc., 1650 Broadway, New York
19, N. Y. User net price, $299.95.
-
-a
VIKING
Two -Speed Stereo Recorder -Playback. The
recorder illustrated comprises the Viking
Series 35 tape deck. and two Model RP62C
record /playback preamplifiers. mounted in a
Model W4SX enclosure. The 85 1s the finest
Viking deck designed for the home music
system. Containing two motors -one for record. the other for rewind, fast forward and
footage counter
uses a dual concentric
switch knob to control all mechanical operation. The inner knob controls forward, stop,
-It
print
Tape Accessories
Name
Address
ERCONA
Renewal
New
Erase current and bias are adjustable. NARTB
tape equalization is fixed in recording, variable in playback. Distortion is less than 1.0
per cent at indicated normal recording level.
The W4SX enclosure, available in polished
walnut or fruitwood. accommodates the 85
Series tape deck and two vertically- mounted
RP62C's. The bottom panel is removable for
installation of power amplifier(s) or mixer
controls. Viking of Minneapolis, Inc., 9600
Aldrich Ave., South. Minneapolis, Minn. User
net prices : Model 35ES tape transport
equipped for monophonic and stereo record playback- erase. $147.00. Model RP62C record/
playback preamplifier, $77.50. Model W4SX
cabinet, $39.50.
Splicer. An indispensable accessory
for any tape recordist, this new British -made
splicer is extremely simple to use and can
he employed both for mending broken topes
and for editing purposes. Made of nickelTape
Nam
Addren
unit functions precisely as does a turntable
strobe disc. To use the Irish stroboscope, the
user holds it lightly but firmly against the
surface of the moving tape. Extremely low friction needle bearings allow the disc to
revolve freely in correspondence with the tape
Renewal
New
Nam
Address
Renewal
New
Name
Address
Renewal
New
plated brass. the BIB splicer comes mounted
on n flock -sprayed base, or can be mounted
directly on any tape deck. The body of the
splicer has two pivoted clamps which lock the
tape sections in a channel. Both vertical and
diagonal mitres are provided for either editing or mending. Horizontal mitres are also
provided for use in trimming off surplus
mending tape. Distributed in the United States
by Ercona Corporation. 16 W. 46th St., New
York 36, N. Y. User net price. $3.95.
Nam
Address
Renewal
New
Nam
Addren
Renewal
New
U. S., Possessions, and Canada
IRISH
only
checking the
an Ampex 601 is the Irish tape
stroboscope. a device consisting of a handle
and n Bakelite disc marked off to three concentric rings of radiating lines, with each
ring representing n nominal tape speed. The
Tape
RADIO MAGAZINES, INC.
P. O. Box
629, Mineola, N. Y.
Stroboscope. Shown
speed of
motion. Accurately scaled and ruled, one of
these devices should he included in the gear
of every serious tape recordist. ORRadio Industries. Inc., Shamrock Circle, Opelika, Ala.
User net price. $4.95.
ROBINS
Bulk Tape Eraser. This device is for the
serious recordist who wishes to lower the
degree greater than
noise level on tape to
is possible with the average home tape recorder, also for those persons who wish to
save the time normally consumed by running
tape from reel to reel over an erase head. The
Robins Model 99 will erase a full reel of tape
in a matter of moments. By simply placing a
AUDIO
110
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
Out-Performs any
STEREO
TAPE RECORDER
..r.to
t
44
`P e!r
reel on the spindle and rotating it. the re-
TO MAKE YOUR
STEREO AND HI -FI TAPES
LAST LONGER,
SOUND BETTER
ROBINS ME -99 MAGNETIC BULK ERASER
Improve your tape recordings by removing completely recorded and unwanted signals. The ME99 reduces background noise levels of tape from
3 to 6 db below normal erase head level. If your
tape deck is geared to stereo and does not have
stereo erase, the ME -99 does the job quickly and
eliminates sending tape
through single -track erase
head twice. In a matter
of seconds it demagnetizes
tapes up to %a inch wide
cordist immediately erases the signal, lowering
the background noise level by 3 to 6 db below
average erase head levels. It can handle reels
up to 10 ins. in diameter, and erases tapes
up to one -half inch wide. It operates on ordinary 117 -volt 50/60 -cycle house current. Robins Industries Corporation. 36 -27 Prince St.,
Flushing, N. Y. List price, $33.00.
ESK series Rec care kits
$2.00 -5,00
"Gibson Girl" tape care kit
Miscellaneous
BLONDER -TONGUE
Audio "Baton." This is a unique high fidelity instrument for providing complete
control of the audio spectrums. It provides a
28 -db control range for compensating for
deficiencies in program source or in reproducing equipment. Nine compensator controle
are octave- spaced at 40, 80, 160, 320, 1280,
2560, 5120, and 10,240 cps. Input is 1.5 volts
accepts reels up to I0 ".
List $33.00
t-n
ROBINS TAPE HEAD DEMAGNETIZER
MODEL HD -6
Removes
any residual permanent magnetism
from your recording head thus eliminating high
noise level and harmonic distortion caused by
magnetism. Protects your tapes and your head
and assures professional recordings. An extended
pole -piece provides easy access to the heads of
all leading makes
of tape recorders. -(,
List $10.00
o
ROBINS M/M MAGNETIC
RECORDING HEADS
3.50
.>r?r
Exclusive Tandberg features assure
the finest stereo quality and performance. You get more tape value,
too-up to 8 hrs. and 32 min. on one
reel! Tandberg Stereo plays back two
and four track tape. Besides incomparable stereo performance, it is the
first to offer recording and playback
on four monaural tracks. And only
Tandberg offers superb tape motion
at I ?a I.P.S.
Monaural tape recorders are available in 2 or 3 speeds, with or without
foot pedal for remote control.
Stereo Features
3 operating speeds
CC'CMINIONItt:
s^i
r-Y".
-
1
r/e, 334,
2 built -in preamplifiers and
power amplifiers
4 -track record -playback head
and 4 -track erase head which
can erase or 2 tracks at a time
Automatic tape stop at end of
rms, maximum, with Impedance of 125,000
ohms at 1000 cps. Output is 1.5 volts rms,
maximum, with impedance of 20,000 ohms at
1000 cps. Hum and noise are 60 db below
rated output. Frequency range is 20 to 20,000
cps ± 2 db. Harmonic distortion is well under
1.0 per cent. A panel- mounted switch permits
by-passing the Audio Baton when desired.
This is an excellent instrument for the
perfectionist in reproduced sound. Blonder
-
Tongue Laboratories Inc., 9 Ailing St., Newark
2, N. J. User net price, $119.05.
-
and 7''2 I.P.S.
4 -track Stereo, 4 -track monaural
recording and playback, plus
playback of 2 -track Stereo and
!4 -track monaural
nrn'n!,p mttrtrrtrrTrruiwcql
Upgrade your present recorder, convert to stereo
with these precision magnetic recording and erase
CLAROVOX
heads. Consider Model SQS, a 1/4 track stereo
Record Handler. Especially designed to prerecord /playback head, precisely engineered for vent damage to records
during handling,
conversion of many popular tape recorders. Note Clarovox "Miragrip" enables any record tothe
be
these quality features: exclusive "golden gap" of picked up with ease and firmly held without
leaving visible or audible narks, and with no
80 microinches for performance at PA
track approaching performance at 7%2 IFS., %a danger of slipping. The Pliers -like design is
that the Miragrip can be conveniently
track; flush shield construction for greatest hum such
used with one hand, as negligible effort Is
rejection and less poll piece wear; crosstalk fig- needed to hold
the record absolutely
ure of merit: 10 lb or better; colinearity and metal handles are chrome-plated firm. The
and
straightness of gaps: within 5 millionths of an rubber gripping sleeves are available inthe
variety of colors. The Miragrip is manufac-a
inch. $30.00 list.
tured by Clarovox Products of Coventry, Eng.,
Also available: Model 9QE3
and is distributed exclusively In the United
States by Ereona Corporation, 16 W. 46th St.,
%4 track erase head. $14.00 list
New York 30. N. Y. User net price, $4.95.
Tell us what model you have,
and we'll let you know what
head will modernize or convert
your recorder to stereo.
1
play
One lever control for tape start stop, fast forward and rewind,
record -play
Distinctive style, mahogany finish, leather case
NOW
another Tandberg
FIRST!
Tandberg Model 4
The ONLY Four -Track
Monaural Tape
Recorder, PLUS
Stereo Playback.
Records on all four tracks separately.
4 -track erase head erases one track
at
a time
without affecting other record-
ings on the same tape.
of recording on one reel of tape.
Plays back all stereo or monaural tapes.
17 hrs.
See your dealer or write to:
TAN DBERG
Robins Tape and Record Care
Accessories are available at high fidelity dealers
everywhere, or write for FREE catalog.
8
Third Avenue, Pelham, N. Y.
Canadian Agents: Engineering Sound Systems LN.,
167 Kipling Avenue South,
Toronto 1e, Ontario, Canada
Clike, 245 W. Osborne Rd.,
Ne. Vancouver I,C., Canada
Circle 111B
ROBINS INDUSTRIES CORP.
36-27 Prince Street, Flushing 54, N. Y.
Circle 111A
AUDIO
Tandberg
MODEL 5 -2
AUGUST, 1959
111
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CLASSIFIED
Rates: l0c per word per Insertion ter nonoemutrelai
advertisements; 251 per word for commercial advr
tlsements. Rates are net, and no discounts will be
allowed. Copy meet lie ateompanled by remittance I.
by the
full, and mast math the New York
first of the month preceding the date et Issm.
Ali
ARKAT
STEREO
CS
-28
TRADE UP TO STEREO Largest selection
of new, used Hi -Fi components. Professional
service facilities available. Write Audio Exchange, Dept. AE, for trading information.
153.21 Hillside Ave., Jamaica 32, N. Y.
Branches in Brooklyn, White Plains, Manhasset.
AMP /PRE -AMP
:
COMPLETE
CENTER
CONTROL
full
watts IWO
two-channel gill
reverse stereo
balance control
lull range biss and treble controls IM distortion, 4
harmonic distortion, 1% 30.20.000 coo dual preamp 2V
responve,
output jacks
speaker outputs. 4. 0. 16. 32 ohms
puth -pull Elle Williamson circuit. e
2040.000 cps
26 watts stereo or monaural. 60 watts peak
14
channel
control
to
1
,s
,8
44,-r
CONRAC "FLEETWOODfS
High Quality TI' Choaaia. The Fleetwood
da Vinci" is a wall- or bookshelf -mounting
ARKAY ST-11 AM -FM
21 -1n. TV receiver with remarkable audio and
STEREO TUNER
visual performance. It Is designed to permit
Here. for the first time, Is an AM.
picture framing. Installed in a wall the da
FM STEREO Tuner within the
Vinci takes on the appearance of any picture
of every audiophile. Unmatched by
urn costing twice me price, the one might choose to hang in the home. The
aril is two distinct receivers In Fleetwood remote- control tuning unit prodD quieting. Variable AK. singe front
one featuring 4 vvl for
vides, at viewing distance, every control necespanel switch controls AM, FM or sTEaEO selection.
,t
caved and tested $74.50
Easy-to -build Kit $49.95
sary for tuning television -on /of /volume.
channel selector /fine tuning, brightness, contrast, and definition. Separate cathode followers are provided for audio and vido circuits. Supplied with 40 feet of cable. the
remote unit may be used at any practical disfi
tance from the receiver. The Fleetwood da
Vinci uses a special 21-in. 110-deg. short -neck
ARKAY SP -6 STEREO
ARKAY SPA -55
picture tube which permits an over -all set
CONTROL CENTER
AMP
STEREO
depth of only 14 ins. A high- fidelity audio
Versatile stereo pramap WIM
Two 27
dual inputs and outputs. RMN
channel affords faithful reproduction of the
M41 amplifiers fori stereos
filters, reverse position, bal.
BSI asm55 watt monaural amTV FM -sound transmission. Two separate
ance control. Less covet.
plifier.
$6495
audio outputs are provided-one for connecfiueruild Kit $6495
Easy- o-buiid Kit$3995
tion to a loudspeaker, the other for connection
Wired and tested $62.95
and rested $79.95
to a high -fidelity music system. Conran, Inc..
Glendora, Calif. User net price, Including
See and hear ARKAY Kits at your deafer.
A
Dept.
21 -in. picture tube and remote control unit,
FREE! Stereo booklet and catalog. Write
Wired and tested $99.95
Easy -to-build Kit
s
(
E
All prices 5% higher west of Mlsslsslpel
88 -06 van Wyck Expressway
Richmond Hill 18. N.Y.
$399.00
800 chassis and remote unit
810B self -contained chassis
Circle 112A
IF YOU ARE
$299.50
249.50
DEXTRAFIX
Tone -Arms Control. This device Is called the
"Dextrafix" and is suitable for virtually all
types of independent tone arms used In con-
MOVING
HIGH FIDELITY SPEAKERS REPAIRED
Amprite Speaker Service
70 Vesey St., New York 7, N. Y.
BA
ENJOY PLEASANT SURPRISES?
write us before you purchase any hi -fi.
be glad you did. Unusual savings. Key
tronics, 120 Liberty St., New York 6,
EVergreen 4.6071.
7 -2580
Then
You'll
Elec-
N. Y.
WRITE for confidential money -saving prices
on your Hi- Fidelity amplifiers, tuners, speakers, tape recorders. Individual quotations
Ychange,
only; no catalogs.
yn
AR, 2375 E. 65th StCBro keld34,
,1E
1
INDUCTORS for crossover networks. 118
types in stock. Send for brochure. C & M Coils,
3016 Holmes Avenue, N. W., Huntsville, Ala.
VALUES. Hi -fi components,
UNUSUAL
tapes, and tape recorders. Send for package
quotations. Stereo Center, 18 W. 37th St.,
N. Y. C.
CROSSOVER NETWORK KITS. Custom
and contract coil winding. Write Watson Industries, 110 Mildred, Venice, California.
SELL : Pilot SP -125 stereo preamp, $85 ;
cartridge. $14 ; Altec 039A microphone, $55. Jac Holzman, 115 W. 16th St.,
N. Y. C., AL 5-3958.
G. E. stereo
CONCERTONE 61K monophonic record/
playback, used less than a year, in excellent
condition. With 2 101/2 -in. reels, $430. Robert
Baum, 435 Summit St., Lemoyne, Pa.
SELL : Pentrol T-90 "Pacemaker" tape
recorder, new condition, $65 ; Acrosound 60watt amplifier, $55 Garrard record changer,
with Pickering cartridge, $25. V. R. Hein, 418
Gregory. Rockford. Illinois.
notify our Circulation Department
at least 5 weeks In advance. The Post Office
does not forward magazines sent to wrens
destinations unless you pay additional pest.
Please
age, and we can NOT duplicate copies sent
to you once. To save yourself, us, and the
your old address and your new address.
WANTED: Altec Lansing speaker system,
model 820 C. Communicate with William S.
Cooke, 403 Grandview Ave., Pitman, N. J.
a headache, won't you please
cooperate? When notifying us, please give
Post Office
FOR SALE : Mixing panel, custom made,
six- position, two microphone inputs, four high level inputs, two of which are bridging. Cinema
amplifiers, separate power supply, rack- mounting, 19" x IOs/s" stainless steel panel. Excellent condition. $500. A. C. Smrhn, 12 Mona tainview Drive, Mountainside, N. J.
Circulation Department
RADIO MAGAZINES, INC.
P. 0. Box 629, Mineola, N. Y.
-
also trade
CASH for used 401A Ampex
400A 1/2-track for full. Peter J. Helfrich,
R. D. #1, Wescoessille, Pa.
SMOOTHER OUTPUT!
PURITY OF SOUND!
speaker enclosure
Standard Audiofelt glued inside your stereo or hi -fi
waves
corrects cabinet radiation, spurious resonances and standing
which distort sound.
Audiofelt is
Developed specifically for enclosure damping, Standard
you full, natural
easy to apply and will last the life of your set. It gives
sound free from coloration.
Cal.;
Write or phone Standard Felt Co., 29 S. Palm Ave., Alhambra,
7, III.;
Chicago
St.,
S.
Green
231
Y.;
N.
10,
York
New
St.,
114 E. 25th
693 Mission St., San Francisco 5, Cal.
Circle 1126
WANTED: Presto 16 -ohm 1 -D disc cutters.
State condition and best price. 612 40th St.
N.E., Cedar Rapids, Iowa.
FOR SALE: Pilot AA -903 amplifier and
preamp and Garrard RC -80 changer with
G. E. magnetic cartridge (diamond stylus)
and Formica base, $60 plus shipping. AUDIO, Box CH -I, P. O. Box 629, Mineola,
N. Y.
WANTED: McIntosh amplifiers, type
50W2, in good condition. Bell Sound Studios Inc., 237 West 54th St., New York
19, N. Y.
POSITION OPEN for audio-oriented
electronic engineer or superior technician
in New York recording studio. Call JUdeon
2-8815.
AUDIO
112
www.americanradiohistory.com
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AUGUST, 1959
PROFESSIONAL
DIRECTORY
junction with high- fidelity turntables. It is
also useful with changers where it is desired
to use the tone arm manually. Dextrafix acts
as a safeguard
America's foremost
high performance FM
broadband Yagi
more good music stations
with your FM tuner. Improved
Get
sensitivity increases signal
against tone arm accidents
which- ordinarily result in damage to records.
stylus and cartridge. It is used to lower the
cartridge into the record lend -in groove gently
and accurately. At the end of play, or at any
desired point on the record, it may be used
to lift the stylus. The stylus cannot touch
the record or table until the lift bar 1a
lowered for the next play. Installation can
be made in minutes. The Dextraflx is a most
useful device. affording music lovers the same
means for preserving their records employed
by most broadcast stations, Dexter Chemical
Corporation, 845 Edgewater Rond, New York,
N. Y. User net prier, $4.05.
KINEMATIX
Stereo Balmier .lfcfer. Designed to assure
optimum sound balance of stereophonic
speaker systems, this instrument Is intended
strictly for home use. and once installed
requires no further adjustment or manual
operation. The attractively finished natural
wood case houses a single easy -to -read meter
Stops record damage!
Do you know all your records contain dust in
of groove? This unretouched photomicrograph, courtesy of Wireless World
every inch
(London), shows how much is removed by one
use of the ESL Dust Bug. If not removed, these
particles cause noise (especially on stereo
records), and also inflict permanent damage
upon valuable records and styli.
The only safe, effective method of cleaning
records is the ESL Dust Bug, acclaimed by more
than 200,000 delighted users throughout the
world. It's easy, too -- it cleans automatically
strength and minimizes fading,
distortion and background noise.
To be fully informed,
send 25e for book
"Theme And Variations" by L. F. B. Carini
and containing FM
while the record
FOR LISTENING AT ITS BEST
APPARATUS DEVELOPMENT CO.
9,
Connecticut
Circle 113C
Fastest, Easiest Way To Learn All About
Audio
NEW Rider "Picture- Book" Course
BASIC AUDIO
by Norman H. Crowhurst
The Rider "picture- book" approach has made
many technical subjects understandable to many
hundreds of thousands of people. Now, everything
about sound and audio reproduction
crystal- clear. If hi -fi is your interest -oris ifmade
you
work with tape recorders -or the broad subject
of sound reproduction interests you, -or if you
assemble your hi -fi equipment or buy a
complete
"package" -you must read BASIC AUDIO.
If you already own sound reproducing equipment
-this "picture- book" course will give you an allaround background on all the important details
of
sound reproduction. It will enable you
to get the
most from your equipment.
You can learn easily, rapidly at very low
cost.
You build your knowledge step -by-step.
There's
one idea and one specially prepared
per page. More than 400 illustrationsillustration
for
maximum understanding.
Beyond
knowledge
vl,no previous lct onelectricity
experen a is needed
to get the maximum fromcthis
course. Whatever
electronics circuit theory is required
to make the
entire panorama of sound reproduction
and recording visible to you is provided.
This Rider "picture- book" audio course
is completely different from anything that has ever
presented. We guarantee your satisfaction. been
#201. 3 vola., soft covers . . . 88.70 per
set
At your jobber or book store, or order direct A8
John F. Rider Publisher, Inc., 116 W. 14th
St., N. Y. 11
In Canada; Charles W. Pointon,
b Aiuna Ave.
which Is connected to amplifier output terminals. The user simply- adjusts his volume
controls until the indicator on the meter is
centered, thus assuring accurate stereo balance. On the back of the meter housing are
two volume controls which permit the user
to purposely unbalance the stereo channels to
compensate for acoustic problems or off- center
seating arrangements. Sinematix, Inc.. 1616
N. Damen Ave., Chicago 22, Ill. User net price,
LOOK
further
.
If you're
searching for hl -fl savings.
Writs n your moviesmoms now..
Key Electronics Comma,
128-8 Lanny
ev
It, N.Y. L, .Y.
4-on
Circle 113E
AUDIO
A 35 -54 36th St Long Island City 6,NY
Circle 113A
FOR INTEGRITY IN MUSIC
~.THERE IS NOTHING FINER
PHONO PICKUPS AND ARMS
9K fuie
THAN A STROMBERG-CARLSON
sep less,:lie4 9d ü e
7
special
recording tape
$1.19
"-
1200 ft.; 7
guaranteed splice -free
1800 ft.; 7"
$1.89. Enclose 10t for
each reel to cover postage and handling.
.
O.,
7.
Z
Ea
0")
Li..
nIt
"STEREO 60"
DUAL - CHANNEL AMPLIFIER
.
SOUND CORPORATION
820 W. OLYMPIC BLVD., LOS ANGELES 15, CALIF.
Circle 113F
CANADA
Circle 113D
Laboratories, Inc.
Dept
$14.11.5.
Toronto
no
Only $5.75
$4.75),
Electro -Sonic
Station Directory.
Wethersfield
is being played.
complete (record changer model only
High Fidelity Equipment
Complete Lines
Complete Service
HI -FI Records
Components
-
and Accessories
&LECTROTO10E
SOUND SYSTEMS
126 DUNDAS
ST. WEST, TORONTO,
CANADA
Circle 1130
AUGUST, 1959
Here are performance and control features
found ogly in amplifiers much higher in
price. Some of these are: each amplifier
on a single chassis provides 30 StrombergCarlson watts* of clean balanced power;
exclusive Stereo Tone Balance Signal; channel reverse switch; separate volume, bass
and treble controls on each channel; master
gain control. Price $169.95 (Audiophile
Net, Zone 1). Your dealer is listed in the
yellow pages or write for specifications.
'Our deliberately conservative ratings exceed published
specifications, bused on ASRE measurement procedures.
STROMBERG -CARLSON
GENERAL DYNAMICS
1418 N. Goodman Street
Rochester 3, N.Y.
Circle 113B
113
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ADVERTISING
INDEX
Soundcraft's MAGNA -SEE Kit lets you
see the sound on your tape
113
112
106
108
87
6
96
7
Belden
Bell Telephone Laboratories
Best of Audio
Bogen -Presto Company
Bozak
Bradford Audio Corp.
Head Alignment Head
Track placement and balance
Contains: % pint
Chocks for:
British
20
4,
Industries Corporation facing
Concrac,
27
43
GREAT PASTURE ROAD. DANBURY, CONNECTICUT
West Coast: 342 N. La Brea., Los Angeles 96, Calif.
Canada: 700 Weston Road, Toronto 9, Ont. Canada
Circle 114A
113
Cov. IV
General Electric
Gotham Audio Sales Co., Inc.
Grado Laboratories
Gray High Fidelity Division
102
59
31
Coy.
Kingdom Products Ltd.
KLH Research & Development
Corporation
Lansing, James B., Sound, Inc.
Lesa, Electrophono Cr Parts Corp.
Marantz Company
Midland Furniture Corporation
Neshaminy Electronics Corp.
Newcomb Audio Products Co.
North American Philips Co., Inc.
Paco Electronics
BIGGEST VALUES EVER! Save
Co.,
Inc.
Pickering Cr Company
Pilot Radio Corporation
Precise Development Corp.
Professional Directory
most
on Stereo hi -fi. See top buys in Allied -
Address
29, 53
60, 61
94
Key Electronics
Kierulff Sound Corporation
ORRadio Industries, Inc.
Name
105
Jensen Manufacturing Company
BARGAIN
SUPPLEMENT
Please send FREE illustrated catalogue of
MIDLAND high fidelity enclosures.
16
JansZen Loudspeakers
ALLIED'S
MIDLAND FURNITURE CORP.
Oep't 8A, Lisbon, N. H.
113
Fairchild Recording Equipment
Corporation
Fisher Radio Corporation
Frazier International Electronics
Corporation
Fukuin Electric (Pioneer)
....
SEND FOR
MIDLAND
13
114
Hartley Products Company
Heath Company
_
89
66
-
Electronic Organ Arts, Inc.
Electro-Sonic Laboratories, Inc.
Electro- Voice, Inc.
Electro-Voice Sound Systems
Ercona Corporation
,sounocaaFr..
3
101
EICO
brochure, write
MIDLAND high fidelity enclosures are
designed by acoustical experts. Carefully controlled mass production
techniques and over 25 years of experience as manufacturers of fine
furniture keep prices low without
sacrificing quality. Interior designs
for any hi -fi problem, monophonic
or stereo. See them at your local
high fidelity showroom.
112
102
Inc.
Dexter Chemical Corp.
Dynaco, Inc.
instructions.
Makes editing easier
. -.more exact.
5
49
55
90
107
Continental Felt Co.
Cosmos Industries, Inc.
of your developed
track, and complete
tEW-
1,
Broadcasting System, Inc.
Classified
Connoisseur
Plastic bath
Eye -piece magnifier
Pressure-sensitive
tape 5 glass slides
for permanent copies
ALLIED'S
p
CBS Electronics, A Division of Columbia
Magna -See Solution
For free MAGNA-SEE
33, 34, 65
Ampex Corporation
Apparatus Development Co.
Arkay
Atlas Sound Corp.
Audio Bookshelf
Audio Fidelity Inc.
Audiogersh Corp.
Audio Tech Laboratory
YOUR TAPE RECORDER
ON THE SPOT:
wear
94
114
Allied Radio Corp.
CHECK OUT
... more cabinet
for your money
14
Acoustic Research, Inc.
Acro Products Company
III,
Circle 114C
91
95
8 -11
99
39
ELECTRONIC
113
113
107
ORGAN
HOME!
51
15
99
17
SUPPLEME
ALLIED RADIO, Dept. 146 -He
100 N. Western Ave., Chicago SO, 111.
Send FREE Allied Supplement No. 185
Tandberg
Tannoy
Thorens
Trans -World Electronics
Tung -Sol
Name
Address
zone
State
YOURSELF
63
SAVE!
19
45
57
113
Coy. II
93
114
113
35, 103
2
11
1
25
84, 85
106
83
Now you can own a professional electronic
organ and save up to 50% on an easy
The world famous
pay -as-you -build plan
14 models from the
ARTISAN ORGAN
popular 2- manual Home entertainment style
to the majestic 4-manual Theatre and Church
style is now available in kit form. Simple step
by -step instructions, pictorial diagrams and
schematics make this an ideal sparetime
-in
...
-
project for anyone.
FREE LITERATURE on REQUEST
Get the Artisan Story before you purchase
any Organ. Kit or commercial model.
1
ALLIED RADIO
LCity
r
104
Sherwood Electronics Laboratories
47
Shure Brothers, Inc.
112
Standard Felt Co.
Stromberg-Carlson, A Division of General
113
Dynamics Corporation
104
Studio Supply Co.
H. H., Inc.
,1 0110011
62
products. Save as never before!
Scott,
a" BUILD -IT-
92
114
Radio Corp. of America
Radio Shack Corporation
Reeves Soundcraft Corp.
Rider, John F., Publisher, Inc.
Rigo Enterprises, Inc.
Roberts Electronics, Inc.
Robins Industries Corp.
Sargent Rayment Co.
Schober Organ Corporation
for your
100
recommended complete systems,
KNIGHT quality Stereo components, and KNIGHT -KIT build your -own Stereo. Hundreds of values
in famous name amplifiers, tuners,
changers, speakers, accessories -as
well as recorders, P.A. systems, test
instruments and electronic supplies.
Send for your FREE Allied Supplement packed with bargains and new
Rockbar Corporation
State
Zone
City
J
University Loudspeakers, Inc.
Viking of Minneapolis
Weather
Industries
ARTISAN
MUSIC HALL
,.a
New Home of
ARTISAN ORGANS
ORGAN
KITS
111
and
102
97
98
4
88, 109
41
64
Circle 1148
COMPONENTS
ELECTRONIC
ORGAN ARTS, INC.
4949 YORK BLVD., Dept. A -8
LOS ANGELES 42, CALIF.
Circle 114D
AUDIO
114
www.americanradiohistory.com
AmericanRadioHistory.Com
AUGUST, 1959
START YOUR HIGH FIDELITY SYSTEM
WITH A GRAY COMPONENT wsamaZEo
...GRAY COMPONENTS for expert workmanship at low cost to you
GRAY Hysteresis -
GRAY Custom DeLuxe
Synchronous Turntable Kit
Precision engineered parts.
Balanced for both stereo
and monophonic use. 331/2
RPM belt drive.
HSK -33 turntable .. $49.50
SAK-12 tone arm.. 23.95
TBA base
Turntable
212 SX 12" arm
17.95
GRAY Tone Arm Kit
Outstanding features such
as linear fluid damping,
turntable, arm and base
Factory assembled components
that give you all the extras you
need for the most complex system.
33 H (Hysteresis- Synchronous)
33
C
Wood Base
$79.95
34.00
23.95
GRAY Micro - Balanced Pressure Gauge
Indicates pressure on record
surface so that adjustments
can be made for proper tracking. A true balance without
springs.
PG 200 gauge
$2.50
quick- change cartridge
slide, adjustable static
'
balance, and versatile wiring for all cartridges makes SAK -12 tone arm your best buy.
SAK -12 12" arm kit
$23.95
Visit your friendly quality Gray dealer for a full demonstration. Write to us for complete literature.
our 67th year in communications ..
GR
.
High Fidelity Division
YDEPT. 6
16 ARBOR STREET, HARTFORD 1, CONN
www.americanradiohistory.com
AmericanRadioHistory.Com
Ooûooiti»tfie
...WITH
2 -WAY
1//1
WIDE -RANGE
MUSICASTER
all- weather high -fidelity speaker system
Now you can very easily set up a permanent or portable
outdoor extension of your high-fidelity music system
... for relaxed enjoyment. Take the MUSICASTER to the
patio, or pool ... and treat yourself, your family, your
guests to the pleasure of a full concert or background
music ... or even the ball game.
Unique design of this compact, integrated loudspeaker system assures superb musical balance
%
and clarity. Exceptional bass response is
r"'
achieved through the back- loaded folded horn.
High frequencies are smoothly and efficiently
radiated from the exclusive E-V Radax dual cone speaker. Wide projection angle simplifies
placement of the MUSICASTER for complete
listening coverage.
All -weather performance is guaranteed by special silicon treatment of the cone assembly. The speaker is fully protected
handsomely finby the rugged diecast aluminum housing
ished in Mesa Tan baked enamel. You can set the MUSICASTER
anywhere on its built -in rubber feet. Use the mounting bracket
as a convenient carrying handle.
...
DOUBLE YOUR FUN WITH STEREO. You can add the excitement of stereo sound outdoors with a second MUSICASTER.
Ideal combination of wide -range response and wide -angle
dispersion gives you the startling realism of 3- dimensional
reproduction.
E -V
MUSICASTER High -Fidelity Speaker System. Response: 60-
cps. Dispersion: 120 °. Impedance: 8 ohms. Power handling
capacity: 30 watts. Size: 21'/," h. x 21%" w. x 8'/," d. Net wt. 23 lbs.
List Price, $80.
Net Price, $48.
13,000
Accessory Model MB -1 Surface Mounting Bracket. For neat, unobList Price, $4.50. Net Price, $2.70
trusive installation on flat wall.
See it
... Hear it ... Enjo y it ... on Money -Back Guarantee
At Your E-V Franchised High -Fidelity Dealer
-or write for
Free Bulletin No. 258A to Dept. 89 -A
ELECTRO -VOICE, INC.
BUCHANAN, MICHIGAN
Research- Engineered High-Fidelity Speaker Systems,
Phono -Cartridges, Microphones, Sound Projectors,
Communications Equipment, Marine Instruments,
and other Electro- Acoustic Products.
www.americanradiohistory.com
AmericanRadioHistory.Com
-
-
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