engineering music sound reproduction
.
APRIL, 1955
50c
I
MUSIC
ENGINEERING
SOUND
0
REPRODUCTION
R6 4700
s
o
C
-if-
V1-65,17
aN61N7
V2s
V26
^46
a
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05
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50
140
O
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40
6
-
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ilv
This small amplifier, designed originally as a monitor am9r.fier for a broadcast
station, will serve admirably for a home music system where the power requirements are not too severe but where qt-ality is extremely important. See page 26.
Building a portable phonograph in. a case suitable for travel and designed fcr use under varying
conditions proved most interesting. See page ;7.
AN AROUND -THE -WORLD PORTABLE
HIGH QUALITY-TEN WATTS SMALL PACKAGE
-
SIMPLE DESIGN FOR STATION -BUILT CONSOLE
MAKE YOUR OWN METER SCALES
www.americanradiohistory.com
The Ampex 600 monitor selector switch lets you make
Tlaneous listening comparison between what is fed to the tape and ..
tope plays Back
to you. (Ask your local Ampex distributor for this ae:::onstration)
... and you will hear how perfect
a tape
recorder can be
On the Ampex 600 it takes the most perceptive listening to hear even the slightest difference between what
goes into the recorder and what the tape plays back.
Listen again .
after an Ampex has run for thousands of hours. The comparison will still be equally
favorable. This sustained performance is something
that specifications do not show. But this is the
reason why Ampex has become a magic name.
.
.
For recording from
F
-M radio, copying of valuable
records, playing of pre- recorded tapes or the
making of personal or professional recordings, the
Ampex 600 is a permanent investment in satisfaction.
ARTHUR FIEDLER
listens.
"A studio Ampex
is a cherished part of my home high
hearing this new Ampex 600 was a real
surprise. It's such a convenient size, yet like my big Ampex
it is a superb recording and reproducing instrument."
fidelity system.
But
(NOTED CONDUCTOR
OF THE BOSTON POPS ORCHESTRA)
AMPEX 600 PORTABLE MAGNETIC RECORDER
40 to 15,000 cycles response at 71/2 in /sec. (± 2 db from 40
to 10,000 cycles; down no more than 4 db at 15,000 cycles).
Over 55 db signal -to -noise ratio.
Flutter and wow under 0.25% rms.
Prices
$498 unmounted, $545 in portable case.
-
AMPEX 620 PORTABLE AMPLIFIER -SPEAKER UNIT
Matches the Ampex 600 in appearance and quality.
Price
$149.50 in portable case.
-
For
full specifications, write today to Dept. 8 -1887
AMPEX
CORPORATION
934 CHARTER STREET
REDWOOD CITY, CALIFORNIA
Distributors in principal cities (see your local telephone directory under
"Recording Equipment ''). Canadian distribution by Canadian Gene'ol
Electric Company.
www.americanradiohistory.com
VOL. 39, No. 4
APRIL, 1955
Successor to RADIO, Est. 1917.
666
AUDIO
ENGINEERING
Alt -elc
CnistpPetel!q PLeat
StUND REPRODUCTION
VARIABLE D`
C. G. McPraud, Editor and Publisher
Henry A. Schober, Business Manager
Harrie K. Richardson, Associate Editor
Florence Rowland, Production Manager
Edgar E. Newman, Circulation Director
CARDIOID
DYNAMIC
for TVand BC
Sanford L. Cahn, Advertising Director
Representatives
H. Thorpe Covington and Dick Knott
Special Representatives
7530 North Sheridan Road, Chicago 26, Ill.
Sanford R. Cowan, Mid-West
67 W. 44th St., New York 36, N. Y.
West Coast
J. W. Harbison
James C. Galloway
816 W. 5th St., Los Angeles 17, Calif.
CONTENTS
Audio Patents -Richard H. Dorf
New Literature
Letters
About Music-Harold Lawrence
2
6
8
Coming Events
Editor's Report
An Around -the -World Portable-Arnold J. Gassan
Simple Design for Station -Built Console-C. M. Edmonds
High Quality
Ten Watts
Small Package-Harold Reed
Make Your Own Meter Scales -Ronald L. Ives
Amplifiers -Edgar M. Villchur
Equipment Report-McIntosh C-8 Audio' Compensator and Mc -30 Power
-1 Phono Arm- General Electric AI -901 Record Filter
Amplifier
Audio ETC -Edward Tatnall Canby
Record Revue-Edward Tatnall Canby
Employment Register
New Products
Industry Notes
Industry People
Advertising Index
...
...
-B
10
12
14
17
21
26
30
34
44
50
52
59
60
70
C.
1
-U.
G.
RADIO MAGAZINES, INC., P. O. Box 629, MINEOLA, N. Y.
AUDIO
APRIL, 1955
reverberation and equipment rumble.
Uniformly smooth response 40- 15,000
cps, laboratory controlled. Highest
front -to -back discrimination.
Virtually no proximity effect. Output
-57 db. E -V Acoustalloy diaphragm.
Blast filter. Detachable clamp -on
swivel stand coupler. Weighs only
11 oz. 71.¡C x 135'. TV
gray. 20' cable. 50 ohms.
Readily changed to
150 or 250 ohms.
71
Model 666 Microphone. List $245
72
Model 366 Boom Mount.
List $40
Model 300 Stand Coupler.
List $10
Model 420 Desk Stand.
List $20
Normal Trade Discount Applies
(title registered U. 8. Pat. Off. Is published monthly by Radio Magasines. Inc., Henry A. Schober, President;
McProud, Secretary. Executive and Editorial Offices, 204 Front St.. Mineola. N. Y. Subscription rates
8..
Possessions, Canada and Mexico, $4.00 for one year, $7.00 for tao years, all other countries, $5.00 per year. Single
copies 50e. Printed in U. S. A. at Business Press, Inc., 10 McGovern Ave., Lancaster, Pa. All rights reserved. Entire
eontenti copyright 1955 by Radio Magazines, Inc. Entered u Second Class Matter February 9, 1950 at the Poet Ofdee,
Lancaster, Pa. under the Act of March 3, 1879.
AUDIO
OUTPERFORMS ALL OTHERS
Combines ruggedness of single
dynamic element with new acoustic
principle. Eliminates pick-up of
ambient noise, unwanted
EV Pat. Pend.
Write for Data Sheet No. 39
gICCZSYCZ
B U C H A N A N
,
M
I
C H
I
G A N
1
www.americanradiohistory.com
Among
important activities
at Hughes is a
program involving
AUDIO PATENTS
comprehensive
testing and evaluation
in connection with
Hughes -developed
RICHARD H. DORF
radar fire control and
navigation systems
LIKE ANY
for latest type
OTHER
electronic organ, the
Wurlitzer requires some means of
controlling how loud it wurlitzes, and
Francis M. Schmidt of North Tonawanda,
N. Y., home of the organ plant, has invented a new circuit for use with swell
shoes. It is essentially a d.c.-operated volume control compensated so that as level
military all -weather
interceptors.
Convair
Fa02
all-weather
interceptor.
System
Test
Engineers
There is need on our Stafffor qualified
engineers who thoroughly understand
this field of operation, and who have
sufficient analytical and theoretical
ability to define needed tests; outline
test specifications; assess data derived
from such tests, and present an evaluation of performance in report form.
Engineers who qualify in this area should
have a basic interest in the system concept
and over -all operation of test procedures;
2 experience in operation, maintenance,
"debugging," development, and evaluation testing of electronic systems, and
knowledge of laboratory and flight test
procedures and equipment; 3 understanding of basic circuit applications at all
frequencies; 4 initiative to secure sup-
l
decreases bass is emphasized to make up
for the ear's relatively poor response to
low frequencies at low levels and keep
over -all balance constant.
What makes this rather simple circuit
interesting even to a great many people
who for some unaccountable reason don't
care to build electronic organs is that it
could be used to great advantage by any
sound-system owner as a remote loudness
control. Due to the d.c. operation, the control line (just three wires or perhaps a
2- conductor shielded microphone cable with
a pot on the end) can be run as far as
you like without any impairment of operation of either the control or the system.
The bass-boost -at- lower -levels feature probably doesn't give the authentic Fletcher Munson curves to great accuracy, but
human ears come off an assembly line subject to large manufacturing variations and
probably Fletcher's personal loudness contours didn't even match Munson's.
The patent, which is assigned to The
Rudolph Wurlitzer Company, is numbered
2,695,386. The three principal objects of
the invention are (a) a frequency- compensated control, (b) one which tends to wash
out the effects of "noisy" pots, and (c)
probably a remote-type control which didn't
involve problems of carrying high -impedance leads all over, though this isn't stated.
The circuit of the primary embodiment
of the invention appears in Fig. 1. The
triode doesn't do any amplifying- doesn't
even carry signal ; it is simply a variable
resistance. The incoming signal passes
* Audio Consultant, 255 W. 84th St., New
York 24, N. Y.
o--U -C4
RI
I
N
ooi
CI
through R,, which acts as the series leg
of a voltage divider. Ignoring C, for the
moment and treating it just as a d.c. blocking capacitor, the shunt leg of the voltage
divider is the plate resistance of the tube.
The level of the output signal is controlled
by varying the plate resistance.
As a matter of fact, C, has a definite role.
It is in series with the plate resistance,
that is, with the shunt leg of the voltage
divider, and it has a significant reactance.
When the plate resistance is low, the reactance of C, is relatively large. This means
that the shunt leg of the divider is composed
mainly of a reactance which varies with
frequency. At high frequencies the reactance
is small, so that highs tend to be bypassed
to ground. At low frequencies, the reactance
is high so there is greater output. Curve
B of Fig. 2 shows the frequency response
at lowest level, while curve A shows that
response is flat at maximum level. It varies
between these limits at intermediate volume
settings.
A return to Fig. 1 shows how the system
is controlled. A definite positive voltage is
applied to the cathode by the voltage divider
R,-R, operating from the B- supply. R, is
bypassed by C, in the standard manner.
R, is the control potentiometer, probably
a wirewound in real life for long wear and
current carrying. The arm carries direct
voltage to the grid through a time-delay
network consisting of R. and C,; the latter
can also be made big enough to ground the
grid for any stray a.c.
When the arm of R, is at ground the
grid assumes its maximum negative potential with respect to cathode. The tube barely
conducts (or may be brought to cutoff),
the plate resistance is at maximum, and
output level is highest and response flattest.
With the pot arm at cathode, grid and
cathode potentials are equal, the tube conducts, the plate resistance is least, and level
is minimum, though not zero. Also, plate
resistance is small with respect to the
reactance of C, at the lower frequencies,
so there is relative bass boost.
The timing network R.-C, has two effects. First, it makes volume changes smooth
because the grid voltage must change ex-
R
Ic2
porting informationfrom obscure sources.
Hughes
RESEARCH AND DEVELOPMENT
LABORATORIES
SCIENTIFIC AND ENGINEERING STAFF
Culver City, Los AngelesCounty, Calif.
Fig.
1.
2
Fig
AUDIO
www.americanradiohistory.com
2
APRIL, 1955
Since 1935
the Garrard has been
sold and serviced
throughout the United States.
It is recognized every where
for superior
performance, ruggedness
and reliability.
juRES.
CHECK
CRa
MAD
SERVICE
this
PRICE
1sr.
change
el tYlrecord
and wor1d'slNunderstand
thé
W0
"RIGHTS" and "WRONGS"
of record charger design
(important
In p
electing
records).
yous
RIGHT:
Garrard Precision Pusher Platte-m ...
the only record changing des ice that insures
positive, gentle handling of records with standard
center holes.
WRONG:
"Overhead Brdges" (as on ordinary changer.)
.. which may damage or dislodge records
accidentally.
RIGHT:
Garrard remokable and interchargeahle
spindles
Easìy inserter; accommodate all
...
records, all sizes, as they were made to be
played; pull ou Instantly to facilitate removal of
records from turntable.
WRONG:
Fixed Spindles (as on ordinary chargers)...
which require ripping recorcs upwards over
metallic spindle projections after D aying.
Other Garrard features include:
-no rumble, no induced
-no wows, na waves
pole motor
heavy drive shalt
weighted turntable-
hum
misting swn:h
flywheel action, constant speed
silent automatic
-silence between records
stop -shuts off after last record; no disturbing
"plop ".
easy stylus weight adjustment-probalar.ced. mounted
tects long -play ng records
tone arm -true :angent track ng u niversal shell
--fits all popula high fidelit" cartridges
rld's Finest Record Changer
A Quality Endorsed Product of the 3RITISH INDUSTRIES GROUP,
which also includ_s
WHARFEDALE LOUDSPEAKERS .. designee and built under the personal supervision of G. A. Briggs... world renowned avthority on sound. 'Wha,feaale Loudspeakers
offer the unique construction feature o cloth su:pensioe -a felt buier between speaker
frame and cone -and cost chassis.
LEAK TL /10 -High fidelity AMPLIFIER
coco alete with "Point One" REMOTE CONPREAMPLIFIER. Most economical ampl.fer combination ever bull. by Leok.
Harmonic disto'tion only one terth of one oe cent. Insures flawless reproduction.
EXCLUSIVE FEATURE! Convenient tope recorder Ìccks (input and output) on front panel
for instantaneous owl
TROL
LOUDSPEAKER. ENCLOSURES- "Mcaimum Bass- Minireum Space" Hearing
believing! R -1 Speaker Enclosures 'nave estoolished an entirely new trend in audio
design with thrilling performance fron any loudspeaker. Bookshelf and Floor Models.
THE R -J WHARFEDALE... First and only complete R -1 unit! 'Two great products
e been
.i 31
WHARFEDALE SPEAKER
Ihe R -1 single shelf ENCLOSURE and o
tive comhination among compact high the definitive
brilliantly matched in this
R -J
is
-
...
performance speakers.
www.americanradiohistory.com
WRITE FOR A COPT OF
"SOUND CRA rTSMANSHIP"
Mall coupon today for a compl mentor,.
copy of "Sound C aftsmanship" 16
pages illustrating and describing all
products of the Briish Industries Group.
BRITISH INDUSTRIES CORP., Dept.
A4 -5
164 Duane Street
New York 13, N. Y.
Please send "Sound CraftsmanahlR"
le:
--f
Name
Address_
City
-
Zone
-
State
Fig. 3.
ponentially at a rate determined by the
component values and arm voltage to charge
C,. Second, the network may be looked on
as a low-pass filter, so that abrupt small
changes of voltage at the pot arm caused
by imperfect contact and dirt on the resistance element are filtered out.
No component values are given in the
patent specification but they should be
easy to find. R, should be rather large relative to the maximum plate resistance of the
triode; since this is infinite at cutoff, perhaps a value such as 0.47 meg or so would
be useful. Proportion R, and R; so that
with the arm of R, at ground plate current
is almost but not quite cut off. A time
constant of about 0.1 second is a guess
at a good time constant for R,-C, and 0.1
megohm seem reasonable values.
tsf and
Now substitute temporarily a large value,
say 0.25 pf, for C, and select R, so that
volume -control action is suitable when R4
is varied. Then select a permanent value
for C, which gives the right amount of
bass boost at various settings. The larger
the value, the lower the turnover frequency.
The adjustment can be made by ear while
listening to music which has some bass,
middle, and treble well distributed. C4 is
just a blocking capacitor and depends for
its value on the following grid resistor as
in any voltage amplifier. R4 can be lifted
from the circuit and placed on the end of
1
a cable.
Only ALTEC
has the remarkable 290C Driver Unit Loudspeaker
capable of handling power up to 125 watts above 300 cycles. The 290C
is
especially adaptable for public address systems, and, like all Altec
equipment, it
is
engineered with exact precision for more power
and better quality. Used with the Altec multicellulcr horn there
For those who care for a somewhat different type of compensation, the circuit of
Fig. 3 is offered. Figure 4 shows what happens, with three curves illustrating frequency responses between maximum level
(A) and minimum (B). In the earlier circuit, Fig. 2 shows that the middle and upper
response remains flat and drops straight
,hnao with decreasing level. In the circuit
(Continued on page 67)
is
no finer combination for reaching large groups of listeners.
Whether you must reach one hundred people
or one hundred thousand. Altec manufactures
ALTEC
the finest equipment to fill your needs.
Dent. 4-AP
9356 Santa Monica Blvd., Beverly Hills, Cal.
161 Sixth Avenue, New York 13, N.Y.
A
SOUND REPUTATION SECOND TO NONE!
4
Fig.
AUDIO
www.americanradiohistory.com
4.
APRIL. 1955
AND
FOR EVERY
ELECTRONIC
PRODUCT
-
WIREMAKER FOR INDUSTRY
,TZN111
`-
EINCE 1902
,
-
....
,,
ONE LINE
ONE STOCK
ONE CATALOG
FC
1
AUDIO
-8
Belden Manufacturing Company
AFRIL. 1955
Chicago
5
www.americanradiohistory.com
NEW LITERATURE
Premier Metal Products Co., 3160 Webster Ave., New York 6?, N.Y., describes its
complete line of metal housings in a new
1955 catalog which has just been released.
Tabbed for easy reference, the 16-page
booklet illustrates more than 460 standard
stock metal housings for the electronics
industry. Included are full details of many
newly -designed items not found in previous catalogs. Copy of Catalog No. 550 may
be obtained by writing direct to the manufacturer, or through local distributors.
A -1
Big brother to the famous': "Largo 8"
Atlas Sound Corp., 1451 39th St., Brooklyn 18, N. Y., designers and manufacturers
//I
of public -address loudspeakers and microphone stands and accessories, has just
released two catalog sheets on two new
Atlas products, namely, the Model CJ -30
Cobra -Jector speaker, and the Model BS -37
Porto -Boom professional microphone boom
stand. Both sheets list complete specifications, applications, and prices, and will be
mailed free on request.
1-1
T1z, Inc., Dept. KP, Telex Park, St.
Paul 1, Minn., outlines the advantages and
applications of the company's new miniature jack- and -plug combination in a catalog sheet which will be mailed on request.
One -third the size of previous models, the
combination can be installed In computers,
dictating machines, tape recorders, and
miniature radio receivers. The sheet lists
complete specifications.
A -3
New, complete two -way speaker system
-
with all the time -tested, proven features of the "Largo 8"
plus:
More powerful Super Royal 12" Speaker
New, larger, back-loaded horn enclosure
Full 20 -watt power -handling capacity
Smooth peak -free response ... 30 to 16,000 cycles
Combined with:
Scientifically matched 32KTR Super
Tweeter
Slanted speaker panel for proper sound focusing
High- frequency balance control
Horn loading of back
wave thru unique cabinet base. The Largo 12 is precision constructed of beautiful 3/4" Mahogany or Korina
Blonde cabinet woods. Impedance, 8 ohms.
Size: 231/e" H, 271/2" W, 15'/2" D.
Audiophile NET
$149.50
(Also available in Walnut at slightly higher price.)
Terminal Radio International, Ltd., 85
Cortlandt St., New York 7, N. Y., radio-TVelectronics equipment and parts distributor serving the export market exclusively,
has issued a 4 -page folder which describes
the company's facilities and special services. It also provides a complete list of
American manufacturers whose products
Terminal International sells. Brief information on export- Import procedure, packing, and transportation is also incorporated. Free copy will be mailed on request.
A -4
Alton Lansing Corporation, 9356 Santa
Monica Blvd., Beverly Hills, Calif., is now
distributing a new Jobber Sound Products
Catalog in which is displayed and described the comprehensive line of sound
equipment manufactured by the company
for specific applications in the field of
commercial electronics. Included in the
listings are microphones, utility speaker
assemblies, amplifiers for p. a. use, and
70 -volt matching transformers. Professional users of quality equipment should
have a copy of this catalog in their file.
A -5
available under the exclusive Permoflux insured Home
Try it in the comfort and quiet of your own home for
15 days -with your own records and associated egLipment. For a limited
time only, each HTP participant will receive -absolutely FREE -the new
Permoflux "Maestro" speaker- Headset Control Box ($10.00 value). Also
available under HTP: the Diminuette ($49.50); the Largo B ($99.75).
The Largo 12 is
Trial Plan (HTP).
'
Only Permoflux gives you all the features you should hove in a 2way high -fidelity speaker system. See and hear the Largo 12 and
other Permoflux systems at your hi -fi dealer today. Also ask him
about HTP-or write:
CORPORATION
Dept. D, 4902 West Grand Avenue
West Coast Plant
Canadian
Li
Chicago 39, Illinois
Glendale 4, California
Campbell Manufacturing Co., Ltd., Toronto, Canada
4101 San Fernando Road
New Jersey Electronics Cory., 395 Carnegie Ave., Kenilworth, N. J., has developed a simplified approach to buying
regulated power supplies which is described in a new 8 -page catalog titled "A
Sensible Approach to Regulated Power
Supply Design." By standardizing the
great majority of conventional power supply applications into single and multiple
variations of eight basic ranges, arising
out of two basic circuit designs, selection
of the most flexible and least expensive
supply to suit a given requirement is
easily accomplished. Sixty -four variations
of single and dual supplies are described.
A -e
General Transistor Corp., 95 -18 Sutphin
Blvd., Jamaica 35, N. Y., manufacturers
of transistors and related semi -conductor
products, has just released a new catalog
sheet of diffused p-n -p junction transistors. The bulletin, which is available for
the asking, illustrates the company's
unique double sealing process. It also includes absolute maximum transistor ratA -7
ings and characteristics.
AUDIO
www.americanradiohistory.com
MARCH, 1955
i
It Has Ever ything
Beauty
-
Operating Convenience
..
-
Quiet Performance
....,--'-.`-..
Quiet, constant -speed operot on is obtained with a precision helical gear drive
This was developed for H. H. SCOTT by
international authority Professor Earle
Buckingham of M. I. T., designer of the
drive mechanism for the Mt. Folomor 20C
inch telescope.
FREE
TECHNICAL
THE NEW
BULLETIN
A -:.54
STROBOSCOPIC TURNTABLE
The 713 -A ir.corporates major new contributions to turntable
engineering. These include: dual -stage mechanical and torsiona filtering, expanded -scale optical stroboscope, Vernier speed drive and integral
connection of pickup -arm mounting -board to main turntable bearings.
Revolutionary NEW design
Expanded scale optical stroboscope, with electronic peak pulsing
for greatest clarity, is visible even while record is playing, for exact
speed control at all times.
1.
2. Precision helical drive gears, of hardened steel and nylon, for
smooth silent flow of power to turntable. Gears housed in an cil -filled
transmission for quie: trouble -free operation.
3. High- compliance torsional filtering reduces annoying speed variations, such as wow and flutter, to less than 0.1 %, far below audibility.
4. Dual -stage mechanical filterirg between motor and turntable reduces motor rumble to more than 60 db below recording level, an outstanding engineering accomplishment.
5.
Integral pickup -arm mounting board, accomodating all
leading pickup arms, is rigidly connected to turntable bearings
by a heavy aluminum casting. This eliminates acoustic feedback and other undesirable vibration differences between pickup arm and turntable.
Prices
7. Heavy -duty induction motor, with dynamically balanced rotor and extremely low external hum field, designed specia:ly
for this-turntable.
710 A Turntable, finished 'n stainless steel with mahogany pickup -arm mounting board. $102.00'Nef
710x1 Hand- finished modern mchegany base for convenient, attractive installation: $14.95' Net
H. H. SCOTT
AUDIO
6. Vernier speed drive with special long -life neoprene idlers
perm:ts separate adjustments of 331/2, 45, and 78 rpm speeds
by ±5% to match the pitch of accompanying musical instruments. Convenient push- button selection of each speed and
OFF position. Unique clutch permits cueing turntable.
APRIL
inc.
'West Coast Puces: 7104 $107.10
710 -XI $15.70
385 PUTNAM AVENUE, CAMBRIDGE 39, MASSACHUSETTS
7
1955
www.americanradiohistory.com
Eye -wise and ear -wise
LETTERS
pleases
as no other can
it
Minimal Plate Current?
SIR:
In Fig. 9, p. 30 of your March, 1955,
issue, the first tube 17,a looks silly sitting
in plain view with only 3.7 microamperes
of cathode current. Did the author mean
this to be a transistor instead of a vacuum
tube perhaps? It seems a shame for Mr.
Schwartz to spend thousands of dollars on
audio equipment and then not be able to
enjoy it because his amplifier won't work.
Or perhaps the gremlins have been busy
again?
A. REEDER, (Dom de plume)
Dallas 30, Texas.
(They have, but not on this. Mr. Reeder
fails to note the 9000-ohm feedback resistor
R.
and the secondary of the output transa parallel path for the
cathode -to- ground circuit of this tube. En.)
former which is
Ultrasonic Bird Cure Wanted
IIR:
All over central Florida, corn and rice
,rowers are fighting a losing battle with
Ma/S21
1
Compare this Sonotone HFA-100 for
both performance and appearance
with any amplifier you can buy -at
any price!
Its 12 -watt output is ample for the
largest living room. Frequency response is flat beyond audible limits, at
any volume setting. At normal listening
levels distortion is virtually unmeasurable, and only 0.15% at maximum!
Hum and noise, too, are completely
negligible.
Cabinetry is equally superb- either
solid mahogany or solid walnut: the
panel, softly -glowing solid brushed
brass. Picture this unit conveniently
at your chairside ... its beauty is at
home in any home.
ed winged blackbirds, using airplane
patrols at $7 and up per hour and shotgun
sentinels riding on high -clearance corn dusting machines at $50 per day, with
losses running from 20 to 100 per cent.
Do you know of any experiments with
sound which may have resulted in the determination of a frequency which will annoy
the birds enough to discourage them? Do
you have any recommendations about oscillators, amplifiers, and speakers that you
could pass along. Any information would
be greatly appreciated.
C. S. CLEMANS, Chief Engineer,
Radio Station WSWN,
Belle Glade, Fla.
(Back in '48 the same question was asked
of S. Young White who wrote a series on
Ultrasonics for Æ. His answer was that
///v
The Sonotone HFA -100 is for use with
fine ceramic phono cartridges, tuners,
tape recorders, television, etc. If splendidly reproduced, noise -free music is
your interest, rather than gadgetry and
knob -turning, here is the amplifier for
you. $117.50. ($99.50 less cabinet).
SONOTONE CONTROL UNIT
Similar in appearance to the HFA -100
above, this CU -50 is
a self - powered control amplifier, designed to work with
any power amplifier.
Used with ceramic phono cartridge, tuner,
tape, or television sound, the CU -50 gives
you complete chairside tone, volume and
selector control, for your relaxed listening
pleasure. $59.00. 549.50 less cabinet)
Mt MIte
1
SONOTONE
Corporation
Elmsford, N. Y.
.
1,ry
NC
ire will gladly supply full technical information on request to Dept. AA -45
the power required would be prohibitive.
However, work may have been done in this
field since then. and we too would like to
know about it. En.)
More AES Fellowships
SIR
:
We appreciate your interest in the Los
Angeles Section activities in connection
with the 1955 Audio Fair -Los Angeles.
In your March EDITOR'S REPORT, you mentioned that Bert Berlant was honored for
his work in magnetic tape recording and
made a Fellow of the Society.
It should be noted that Mr. Berlant was
not the only one so honored. The full list
of those awarded Fellowships is as follows:
Ralph E. Allison William A. Palmer
Alexis Badmaieff William V. Stancil
Emmanuel Berlant
Howard M. Tremaine
Arthur C. Davis E. H. Uecke.
In addition, Certificates of Recognition
were presented to William L. Cara, C. T.
Kierulff, and Harry Reizes.
Since AUDIO is recognized as a source of
industry news, and since all of the people
honored are of importance in the audio
field. we feel that you will want to give
them recognition.
RICHARD F. HASTINGS,
Western Vice President,
Audio Engineering Society
AUDIO
fi
www.americanradiohistory.com
APRIL, 1955
Now...record the whole performance...
without a break
Got a favorite concert or opera program )ou'd like to preserve
on tape? Symphony or dramatic production? Now, record it all using
new "Scotch" Brand Extra Play Magnetic Tape.With 50% more tape
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You'll notice a crisper tone and higher fidelity, too -the result of
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"Scotch" Brand has been able to produce a super-sensitive, high -
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Try new "Scotch" Brand Extra Play Tape on your own machine.
REG,
New
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B
Electron Photo Microscope Shows the Difference!
At left, artist's conception of magnified view of
old -fashioned oxide coating still used by most
ordinary long play tapes. At right. "Scotch"
Brand's new dispersion method lays fine -grain
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AUDIO
o
9
APRIL, 1955
www.americanradiohistory.com
Listen lug
Quality
HAROLD LAWRENCE
everything!
is
The Composing Machine -Cont'd
All the flowery specifieations in the world cannot
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You can tell what
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HOME. Available for use on the better
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COMPASS -PIVOTED ARM
Universally acknowledged as the most
efficient arm, barring none; yet it costs
less. Useable with other cartridges too.
Adapter is of all metal con-truction.
STYLUS-BALANCE
75% of cartridges in use operate with
incorrect stylus pressure. This means distortion and record destruction. Stroboscope -like, STYLUS -BALANCE indicates
correctness or incorrectness of stylus pressure. Works with any cartridge, any arm.
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.
this really works
....
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FREE copy of ELECTRONIC
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or write us.
AIJDAH COMPANY
500 Fifth Ave. Dept. A New York 36
Fine Audio -Electronic apparatus over 30 years
THE SEPTEMBER ISSUE of AUDIO, this
coated paper the keys make perforations
column dealt with the imminent appearnot unlike holes on player -piano rolls. Then
ance on the musical scene of the comthe perforated paper feeds its message to
posing machine, a device that would enable
the synthesizer. The machine responds by
the composer of the future to create, score
sending the desired sound wave to a stylus
and record his own work simultaneously
and turntable. Here the sound is recorded
without once putting pen to paper. While
on a disk. When the disk is connected to a
this article was being written, Dr. Harry
conventional amplifier and loudspeaker the
F. Olson, director of R.C.A.'s Acoustical
sound is heard by the listener.
and Electro- Mechanical Research Labora"At present the machine can send the
tory, and his senior engineer, Herbert Belar,
tones of one instrument at a time. If a
were quietly putting the finishing touches
number of instruments are required the part
to just such a m_chanism. On Friday, Janof each must be recorded on a disk and then
uary 28th, the doors to their laboratory
all must be brought together on a new rewere thrown open to reporters. Along one
cording to cause them to sound simultanewall were six large panels containing 300
ously."
electronic networks and something that
A laborious procedure, indeed. But, after
looked remotely like a typewriter jutting
all, the crank- operated turntable was a
out from one of the panels. Its name: the
pretty clumsy device, too. And no doubt a
R.C.A. Electronic Music Synthesizer. It is
more streamlined method of operating the
claimed to be able to duplicate any sound
synthesizer will come along.
and to be able to synthesize sounds that
Now what does this latest development
have never on earth been heard, literally
mean to music as we know it? In terms of
bringing to man the "music of the spheres." standard repertory and of works composed
The debut of the Synthesizer was no
for specific instruments and voices, the synventure into outer space. Musically, it did
thesizer is of as much use as the mechanical
not even get off the ground. The program
nightingale in Hans Christian Andersen's
consisted of a Chopin Polonaise, Bach's
story. Only 'live' performers can convincFugue in C Minor from Book I of the
ingly re-create a Beethoven symphony or a
Well- Tempered Clavier. Holy Night, a
Bach prelude and fugue. And since works of
Stephen Foster medley, and Blue Skies, as
lasting value may be given any number of
though played by a piano, clavichord, elecvalid interpretations, why not call upon the
tric organ, - hillbilly band. and jazz band
artists and instruments themselves? A
respectively. Home Sweet Home and Nola
musician thoroughly at home with an imwere heard in "new" instrumental sounds.
proved synthesizer could perhaps turn out
Although crude -sounding, the results never- a creditable electronic performance. But
theless came near to the actual qualities of, then, without the impetus of living and
the instruments, near enough to make them
breathing musicians, how many music
almost credible. As for the "new" sounds,
lovers do you suppose would go to Carnegie
that will have to be left to the creative
Hall to listen to a concert played back
musician rather than to the engineer to
through a bank of impersonal loudspeakers?
exploit. But to criticize the "performance"
A glimpse into the future however might
in terms of absolute musical values is to
very well include new recordings of symquibble. Far more significant is the very
phonies as performed by conductors who
fact that it was done at all.
have never appeared before an orchestra in
Before they could start building their
their lives, by singers who have never
machine, Olson and Belar had to break
sung a note, by quartets that do not exist.
down and calibrate such sound -wave characWith the synthesizer, any recording comteristics as frequency, intensity, growth,
pany could create a new singer whose range
duration, decay, portamento, vibrato and
would put even Yma Sumac to shame. To
harmonics. The machine's "keyboard" is a
carry this a step further, the technical limiset of keys which performs varying functation would become a thing of the past;
tions four keys are for frequency, three for
speed, fingering, range, etc., throwing no
multiplying and dividing frequencies, four
obstacles in the path of the all -powerful
for harmonics or overtones, three for attack electronic device. With painstaking experiand decay, and four for amplitude. Another
ments, the machine could be made to repro"register" of seventeen keys duplicates the duce the sound characteristics not only of
first, offering countless possibilities for
an orchestra, but of its concert hall as well.
tonal variations. As reported in the New
There would be no need for the recording
York Times: "When pressed down on director to tour churches, auditoriums, and
:
10
AUDIO
www.americanradiohistory.com
APRIL, 1955
1
k
The Greatest Reward
is BUYER APPROVAL
The NEW
12-INCH TURNTABLE S
...
were received by you with the kind of enthusiasm that
is
every manufacturer's dream. Your acceptance and approval of
these products have confirmed our confidence in their quality
and justified the years of work devoted to their development.
We are both gratified and encouraged. We shall continue to
give our best talents and efforts to the cause of high quality
sound reproduction
- moving always nearer the ultimate. And
one day, we shall be able to give you 'the perfect turntable'.
Until then, we offer you the Rondine Turntables, representing
the closest approach to such perfection.
If you are not yet familiar with the Rondine Turntables,
write for a complete description to Dept.YD -1.
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Th.
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APRIL, 1955
The
RONDINE Jr.... S4995
11
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America's mos
complete line
theatres in quest of the "perfect" acoustical
setup. Come to think of it, there would be
no need for the recording director at all.
Only the relatively easy task remains of
selecting, in the case of an electronically
recorded concerto, for example, names for
the "orchestra," the "conductor," and the
.
"soloist."
Turning 110W to the place of the "live"
musician in the age of the synthesizer. the
the future does not look entirely black. It
may be years before the machine will be
made to equal (not merely resemble) the
sound of actual instruments and voices.
More important, the primary function of
such a mechanism should not be to imitate
the quality of existing sounds, but to create
and experiment with new sound. This is
not to imply, by any means, that composers
have exhausted the potentials of available
timbres. According to men like Cage,
Schaeffer and Varèse, there are still worlds
to explore. However, as another medium of
expression, the synthesizer may some day
offer remarkable opportunities to the composer- provided he has the patience and
skill to manoeuvre Iris way around the complicated networks.
ROTARY POWER
IS
BEST
'he "clop- clop" of
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more vibration than the
smooth Rotary Power
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for mo-
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and for all DC to AC
conversion .. smoother
.
. more
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,
.
DC TO AC CONVERTERS
operating tope recorders, dictating machines, amplifiers and
other 110 -volt radio
For
audio devices from
DC or storage batteries. Used
by broadcast studios, program producers, exec
utives, salesmen and other "field workers ".
DUO -VOLT GENEMOTORS
The preferred
power supply for 2 -way mobile radio
nstallations. Operates
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motors are standard equipment in leading makes
of auto, aircraft, railroad, utility and marine
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May 16-19- Electronic Parts Distributors
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SATISFIED
AC can be produced by
ing the flow of DC, like
throw-
ing a switch 120 times a second. But ROTARY converters
actually generate AC voltage
from an alternator, same as
utility stations. That i why
ROTARY power is such s clean
AC, so dependable
essential for hash -free operation of
recorders from DC power.
May 24-26 -NARTB Broadcast Engineering Conference and the Annual Convention, Shoreham and Sheraton -Park
Hotels, Washington, D. C.
.
May 26-27- Electronic Components Conference, Los Angeles, Calif.
MAIL COUPON for illustrated bulletin
with complete mechanical and
electrical specifications and nerrorn.r,
charts. Carter Motor Co., Chicago 47.
-- ,
r
CARTER MOTOR CO.
I
2648 N. Maplewood Ave.
Chicago 47, Illinois
1
Please send illustrated literature containing
plete information on
Carter "Custom"
verters and
Dynamotor Power Supplies
rom-I
Corti
NAME
Address
-------------- - - - --J
I City
Ins
Apr. 13- 15-Symposium on Modern Network Synthesis, II. Part of the celebration program of the 100th Anniversary
of the Polytechnic Institute of Brooklyn.
Engineering Societies Bldg., 33 W. 39th
St., New York City.
Apr. 27-29- Seventh Region Technical
Conference and Trade Show, I.R.E..
Hotel Westward Ho, Phoenix, Arizona.
tor models. Made by the
to "cooperate with those developing any
method whereby the composer can communicate directly with the listener, without the
distortions or intervention of performers.
The sooner something is accomplished in
this realm, the better for all concerned."
Like a number of other composers. Darreg
has been increasingly dissatisfied with the
shortcomings of the instruments at our
disposal in the symphony orchestra. He has
built an "amplifying clavichord," a "keyboard electronic oboe" and a "keyboard
drum." (He has played the "oboe" in an
orchestral work and claims it blends well
with other instruments.)
Many other electronic instruments have
been devised over the past thirty years,
and there will probably be many more to
come. But, with the construction of the
Electronic Music Synthesizer by the Radio
Corporation of America, electronic music
ha, taken it, first giant step. Nine it's up
coota vENTS
Apr. 27 -28-Canadian High Fidelity Show.
Prince George Hotel, Toronto, Ont.,
Canada.
CHANGE -A -VOLT DYNAMOTORS
To some composers, the synthesizer will
be looked upon hopefully as the whip with
which to drive the performers out of the
Temple of Music. In a letter to Aunto,
"electronic" composer Ivor Darreg of Los
Angeles, California, wrote of his eagerness
July 18-21-MUSIC -ORAMA-Music Industry Trade Show, Palmer House,
Chicago.
Ang. 24-26- Western Electronic Show and
Convention, I.R.E., Civic Auditorium,
San Francisco, Calif.
Sept. 30 -Oct. 2 -The 1955 High Fidelity
Show, Palmer House, Chicago.
Oct. 3-5- National Electronics Conference,
Hotel Sherman, Chicago.
Oct. 13- 16-The Audio Fair, Hotel New
Yorker; New York City.
Oct. 21-23-New England High Fidelity
and Music Show, Hotel Touraine, Boston, Mass.
Nov. 4-6- Philadelphia High Fidelity
Show, Benjamin Franklin Hotel. Philadelphia, Pa.
earning riexlt
~oat:
Miniaturized
PREAMP WITH PRESENCE
Combining most of the features of the original Preamp with Presence,
yet in much smaller form, and using a printed circuit panel to simplify
the construction.
State
AUDIO
12
www.americanradiohistory.com
APRIL, 1955
Partial view of COP in, talation at moiern
Lincoln Fields lace Track, located
just south of Chicx7o at Crete, llbnois
.:.i.i,i......
OFF AXIS and ON AXIS
Coverage is Ciear, Peretrating, Uniform
Electro -Voice CDP Pub.ic Address Loudspeaker System was ciosen for the 8 248 seat
North Side Gym, Elkhart, Indiana, cne of the
nation's largest high :chor1 gyms. Cluster of
stacked CD P's can be seen in photo taken
during construction.
Model
848
CDP.
;
25
watts.
16
ohms Conserva-
tively rated 5 db from 175 :o 10,(00 cps. Crossover al 1000 cps. Variable Solar paterns. Size:
10'/, in. wide, 20'/, in high, 20 in deep over -all.
List Price: $69.50 Net Price: $41.78
AUDIO
D
COMPOUND
DIFFRACTION
PROJECTOR*
Outdoors or indoors, everyone can comfortably hear everything when
you use the CDP. Listeners off the axis, where the majority of audiences
are, do not have to strain to hear, while those on the axis are not
assaulted by blasts of sound. The CDP provides smooth peak -free wide range response, with 120° sound distribution at all frequencies up to
10,000 cps. Unit energy is far more efficient-there's no wasted power.
You can do a better job with fewer units at less cost. CDP utilizes two
coaxially mounted diffraction horns, working from both sides of a single
diaphragm, plus optical slit diffraction for smooth sound dispersion.
CDP delivers' 234 octaves more musical range than comparative units.
Molded of glass fibers, CDP is weather -proof, blast -proof, splash- proof.
Compare the CDP with any other unit in the environment in which it
actually will be used -in the field or in an auditorium. Prove to yourself
why it is so superior, why it is the best value ever!
p
11,2!111,4
Send for COP Public
Address Handbook
Bulletin No. 195.
Gives complete and
helpful information.
Tat. 0169,504 and
Pat, Pend.
NO FINER CHOICE THAN
ELECTRO- VOICE, INC.
BUCHANAN, MICHIGAN
Erp,rt: 13 East 40th St., New York 16, U.S.A. Cables: Artab
APRIL, 1955
13
www.americanradiohistory.com
EDITOR'S REPORT
AUDIO SHOWS STILL GO ON
-
1' EVER TIRE of hearing about audio shows
whether near or far-and as we have said many
times before, the more people that hear high quality reproduction, the larger will our industry become, the more money will be poured into research, and
the better and better will our sound reproduction become. For some years, those who live in or around New
York, as well as those who were willing-nay, anxious
-to come from afar, were the only ones who were able
to see a wide display of audio equipment in action.
That condition has long since passed, of course, and
now we have shows in Los Angeles, Chicago, Boston,
Philadelphia, Tokyo, Washington, Montreal, and others
too numerous to mention if we include the small shows
arranged by one or more dealers. The next one to come
up is to take place in Toronto on April 27 -28, at the
Prince George Hotel, and a sell -out has already been
accomplished by the show's entrepreneur, Emory Justus.
( Dare we suggest that Emory is the big Wheel of the
Canadian Shows, since he also operated the one at Montreal ?) Anyhow, we'll be at Toronto.
The most .recent event was the Washington High
Fidelity Fair of 1955 which occupied Hotel Harrington
in the nation's capital on March 4, 5, and 6, and which
claims an attendance of 34,000 despite three solid days
of rain. This show is sponsored by WGM S-Washington's Good Music Station. The international interest at
the Fair was evidenced by coverage of the opening
ceremonies by the Voice of America, for later overseas
broadcast.
With the frequency of the shows increasing, there can
not aways be some new and important improvements,
particularly when we must consider that some very fine
quality is available in present equipment. But we must
admit that there will always be some room for improvement, even though we are approaching the diminishing
returns point. But the important thing about the increasing frequency of the shows is that the idea of high fidelity
is becoming more and more widespread throughout the
world, less and less restricted to those who have followed
audio as a hobby for years.
For example, a glance through the pages of Wireless
World, a respected British publication, will show that
more and more of the advertising space is being taken
up by purveyors of high -fidelity equipment. Britain
has never lagged behind us in quality of product-far
from it -but, if we may be permitted to say so, hi -fi
has been considerably less common there than it has
become here in the last year or so. An unbiased observer
would probably say that those who follow the hobby
of audio over there are even more sincerely dedicated
to their hobby than their equal numbers over here. We
would be willing to predict that hi -fi will come into its
own with the general public in Britain within the next
year or so at the most.
WE
We receive regularly a small magazine from Mexico
La Mejor . Musica del Mundo Para Discotecas
Selectas -which we translate approximately as "the
best music of the world for select record collections."
In the center of this book is a section called Alta Fidel idad -High Fidelity-which is listed as "the first magazine in Spanish dedicated to electronic problems and
equipment." The magazine is now in its third year, and
offers some good advice to its readers.
We continually welcome the spread of information
about audio equipment-its use, construction, operation
-and we are glad to see that the spread is not limited
to the U. S. Magazines from France, Japan, Italy,
Turkey, Denmark, and Switzerland have sections devoted to audio -we only wish we could read all of them.
What is the point of these remarks ? Just this. Many
people here have been heard to say that this is just a
passing fad, and that it couldn't possibly last more
than a year or two more. Frankly, we don't think sowe think that the desire for good music will continue
for as long as there are people, and if it is possible to
reproduce music so that it sounds more and more like
the original, people will flock to good audio equipment
from now on. telex i.iun ur nu televi.i in.
-LP,
MAY WE HAVE YOUR CHECK?
Ma) ice Pit ust have our cluck on the blue classification forms that we mail out to you periodically ? There
are two reasons for this classification sheet : most important to the reader is the information we get which
helps in the selection of editorial material to interest
the greatest number ; important to us is the fact that
AUDIO is a member of the Audit Bureau of Circulation
which asks us the questions about our readers that we,
in turn, have to ask you in order to give the right
answer. Just a few seconds of your time and we won't
bother you again. No postage is required in the U. S.
or Possessions. This information is held strictly confidential as to the individual
ends up as a part of a
percentage figure on the semi -annual circulation statement.
So, if you don't mind -may we have your check?
-it
QUESTIONS AND ANSWERS?
Many times we have considered the idea of having
a Question and Answer column in Aunto. Individual
answers to inquiries are costly, and many times one
answer would serve dozens of readers all at once. That's
why we have to restrict our replies to those which are
accompanied by return envelopes and postage.
But with the Question and Answer column we could
probably serve more people more effectively. Is anyone
in favor of the idea? Your answer on a postcard (add it
on one of those in the back of each issue) would help
us to make up our mind.
AUDIO
14
www.americanradiohistory.com
APRIL, 1955
PICKERING
cartridges
models
g-i.e."19,44/fea4
240
g9~`.l/iC7diee ... they are sold separately for all standard arms or
mounted back -to -back to make up the famous
PICKERING 260 TURNOVER PICKUP.
The 220 and 240 are engineered to
maximize performance. By comparison they
are without equal ...
MODEL 220 -for 78 rpm record
diamond or sapphire stylus
The
220 and 240 are
Lighter- 5 1 grams
MODEL 240 -for 33'3
and 45 rpm records
diamond stylus only
Smaller -3/4 by
The
3/4
by
3/4
inches
220 and 240 have
Highest Output -30 millivolts /tocm /sec.
More Compliance with Less Tracking Force
Lower Overall Distortion
Less Moving Mass
Wider Frequency Response
Mu -Metal Shielding for Less Hum
MODEL 260 -turnover
cartridge for 78 or 331/3
and 45 rpm records
(the 220 and 240
back.to-back)
These characteristics have real meaning to those who understand that
maximum performance depends upon components which meet professional
standards. If you want the best that high fidelity can offer, ask your dealer
to demonstrate the 220, 240 and 260 Pickering cartridges .. .
Tí .Avt1[174Wed
mewPICKERING and company incorporated
PICKERING COMPONENTS
AUDIO
Demonstrated and sold by Leading Radia Part. D'
Oceanside, L.l., New York
ARE PROFESSIONAL QUALITY
V; /hie
.
(c'ecrAndeced
woA>4.0e
2+%d& Gm2
'bulo,. evecywhore.
lG;,
hCrZC
For the one nearest you and for detailed literature;
APRIL, 1955
i
write Dept. A.7,
15
www.americanradiohistory.com
Tuning in for radio transmission. Each item
of equipment is not much bigger than a suitcase.
A leapfrog telephone system
for the Armed Forces !
A nor communications system, which takes to the air when water or
rough terrain prevents the stringing of wires, has been developed for the
U.S. Signal Corps by Bell Telephone Laboratories.
The system uses cable and radio relay interchangeably over a 1000 mile range. It is easily portable, unaffected by climate, and rugged enough
for global use. Twelve voices travel at once over a pair of wires or radio
waves -as clearly and naturally as over the regular telephone system.
This is the first time a completely integrated wire and radio system
of this large a channel capacity has been available for tactical use by the
Armed Forces. It is already in production at Western Electric, manufacturing and supply unit of the Bell System.
The new system is a joint achievement of the Signal Corps, Bell
Laboratories and Western Electric ... one of the many results of long and
fruitful co-operation. It shows again how techniques which the Laboratories
develop contribute to our national strength.
Amplifiers like this are used
every 53/4 miles in the cable portions of the system. They are
weatherproof, can be used on
po
Bell Telephone Laboratories
Improving telephone service for America provides careers
for creative men in scientific and technical fields
e
or the ground, and
a
will even
work under water. The system
uses a spiral wound cable developed by the Signal Corps.
Easily raised antennas
send or receive for the radio links.
www.americanradiohistory.com
An Around -the -World Portable
Custom -built phonograph designed for heavy -duty use under a variety of
conditions of climate and power supply serves as an attractive piece of
furniture suitable for use in the home when it is not actually "on the road."
ARNOLD
THE GENESIS of a complete sound system is rarely a casual occurrence.
One does not often say "Today I'll
build myself a phonograph," and sit
down at the workbench, like that, to
build a complete unit. Except for inveterate gadgeteers there is usually a specific need, or purpose. In the case Of
this portable, the reason was the need
for a fine gift.
Certain criteria came to mind when
the possibility developed of a phonograph as that gift. First, it had to be
portable-at least it had to have a handle. Second, it must sound good.
The third condition was that it must
be quite sturdy, able to take great shocks
without developing troubles and to exist
without damage in damp or dusty climates.
Fourth, it had to be able to operate
most places in the world, wherever 50or 60 -cps power is available.
With these basic tequirements outlined, the development was not as difficult as it was simply hard work. The
first step was to develop a compact am*
2176 S. Washington St., Denver 10,
Colo.
J.
GASSAN
plifier with certain basic requirements.
Unfortunately there was a time limitation between the conception and delivery
dates; therefore the final circuitry is not
so much original as it is a gleaning from
various previously tried and approved
sources. This, however, is not too unusual, and the accent here is on the complete system rather than component
parts.
The requirements that were felt to be
necessary for the amplifier were these:
(1) sufficient power to provide clean
average power of the order of 1 watt to
the speaker, which meant that eight
reasonably clean watts of reasonably
clean peak power should be available;
and (2) a minimum of controls
should be provided, as the gift was to
be for a person who did not care to be
bothered by engineering technicalities.
Fortunately the recipient did not have a
large library of recordings, and with the
new policy of using the RIAA curve
being followed by most of the recording
companies, it was felt that fixed equalization to this curve would be sufficient.
That may be a mistake, but time will be
needed to prove it one way or another.
By doing away with equalization con-
trots, only four functions were left: volume, power, treble, bass. These functions
were reduced to one dual -purpose knob
and one concentric control -knob set.
Keeping these qualifications in mind,
a tentative circuit was sketchèd out, and
then assembled after a rough check
showéd that the parts could all be fitted
into a small enough chassis box. The
complete amplifier and power supply
were assembled on a standard chassis
box 2 x 3 x 13 in. The box was of the
type formed out of two interlocking
U- shaped pieces of aluminum; and the
half with the most surface area was used
for mounting the components.
Because of the physical qualifications
necessary, it was felt that the amplifier
should be sturdily shock -mounted within
the enclosure. Partially on this account,
it was decided that the volume, power,
and tone controls would have to be
mounted remote from the body of the
amplifier. The amplifier was tied to the
floor of the enclosure rather than to the
turntable mounting because the floor was
stronger, and because there was no
room on the turntable mounting board,
it being just a half-inch larger than the
turntable. The controls were mounted in
1.
(Left) The Around - the -World
Portable open for placing a record on the
turntable. Fig. 2. (Bottom) Top view of
the portable showing the volume and tone
controls located on the forward edge of
the turntable mounting plate.
Fig.
AUDIO
APRIL, 1955
17
www.americanradiohistory.com
the mounting plate. With these
knocked out and the utility boxes holding the controls mounted directly below
them, the shafts of the controls came up
through the turntable board and the
large concentric control knobs covered
the holes "left by the removal of the vent plugs. See Fig. 2. At least an inch in
front -to -back measurement in the size
of the motorboard was saved by this expedient.
Since this unit might very well be
repaired anywhere in Europe, it was
deemed best to use terminal -board construction. This method, when used properly, is the easiest for strange repairmen
to handle.
Terminal boards do take up more
room than point-to -point wiring, and
of
two small utility boxes, both to simplify
the fastening of the controls to the wood
construction and to provide shielding.
There were inevitable losses associated
with the extra inches of shielded cable
from the amplifier to the control mounting boxes and back, but after measuring
the effect it was decided to let it go,
since there was still a sufficiently wide
range of treble control available.
The decision to make the controls
remote from the body of the amplifier
simplified the construction, since there
wasn't really room within the amplifier
for three potentiometers and a switch.
Besides, the method of mounting the
controls had already been decided upon :
the Bogen turntable finally selected has
two vent -plugs located in the front half
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they must be used properly to eliminate
this disadvantage. For example, the
principal advantage, other than the fact
that they do not load the pin connections
of the tube socket, is that it is easy for a
relatively unskilled wireman to replace
a component on a terminal board, much
easier, anyway, than replacing components on turret sockets or in a point-topoint wiring scheme. All this is true
provided the components and leads are
put on the terminals in a standard manner, and that sufficiently clear text and
drawings correlated with photographs
accompany the unit to make identification of elements unequivocal.
In line with this, a repair manual was
finally made, showing these essentials.
After the amplifier had been decided
upon and laid out, and was in the process
of being built, checked, tested, etc., the
next step was to decide upon a suitable
turntable, arm and loudspeaker. Desire
was toward the best available, but in
turntables the best is large and heavy.
Also, there was the requirement that the
turntable must operate well on either 50
or 60 cps. There was one unit on the
market with a continuously variable
turntable speed, a reasonably well designed tone arm, and a suitable price.
This was the new Swiss -manufactured
turntable by Lenco, sold in this country
by Bogen. And in that there was another,
hidden, advantage parts for repair
could probably be obtained in Europe.
A loudspeaker was the final consideration. There was, to the author's knowledge. only one loudspeaker specificially
designed for very small boxes that was
of good quality. This speaker is the
Western Electric 755A (now made by
Altec Lansing). The 755A is an 8 -inch
unit designed to work best in a box of
2 cubic feet-not even a vented box, but
simply a box. As the final dimensions of
this enclosure worked out, there was
only 1.46 cubic feet enclosed, so a bassreflex -type enclosure was finally decided
upon.
The next step was to determine how
the three main units would fit together
into the smallest attractively proportioned volume. The external dimensions
finally decided upon were 11 x 16% x 20
in. Figure 3 shows how the parts are
arranged within the enclosure.
One important aspect of the external
features of the phonograph was the necessity for the unit to operate well in
any environment. This meant that there
should be some way of completely sealing the unit from outside influences
when it was left unused for any length
of time. This introduces another advantage-if the unit were to be sealed, then
the sealing method should also make the
characteristics of the unit as an enclosure repeatable. That is, if there were a
simple positive sealing method the access
door to the turntable would present no
problems as an unpredictable opening
into an otherwise sound -tight baffle. Figure 4 shows the sealing strip on the top
cover.
The final design added about an inch
to the length of the phonograph from
front to back, because of a .14-in. thick
door (with "break-away" hinges) which
f
A-A-
Fg. 3. Sectional drawing to show placement of components in the cabinet. The letters refer
to the following parts:
Speaker mounting board
A Front protective door
1
Bass reflexing vent
Rubber gasket
B
K
Front "breakaway" hinges
C Corner block
L
Loudspeaker
Bass and treble control
D
M Pilot lamp indicator
E
Utility box shielding tone controls
N
Volume control, on -off switch
F
Turntable
O Lid of cabinet
Amplifier
G
P
Turntable motor
H
Utility plate access port
Q Motor board
I
AUDIO
18
www.americanradiohistory.com
APRIL, 1955
Complete
phonograph in playing
position. Lid is closed to provide back enclosure for speaker.
Fig.
4.
protects the grill -cloth and loudspeaker.
Both this front protective door and the
"lid" or access door to the turntable
carry a ring of sponge rubber % in.
thick by h in. wide, set in a slight
trough. This strip of rubber functions
as an efficient sealing gasket. The front
door is hinged rather tightly, so that a
definite effort must be made to latch or
unlatch it, thus guaranteeing a positive
seal. The lid is hinged so that it will
normally remain all but about 1/16 in.
from being flush with the adjacent surface at the front edge when it is just
lying in place. This was found to be
"acoustically closed" even if it were not
mechanically shut tight. The side latches
are not normally used on the lid, except
when the unit is being shipped, or
standing idle for some time.
The trouble with most portables is
that they look like portables. Because of
this it was decided to finish it in a good
r
-i
hardwood -birch in this case. Plywood,
Vz in. in the body, and Y4 in. in the
doors, was used, and a method of cabinet
construction which incolved mortising
the edges of the % in. plywood in such a
way that a 3/16 -in. corner was left
empty, this corner then being filled with
a solid chunk of hardwood. All this was
to prevent splintering of the plywood at
corners where end-grains meet.
The finish was made up of ten coats
of synthetic lacquer, and then polished
with rubbing compound. The advantage
of this finish is that waxing is unnecessary. If the finish begins to dull, one
needs only to rub violently with a soft
cloth to renew the gloss. Another advantage is that alcohol has little effect on
lacquer, and in these days that is important.
However, if one has a nice finish one
would like to keep it nice, and this can
be done by having a protective carrying
case. The case was finished on the outside with a vinyl -on- canvas truck seat
fabric, and then lined with a protective
layer of half-inch sponge rubber, with
an inside lining of the fabric used in
automobile upholstry for "headlining."
When the front protective door is removed and the unit set on a table, it is
not immediately obvious that this is a
portable phonograph, as seen in Fig. 4
in fact, it makes a rather handsome, if
severe, piece of furniture. The extreme
cleanness of line enables it to mix with
other styles of furniture fairly well.
At the rear of the unit is a suitcase type carrying handle which normally
hangs down over a recessed utility plate,
Fig. 5, protecting it from accidental exposure to idle hands. The utility plate
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The amplifier is quite straightforward,
and is shown schematically in Fig. 6.
The first stage, Vra provides amplification. The gain control is located between the second and third stages. The
third stage, Vo, makes up the loss in the
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The Amplifier
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UTILITY
PLATE
carries an open fuse -clip, an a.c. power
inlet, and a phone jack. The fuse -clip
was used, rather than a neat fuse holder,
because European fuses are unlike our
own. Both German and English manufacturers produce fuses with tapered
(i.e. conical) end contacts rather than
square ones. The phone jack on the plate
is a closed -circuit type which connects
between the first and second stages of
the amplifier, making use of the gain
control but bypassing the effects of the
equalizing feedback loop. The utility
plate is also sealed to the wood body with
a rubber gasket, in order to make the
unit a closed box with constant characteristics.
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Fig. 5. Utility plate, located on the back of
the cabinet, provides fuse mounting, a.c.
inlet plug, and jack for tuner or tape
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Fig. 6. Schematic of the entire amplifier unit. Figures in italics indicate d.c. operating voltages.
AUDIO
APRIL, 1955
19
www.americanradiohistory.com
7
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Fig. 7. External view
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tone -controls and also provides a convenient place to tie in the negative feedback loop from the transformer secondary. Since the transformer, was not a
high-quality unit, relatively little feedback was used-just as much as could
safely be applied, experimentally. The
third stage also drives a paraphase split -
ter.
The inverter feeds the two output
tubes, Vs and Vs, a pair of 6AQ5's.
The power supply is conventional, using a capacitor -input and a 15 -H choke
for filtering. The d.c. output to the power
tubes has a calculated ripple factor of
0.02 per cent. The normal decoupling
circuits follow the first filter. The hum
figure for the amplifier at 60 cps is
fairly good, 8.2 millivolts across 6 ohms,
which is about 60 db below 3 watts.
Performance
The author was quite frankly pleased
at the results of the various response
checks (see Figs. 9, 10, and 11), principally because of the dubious quality of
the output transformer, which was the
only fairly heavy duty, easily replace-
able, transformer that would fit into the
space available. The lack of pedigree
does show in the graph of distortion vs.
frequency (Fig. 9) at a fixed power
level, and this is not what would be desired. However, the upper curve is at
quite a high power-level in terms of the
listening qualities of this unit. And, it
must always be kept in mind that this
unit has to be easy to repair anywhere
-and while the chances are that the
output transformer will last longer than
any other part, there is the chance that it
will blow.
Once the entire unit was realized, the
necessity of creating a repair manual
developed. Most units built by experimenters spend their lives within reach
of a soldering iron. Since this unit may
very well never again be seen by its
maker, it was necessary to prepare a
thorough manual to accompany it. This
includes a standard schematic, and a
semi-pictorial schematic in which the
components are shown pictorially on the
terminal boards to a scale of 1% times
normal size, and the interconnecting
wiring is schematic. See Figs. 7 and 8.
The manual also includes photographs
9.
M C.«ESm.ER
SECOND
Distortion vs. frequency
istic of the amplifier.
character-
of the amplifier from two views, both
showing overlapping sections of the
interior construction, as well as a photograph of the outside of the amplifier. All
the photographs have arrows indicating
the components by number, correlating
the visual aspect of the opened amplifier
with a pictorial- schematic, and a standard- symbol schematic. This redundancy
is felt to be necessary since it is not
practical to provide a multilingual text
explaining each stage of the circuitry
and each item of the construction.
Assembly
The unit is assembled with both glue
and screws in some parts, with wood
screws alone in other parts. For example, the front board which carries
both the speaker and the grill cloth, is
bolted to a hardwood ring and then the
ring is held to the inside of the case by
a slumber of wood screws. This assembly
was made so that the grill cloth could be
changed if necessary. The bottom piece
is also held on only by woodscrews, since
all access to the amplifier, etc., is
through the bottom. The screws, in this
case, tie into an internal ring of g in.
square hardwood rather than into the
edge of the plywood.
The final assembly and testing was
made with some sense of worry. Attempting to put a wide -range unit into
a small package can be disastrous, from
at least one viewpoint. There is always
the possibility of acoustical feedback at
(Continued on page 63)
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Fig. 8. Inside of the amplifier, with identifying arrows. Arrows not labeled result from last minute changes.
4
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www.americanradiohistory.com
7
8
9
Fig. 10. Distortion vs. output, using a 1000 cps signal into a 6-ohm resistive load.
AUDIO
20
6
WATTS
APRIL, 1955
Simple Design for
Station -Built Console
Designing and constructing a console for the specific requirements of
an FM station proves to be effective from the standpoint of operating
flexibility as well as money -saving -also in operating convenience.
C. M. EDMONDS
CIAO BEEN on the air at KCMSFM about one year when it became almost painfully obvious we
needed more control facilities and more
flexibility. The new equipment would
have to meet the high standards of the
critical Audiophile listener and be
within the cost limitations imposed by
an FM station's budget. The preceding
WI.
.
Radio Station KCMS -FM, Manitou
Springs, Colo.
*
sentence contains an inconsistency that
was solved only by building theequipment ourselves.
We established the standards and the
abilities. They were:
6 microphone inputs
6 remote telephone lines or 0 -db
inputs, balanced, and with automatic cue
3 turntables, with record cueing
and control of turnover and rolloff
2- channel operation (for possibility
of binaural)
2 monitor amplifiers, one for con3
trol room and one for studios
provisions for interlocking phone
bells and warning lights
Standards:
Maximum of 0.2 percent distortion
Noise down 80 db from operating
level into transmitter. (+ 10 VU
max)
Sine -wave frequency response, 10
to 50,000 cps ± 1Y2 db
Minimum number of tube types
The Basic Design
Referring to the detail schematic,
Fig. 2, it will be seen that all of the
preamps, both microphone and phonograph are essentialy identical. A single
12AX7 is itsed in a regular phonograph
preamp circuit using negative feedback
equalization. The microphone stages
had an A-10 (UTC) input transformer
loaded with 50,000 ohms (UTC's recommendation for best response) and the
feedback capacitor and resistor were
selected for flat response and 8 db of
feedback. This value brings the microphone control to "straight up" position
to match the average LP record
at "straight up" (Fairchild or GE
pickup). The phono stages are equipped
to provide turnover frequencies of 200,
400, and 800 cps, in addition to flat, and
a fifth position connects the preamp to
a remote line transformer. Note there
is no grid input resistor; this is in accord with GE's specifications for the
Al -900 high-frequency compensator.
The program amplifier and control
room monitor are similar and will be
recognized basically as Williamson
types. The program amplifier is located
on the main chassis, and the spare
which is used as the control-room monitor-is located on the power -supply
chassis. The "house" or studio amplifier is beside the spare and is single
ended. This latter amplifier has only 3
watts output, which has proved enough
for the purpose it serves-two 8 -in.
speakers in two studios. The power
-
Fig.
AUDIO
1.
Tie comple *ed console
in its operating position with the annou.cer's microphone directly above it.
APRIL, 1955
21
www.americanradiohistory.com
MICROPHONE
PROGRAM
STAGES
AMPLIFIER
+150V
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MIC IA
IN
A10
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PROGRAM
0.1
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100
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EXCEPT FOR FINAL STAGE
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CONTROL ROOM
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COL POOR
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DETAIL OF REMOTE INPUT AND
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Fig. 2. Detail schematics of the various individual sections of the entire console. These units are interconnected as shown in the block schematic,
Fig. 3.
AUDIO
22
www.americanradiohistory.com
APRIL, 1955
-a
regulated
supply has two sections
low voltage of 150 volts for the preamps
and a regulated 300 volts for the program. spare, and house amplifiers. The
filaments in the main chassis are d.c.
and the remainder, balanced a.c. to
ground. Figure 1 shows the unit in
operating position, and Fig. 3 is a block
schematic which uses the detailed
sections of Fig. 2.
Actual Construction
Six microphone inputs were required.
Actual practice indicated that seldom
more than two were used at one time.
so three stages were installed, which
should give a reasonable safety factor.
One is located behind each key, and each
key can select between two microphones,
which also selects the proper interlock
relay. The three phono stages were
similarly installed, one behind each key.
4. The console and its
associated power supply during the testing process.
Fig.
CATHODE FOLLOWERS
MICIA
+150
-
GD
12AKr
MIC
'1 ¡
RELAY
l
MIC2A
MIC 2B
o
o-o
PHONES
SW
50011
-41
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FM
1
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TRANS-
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MITTER
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LEVEL
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8000
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ITOR
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4000
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THESE RESISTORS
CHOSEN TO LIMIT
CHANGE TO IDS WHEN
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CUEING
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Fig. 3. Block schematic of the console. The actual schematics of the various sections are shown in Fig. 2.
AUDIO
APRIL, 1955
23
www.americanradiohistory.com
Fig. 5. Topside view
of the console chassis.
On the front of the panel, above PHONOS
2 and 3, are installed two six -position
double-pole switches. Six remote inputs
are tied to these two switches wired in
parallel. The output of each switch goes
to the key. The center position of the
key feeds cue out on the remote position
selected. The small toggle switch above
PHONO KEY 1, removes this cue and
substitutes the house phone. This makes
it very simple to talk to an engineer on
a remote. Moving the key to PROGRAM
or AUDITION automatically disconnects
the cue and connects the line to the
input transformer, which is strapped
for 500 ohms. Each of the six inputs
has. a 220 -ohm resistor across it. This
presents the proper load of 125 ohms
for Western Electric 23 -A equalizer.
This equalizer is on the patch field and
can be dropped across any pair. A 200 ohm wire wound pot is in series with
it and is adjusted for equalization necessary. The 23 -A was designed for 8500
cps, but we have found that we can
equalize local lines so they are down
only a few db at 15 kc. Under each key
is its gain control. Turning any one of
the three phono gain controls to zero
switches the input to the cue bus. Just
below and to the left of each gain control
is a small knob which selects the turnover position ; the fifth position removes
the phono output and picks up the remote line transformer output. Remote
lines may be auditioned on the local cue
bus. This same switch loads the secondary of the remote lines transformer to
prevent cross talk if a remote line
selected has high level accidentally
switched in (guess how we found we
needed this ?). It was also necessary to
roll off the high -frequency response of
the remote cue level. Since the amplifier
supplying this cue had negative feedback over the output stage, it was necessary to pad the level down 12 db, then
roll off the high- frequency response.
The response is down 6 db at 5000 cps.
The six -position switch above phono
No. 1 switches the headphones as a
balanced pair to any of the six remote
lines. There are three switches below
and to the left of the three microphone
gain controls. These switches select
between microphone lA and 1B, and
operate the interlock relay. They also
complete the symmetry of the front
panel.
Circuitry
The stage following the preamps is
a cathode follower. This was done so
the control room and house amplifiers
could be located on the power- supply
chassis. There are three of these cathode
followers, one for the program amplifier,
(to maintain circuit symmetry) one for
the control room and house amplifiers,
and the third is used for a recording output or AM transmitter. This required
two 12AU7's. The fourth triode section
is used as the first amplifier for the
phono cue system. The final portion of
the phono cue system is identical to the
house amplifier except it has no feedback. Please note the series resistor
from the cue volume control to the
6AQ5. The grid of the 6AQ5 is shorted
when the control room microphone is
in program position. The series resistor
prevents grounding of the audio to the
earphones.
The cue volume is above Mic 1 key.
The control above ?die 2 key is a six position double -pole switch. Position 1
is balanced and is across the program
output line; position 2 is balanced and
is across the remote cue. Position 3 is
unbalanced and across the phono cue
position; 4 is balanced and is fed from
the six -position selector for remote
lines. Positions 5 and 6 are not used.
Note that the head phone jack is insulated from ground. Note also the
series resistor of 1,000 ohms -this prevents inexperienced personnel from
dropping a 50 -ohm headset across the
program loop. The control above Inc 3
is a VU multiplier, providing for 4, 8,
12, 20, 24, and 30 VU levels at the indicated "0". The control in the extreme
upper left edge is house amplifier gain.
The three keys to the right of the VU
meter are (1) house amplifier input,
(2) control room amplifier input, and
(3) recording output. All are wired the
same -left for program, center "off
air," and right for audition. The three
small holes above each key are screwdriver- adjusted gain controls for program, off air, and audition. Circuits
may thus be switched from one position
to another with no change in volume.
Two controls are yet to be noted.
Immediately under the VU meter, the
master gain control and under this
on the vertical portion of the panel is
the control room gain.
Construction
The amplifier was constructed on a
the front panel was assembled
and then the two were joined and the
interconnections made. Volume controls
may be replaced and switch keys may
be cleaned without disassembling. Figures 5 and 6 show the above- and below chassis appearance.
Two other controls are located on the
power supply chassis
series resistor
to set the d.c. filament voltage, and a
level control for remote cue. The power supply is shown schematically in Fig. 7,
and its underside is seen in Fig. 8.
Other construction details of importance are now noted. Both chassis have a
one -point ground a piece of No. 10 copper wire then passes over the various
components. The grounded point in both
cases is the low -level input. One ground
wire is carried from power supply to
amplifier chassis. Filaments are balanced
in the main chassis, so in the event of a
pan,
-a
;
6.
Underside
view of the console
chassis. Note that
there are no shielded
wires, and the one
heavy
ground
bus
serves for all ground
connections.
Fig.
24
AUDIO
www.americanradiohistory.com
APRIL. 1955
FILS FOR CONTROL
63 V
ROOM
loo
100
3A
6x5
-40
40
40
.1 150V
t
1"--4.12-- 30
pfo-
5V
SEG
DELAY
50
1-
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T40
50
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COMMON
TO RELAYS
o
5V
A"
30
6.3V
TO
FILS
6000
OF
HOUSE AMPL
300V
e
OD-3
o
63VDC
AT
CHASSIS
o
Fig. 7. Schematic of the power supply circuits.
d.c. failure, they may run on a.c. until
the trouble is cleared. To prevent ground
loops, the two shielded lines carrying
audio for control room and house amplifiers are grounded at the main amplifier
chassis only. The ground connection on
the input transformers is not connected
to the ground bus.
The telephone type relays, shown on
the power-supply chassis at the left in
Fig. 4, are operated on d.c. ahead of the
series dropping resistor ; the terminal
strip next to them is for phone interlock
and red lights. The output transformer
for the control room did not have a
balanced 500 -ohm circuit, so a small
line-to- speaker transformer was connected in reverse to provide balanced
remote cue. The voltage to feed the
bridge rectifier was obtained by connecting the 6- and 5 -volt filament windings in series. The output of the bridge
rectifier was connected to a 6,000-4
capacitor (never underestimate the
peak -to-peak value that 6,000 if
can provide). The rectifier supplies
thirteen volts under load at its output
terminals. The 5 -volt filament of the
small transformer operates the 5U4GA
and the low -voltage supply uses a
6X5GT. Only 6 tube types are used
including the rectifiers and VR's; 612AX7's, 7- 12AU7's, 6-6AQ5's, 16X5, 1-5U4GA, and 3- OD -3's (VR150)-a total of 24 tubes.
A time delay of thirty seconds is incorporated in the B - leads to prevent
overload of the VR's during the tube
warm up. No shielded wire is used in
the construction of either chassis, yet
crosstalk is down 50 db. The big rectifier was obtained from an old pin ball
machine. High -frequency equalization
was accomplished by the cut-and -try
method in the case of the Fairchild
pickups, using the Dubbings test record,
and follows within 1 db. We sent our
equalization system and the values
chosen to Fairchild. We quote from
their letter, ". . . with regard to the
circuit which you propose for equalization, we feel that this may very well
prove satisfactory as far as matching is
AUDIO
concerned. However, it should be
pointed out that high -frequency attenuation at this point in the circuit
will result in a poorer signal to noise
ratio since the total noise of the first
stage is passed on to later circuits."
The instruction sheets issued with
the Fairchild pickups advise rolling
off the highs in a plate circuit. This
was impossible since the stage involved
has negative feedback and following
stages are mixed with other signals.
Further, we wanted to be able to use
other manufacturers' pickups, and most
of these use some type of front end
equalization. The output of the new
Fairchild 220 with the new coupling
transformer is more than a GE. All
of the resistors in the program amplifier
are wire -wound to keep down noise.
Post Mortem
The console has been in operation for
three months now. During this time we
have had no break -downs, but we can
suggest some improvements. The telephone type keys could be replaced with
lever action rotary. This would greatly
simplify their wiring. The 6- position
Fig.
the
8.
switches for remotes should be pushbutton types so wired as to give one input
priority. We have found on some remotes that we needed an electrostatic
shield, so we patch in a W.E. 111 -C lineto -line transformer (repeating coil) for
this condition.
UTC has informed us that the LS -55
can be wired for an approximate Ultra Linear operation, and we have since
tried this with the result that the amplifier is apparently more stable, and it
provides a "richer" sound in the low frequency range. The connections to the
LS -55 for this type of operation are, to
quote from a letter from UTC: "tie the
present plate points together to B+
(terminals 1 and 6; connect terminal 4
to plate 1, terminal 2 to screen 1, terminal 3 to plate 2, and terminal 5 to screen
2. This will result in a somewhat higher
stage gain than is possible with the
triode connection, and will require a
change of the feedback resistor to maintain 10 db of feedback." We did not find
it necessary to change the resistor.
It is also desirable to remove the 51;
000 -ohm resistors from the secondaries
of the three microphone input transformers when used with the W.E. 639A,
and the RCA velocity microphones. The
resistor should remain in the circuit with
the Altec 21C and with most dynamic
models, however.
We have had no trouble with microphonics. You can pound on the front of
the console and not hear a thing.
The most gratifying part of the construction of this console was the response of our listeners. Some of them
are most critical and they tell us how
much they like it. When listeners call in
and tell us the same record sounds better
"off the air" than it does on their own
equipment, we feel that we have "clean"
operation.
The approximate cost of this console
was $200, but we used many parts from
the junk box. It took approximately four
weeks to build it, including testing. but
the work was spread over about a year.
With steady work it could be done in a
40 -hour week. We will be pleased to
answer any correspondence concerning
this "station-built" console.
Underside of
power
supply
chassis
.
APRIL, 1955
25
www.americanradiohistory.com
High Quality ...Ten Watts
Small Package
.
.
Adequate for the average home system, this unit which was originally designed for broadcast monitor
applications is relatively inexpensive, simple to construct, yet capable of excellent reproduction.
HAROLD REED
THE audio amplifier described in this
article was designed originally for
use as a program monitoring ampli-
fier in conjunction with a broadcast station audio console. Because of its compactness, its possibilities for numerous
other applications became apparent as it
approached its final form and reached
the production department.
The photographs of Figs. 1 and Z are
of the original laboratory model. The
component parts are assembled on an
aluminum sheet 5 x
in. The reason
for this type of construction is that the
unit was to be mounted on a chassis side
by side with other equipment constructed
on aluminum plates of the same
-inch
dimension. Construction, of course, can
be in the conventional chassis or cabinet
form but regardless of the manner selected it is recommended that there be
little deviation from the parts placement
shown in the model.
8/
8/
3917 Madison Sl., Hyallsvillc, Md.
Referring to the Fig. 1 (left), the layout is as follows. At the top is the 6SJ7
input stage. Beneath it is the 6SN7 voltage amplifier-phase splitter tube, followed by the pair of 6V6 output tubes
working into the output transformer located at the bottom. The electrolytic capacitors can be seen mounted alongside
the tubes. All small parts are mounted
beneath the plate. mostly with point -topoint wiring as shown in Fig. 2 (right).
The other unit in the photos is the power
supply. of which more later.
The schematic is shown in Fig. 3. The
input stage is a 6SJ7 voltage amplifier
with provision for coupling to the signal
source provided by capacitor C, and
through the 0.1 -meg potentiometer, or
volume control, R. The 6SJ7 is followed
by a 6SN7 twin triode tube, the first half
Fig. 2. Underside of the amplifier. The volume
control is on an extension cable to permit flexi-
functioning
as a straight amplifier and
the second half as a phase splitter. The
output stage consists of a pair of 6V6
tubes in push pull. The negative feedback loop extends from the secondary
winding of the output transformer to the
bility in mounting.
cathode of the second voltage amplifier
stage.
It is to be noted that direct coupling
is employed between the plate of the second stage and the grid of the phase split ter. This contributes to the stability of
the amplifier as this point in the circuit
is included within the feedback loop, and
the direct coupling reduces phase shift.
The constructor should recognize that
with this phase splitter the cathode of
V,. is at a relatively high positive potential with respect to ground, and because
of the direct coupling, the grid of V.. is
at the saine positive potential as the
plate of the driver triode,
The bias
on the grid of V,. is then determined by
these two positive potentials, and is,
therefore, dependent on the values of R.,
R. and R.., so these are fairly critical
components. The phase splitter resistors
R. and R. should be as closely matched
as possible. In the unit described here,
the plate voltage of V... is 79 volts, which
of course, is also the potential on the
grid of V... The voltage from V. cathode to ground is 84 volts. The difference
between these two voltages-that is, 5
volts
the bias on the grid of V,. with
respect to its cathode. Resistors R. and
and capacitors C. and C, should also
be fairly well balanced.
The response characteristics of this
little amplifier are quite good. A signal
input of 80 millivolts will drive the unit
V.
Fig. 1. The author's
amplifier and power
supply. Note the use
of separate filter capacitor cans.
-is
R
AUDIO
26
www.americanradiohistory.com
APRIL, 1955
'till you hear the BIG news
ABOUT THE COMPLETE NEW
giee'rei'e&o
AMPLIFIER and TUNER
ELECTRONIC LINE
Doh/
Our comprehensive electronics program
is 'way ahead of schedule. In weeks instead of
months, we will bring you a sensational line of
amplifiers and tuners, in every price range -so
complete, so daring, so fundamentally new,
highly styled and sound in value that you will
want nothing else.
ELECTRO -VOICE, INC.
BUCHANAN, MICHIGAN
AUDIO
APRIL, 1955
www.americanradiohistory.com
it may be connected to the cathodes of
the 6V6 output stage to obtain a positive
biasing source to the heater circuit. If
a.c. hum difficulties should prove to be
particularly troublesome, a higher positive heater biasing source may be obtained by increasing the value of R,..
As can be seen in the photographs,
this power supply unit requires little
space and will power not only the 10watt amplifier described, but will handle
a complete audio reproducing system,
from phono input to loudspeaker.
NW
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Fig. 3. Schematic of the
to 10 watts output across a 4 -ohm load.
The frequency response is flat within ± 1
db from 30 to 20,000 cps. Distortion at
1000 cps for 2 watts output is 0.7 per
cent at 4 watts 0.8 per cent. 8 watts gave
a 1 per cent reading, with 2 per cent
measured at 10 watts. Measurements
were made with a Hewlett- Packard dis-
tortion analyzer.
To the constructor who does not hesitate about pushing tubes a little harder
the following may be of interest. It was
observed that by increasing the supply
voltage to 300 volts, which is 15 volts
above the maximum rating for the
screens, distortion at 2 watts measured
0.68 per cent, 4 watts 0.78 per cent, 8
watts 0.84 per cent, 10 watts 0.88 per
cent, 12 watts 1.4 per cent, 13 watts 1.6
per cent and at 14 watts 3 per cent.
This compact amplifier can be utilized by the audio enthusiast as a companion piece with a preamplifier- equalizer -control unit as it can be built nicely
into a sound system for record reproduction and AM /FM tuner outputs. With
proper transformer input coupling it
may be employed in broadcast and studio
applications as a bridging amplifier
across balanced low-impedance lines.
1
Power Supply
amplifier section.
liamperes, which is approximately 25
milliamperes higher than the current requirements of the amplifier, so that the
power supply can also be used to power
a preamplifier in a complete audio reproducing system as well. Sufficient filtering is provided by the choke coil, L,,
and the 2045f capacitors.
Resistor Ru serves as a bleeder resistor, contributing to improved power supply regulation. Rn is a voltage dropping
resistor to provide the proper d.c. voltage to the amplifier as well as additional
filtering. The value of this resistor may
be varied to obtain higher or lower supply voltage.
The total current required for the
amplifier filaments is 1.8 amperes. The
current rating of the 6.3 -volt filament
winding of the transformer specified for
the power supply unit is 4.5 amperes,
which is sufficient leeway to furnish
power to preamplifier tubes.
A 100-ohm, 2-watt wirewound hum balancing potentiometer is shown across
the filament winding of the power supply and will prove helpful in reducing
a.c. hum voltage to a minimum. This
control is a necessity if the supply is
used to power low -level preamplifier
stages. The center arm of this potentiometer may be connected to ground, or
The power supply voltages for this
amplifier were furnished by the
main power supply of the audio console
with which it was associated. However,
so that the unit could be used as a general purpose amplifier, an individual
power supply is shown which will furnish the filament and d.c. voltages. This
C,, C,
.01
C,, C., Co
C,
Cr, C,
50 µf, 50 v, electrolytic
0.5 µf, 400 v, paper
40 µf, 450 y, electrolytic
C.,C7
0.1 µf, 400 y,
C,., C,,, Cn
20 µf, 450 v. electrolytic
L,
Filter choke,
R,
0.1 -meg
µf, 400 v, paper
paper
7 Hy, 125 ma.
potentiometer, audio
taper
V watt
watt
0.33 meg, % watt
0.22 meg, % watt
22,000 ohms, % watt
2700 ohms, V watt
4700 ohms, Va watt
0.1 meg, % watt
27,000 ohms, 1 watt
27,000 ohms, % watt
0.47 meg, V2 watt
180 ohms, 2 watts
12,000 ohms, 25 watts
500 ohms, 15 watts
0.47 meg, 2 watts
33,000 ohms, Va watt
1500 ohms,
R,
1.0 meg, %
R,
R,
R,
R.
R7
R,
R,
R,., Ru
R»
R,,, R,.
Rn
R,.
R,7
R
R,.
R,,
100 -ohms potentiometer, linear
taper
Output transformer, 8000 ohms
T,
plate -to- plate, 4 -, 8, -, and
16-ohm secondary
(Triad
S -31A or equivalent)
T.
Power transformer, 350 -0 -350
at 125 ma, 5v at 3 a, 6.3 y
at 4.5 a.
6SJ7
6SN7
6V6
5Y3GT
10 -watt
supply was assembled on an aluminum
plate of the same dimensions as used for
the amplifier, that is, 5 x 8% inches, and
is seen in Figs. 1 and 2. The constructor will, of course, have his own ideas
as to the layout desired. The schematic
of the power supply is shown in Fig. 4.
The power transformer secondary
provides 350 volts a.c. each side of center tap and is rated at 125 milliamperes.
The filter choke is also rated at 125 mil-
L1
R17
72
+280
000
v5
5v
5r3
3A
350v
5
Fig.
4. Schematic of
VAC
I
MG
the power supply
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7H
12SMA
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500
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TO GROUND, TO CATHODES OF AMPLIFIER OUTPUT STAGE, OR TO POINT X
28
AUDIO
www.americanradiohistory.com
APRIL, 1955
Introducing
a
:dot
new Triumph in engineering
and designing skill created by
MODEL AF -825 $129.50*
Complete AM -FM tuner
-
- preamplifier
and equalizer
with greater sensitivity and selectivity
The
//l/,.m//,
in High
Fidelity
..
a
MATCHED CCMPANIONS TO AF 825
proud achievement in engineering
efficiency exemplified by Pilot's vast electronic experience for 35 years.
Armstrong Cascaded Limiter Discriminator Circuit on FM.
FM
sensitivity better than
AM
sensitivity better than
3
5
microvolts for 20
microvolts for 20
db
db
of quieting.
signal to noise ratio.
AA-410 PILOTONE
AM?L'FIER
$49.50`
Automatic frequency control (AFC) for ease in FM tuning.
Tuned RF amplifier stage for improved sensitivity End selectivity on both
AM and FM.
Temperature compensated oscillator for drift free operation.
Complete preamplifier and equalizer with 3 inputs and cathode follower output.
Equalization switch irovides compensat on for LP, NAB, AES, RIAA and foreign
curves.
Two stage Audio Amplifier with bass and treble tone control circuits.
Phono preamplifier inputs are variable for precise loading of all magnetic
or variable reluctance cartridges from 6800 ohms to 100,000 ohms.
Selectively illuminated dials and indica-or light fa- phono positions.
Write for free brochure Dept
AUDIO
$89.50*
$129.50*
'Slight
A 4
PILOT RADIO CORPORATION
At.-504 PILOTONE
AMPLIFIER
y
h'gher West of Rockies
37 -06 36th ST., LONG ISLAM) CITY 1, N. Y.
APRIL, 1955
29
www.americanradiohistory.com
Make Your Own Meter Scales
RONALD
L.
IVES
Simple instructions on how to make scales for shop- constructed equipment to give a professional appearance with a minimum of cost and time.
SCALES on special instruments, in all too many instances,
are poorly drawn and hard to read.
With a few notable exceptions, scales on
special meters are not as well drawn as
the dials on bargain alarm clocks; and
some of them appear to have been drawn
on used blotting paper with a dime -store
ball point pen. This prevalent unsatisfactory condition not only reflects unfavorably on the makers of the instrument, but also impairs the accuracy of
all readings made from the instruments.
Most people will read a workmanlike
instrument scale with considerable care,
but will give only a cursory glance to
a sloppy dial.
By use of a number of improved and
simplified drafting techniques- originally developed for newspaper work
where speed of production is essential,
and more recently applied to technical
drafting' 2.3-workmanlike scales for
special instruments can be constructed
at relatively low cost in both hours and
dollars.
MEÇER
ZIP -A
-TONE SCREENS
WHITE
Fig. 3.
screens
Zip -A -Tona
(left) and
Artype special symbols (right).
ready employed full -time by instrument
and watch manufacturers.
Large Scale Drafting
\lo.t of the difficulties inherent in
the fine line work and small lettering
required on most meter scales can be
eliminated by drawing the scale several
Direct Drafting Procedures
Special instrument scales can be drawn
directly on the scale card by an ordinarily skilled draftsman, using black
India ink throughout, and applying the
lettering with the aid of a Leroy or other
lettering guide. This procedure is quite
satisfactory for large scales, when only
one of a kind is needed; but becomes
quite difficult as the size of the scale decreases. Direct drafting is not satisfactory when a number of identical scales
is needed, and the procedure is not suitable when the scale card has a special
surface not suited for ink work.
Highly skilled draftsmen can draw
complicated instrument scales not much
larger than a postage stamp, and do
"perfect" freehand lettering upon them.
Draftsmen having these capabilities are
few in number, and most of them are al* Cornell Aeronautical Laboratory, Inc.,
Buffalo, N. Y.
MONSEN TYPE
I5S 159
165. 166. 107 160.
156 157
l ez
rot
1
1
á1113
á 0a0ó
ARTYPE
161
.
169-
O0
IOW
COLDEST
SHCEETFLOOOING WINDS
ALLEYS AUGUST
TEMPERATURES WEEKLY
PRECIPITATION WARMER
FRONTOLYSIS POSSIBLE
INDIANAPOLIS SUNSHINE
MOUNTAINOUS PERCENT
OCEANOGRAPHY INCHES
OSCILLATING
CCCCDDODDDD
AAAAAAAABB
EFFFFGGGGHH
'aaaaaaaaaabb
ffffffggggóhóh
Fig. 1. Samples of trans -adhesive lettering. At
is Monsen type; at right is Artype. Note
guide lines furnished with the latter.
left
PREPARED BY
DEPARTMENT OF GEOGRAPHY
INDIANA UNIVERSITY
BLOOMINGTON, INDIANA
Fig. 2. Map label printed on
trans -adhesive
material. This is handled as a single unit, and
can be applied in about 20 seconds.
times as large as the desired finished
dimensions, and reducing it photographically. This same procedure makes
possible the production of any reasonable number of scales all alike. Both
Leroy and Copperplate lettering will
stand great reduction without loss of
legibility; and many minor and unavoidable defects inherent in hand drafting will "drop out" in the reduction
process.
Optimum results are obtainable with
this method when the drawn scale is
about three times as large as the finished
dimensions; and when line weights and
type faces are chosen so that no line is
narrower than about .01 in. in the reduced scale and no letter or symbol is
<Inaller than about 1 /16 -in. high. Although thinner lines and smaller letters
can be produced by this method, they become difficult to read, even when perfectly executed and skillfully copied, so
that the smaller sizes should be avoided.
An instrument scale, no matter how accurate it may he, isn't much use if you
can't read it
!
ti
MISCELLANEOUS SYMBOLS
6
000
000
www.americanradiohistory.com
OOQ90
Pre -Printed Letters and Symbols
Use of printed symbols, letters, and
words in illustrative material has been
common in the graphic arts industries
for more than half a century. During
the last two decades, a number of manufacturers of graphic arts supplies have
produced and marketed a wide variety
of pre -printed patterns, symbols, and
letters. One of the pioneers in this field
\v as the Craftint Co.,' who produce a
variety of patterns printed on trans parent acetate sheeting. The base (sheeting) is cemented to the drawing over
the area to be patterned, and surplus
pattern is rubbed off the upper surface.
A convenient method of assembling
textual material has been developed by
Fototype.5 Their product consists of individual letters, printed on cards. These
are assembled upside down in a composing stick (supplied by them). The
assemblage is made permanent by applying cellophane tape over it. The completed text, removed from the composing
stick, is mounted, as a unit, wherever
desired. More than 300 sizes and styles
of type are provided by this manufacturer.
Best suited for most meter scale work
is trans -adhesive type, which consists of
type symbols printed on the under side
of thin transparent acetate sheeting.
This is then coated with a white waxy
adhesive, also on the under side. Trans adhesive type is cut from the sheet,
placed in the desired position, and then
burnished into place.
Several kinds of trans -adhesive material are available. Words and special
symbols, to order, in almost any type
face extant, are produced by Monsen.e
Samples of Monsen copperplate are
shown in Fig. 1, left. This material is
manufactured for a setting charge plus
a charge for each impression, so that
AUDIO
30
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APRIL, 1955
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2
the cost per sheet depends upon the takes place when a large area is inked
number of impressions ordered at one in solid.
time. Monsen will also print to customer's specifications, on trans -adhesive Scale Construction Procedure
sheets, almost any trade mark, label,
l'rocedure for making a special meter
title -box or caption desired, as in Fig. 2. scale, using these art aids, is relatively
Use of Monsen trans -adhesive material simple and straightforward.
First step
is economically advantageous when the
same words or symbols, in the same type is to calibrate the meter in terms of any
scale which you choose to put on it.
face, are used quite frequently.
Some reduction in the amount of Usually the scale supplied with the
printing needed can be brought about meter will be entirely satisfactory.
Remove the scale from the meter, put
by careful choice of words, as the setting charge is usually on a per word it on a piece of black paper, and make a
basis. Combinations of substantial parts photostatic copy of it. This, for conof words can also be made quickly and venience should be a positive photostat,
neatly. For example, if the word milli- and should be enlarged by a convenient
amperes is ordered, it is not necessary factor, such as 2, 3, or 5, to simplify
to order amperes also; and the micro drafting procedure. Such a copy is
fsom tnicrofarads can be combined easily shown at A in Fig. 4. The black paper
with the amperes from milliamperes to backing outlines the scale, and shows
produce microamperes. Some draftsmen, the mounting holes plainly.
Mount the photostat on the drawing
particularly those who speak more than
one language, become highly skilled in board using drafting tape in any alignfinding and using desired letter groups. ment convenient to the draftsman. Cover
Although the setting charge for a "two it with tracing linen or matte acetate,
dollar word" is usually the same as that and ink in all lines desired on the new
for a "ten cent word," copy containing scale. Be sure to locate the scale outline
and mounting holes accurately. Tracing
jawbreakers such as polydipseudaukistrodesmus pietenpolensis (the name of a with completed line work will appear
diatom) is likely to carry an additional as at B in Fig. 4.
Apply the desired lettering and symcharge for "difficult copy."
Trans -adhesive alphabets and a wide bols to the scale by the standard method
variety of symbols are produced by for the art aid employed. Trim away
Artype.7 This material consists of in- all guide lines and other extraneous
dividual letters, with attached guide material, and the scale is ready for
lines (Fig. 1, right). The text is as- photographing. Finished scale appears
sembled in the desired location on the as at C in Fig. 4. Other samples of
drawing, aligned by use of the guide scales made by these methods appear in
lines, and burnished in place. The guide Fig. 5.
To insure that the finished scale has
lines are then removed and discarded.
With a little ingenuity, symbols not the proper dimensions, mark the finished
contained in English type fonts can be dimension on some part of the scale very
produced with Artype,8 and only an ex- plainly for the photographer. A conpert printer can tell, from the appear - venient method of doing this is to draw
ance of the finished work, that these a line equal to the exact dimension besymbols were not printed directly from a tween the mounting holes on the scale to
be photographed, and label it "Reduce
special type font.
A few of the many special symbols so that this line is exactly 2 inches
made by Artype are shown in Fig. 3 long," the dimension here given being
(right). Repeated symbols, patterns, correct for a Triplett Mod. 327 -T scale.
shades, and screens printed on a trans adhesive base, are manufactured by the Copying
Reduced copies of original drawn
Para-Tone Co. ,8 and marketed under
the name Zip -A -Tone. These, a few of scales are normally made by a photogwhich are shown in Fig. 3 (left), are rapher, using standard copying equipuseful for zoning meter scales. Solid ment and films. Use of a process lens is
white Zip -A -Tone is useful for blocking desirable, to obtain maximum resolution
out parts of a drawing; and solid red in the copy negative; and lithographer's
Zip -A -Tone, which photographs black films, such as Reprolith, Kodalith, and
with most engravers' films, is ideal for Lithaloid, exposed and developed acfilling large black areas uniformly, and cording to manufacturer's instructions,
without cockling the paper, as commonly give adequate contrast.
ri
°POWEN OUTPUT'.
A
MCC C411 LINZ
i/P
°
rM°"
vu
D
Fig. S. Special meter scales made by use of
standard drafting for the line work and trans adhesive lettering for the text and symbols.
A wide variety of printing papers is
available, and most glossy and semi matte papers make suitable scale prints.
Some care is needed in printing from
scale copy negatives. Contact between
negative and paper must be intimate, or
lines will be widened and blurred. Overprinting must be avoided, or parts of the
image will "bleed" into surrounding
areas ( "all the o's fill in "). Development, fixing, and washing, in accord
with good standard practice, will give
entirely satisfactory prints. Life of a
photographically produced meter scale
is somewhat more than fifteen years,
most of those made by the writer prior
to 1940 still being in service (1954).
Prints may be mounted on the meter
scale plate by use of high -grade library
paste, purified rubber cement (the stationer's variety, not from the garage),
or dry mounting tissue. Most of the
library pastes are short -lived in this
service, the paper coming unmounted
from scale plate after three or four
years. The better grades of rubber cement are apparently immortal if correctly used. Best procedure seems to
be to coat the scale plate lightly with
cement, then coat the back of the print
with a medium thickness of cement, then
let both dry for a couple of minutes.
When the cement is tacky, align the
holes in the scale print with the holes
in the scale plate, and press the print
firmly onto the plate. Keep the assembly under heavy pressure for a reasonable time, such as 30 minutes, then
trim the edges and install.
Dry mounting tissue, which is a thin
sheet of paper impregnated with wax,
can also be used, and gives very good
results in skilled hands. The tissue is
tacked onto the scale plate with a small
tacking iron, then the scale is placed
over the plate in proper register, and
the whole heated under pressure. After
cooling, the edges are trimmed, and the
scale installed in the meter.
Special Features
Fig. 4. Steps in making a special meter scale. (A), photostat of the scale, taken against a black
background. (B), tracing of (A) on which the new scale has been drawn. (C), the same tracing,
with lettering applied.
32
By combining the best features of
standard drafting and trans -adhesive
letters and symbols, a wide variety of
special meter and instrument scales can
(Continued on page 64)
AUDIO
www.americanradiohistory.com
APRIL, 1955
RUSHE
IT TAKES TIME
TO CONVINCE
A STUBBORN
And
it
"CUSTOMER"...
takes time to make a good recording disc...
Time -saving devices are taboo at PRESTO...manufacturers of
superior recording discs. PRESTO knows that when you step up production,
you step down quality. Only by lavishly expending time-as well
as skill and care -is it possible to obtain the consistent quality
and famous performance of PRESTO discs.
It's easy to hear the difference when you listen to a recording on
PRESTO -the world's finest recording discs. Competitively priced!
PRESTO Green
Orange
TIME CONSUMING
STEP 4
IN MAKING A PRESTO
RECORDING DISC
Brown
and White label discs are used
throughout the world wherever
fine recording is done
RECORDING
it r k> and rwit : on tlu'surface of
recording discs show up in less than
perfect performance. That's why PRESTO
takes the time to give each disc an
individual "eye examination." Discs are
slowly rotated under special "flat" lights,
carefully checked for tell -tale surface
reflections by trained inspectors. Quick
mechanical tests can't compare to
PRESTO'S slow but absolutely thorough
disc inspections! Only those discs passing
PResTO's rigid surface tests are allowed to
carry the famous PRESTO Green label
trademark of the world's best performing
and most durable recording discs.
CORPORATION
-
PARAMUS, NEW JERSEY
Export Division:
Canadian Division:
WORLD'S
LARGEST
25 Warren Street, New York 7, N. Y.
Instantaneous Recording Service,
42 Lombard St., Toronto
MANUFACTURER
OF
PRECISION
RECORDING
:OUIPMENT
www.americanradiohistory.com
AND
DISCS
Amplifiers
EDGAR M. VILLCHUR
An analysis of the fundamental nature of amplification, and a
description of the working principles of pneumatic, mechanical, carbon, vacuum -tube, transistor, magnetic, and dielectric amplifiers.
of the
word "amplifier" is "a device that
makes things bigger." But in technical language the term has a much
more restricted meaning; the device referred to becomes an amplifier only
when the things that are made bigger
consist of energy -patterns. The nature
of amplification can probably be better
understood by considering first the operation of another energy transmission
device that is not an amplifier -an instrument that is called, in mechanics, a
machine.
The machine receives input power,
shapes it for the required task, and releases it, less the inevitable losses from
friction, in its new form. Were it not
for these losses the amount of energy
released would be exactly equal to that
received. Although the Indian hunter
was able to bring down buffalo with bow
and arrow, his arrow was driven by less
energy than had been put into flexing
the bow. His machine was able to store
and concentrate the power that it received when the string was drawn back,
so that the shaft sped with lethal velocity. Without the machine the hunter's
strength would have been totally ineffective.
The mechanical lever, the acoustical
horn, and the electrical transformer
are other examples of transmission devices whose useful output energy, while
re- formed in such a way as to be most
suitable for the application at hand,
must always be somewhat less than the
input energy. The word "machine" applies to mechanical devices only; the
term which includes all instruments of
this nature, whatever type of energy
is transmitted, is passive transducer
(from traducere, to lead across).
An amplifier is also an energy transmission device, and hence a transducer,
but it is an active one. It does that which
would be impossible without a sort of
provides
engineering sleight -of- hand
a transmission channel whose output,
seemingly the same in identity to the
received stimulus, contains more energy
than its input. The difference is that
between a pulley and a powered capstan.
It is obvious that the useful output
energy of an amplifier cannot be greater
than the total energy supplied, any more
than it is possible for such a condition
to exist in the case of a passive transducer, or energy will have been created
ACOMMON -SENSE DEFINITION
-it
out of nothing. The trick is that the input stimulus borrows and directs power
from an independent second source
(such as the electric company's generators), and shapes this independent
power to its own form.
The need for amplifiers arises when
we are dealing with impulses which
must remain in a very definite time
pattern if they are to be useful. One of
the earliest amplifying devices was the
pipe organ, whose player was able to
control, with relatively light pressures
of his fingers, the steady flow of air
produced by sweating bellows -operators. Amplifiers in the more generally
accepted sense, however, were invented
when nineteenth century technology became concerned with the transmission
and reproduction of vibratory power:
first sound, and then radio waves.
Sound consists of successive and alternating compressions and rarefactions radiated by an oscillating source.
The telephone and the phonograph
therefore depended for their operation
on acoustical, mechnical, or electrical
forces which continually reversed their
directions, and which carried the transmitted intelligence in the time sequence
and pattern of these oscillations. The
problem that faced engineers was to
extend telephonic communication over
longer distances, to make phonograph
reproduction louder than was possible
with the original, limited power. The
first approach, successful up to a point,
was to increase the efficiency of the
passive transducer elements. But the
best acoustical and electrical passive
transducers that could be designed to
harness effectively the sources of this
oscillatory energy proved inadequate.
Sound generators like the human voice
mechanism, or the phonograph pick -up
diaphragm following the record groove,
simply didn't have enough driving
power for the work they were called
upon to perform, even with the carefully designed horns that increased
their radiating efficiency. The solution
was to inject outside energy into the
systems and to use the original stimuli
as controlling rather than driving
forces, which is to say, to amplify.
Early Amplifiers
In 1876 Edison patented a device
which he called an aerophone. It was a
pneumatic public-address amplifier, illustrated in Fig. 1, in which the
speaker's voice controlled the instantaneous flow of compressed air by means
of a sound -actuated valve. The air was
thus released in vibratory bursts and
puffs similiar to those that came from
the speaker's mouth, except that they
were more powerful, and the speech,
still intelligible, was louder. Edison envisioned broadcasting in stentorian
tones over distances of several miles.
Such a system has actually been used
in ports, but it found its main application in the designs of two British inventors who applied it to the phonograph. Short developed, and Parsons
further improved the auxetophone,
whose pneumatic valve was attached
directly to a phonograph reproducing
stylus. Although pneumatic phonographs
produced a constant background hissing noise due to escaping air, they were
fairly popular in Europe, and in the
early nineteen hundreds the French
Pathé company experimented with them
1. Edison's aerophone, or pneumatic
amplifier, provided a
transmission
sound
channel into which
Fig.
additional e n e r g y
was injected in the
form
of compressed
air. Inset shows how
sound- actuated
the
throttled
a
valve
steady flow of air,
to create an instantaneous variation in
flow that imitated
the original sound
vibrations.
Woodstock, N. Y.
AUDIO
34
www.americanradiohistory.com
APRIL, 1955
;.
.
I
-1
_
'
'`,1 ''R
Il
.
'
'
IN THE HOME
OR THE THEATRE
THE FINEST SPEAKERS
ARE ALTEC LANSING
¡.
More than 10,000 theatres throughout the world are equipped with Altec Lansing sound
products. Stereophonic sound is recorded with Altec microphones, reproduced on Altec
speakers and amplifiers. Experience, precision engineering and highest standards of craftsmanship are behind the superb sound equipment Altec Lansing manufactures for the home.
The Altec 820C Speaker System is, truly, the finest speaker made for the home. Utilizing the
exclusive design of the world renowned Altec Voice of the Theatre Speaker systems, it consists of a direct radiating low frequency horn in a bass reflex cabinet, an 802C High Frequency
Unit mounted on the H -811B Sectoral Horn, two 15 inch 803A Low Frequency Units, and an
800D Dividing Network. It is unconditionally guaranteed to reproduce all the tones from 30
to 22,000 cycles. The beautifully finished corner cabinet makes the 820C ideal for any location
where the absolute finest in high fidelity reproduction is required. The 820C Speaker System
sells for $525. Without the furniture cabinet, for custom installation, $388.
There is an Altec high fidelity speaker in every price range. The Altec Dia -Cone Speakers,
ranging in pricefrom$21.60to$66.00, are unsurpassed in their field. The famous Altec "Duplex"
speakers, priced from $99.00 to $156.00, offer the highest quality, and carry an unconditional
quality guarantee which no other speaker or combination of speakers can equal.
`
%S.
your
High Fidelity Dealer`
or write Dept. 4-A
See
Fll
ALTS C c''
O
ALTEC FIDELITY IS HIGHEST FIDELITY
LANSING COIIOR*UON
Dept. 4 -A
9356 Santa Monica Blvd., Beverly
161
AUDIO
Hills, Calif.
Sixth Avenue. New York 13, N.Y.
35
APRIL, 1955
www.americanradiohistory.com
sums, and rolled cigarettes were the
wonders of applied science, was passing.
Electronics was taking over, and the
amplification of sound was destined to
Fig.
2. The Pathé phonograph of 1905
a compressed -air amplifier.
used
with a view towards developing talking
motion pictures. (See Fig. 2.)
Another type of device, the mechanical or friction amplifier, found
more favor in the United States. It was
used in certain models of Columbia's
cylinder "graphophone," as shown in
Fig. 3. The reproducing stylus of these
instruments, instead of being coupled
directly to its diaphragm as in standard
acoustical phonographs, was attached to
the diaphragm via a string and friction
shoe that passed over a rotating drum.
When the stylus tightened up on the
string, friction between the shoe and
the drum was increased, and force
picked up from the drum augmented
the displacement of the diaphragm.
When the record groove forced the
stylus in the opposite direction, so as to
loosen up on the string, the diaphragm
returned to its original position due to
spring tension. In this way the vibratory path of the diaphragm was extended
by the energy of the independently
driven drum, and sound output was increased.
Both of the above designs were referred to at the time as relay systems.
The original stimulus was thought of
as touching off latent power, like a relay
runner passing the baton to his successor. These systems were the forerunners of our present-day electronic
amplifiers, but they were themselves
doomed to a short life. The golden age
of mechanics, when the diabolical iron
fingers that set printing type, tabulated
include an intermediary step, the temporary transformation of mechanical
vibratory energy into electrical energy
possessing the same characteristics in
time.
Electrical amplification may be
achieved (and still is, in some telephone circuits) by carbon amplifiers,
which extend the principle of the carbon
microphone. The carbon granules
through which current is directed act
as a variable electrical gate, whose
resistance to current flow is controlled
by the pressure of a diaphragm. Changes
of pressure, such as would be created
by stimulating the diaphragm with
sound, create corresponding changes in
the amount of current drawn from the
source of electric power, and the electrical source releases energy greater in
magnitude than that possessed by the
input stimulus.
The Vacuum -Tube
The device which really opened up the
field of amplification was the vacuum tube. Fleming had made an electronic
valve that contained two electrodes
sealed in an evacuated glass chamber,
a cathode emitter and an anode collector.
When the cathode was heated a cloud of
electrons was given off, and if the device
was then connected in series with a battery, in such a way that the anode was
positively charged relative to the
cathode, the electrons were attracted to
and entered the anode. Since electrons
in motion constitute electrical current
the circuit was completed through this
one -way path.
The stream of electrons flowing in
the empty space between cathode and
anode provided an especially favorable
area for sensitive control of the current
drawn from the battery. The opportunity was seized by de Forest, who introduced a control element into the valve
by inserting a "grid "-an open network
of fine wire-across the electronic
stream. De Forest's grid was a sieve
mechanically, but if it was charged
negatively relative to the cathode it
tended to repel electrons (which are
also negatively charged) and to retard
current flow. A weak input "signal"
voltage applied between grid and cathode, varying according to a given frequency and wave form, produced an
Fig. 4.
Amplification
of a weak electrical
impulse is achieved
vacuum -tube
by a
circuit. The input
electrical
stimulus
has alternating polarity, while the output is in the form
of pulsating one -way
current. The cathode heating element
is not shown.
Fig. 3. The stylus of Columbia's cylinder graph ophone was coupled to the reproducing diaphragm through a lever -type shank, a string,
and a friction shoe that picked up extra energy
from the rotating drum.
imitative variation in the relatively
heavy output current flow, as may be
seen in Fig. 4. This output power could
follow the input characteristics more
closely than had been possible with any
other device designed previously. The
limits imposed by mechanical systems
their intractability when subjected to
forced vibration in modes foreign to
natural resonances, the uneven restraint
of elastic suspensions, and the fact that
supposedly rigid parts become flexible
when subjected to vibration at high
frequencies-all disappeared, and development workers found themselves
operating in a dream -world of virtually
massless units, where incredibly swift
oscillation could be controlled and amplified without having to reckon the
price of inertia, elasticity or gravity.
An early application of vacuum -tube
amplifiers was to the generators and
receiver of radio waves. Like sound,
electromagnetic radio energy is oscillatory, although at frequencies which
may be millions of times higher than
those of acoustical vibrations. The element analogous to the phonograph horn
is the antenna, acting as a passive transducer to the "atmosphere" -and, as in
the case of the horn, more efficient
antennas were not enough. With transmitter output amplified, however, from
a few watts to hundreds of kilowatts,
and receiver sensitivity raised to the
point where a few millionths of a volt
at the antenna created usable reception,
wireless global communication became
possible. Other applications followed
quickly. The recording and reproduction
of sound, the detection and measurement of very small quantities of light,
sound, pressure, or voltage, the myriad
-
AUDIO
36
www.americanradiohistory.com
APRIL, 1955
l
high fidelity line!
NEW
SPEAKER
SYSTEM
the National CATENOID
The National Catenoid Speaker
System is the first basic im
provenent in loud speaker design :n more than ten years.
A trLe corner horn, (not a
back .oaded or semi -horn) the
Catenqid is the only practical
means of reproducing the power
and dynamic quality of rich
bass Bones.
The Catenoid System consists
of a lull catenoidal horn from
the 30 cycle region to 300 cycles; a direct radiator from 300
to 6500 cycles, and a high frequenci tweeter unit from 6500
to beyond 17000 cycles per
seconc.
HORIZON Criterion, AM -'M fL'NER
min ov1 s 'or 20 db quiet
FM sensitivity
ing! Exclusive FM mulamatic tatting. Full band
AM. Binaural provision.
-.5
Rho
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Bass response oxtends smoothly
to very (owes fundamentals
i
high frequen s are free from
harshness, dirsct,onal effects
and the mi.:: range gives a
feeling of presence little short
of miraculous
Impedance: S ohms. Capacity:
30 watts. Size_ 36" high, 401"
wide, 271/2" ceep. Available in
hand-rubbed walnut or mahogany or wi i Formica wood
grain finishes i blonde mahogany, walnut or natural mahogany to resist scratches, scuffs,
burns or liquids.
National FANTASIA
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cull, or end table deign featuring
laboratory- developed dual clusters of d' 'bated
ports and internal vents with dual heavduty
ceptional peak -free bass in
ini
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finishes
blonde, natural mahogany or
walnut.
Exclusive
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Distributed ports Dual 8 -inch driven. Equalized
super tweeter. Incredibly smooth response over
entire audio spectrum. Impedance 16 ohms.
Available in Formica wood grain finishes in
hand -rubbed blonde, walnut or mahogany.
.
HORIZON 20, 20 watt amplifier
revolutionary
new
unity. coupled"
Utilizes
output stage. Frequency response is ± 1 db 20
cps to 20 In at full rated output.
HORIZON 10, 10 watt amplifier
Built -in preamp -control unit 3 inputs. 3 record
equalization curves, loudness ontrol, separate
bus and treble controls. "Uni.,' Coupled" output stage.
A.Psa
.4.
HORIZON 5,
the HORIZON 100
A two -way system of moderate cost featuring
heavy &sty 8" driver and superb high flux
density tweeter for silky highs. New porting
fie
wood
system. Impedance 8 ohms. In Formica
grain finishes in blonde, walnut or mahogany.
:J
preamp -control
4 inputs.
7 record equalization curves, loudness
volume control, separate bars and treble controls.
Plugs into tuner or 20 -watt amplifier.
1omoroo
ioíze
Distributed in Canada by Canadian Marconi
Company, 830 Bayvine Avenue, Toronto, Ontario.
For foreign soles, contact American Steel Export
Company,
3 -17
Madison Avenue, New York, N Y.
Jam -proof ' Stall-proof ! Quiet: Intermixes all
size records ! 4 -pole motor,
2-knob
control,
weighted turntable, automatic idler disengagement, shut -off and muting switch, universal
spindle, rubber turntable mat, stylus pressure
djustment, 2 plug-in heads. Complete with
blonde or mahogany base, G. E. cartridge, all
cables and connectors.
ationa
Products zee sold only through authorized distributors.
R RITE FOR COMPLETE DETAILS ON 16 SUGGESTED HIGH FIDELITY SYSTEMS TO DEPT. A-955
NATIONAL COMPANY INC.,
AUDIO
61 SHERMAN
ST., MALDEN 48, MASS.
APRIL, 1955
37
www.americanradiohistory.com
Fig. 5. The junction
transistor
compared
"
s u
b
is
to
tiny
the
miniature "
the smallest
-
tube,
type made. These are
approximately f u I I
size. I Courtesy General Electric Co.)
tasks performed by calculating machines,
and the sensitive control and regulation
of massive machinery became part of
the electronic field.
But with poetic injustice, after the
vacuum-tube has served as the vehicle
for the modern science of electronics,
it is being prepared for the scrap -heap,
at least in certain applications. The
vacuum-tube has several disadvantages,
foremost among which is its unreliability. Besides having too short a normal
life, the possibility of failure at any time
after installation must always be taken
into consideration by design engineers.
The unreliability of the vacuum-tube is
such an accepted fact -of -life that instead
of being wired permanently into the
circuit, like other components of electronic apparatus, it is plugged into a
tube socket to facilitate periodic replacement. In addition to this unreliability
the vacuum-tube requires a separate
power supply to heat its filament (diverting and wasting most of the energy taken
from the independent source), it must
be given a warm -up period prior to service, and it is too bulky in some applications. The feature which redeems all of
these disadvantages is the superb control
which may be exerted over the captive
electron stream.
Without abandoning the last feature,
new ways in which electrons can be
made to submit to instantaneous regulation at high frequencies are being investigated. The transistor, a revolutionary experimental device a few years ago,
can aready be ordered by the part number at radio dealers, and development
work is also being performed on magnetic, dielectric, and other types of amplifiers.
Transistors
From the electrical point of view
materials may be classified according
to their resistance to the passage of current, as conductors, insulators, and
semi -conductors. In an atom of a good
electrical conductor the outermost electronic shell is held so loosely that its
electron inhabitants are not associated
exclusively with any particuar parent
atom. The attachment, originally weak
because of the relative distance from
the nucleus, disappears with the close
atomic spacing typical of these materials, and the outer electrons are free
to rove. These free electrons are able to
respond to the force of an electric potential applied across the conductor, and
form an electronic wind blowing across
the relatively stationary atoms themselves towards the positive terminal,
constituting the flow of current. Current
does not flow to any appreciable extent
in non -conductors because the atoms of
insulators hold on grimly to their outer
shell electrons, which are more numerous, closer to the nucleus and much
more difficult to dislodge.
To impart motion to an electron is to
give it added kinetic energy. Quantum
requirements dictate that the electrons
must fill certain discrete energy levels,
that is, that they cannot possess a random amount of energy, and that each
energy level can only accommodate a
given number of electrons. Therefore
the energy of an electron can only be
increased or decreased by an amount
which brings it into a new step level in
which a vacancy exists. The quantum
levels of the atoms of a conductor have
vacancies, permitting electronic transfer
from one level to another. The energy
levels of the atoms of insulators, on the
other hand, are all filled, so that the
system is locked.
The energy level states of semi-conductors (substances such as germanium,
selenium, silicon, and the oxides of copper and barium) form a special case.
The locked system is upset by the presence of minute impurities, whose outer
electronic orbits contain electrons in a
number either greater than or less than
the amount normal to the pure substance,
and which introduce energy levels capable of releasing or accepting electrons.
Where the number of outer electrons
is greater than normal, excess electrons
are available for current flow in the
form of an electronic wind, and the substance is called a donor. Where the
number of outer electrons is less than
normal, the substance is called an ac-
ceptor, and vacancies are available for
electronic current flow in the form of
"hole" conduction (an effective migration of the unfilled spot from one atom
to another, a phenomenon which has
been aptly compared to the motion of
an air bubble in water). These two
modes of conduction occur in opposite
directions and are called, respectively,
n-type for negative, and p -type for positive. Hole conduction has a positive
designation because the migration of
holes has the same experimental effect
as the transfer of positive charges.
The development of semi- conductor
devices has followed the same course as
that of the vacuum-tube, from two terminal systems providing a one -way
electronic path, to three -terminal systems in which the electronic flow is made
subject to control from an area astride
the path. Semi -conductors were used
as rectifiers of alternating current long
before the word transistor was coined.
A potential applied in one direction
across the junction of a p -type and an
n -type substance will encounter relatively low resistance to current flow,
but relatively high resistance if the
polarity and hence the direction of current flow is reversed. This is because
the electrons and holes travel towards
each other for one polarity, facilitating
transfer across the junction, and away
from each other for the opposite polarity. The rectifying action may also be
described from the point of view of
energy-level states ; for one polarity,
electrons belonging to energy levels
capable of releasing electrons are driven
towards atoms containing energy levels
capable of receiving added electrons,
while for the other polarity the opposite
effect occurs.
A p -type substance sandwiched between two n-type substances, or vice versa, creates the basic design of one
type of transistor amplifier. The conducting properties of one of the junctions for "wrong -way" current may be
controlled by creating either hole or
electron carriers in the sandwiched element (by means of a current through
the other junction)-to put it another
way, by causing a shift in the electron
energy level states responsible for conduction. The pattern of variation of a
small controlling current shapes the instantaneous resistance of the unit, and
large currents may then be forced to
follow the same pattern in time.
The transistor requires no warm up
period, is smaller (see Fig. 5), cheaper
in operating cost, and is potentially so
much more reliable than the vacuumtube that it may be wired permanently
into the circuit rather than plugged
into a socket. Transistor hearing aids,
for example, which are already produced
commercially, are smaller than their
vacuum -tube counterparts, consume only
a small fraction of electrical power for
the same amplification (they have no
A battery) and may ultimately be expected to require less service. The tranAUDIO
38
www.americanradiohistory.com
APRIL, 1955
AND ONLY
THE
8"
TRIAXIAL SPEAKER-
MODEL 308
No other speaker like it! An 8" 3 -way speaker -ideal for
hi -fi installations where space is at a premium and quality is
not to be compromised. Response down to better than 50
cycles, provided by voice coil and diaphragm operated with
the exclusive University Alnico -5 "W" magnet. Rich, full- bodied
mid -range is achieved through the use of the patented "Diffusicone" section of the unit, crossing over at 1,000 cycles. The high
frequency reproducer, a compression driver unit wide angle
tweeter which extends to 15,000 cycles, crosses over electrically
at 5,000 cycles. Impedance 8 ohms, power capacity 25 watts.
IT'S A
3-WAY WONDER
A new advance by University in the 12" field. Full range
response from 40 cycles to inaudibility. Employs the
"Diffusicone" principle for full- bodied mid-range and the
HF -206 Super'weeter for clean, brilliant highs. Built-in
L/C nerwo-k end "balance" control permit you to adjust
tonal cuo ty to your own listening tastes. All- Alnico -5
excludve University "W" magnet and duraluminum
voice coil suspension in woofer section results in deep
and highly efficient bass response. 8 ohm! impedance,
25 watts power capacity.
-
MODEL 315 TRIAXIAL
BY
Reproduces the entire range, from 30 cycles to inaucibility with such amazing clarity and presence that the
superiority of this unit is readily obvious. Built around the
sensational CI5W woofer assembly, mid -range is provided by the patented "Diffusicone" device, while the
clean and brilliant hi,lhs are reproduced by a compression
driver unit with wide angle horn through an L/C electrical
network crossing over at 5,000 cycles. Impedance 8 ohms, power capacity 50 watts.
Speaker Systems
Custom Design For
Speaker El:to,ures Engineered To Acoustically Enhance
The Perfomance Of University Speakers ... Tastefully Styled To
Complement The De:or Of Your Home Rather Thon Dominate It
Fine
101/4
/s
Wt7'
Engineering Superiority
...
Proven by Years of Acceptance
EN -1S
loading,
phase inversion, and dir tct radiation are
integrated to result in a highly efficient,
extended ronge enclosure capable of
unusual power handling capacity and
excellent transient response. Ideally
suited for the Model 312 or Model 315
Triaxial speakers, or an of the other fine
12" or 15" University speakers. Avail.
able in cherry or blond mahogany at no
extra cost, or unfinished.
The EN -15 comes equipped with adapter
The best features of recr horn
Model 6200 Extended Ronge Speaker
Full bodied response to beyond 10,000 cycles
makes it ideal for radio, TV and Fhono applications. Excellent basic unit. Eight ohms
impedance, 25 watts power capo:ity.
-8"
Diffusicone
and 12" Coaxial Speakers
Exclusive patented " Diffusicone" desiin w th
1000 -cycle mechanical crossove- resul's in full
fidelity anywhere in the room... full und storted response without loss of highs of listening points progressively off spec Ser ax s. Eiç ht
ohms impedance, 25 watts power copaciy.
boards for mounting 2 o. 3 -way combinations of University woofers and tweeters.
EN -8
Utilises a combination of rear horn loading for
unexcelled powe- hardlig and distortion control, and tuned Forn mowM+ for phase inverter
action for increased bass efficiency. The perfect
enclosure for the Model ,08 Triaxial speaker
or Diffusicone-8. Available in cherry or blond
mahogany at no extra :ost, or in unfinished
mahogany.
Model 6201 Dual Range System
Acknowledged as the industry's finest value in
a high quality 12" loudspeaker. Complete with
coaxial tweeter driver and wide angle horn, it
is one of the few true dual range systems in its
price class. Built -in 1/C network and balance
control. Eight ohms impedance, 25 watts power
capacity.
The EN -8 has cet -ouf for University tweeters
for use with Sr woofer or other cones.
For complete inf rmation on the entire University high
fidelity line, write Desk 68
INC.
80 SOUTH KENSICO
AUDIO
AVENUE,
APRIL, 1955
WHITE PLAINS, NEW YORK
39
www.americanradiohistory.com
and the material of the core. None of
these can be manipulated at high frequencies, but there is another, more
easily controllable characteristic that
can influence the coil's field strength and
a.c. impedance-the magnetic condition
of the core. The core will not continue
Magnetic Amplifiers
to accept added magnetization indefiThe electrical amplifiers that have nitely; there is a natural limit to its
been here described provide circuit paths capabilities. As the current is increased
whose resistance to current flow is var- the core begins to saturate, which means
ied by an input signal. Such a path may that a further increase of current flow
also be produced by an electro- magnetic through the coil will produce less than
rather than a resistive unit, which is the corresponding increase in magnetic
field strength.' The degree of this satcalled a saturable reactor.
The impedance of an electrical coil uration may be controlled, electrically,
by the input signal.
to alternating current is far more than
A separate winding on the same core,
would be expected from the inherent
resistance of the wire. Each time that through which the controlling input curthe current increases, drops to zero, and rent flows, will cause the degree of satthen increases in the opposite direction uration to increase and decrease accorda magnetic field around the coil builds ing to the instantaneous polarity and
up, collapses, and builds up again with value of the input signal. A larger curreversed polarity. This pulsating mag- rent flowing in the output winding,
netic field cuts the wires transversely
drawn from an a.c. source of power, will
each time that it builds up and each then vary in step with the varying imtime that it collapses, inducing current pedance.
of such instantaneous direction as to
If the input current must do all of
oppose and reduce the original flow. the saturating the power gain will be
This is the descriptive analysis of in- low, as an appreciable amount of energy
ductive reactance. In the magnetic am- is required to saturate the core. A third
plifier the input signal controls the in- winding is therefore assigned the major
tensity to which the self -induced field burden of saturation. This winding may
can build up, and hence it controls the carry direct current from a separate
electrical supply, or it may carry rectielectrical impedance of the coil.
Among the factors that determine the fied current from the output circuit.
intensity of the field are the number of In the latter case the third winding inturns in the coil, the size of the core, troduces "positive feedback," because
the effect of a small input current is
re- introduced into the circuit in such a
way as to intensify the effect on the
output. Small input currents can then
AC POWER
control very much larger output curo
rents, and power gains of the order of
INPUT
LOAD(
100,000 times are obtainable.
In practice it is found necessary for
the independent energy source of the
magnetic amplifier to supply pulsating
direct current rather than alternating
AG POWER
current, as shown in Fig. 7, so that the
INPUT
LOAD
saturation effect of the current in the
RECTIFIERS
output winding can never oppose that
of the input winding. Pure direct current in the output circuit, however, such
as is used with vacuum-tubes and transistors, will not work. Direct current
would remain uninfluenced by the
changes in core saturation ; the impeINPUT
LOAD
dance of the coil to d.c. is entirely a
matter of the resistance of the wire
conductor. Thus the power that is varied by the input signal is itself a steadily
oscillating quantity, but it is a relatively
simple matter to separate and extract the
amplified impulses from the alternations
INPUT
LOAD
of the power source. For this purpose the
frequency assigned to the power supply
is made much higher than the highest frequency input that is to be amplified.
Magnetic amplifiers are very reliable,
have the ability to withstand severe
Fig. 7. The top diagram shows the essentials
shock, and require no warm -up period.
of a magnetic amplifier circuit. Current in the
They are also exceptionally efficient,
input winding controls magnetic saturation of
because most of the impedance which
the core, which in turn controls the impedance
they introduce into the output circuit
of the output winding to the flow of alternating
sistor has been developed to a point
where it can duplicate many, although
not all, of the vacuum -tube functions.
One application of the transistor is
illustrated in Fig. 6.
'
+
o
...VIE
`11.1
current. The bottom diagram includes rectification of the a.c. power to pulsating d.c., and
use of an additional "positive feedback" winding to increase power sensitivity.
'A
familiar example of this phenomenon
is the decrease of inductance in a choke
when the current rating is exceeded.
Fig. 6. With the transistor reducing space requirements of tubes and batteries, an electronic
megaphone can contain microphone, amplifier,
batteries and speaker in one independent unit.
(Courtesy General Electric Co.)
is of a type called reactive, which does
not itself absorb energy. (The resistive
barrier to current flow introduced by
vacuum -tubes and transistors wastes
energy in heat.) Magnetic amplifiers
are at present advantageously applied
in circuits which must control appreciable amounts of power at relatively
low frequencies adjustable -speed motors, winding reels, automatic pilots,
voltage and frequency regulators, and
other automatic control apparatus. A
magnetic amplifier used in servo work
is illustrated in Fig. 8.
-
Dielectric Amplifiers
In the search for new, more compact,
and simple amplifier devices research
is being pursued in yet another direction,
that of the capacitor or dielectric amplifier. The principles of operation are
quite similar to those of the magnetic
amplifier, in that a circuit element with
variable a.c. impedance is connected in
series with an a.c. source of power. The
element is not a coil, however, but a
capacitor, a system of parallel plates
separated by an insulating material or
dielectric.
If a battery is connected across a
capacitor there will be no steady -state
current flow. Electrons move from the
negative terminal and charge one side
of the capacitor by surfeiting its plates
with negative charges ; at the same time
electrons move from the opposite plates
of the capacitor into the positive battery
terminal, and leave these plates positively charged by reason of their lack
of the normal number of negative
charges. The process continues for a
short time, until the storage "capacitance" of the device for electric charge
is reached, at which point the short-
AUDIO
40
www.americanradiohistory.com
APRIL, 1955
Did you know you
1-2
can reduce speaker
distortion by 76%
with an amplifier?
0
2 DAMPING FACT('
111
PATENT
PENDING
Meet Bogen's new amplifiers
with 'ultimate damping'
Now you can enjoy more hours of perfect listening without fatigue. The famous Bogen DB20 and D030 ampli-
fiers are now available with the exclusive BOGEN
VARIABLE DAMPING FACTOR CONTROL (VDFC)
which permits you tc minimize speaker distortion and
eliminate system resonances.
The Bogen control is the first to offer a range from +2
through infinity to -1 ... which is that magical point,
we call it "Ultimate Damping", at which the speaker
resistance is negated and distortion reduced to an imperceptible value.
THE DB2ODF AMPLIFIER
This is our famous Bogen
DB20 amplifier, rated as having "Best Overall Quality"
by a leading consumer
testing organization, with
Q
Yes, now you can get true bass with any speaker!
It is easy to set your Bogen VDFC for Ultimate Damping ... no instruments are needed. As you can see from
the enlarged control shown above, you merely turn the
slotted shaft with a screwdriver to the desired setting
when you install your system. No later adjustment is
required.
*Acoustical measurements by an independent laboratory
using a quality hi-fi speaker system operating at 5 watts
and 25 cycles showed 96% distortion with damping
factor of 10 (typical amplifier), and only 20% with
Bogen Ultimate Damping. (Amplifier distortion itself
was well under 0.5 %.)
BOGEN DO3OA POWER AMPLIFIER
This brilliant unit now features the exclusive Bogen
variable damping factor
control as standard equipment ... which adds to its
stature as the perfect companion to the all- control
tuners -such as the Bogen
the added feature of the
Variable Damping Factor
Control. This amplifier gives
you 20 watts of power at
0.3% distortion with a 5- position Loudness Contour
Selector, a 10- position input selector-phono equalizer,
output jack for tape recorder and non -resonant, separate
bass & treble tone controls. With Variable Damping
Factor: $108.00 (DB20 without VDFC: $99.00.)
SECOND PRINTING :
"Understanding High Fidelity" is fast becoming a
standard manual of hi -fi theory and application. Clearly
and concisely, this new enlarged 56 page edition presents invaluable practical information to help you get
more out of any sound system. "For the Audiophile first
seeking his way ... a surprising introductory work."
says the Saturday Review. Send 25¢ for your copy.
R750 FM -AM Tuner where
tuning, volume, bass tone, treble tone and selector controls are all on the tuner panel. The D030A amplifies all
frequencies uniformly from 10 to 20,000 cycles within
0.2 db at rated output of 30 watts. Variable Damping
Factor Control is the same as that on DB2ODF. $99.00
David Bogen Co.. Inc. Dept. Y
29 Ninth Ave. New York 14, N. Y.
Send "Understanding High Fidelity" (25¢ enclosed).
Name
Address
HIGH
I-
City
Zone
state
Send only free catalog and where -to- buy -it guide.
BECAUSE IT SOUNDS BETTER
AUDIO
APRIL, 1955
41
lived current drops to zero again. If the
battery is then disconnected, and the
two sides of the capacitor are connected
through an electrical conductor, there
will be another momentary surge of
current, this time in the opposite direction. The second surge is created by
the capacitor's discharge, which brings
the plates back to their original neutrality of charge.
Except for the initial surge, then,
capacitors are non -conducting devices
for direct current. In an alternating current circuit, however, they are effectively conductors. Although electrons
never actually cross the dielectric bridge
between plates, each side of the device
alternately accepts and discharges electrons, so that as far as the a.c. source is
concerned it is able to send electrons
into the circuit and receive them back
again. The impedance which the capacitor offers to the flow of alternating current is inversely proportional to the frequency of reversal of the electrical alternations and to the value of the capacitance.
In the dielectric amplifier control of
current flow is achieved by varying the
capacitance. One of the elements upon
which the value of this capacitance depends is the material of the separating
dielectric. The electrostatic field created
by the application of voltage across the
capacitor plates produces a molecular
strain in this material, and potential
energy is stored by the dielectric in a
manner comparable to the storage of
mechanical energy by a stretched spring.
It is this molecular strain and storage
of potential energy that makes it possible
for the plates to accept and retain their
unnatural charges. The amount of
charge that will be accepted, and the
capacitance of the system, is therefore
limited by the amount of energy that
can be stored in the dielectric. The quantitative index of this characteristic of
the insulating material is called the
dielectric coefficient.
It was discovered that the dielectric
coefficients of certain materials such as
the barium titanates, Rochelle salt, and
tungsten trioxide are not constant, but
vary significantly with the applied voltage. Since the electrical impedance of
the capacitor is directly dependent upon
the value of the dielectric coefficient, the
latter characteristic may be used as the
control element in an a.c. power circuit,
using circuits as in Fig. 9. A high degree of amplification may be achieved
in this way, with many of the same
advantages that are achieved in the
case of the transistor. The same oscillating power supply that is used by the
magnetic amplifier will work here, so
that the dielectric amplifier is suitable
for use in conjunction with magnetic
amplifiers. It is cheaper than the magnetic amplifier, although not as stable,
because the dielectric properties of the
titanates that are currently being used
are affected by temperature changes, and
the gain of the amplifier tends to drift,
requiring compensatory measures.
Functional Categories of Amplifiers
In the beginnings of radio an experimenter was able to buy a single type
of "audion" or three-element vacuum tube. Today the number of specialized
tube types that have been designed for
particular jobs runs into the thousands.
Amplifiers may, nevertheless, be classified into a few basic functional categories. These concern (1) the amount
of output power required, (2) the band
and band -width of frequencies covered,
and (3) the degree of wave form distortion to the original stimulus that can
be tolerated. The total amount of amplification may be regulated by the number
of amplifying stages, of whatever type,
connected in cascade.
Heavy tasks, such as the radiation of
sound into a room, the engraving of the
undulated groove in a disc record, the
control of machinery, or the radiation
of radio waves by a transmitting antenna, require "power" amplifiers. socalled because of the relatively large
amounts of power regimented to the
appointed duty. "Voltage" amplifiers or
amplifying stages do not differ in principle. They, too, increase the input
power, but they are used where the primary requirement is to raise the signal
voltage, without a corresponding decrease in current, and where the amount
of output power needed is not very great.
These conditions are normally present,
for example, when the output of a stage
of amplification is used to drive another
amplifier, perhaps a power amplifier
insensitive to weak signals, or when the
ouptut is connected to a final load with
Fig.
8.
This "servo"
magnetic
amplifier
may be used to drive
mechanical posia
system.
tioning
(Courtesy M a g netic Amplifiers,
Inc./
AC POWER
o
o
INPUT
T
LOAD
AC POWER
o
I
INPUT
o
LOAD
dielectric amplifier permits a small
input voltage to control the dielectric coefficient of a special capacitive unit. The more
elaborate circuit incorporates d.c. "bias" and
a bridge arrangement that keeps a.c.
power
out of the input circuit.
Fig. 9. The
modest power requirement, such as a
pair of earphones.
Amplifiers are designed for various
frequency ranges between zero cycles
(direct current) and the microwave
band. The upper limit of the latter is
considered to be about 100,000 megacycles, approaching the infra-red region
of the electro- magnetic spectrum. Microwave amplifiers are used in radar and
television -relay stations. An amplifier
that can build up d.c. stimuli, or stimuli
that change only slowly, is required for
various types of measurement, including
such medical applications as the detection of minute body potentials. Each frequency region has its own problems of
amplifier design, with regard to both
the amplifying units themselves and to
circuitry. Microwave circuits, for example, use hollow -pipe wave guides instead
of connecting wires, and the transmission lines are often referred to as plumbing because of their physical appearance.
Special tubes for microwave oscillators
and amplifiers- magnetrons, klystrons,
and traveling -wave tubes-have been designed.
Most amplifiers cover only a small
portion of the electrical frequency spectrum, but certain types of signal embrace
an unusually wide band of frequencies.
Video signals, for example, which represent variations of dark and light across
successive strips of the picture screen,
cover the range from thirty cycles to
four megacycles, a ratio of better than
1,000 to 1. Amplifier stages for such
signals require special design treatment.
A sacrifice in gain must be made in
order to achieve broad -band operation.
Increasing the magnitude of the input
signal invariably involves a certain
amount of wave form distortion, and
amplifier stages are classified (as Class
1, B, or C) according to the compromise
that is made between fidelity and effi-
ciency. A method has been found, called
push-pull operation, in which most of
the distortion of a compromise amplifier
stage can be cancelled by a second compromise stage working alongside.
The degree of output inaccuracy in
a high- quality audio amplifier is ordinarily less than the degree of hearing
(Cotttinurd on rage 65)
42
AUDIO
www.americanradiohistory.com
APRIL, 1955
There is
only one
They may look alike...but they can't sound
alike! Never before has any product been so
aped, copied, and imitated as has the R -J enclosure! The important thing is that other enclosures may look like the R -J, but they can't sound
like an R- J...because it's the interior construction principle that makes the difference. The
R-J is so different that it has been granted not
one but two patents* by the U. S. Government.
There is only one R -J enclosure! Unfortunately,
we cannot protect you, by preventing any manufacturer from making a cabinet with the same
outside dimensions and appearance as the R-J.
But it's the inside of the enclosure that determines how a speaker sounds...and the inside
of the R-J absolutely cannot be duplicated!
The best part is that R -J enclosures are as low
as $24.50.
* U.S. Patent Office
Nos.
A quality- endorsed product of the British Industries Group
R -J AUDIO PRODUCTS INC.
AUDIO
2,694,462 - 2,694,463
Garrard, Leak, Wharfedale, R -J components
New York 13, N. Y.
164 Duane Street
APRIL, 1955
43
www.americanradiohistory.com
Equipment Report
McIntosh
an almost unlimited variety
response curves, the McIntosh
power amplifier chassis ; if used with the
D -8 power supply (in this form, the Compensator is known as C -8P) it will furnish
a 2.5 -volt output to any other power amplifier.
Referring to the schematic, Fig. 3, it
will be seen that there are five input channels. The first two have input impedances
of 0.66 meg, and are designed to accommodate high -level inputs, working down
to a minimum of 70 -mv input for full output. The third channel is designed for
low -level inputs, with a minimum of 10 mv
for full output. The input impedance of
this channel is 0.1 meg. These three channels provide flat amplification from 20 to
20,000 cps, and all panel controls except
that for turnover are effective.
Channel 4 is designed for a high -level
magnetic cartridge, and is terminated for
use with the Pickering models. Changing
resistors R. and R, will permit the use
of G.E., Audak, or most other "low- level"
cartridges, since normal output may be
obtained from an input signal of 10 mv.
Channel 5 is equipped with a variable load
resistor to accommodate any of the low level cartridges without any internal
changes. The gain is sufficient that full
output can be obtained with an input of
PROVIDING
in
C -8 Audio Compensator is one answer
to a desire to accommodate any present or
probable future recording curve, as well
as to adjust for the acoustics of the listening room, deficiencies in the speaker system,
or practically any other condition that may
arise.
This unit -which is available either to
work with the entire line of McIntosh
power amplifiers or with its own small
power supply
equipped with the usual
bass, treble, selector, and volume controls,
-is
Fig.
1.
Performance curves for the McIntosh
C -8 Audio Compensator.
Fig
2.
The Audio
and has in addition a rumble filter control,
a loudness compensator switch, five switches
to control the turnover frequency, and five
switches to control rolloff. That may seem
like unduly complicated for the average
listener, but there are many who are of
the opinion that this unit is the only one
which can provide a range of control which
i.s sufficiently wide for the most critical
listener. The Compensator is designed to
mount in an existing panel, using an opening 10 1/16 x 3 5/8 in., or it may be installed
in a small cabinet as shown in Fig. 2 and
used on a table top, if desired. When feeding a McIntosh amplifier, it draws operating power from sockets built into the
Compensator, Model C-8.
-
C -8 Audio Compensator and Mc -30 Power Amplifier
Phono Pickup Arm -General Electric AI -901 Record Filter
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72
C
-El
TAMP
4MA
I.
250K Pot
1140
A4i
A.l
X4'r
Rab
KROK
Owl .ot
III Pot
11
.43
56
Iu .o
Fig. 3.
10011
10K
2
..n00.
IOW
I
Schematic of McIntosh Audio Compensator.
AUDIO
44
www.americanradiohistory.com
APRIL, 1955
HFi
These are franchised
IYOU CAN GET THESE HIGHEST QUALITY
Audio Equipment Distributors:
CALIFORNIA
Thomas Tenney,
AUDIOPHILE
2054 College Aveeue, Herkelr:
Crawford's, 456 N. Rodeo Drive, Beverly HillJack Schiefer, 2121 Blecketon Ave., Fresno
Glendale Recorders. 319 N. Central Ave.. GlrmLar
Cook Electronics, 210 E. Harty St., Inglewood
Itueingtons, 308 No. Irwin St , Hanford
Guptill High Fidelity, 22 S. School St., Lodi
Electronic Sales, 1433 W. Piro Blvd., Los Angeles
Pacific TV SOPDIy, 4032 S. Figueroa St., Los Angeles
Mardonelds Radio & Sound, 35 N. Santa Cruz, Los
COMPONENTS
FOR THE BARGAIN PRICE
OF
$15415
ONLY
Gatos
Madera Music Co., 114 E. Yosemite, Madera
Griffin Furniture Co., 25 N. Knoll Rd., Mill Valley
Olin S. Grove, 2904 Telegraph Ave., Oakland
The Service Shop, 1553 Pine St. Redding
'l'he Hi -Fn Shop, 3525 California St.. Sen Francisco
Market Radio Sound Dept., 1240 Market St., San
Francisco
San Francisco Radio & Supply Co., 1284 Market St.,
San Francisco
Television Radio Supply Co., 408 Market St., San
Francisco
West Coast Electronics. 409 Market St., San Francises
Aliens Sight & Sound, 856 Monterey St., San Lui,
Obispo
High Fidelity Unlimited, 211 S. San Mateo Drive,
San
Mal,»
Pacific Installations,
FLORIDA
The
1225 San Carlos, San Jose
Room Inc.,
1809 Ponce de Leon Blvd.,
('or
.el- lee
Southca.I Audio Co., 930 West Adams St., Jacksonville
Fiagler Radio, 1058 W. Flaeter St., Miami
Kinkade Radio, 1707 Grand Central, Tampa
i
o
to
GEORGIA
Baker Fidelity
Atlanta
Corp.
1429
Peachtree
St.,
N.E.,
ILLINOIS
Electronic Expediters, 2909 W. Devon Ave., Chicago
Losses Radio, 1217 E. 55th St., Chicago
Malone Electronics, 123 Addison St., Elmhurst
IOWA
Gifford-Brown Inc., 726 5th St., S.E., Cedar Rapids
Iowa Radso Supply, 508 Third Arc., Cedar Rapide
Mid-State Distributing Co., 1201 Grand Ave., Des
Moines
Ken -el- Radio Supply Co.. 501 First Ave., No., Fort
Dodge
Ray -Mac Supply Co., 200 Ballots St.. Waterloo
KANSAS
Western Distributors, 227 N. Santa Fe. Salinas
McClelland Sound Equipment Co., 229 W. William
St., Wichita
Radio Supply Company, Inc.. 115 Laura St., Wichita
oe/1-Í01t2
TPR-1 TAPE PREAMP
KENTUCKY
1
Radio Supply,
LOUISIANA
533
S.
7th St., Louisville
N,u Iberia Cart & Trailer Ce., New Iberia
MARYLAND
Fare Eletronics, 4220 Dresden St., Kensington
MASSACHUSETTS
Bond Electronics, 42 Cornhlil St., Boston
Electro Sotmd, 15 Ilalieck St.., Boston
Lincoln Electronic Supply, 790 Commonwealth Ave.,
Boston
Radio Wire & TV, 110 Federal St., Boston
The Radio Shack, 167 Washington St., Boston
HI -FI Electronic Supply, 1077 Massachusetts Ave.,
Cambridge
Young and Young of Lawrence, 262 Lowell St., Law'
Soundm Electronic Supply, 147 Dwight St.. Springfield
Radio Electronic Sales Company, 52 Chandler St.,
Worcester
MINNESOTA
Northwest Radio, 123 E. First St., Duluth
General Supply Co.. 201 W. Lincoln Are., Fergus Falls
Eckco Sound Equipment Company, 116 Lyndale Ave.,
North, Minnegadls
Lew Bonn Co., 1211 La Salle, Minneapolis
Hall Electric Co., 566 No. Robert St., St. Paul
MISSOURI
Ebinger Radio & Supply Co. , 2501 -3 Jefferson St
St. Louis
NEBRASKA
J. B. Distributors,
NEW JERSEY
1616
Case
St., Omaha
Magnetic Recording, 344 Main St., Patterson
Sparger's Record and fil -FI Shop, 34 E. Main St.,
Penn, Grove
NEW YORK
Commercial Sound Systems,
Albany
Adirondack Radio Supply,
Amsterdam
Inc.,
I1
185 -191
N.
Pearl St..
W.
Main St.,
Dares Radio, 22 E. Genessee St., Auburn
Buffalo Audio Center, 326 Elm SI., Buffalo
John L. Reusch, 109 Landon St., Buffalo
Ray Distributing Co.. Upper Glen St.. Glens Falls
Island Radio Distributors, 412 Fulton Ave., Hempstead
Standard Puts Corp., 277 N. Franklin St., Hempstead
The Audio Exchange. 159 -19 Hll:aide Ave., Jamaica
Johnson Radio
Electronics, 119 Bunt Road,
&
Jamestown
Arrow E:ectronice, 05 Cortlandt St , New York City
Goody Audio Centre, 235 W. 49th St., New York City
Harvey Radio Corp., 103 W. 43rd St., New York City
Heins & Bolet, 68 Cortlandt St., New York City
International Audio Exchange. 1101 Lexington Ave.,
New York City
Leonard Radin Corp., 69 Cortlandt St., New York City
Milo Radio and Electronics Corp., 200 Greenwich St.,
New York City
Radio Wire & TV, 100 Sixth Ave., New York City
Sonoeraft, 115 W. 45th St., New York City
Stentor Recording Machine Ca., 469 Fourth Ave., New
York City
Niagara Falls Radio, 1363 Pierce Ave., Niagara Falls
Pavel TV, 204 Long Beach Road, Oceanside
Electronics TV Corp., 2 Purchue St.. Rye
©
fi-tarie
Tit-ism,
TPR -1 TAPE PREAMP
High impedance (I volt) output
Tubes: 6X5GTA, 6AQ5, 12AT7, 5879,
6E5.
r
Utica
Supply, 1427 -29 Sunset Ave.,
Utica
High Fidelity Center, 367 Mamaroneck Ave., White
Plains
Fidelity Unlimited, 63 -03 39th Ave., Woodside
Associated Electronics
NEVADA
Art Rempels Sound Supply, 460 Wells Ave., Reno
NORTH CAROLINA
Shaw Distributing Co., 205 W. 1st St.. Charlotte
Eastern Radio, 532 Hay St., Fayetteville
W. Walnut
Street,
Golds-
Dlllman Radio Supply. 389 W. Center St., Marion
Warren Radio Co., 1002 Adams St., Toledo
OREGON
Carlson, Hatton & Hay, 96 E. 10th Ave., Eugene
Northwest Radio, 110 S.E. Eighth Ave., Portland
Television & Radio Supply Co., '720 S.E. Alder St.,
Portland
Hawthorne Electronics, 700 S.E. Hawthorne Blvd.,
-TV
Ott's Radio
Blvd., Portland
L,
Hi
F'1,
3760 S.E. Hawthorne
PENNSYLVANIA
Air Tone Sound & Recording, 1527 Chestnut St.,
Philadelphia
Magnetic Ree9der & Reproducer.
Philadelphia
Sid Wagner, Electronic
Ave., Philadelphia
Automatic muting switch. Automatic shutoff. Built in 3 -stage tone filter. Spring
mounted chassis.
Price includes famous PE8 dual cartridge
with sapphire stylus.
Schuylkill
Electric Distributors, Inc., 611 Mauch
Chunk St., Pottsville
1373.83 Easton Rd., Roslyn
Consolidated Distributors, 842 -44 Capouse Ave.,
Scranton
Electronic Sales & Service, 734 Market St., Sunbury
West slarleton Electronic Supply, 120 -22 N. Broad
St., West Hazleton
C. R. Minnich, 624 W. Market St., York
Grove Enterprises,
SOUTH CAROLINA
HI'gh
FI'delity, 728 Saluda Ave.,
Columbia
The 59 tine, 209 W. Washington St., Greenville
SOUTH DAKOTA
Warren Radio, 115 So. Indiana Ave., Sioux Falls
TENNESSEE
W & W Distributing Co.,
644 Madison, Memphis
TEXAS
OHIO
furl land
CHANGER
acoustic feedback.
House of Harmony, 1034 Eastern Ave., Schenectady
Stewart W. Smith, 325 E. Water SI., Syracuse
Electronics Labe Sr Supply, 1415 Oriskany St., W,
Womack Electric Supply,
borough
PE REX
The only truly automatic and foolproof
changer (patented), playing ten intermixed records, without pre- setting, in
any odd size between 6" and 12 ".
Precision built: free from rumble and
Bias Frequency 45 -55 Kc
Signal -to -noise ratio 55 db
Separate Power Supply and Hum -Balance
Control
One mike, One high level input
Supply,
FENTON COMPANY
AUDIO
MOTEK TRANSPORT MECHANISM
Driven by three individual AC motors.
Speed 71/2 I.P.S., dual tracks.
All electrical push button switching and
braking.
Hi -Fi record/playback and erase heads.
Frequency response better than 50 - 10,000
C.P.S.
WOW and FLUTTER less than .3%
Accommodates 7" reels (1200').
1533 Cherry St.,
522 W.
Wyondng
MrNicol, 811 N. Estrella St., El Paso
Gulf Coast Electronics, 1110 Winbern St., Houston
C. M.
VIRGINIA
Radio Parts Distributors, 128 W. Olney Road, Norfolk
Radio Sales & Service Co., 416 Monticello Ave.,
Norfolk
WASHINGTON
Pacific Electronic Sales, 1209 First Ave., Seattle
Seattle Iodla Supply, 2117 Second Ave., Seattle
Twrnt let
Century Sales, W,
1021 First Ave.,
Spokane
Kar Radio & Electric, Walla Walla
WEST
VIRGINIA
James M. Black & Sons,
WISCONSIN
The
Ili -F1
or at your nearest Hi -Fi center.
15 MOORE STREET
APRIL, 1955
052 Market St., Wheeling
Center, 2630 No. Downer, Milwaukee
NEW YORK 4, N. Y.
45
www.americanradiohistory.com
Fig. 4. The McIntosh Mc -30 Power Amplifier.
10 mv, which is adequate for Audak and
G.E., or for Leak, Fairchild, or Electro
Sonic pickups when used with an input
transformer. The input impedance may be
varied from zero to 0.1 meg, and by operating a slide switch on the rear apron to
"F.M.," and the load switch to "100"
representing 0.1 meg-the input will accommodate amplitude- responsive cartridges
such as ceramic and crystal types and the
Weathers FM pickup. All panel controls
are effective with both channels 4 and 5.
The Bass Compensation switches work
only with the last two channels, and provide a number of turnover frequencies in
discrete steps when only one switch is
operated, or for a somewhat wider range
when two or more are used. Note that
all stages of the compensator are used for
all inputs, the signal being reduced in
level to apply a maximum of 10 mv. to
the grid of the first tube. The selector
switch eliminates the frequency-selective
components from the feedback around the
first tube when set for channels 1, 2, or 3.
Treble compensation is accomplished by
adding capacitors to the circuit by means
of slide switches-one for each capacitor.
Both compensation circuits employ the
slide switches, and by this means almost
any degree of correction may be obtained
by simply operating two or more switches.
The phonograph compensation curves are
shown in Fig. 1, and while there are five
discrete curves available for both bass and
treble, the range obtainable is best shown
by the shaded portion which indicates a
very wide variety of curves.
The Auxiliary output is connected at the
cathode of the stage prior to the tone and
volume controls, ,and is therefore not affected by them, although compensation and
rumble-filter controls are in the circuit,
making it possible to dub from phonograph
records to tape, for example, with the
-
model are not shown, since frequency response is (naturally) flat from 20 to well
over 20,000 cps and no controls are provided, and IM distortion remained below
0.4 per cent to over 40 watts output (equivalent sine -wave output, which is the method
used in all of these Equipment Reports).
This value is well beyond the limits of our
standard graph sheets.
By now, most audio fans are familiar
with the McIntosh amplifier circuit. Figure
5 is the schematic of the Mc -30, with the
output transformer which provides load
for both plate and cathode. Since the
transformer has a 1: 1 ratio, the same signal voltage exists at both ends of each of
the two windings -one being connected to
the plates and the other to the cathodes.
Note also that the screens are connected
to the opposite plates. Thus the signal on
the screen and cathode of either output tube
is identical, which means that the screens
are perfectly bypassed to the cathodes
condition wherein pentodes and tetrodes
operate best. At high powers, the signal on
the cathodes is quite high, which necessitates the use of a tulle which will withstand a high cathode- heater potential.
The stage line-up in the amplifier consists of a single -ended amplifier tube, followed by a "long- tailed pair" phase splitter,
a push -pull amplifier stage, and a cathode
follower stage which drives the output
tubes.
Feedback from a tertiary winding on
the output transformer returns to the
cathode of the first stage, and the output
is taken from a fourth winding, with 4,
8, and 16-ohm taps being available. A 600 ohm output is provided, being taken from
taps on the cathode winding of the output
transformer. This output is likely to be
several volts above ground (d.c.) since it
is taken from a winding in which current
is flowing, but for most applications this
would not be important.
-a
PRE
THE
B -J
PHONO ARM
Anyone who has ever read anything
about the requirements for good phonograph reproduction, minimum distortion,
low record and stylus wear, and reduced
noise has noted that it is considered desirable for the axis of the pickup to be
tangent to the record groove at all times.
With conventional arms this is impossible,
and it is likewise impossible with any
simple arm whose pivot is not at an in
f6N--OU*PUT--t
IMP iMOUr
OMJPU}
ONO COM
M
9.0
i,C
iJ0
L
o
proper equalization.
The main output -also from a cathode
follower -can be influenced by the aural
or loudness compensator as well as the
volume, bass, and treble controls. The
curves for the rumble filter indicate that
this would be useful in applications where
bass response from a high- quality speaker
system made the rumble objectionable.
Tone -control and loudness -compensation
curves are also shown in Fig. 1.
The Compensator is equipped with three
a.c. outlets for phono motor, tape recorder,
power amplifier, or any other devices intended to operate with the input unit.
Figure 4 shows the power amplifier,
Model Mc -30. Performance curves for this
Construction of these two units is neat
and compact, with ready accessibility to all
parts. While most high -quality equipment
in the audio field seems to show a minimum
of need for part replacement, there is
always the possibility that such a need
may arise, and it is well not to have to
"unbuild" the amplifier any more than
necessary if a resistor or capacitor has to
be changed. Most small components are
mounted on resistor boards ; in the C -8
both sides of the resistor board may be
reached by removing the top and bottom
of the unit simultaneously, while in the
Mc -30 the resistor board is mounted in a
vertical position, and all components may
be reached readily when the bottom cover
is removed. Octal sockets are used to make
interunit connections as well as for output
circuits, so that a plug -in installation can
be made readily. This offers advantages
when the user has occasion to use an
amplifier in more than one location -he can
simply unplug it and plug it in again
whenever he has need to move it.
The first McIntosh amplifiers-50 -watt
units -were noted for their performance
and efficiency. The new 30 -watt model
seems to live up to that reputation, and it
does give excellent listening quality. With
the C -8 Audio Compensator, sufficient
flexibility is available for any application
likely to be encountered.
Re
Ps
1614
RIO
C
e20
RI!
;.:
IVA
3
üv30
R13
331
In
KB
Is.
gr.»
IA
la,
ran,
u«,'ñ
1123
ua.n
IM
R33
131111
430V
K
st
KM
R32
1
3111
am
9Jv
223.2. 3011V
IOW
7701t
â:
JM
300V
tzc
9
Ta
mac
r:ee
y S
Tam, WV
Cll
TO
Tu
CIO
I W.
30K,
vv
9
CI
121K
330V
.om
1001, 4303/
Fig. 5. Schematic of the Mc -30.
46
AUDIO
www.americanradiohistory.com
APRIL, 1955
G -E MATCHED COMPONENTS and CABINETS
so easy to own
o
General Electric has shattered the
high cost barrier on high fidelity
HI
J ownership. Yes, G.E.'s common
sense prices put true high fidelity within the range
of every budget! But price is just part of the G.E.
story. Every component is balanced to give you
utmost enjoyment from today's fine recordings.
Cabinets are designed for beauty and flexibility...
fit anywhere...add richness to any home.
Prove this to yourself. See how easy it is to in-
Beautiful to
see and hear.
Companion cabi-
with existing furniture or, into a
music wall for that important "custom look."
nets blend
AUDIO
... enjoy... install
stall G -E Hi -Fi. Ask for a demonstration. G -E performance, beauty, and sensible pricing will convince
you. Write today for the name of a local dealer:
General Electric Co., Radio & TV Dept., Section
R4445, Electronics Park, Syracuse, Netr York.
Enclosures Amplifier
Hi -fi Cabinets Speakers
Tone Arms
Styli
Pre -amp Cortrol
Cartridges
GENERAL
Pre -amp control and 'power amplifier cornbine for studio clear performance. Tuner may
be added in the cabinet if desired.
APRIL, 1955
ELECTRIC
G.F. spca.cer and cndosurc engineering...
the heart of hi-fi.. . assures smooth, accurate
response over the entire audible range.
47
www.americanradiohistory.com
Fig. 6. The
finite
B -1
Phono Arm, designed to maintain perfect tangency throughout the record area.
distance from the center of the
record.
The B -J arm, a British design that was
recently introduced into the U. S., is
claimed to accomplish just this, however,
and the means by which the feat is accomplished appears to be so simple that
we undertook to prove to ourselves just
how it was done. We made a full -size
drawing of the basic elements of the arm
(Fig. 7 is a reproduction of this drawing)
and actually made a check at several points
to see just how close it came to doing what
was claimed for it.
In the figure, the two fixed pivots correspond to the two in the stationary assembly-that triangular section at the right
in Fig. 6. This entire unit remains fixed to
the motor board, and does not turn as the
record is played. These pivots are needlepointed screws seating in holes in the
tubular arms, and are readily adjustable
and equipped with locking nuts. They are
clearly visible in Fig. 6.
The two arms -both of gold -anodized
aluminum tubing -are represented in Fig.
7 by heavy lines. The long arm is bent
slightly to clear the pivot of the short arm
in the rest position, which is the position
shown by the heavy lines. The two pivots
on the head, also needle-pointed and readily
adjustable, are shown as single circles,
with the position of the stylus projected
forward from the center of the line between
the head pivots.
By laying out the loci of the two head
pivots and scaling off the proper distances
between them, one obtains the axes at
various positions of the arm, and from
these the stylus positions can be drawn.
Outside grooves for both 10- and 12 -inch
records were drawn, as well as a circle
with a radius of 2 in. which may be considered the absolute minimum. Two additional positions were drawn intermediate
through the recorded portion of a typical
record.
Tangency at the point of contact is
equivalent to a 90 -deg. angle between the
center line through the pickup and the
radius of the record passing through the
stylus. This angle was measured carefully,
using a drafting machine for the reference
angles, with the results shown in the figure.
Note that the angle is 88 deg. at the outside of the 12-in. record, and 89 deg. at the
2 -in, radius, while for the remainder of
the arm travel, the angle measured 90 deg.
exactly. It is possible that a slight mismounting of the drawing with respect to
the center of the record might cause a
difference of one or two degrees, but as
accurately as we could measure readily it
appears that there is no greater than ±1
deg. variation from tangency throughout
the entire playing time. Thus while we
have to admit some skepticism at the possibility of maintaining tangency with a
relatively short arm, we must also admit
that the arm does do just that.
General Description
The B -J arm consists of a fixed base
which supports the rear assembly-the triangular section at the right in Fig. 6. This
unit is also moulded, and carries the fixed
pivots. The two arms carry at their forward end the moulded plastic head assembly, which mounts any conventional
cartridge. A thin section at the front may
be cut out with a pocket knife to make room
for the turnover knob on such cartridges
as Pickering, E -V, Shure, Sonotone, and
others which are operated from the front
end of the head. A punchout plate in the
top will permit the use of the G.E. Trip!ePlay cartridge. Stylus force is adjusted by
adding or removing triangular -shaped
weights from the bottom of the stationary
assembly.
The needle bearings used throughout are
sufficiently free that even with the four required for the lateral movement, there is
no apparent resistance. Mounting is accomplished accurately by the use of a
template which indicates the exact points
for locating the mounting screws in relation to the record spindle.
Since the correct mounting location is
important in maintaining tangency throughout the playing of the record, the cardboard template is obviously a necessity, but
when the arm is properly mounted, there
is no question but that nearly perfect tangency is maintained over the entire range
that should be encountered with ordinary
phonograph records.
Any opinion as to improvement in sound
reproduction with the B -J arm would be
subjective, but there is no gainsaying the
obvious advantage of having the stylus
always tangent to the groove with an arm
which is short enough to be practical in a
home system. Broadcast and studio equipment has normally relied on a long arm to
approach a minimum tracking error, and
many a music lover has insisted on using
the long arm for this reason. But many
users have been restricted heretofore to a
short arm, due to space limitations, and
they might well find that the B -J arm
will provide the tangency that is considered most desirable.
Al -901
GENERAL ELECTRIC
RECORD FILTER
While most preamplifiers provide many
curves suitable for the present wide variety
of record characteristics, many users have
been limited to a single bass compensation
curve such as that furnished by such preamplifiers as the G.E. UPX -003A which
provides only a fixed boost at the low end,
with the turnover usually set at around 500
cps. This is satisfactory for the average LP
characteristic, and is nearly correct for the
RIAA curve, but does not match any of the
foreign curves, nor does it give completely
correct equalization for 78 -rpm records.
Furthermore, as the user's system is improved, he may find that increased high and low- frequency response may show up
other defects, such as rumble or needle
scratch, or even possibly some increased
distortion from records which may not be
entirely free from higher- frequency distortion products.
The Al -901 Record Filter, shown in
STYLUS
R
s
RADIUS
THROUGH
STYLUS
OUTSIDE
GROOVES
LOCUS OF
SHORT ARM
HEAD PIVOT
FIXED
PIVOTS
J
LOCUS OF LONG ARM
HEAD PIVOT
9e7
CENTER OF
RECORD
F
7
That tangency is maintained over the full recorded area of a 12 -inch record is shown
by this diagram which represents the B -J arm in various playing positions.
AUDIO
48
www.americanradiohistory.com
APRIL, 1955
HEATHKIT
Fig. 8, is a convenient answer for this
situation, when the cartridge used with the
music system is of the familiar G.E. variable reluctance type. The record filter is
constructed in a small moulded plastic case,
so that it may be used separate from the
normal installation or perhaps with an inexpensive record player: for those who
might wish to mount the unit permanently
in a cabinet, the chassis and front panel
may be removed from the case and mounted
in any other desired panel up to
in. thick.
The filter does not require any power
suppl j, nor does it use any tubes -being
what is called a "passive" equalizer.
However, when used with a preamplifier
that already provides a fixed turnover of
approximately 500 cps and a bass boost
of 17 db at 50 cps -the usual equalization
for a mom- variable preamp-the filter prodifferent characteristics as well
vides
"BUILD IT YOURSELF"
amplifier
kits
qeailFfeCL
WILLIAMSON TYPE
(ACROSOUND
TRANSFORMER)
This ual -chassis high
fidelity amplifier kit provides installation flexi-
i
bility. It features the
&
Acrosound "ultra-linear"
output transformer, and
has a frequency response
within 1 db from 10 cis to 100,000 cps. Harmonic distortion
and intermodulation distortion are less than .5% at 5 watts,
und maximum power output is well over 20 watts. A truly outstanding performer. W- 3M consista of main amplifier and
power supply. Shpg. Wt. 29 lbs., Express
7/V
Model W-3 consists of W-3M plus WA -P2 Preamplifier listthis page. Shpg. Wt. 37 lbs., ExpreseZ69.50
ed on
YOURSELF
only
treatlrkit
WILLIAMSON TYPE
LRtiiiGG
Here is the
Fig. 8. The New Generol Eectric Record Filter
in its plastic cabinet.
as low- and high -pass filtering action. The
center or COMPENSATOR control adjusts the
response to flat, European 78, London LP,
Old AES, RIAA, and Columbia LP
characteristics. The panel is etched to show
the characteristic in use, as well as the
amount of rolloff at 10,000 cps -since this
is the usual manner of indicating the high frequency characteristic. Thus on FLAT
there is no rolloff, or 0; for EIrR 78 the
response is down 6 db at 10,000 cps ; for
LOx LP, it is down 10; for O1.D AES, 12; for
RIAA, 14; and for cot LP, 16. The turnover
frequency is changed simultaneously, together with the bass rolloff required for
col. LP and LON LP. The various curves are
shown in Fig. 9.
The filter section is particularly interesting, since it provides flat transmission at
both high and low ends. or three degrees
of cutoff at each end. In the 80 -cps position,
practically any rumble and even some 60cps hum is reduced appreciably, with the
40- and 60 -cps positions providing somewhat less low -end cutoff. Similarly, the
high -end cutoff reduces transmission above
(Continued on page 66)
.=1'I=
I
I
I
-
.
ene!{011_iiiiiii
iiiiiiiiii1iiiiioìì.,,,Is
MINI I111iiiiIlllQiilia
11111IÌI11111ÌÌÌI:111ÌM.
v<ta
AUDIO
PREAMPLIFIER
and early 78 records,
5
switch-selected inputs
with individually preset
controls, separate
treble tone controts, special hum control,
MODE L WA- P2
etc. Outstanding in performance and most attractive in appearance. Fulfills every
requirement for true high fidelity performance.
Shpg. Wt. 7Ile.
level
bass and
;19.75
(CHICAGO TRANSFORMER)
This hi -fi amplifier is constructed on a single
chassis, thereby affecting
a reduction in cost. Uses
new Chicago high fidelity
output transformer and
provides the same high performance as Model W -3 listel above.
An unbeatable dollar value. The lowest price ever punted for a
complete Williamson Type Amplifier circuit.
Model W -4M consists of main amplifier and pow .r eulq.Iv uu
chassis. Shpg. Wt. 28 lbw, Expres
only
Model W-4 consista of W-4M plus WA-P2 Preamplifier. Shpg. Wt. 35 Ib.., Express only
sir
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FREE CATALOG
APRIL, 1955
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of course were written still earlier,
only a very short time after the big record
price cut was announced. I'm glad to report, as perhaps symptomatic of a general
adjustment, that the Dessoff Choir recording which was about to be dropped, as
of that time, wasn't dropped at all, and the
company in question, Concert Hall, has
since recorded another LP's worth of
Dessoff music. In other words, the first
days of near -panic in the record field occasioned by the radical cut in prices initiated
by RCA Victor gave way to more reasonable and shrewd thinking. Many outfits that
had thrown up their hands in despair,
hauled them back down again after a few
weeks, to reconsider very carefully.
However, don't think that the panic signs
were for nothing. The situation is basically
as I have described it ; the danger that we
will lose a good part of the small- company
material still exists. (The pruning, unfortunately, is not selective; the best material
is as likely to go as the worst.)
Prestige
Most small business operators are, by
dint of their very existence, pretty ingenious people. There are ways and ways to
keep their small boats afloat. Prestige,
always remember, counts heavily in any
business and in small records the prestige
often lies in catalogue items that may not
actually show a direct profit at all. Withdraw your prestige items and you may lose
more than ever. The big price cut has of
course forced a complete reconsideration
in just about every catalogue of LP records, from the biggest to the smallest. But
that long, close look has involved a lot
more than the simple numerical sales
figures for each item, and for that we can
be glad.
Certain very important balancing factors enter the picture. It is highly worthwhile, for instance, to play off the profits
from your
fast-selling, low -brow items
against the sales prestige of slow- selling,
higher -class items. A company that is
reasonably liquid can well afford to keep a
good many slow sellers in the shops, if
there is a cushion to be found in another
part of the line. This is a saving grace of
major proportions, and, may I suggest, it
poses rather a tricky question when we
come to judge records.
Most serious record collectors, I very well
know, tend to be horrified when an otherwise serious -minded record label suddenly
blossoms forth with a line of Parisian
night club stuff or music to dance by or,
maybe, hi -fi sensationalism. Perhaps the
stuff, in a sense, is really unworthy of the
said label.
But before we jump out in condemnation, we should pause to wonder whether
these same low -brow sensations aren't
perhaps footing the bill for the continued
production of the essential high -quality
material ? A record reviewer is in a particularly parlous situation here, for his
duty is to review records for themselves,
regardless of such hidden considerations.
(Hence this discussion here, instead of in
my "Record Revue"
But he's aware
of all this, just the same.
It would take a full -scale professional
accounting, I suppose, to pin down the
factors in a given record company's current policy in this respect- prestige and
quality, vs. popular profit-makers. I'm not
even sure which items are the moneymakers and which contribute more to prestige. The fancy hi -fi demonstration albums
of Capitol, Westminster, RCA, for example are they profit- makers, or do they
contribute to prestige in the technical area?
I'd guess both.
There's a further aspect of this spreading -out of available profits. Side enterprises. Some companies have side enterprises within the record field itself. Concert Hall, for example, has the Musical
Masterpiece Society, selling low -priced
top -notch records via mail-order, which
if the impressive company offices are any
indication -they're filled with row after
row of busy IBM machines-must be a
whopping success. I don't know the set -up,
but I'm reasonably sure that the stability
of Musical Masterpiece sales is a cushion
which allows Concert Hall to keep up its
regular and more specialized line. This
may have saved my own record.
Another possibility is the cushion of a
side -line outside of record selling. If I am
right, Concert Hall was set up originally
from chemical wealth, and the operators
of that record company are, I assume, still
involved. No doubt there are cost-saving
cross -relations between the two enterprises. Peter Bartok's excellent recordings,
mainly of Bela Bartok's music, are perhaps
cushioned by his own extensive recording
and master-cutting operations for others.
No doubt other outside aids to the prestige
of good records exist in many parts of the
....).
:
AUDIO
50
www.americanradiohistory.com
APRIL, 1955
industry. Though we can't get much information about them, we should be aware
of this sort of business tie -up and thankful
that businessmen are ready to sink profits
in one area into possible losses in another
even if, in the long run, the whole thing
turns out to be a species of tax adjustment!
That, too, is perfectly legitimate under the
rules. As legitimate, say, as the vast bequests to universities now being made by
some of the large industrial enterprises.
AIMS*
-
Made in Europe
One not -so-happy outcome of the record
price cut is crystal clear. More European
low -cost recording, less high -cost U. S.
recording. Less work, from the smaller
outfits, for the American musician ; or
alternatively, a cut in his royalties. The
use of European musicians has always had
its unhappy side, however great the
musical benefits, in this necessary bypassing of our own active musicians. Part
of it is related to union policy, which sets
more or less uniform high rates that are
basically keyed to big -time popular and
radio -TV music. This is very possibly a
necessity under the present conditions, but
it does make limited- budget recording very
difficult in the States. The rest is due
simply to the difference in the larger
living standards and to the exchange differences between this country and the
European countries. One can "buy" music
over there for preposterously low sums
even now, though the rates have gone up
somewhat. The same money could not
support any musician over here, and that
is that.
Anyhow -the very cautious trend by
smaller companies toward U. S. recordings in the last few years is bound now to
be stopped in its tracks. One small -company official told me he figured he would
lose 9 cents on every record he recorded
and sold in this country, under the new
price scale. That is perhaps an arbitrary
figure, but a cut of such huge proportions in the final list price as this recent
one -it's far from one -half, 50 per cent,
in some cases -is bound to cause havoc in
any carefully calculated business where,
as the old saying goes, profits (if any) are
in pennies.
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in mind. The new price cut devolves largely
on the record maker. The distributors and
the dealers have taken a little of it-but
they still get their pre -price -cut slices of
the purchaser's payment. Dealers still are
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albums, art work, record annotations, are
not significantly different and of course
overhead expenses like office and plant rent,
tape recording equipment, hall rental, are
as always. No reduction at all.
(Continued on page 68)
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APRIL, 1955
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51
www.americanradiohistory.com
EDWARD TATNALL CANBY*
1.
THE GREAT CROSS ROADS
"^ Liebermann: Concerto for Jazz Band and
Symphony Orch. Sauter- Finegan Orch.,
Chicago Symphony Orch., Reiner.
RCA Victor LM 1888
This is a "controversial" recording in a big,
wide and handsome way, and maybe the most
significant release of the year for the future of
music. A lot of jazz people will groan and many
a Chicago Symphony adherent will moan -but
the stuff went over stupendously when Fritz
Reiner conducted it in ye Windy City and it ought
to do well with many a record addict.
What is it? Perhaps it's not the world's great
est masterpiece, nor the best jazz either. Its composer is practically anonymous for all the attention RCA lavishes on him. He rates (from the
jazz side of things) as an arranger. Arrangers
don't wear halos or have laurel leaves draped
around their heads, like the starving composers
of the Classical.
This is merely a record in which two worlds
meet without compromise for just about the first
time, in which two ways of music- making, music thinking, musicproducing, are joined in a single
piece of music and a single production. Two
vast Systems. And the purport of this record is
simply that, sooner or later, there will be but
One System. Music.
This record also says, in a sort of definitive
way, that the vitality for the musical art of the
future is likely to come from what we've been
calling Popular music all this time -from the
system that includes such diversities as Dixieland
and Modern Jazz, Mambo and hotel lounge music.
But a lot of the structure is going to be inherited
from the erstwhile Classics and the present Moderns, who hold between them a tradition that has
been growing for a thousand -odd years.
This is a wow of a hi -fi record for any old
listener. It's also a piece of 12 -tone atonalism
scarcely removed from Schoenberg, from beginning
to end. It has popular dance items in it, including
blues, mambo, boogie, and the dopiest dancer
will spot them quick as a wink, even in 12 tone
technique. It is as dissonant as the most violent
evocation of the modernists in classical music, but
99 per cent of our non -classical hepcats (or their
equivalents in a younger generation) will find
nothing to object to -won't even notice it as
dissonance. Because so much "popular" music
today sounds just like this anyhow.
And here, of course, is the point. We tend
blithely to ignore the momentous artistic fact
that for many a year popular music and classical
music, so- called, have been heading closer and
closer, over lapping more and more often, and
right now they are positively rushing towards
each other.
When Aaron Copland put some very mild
"jazz" into his early music in 1925 the mixture
was self -consciously feeble, but also very shocking.
Benny Goodman's Mozart, just before the war,
was also sensational in its way, as was his famous
jazz concert in Carnegie Hall, and its successors.
But now all that is gone. Popular music gets in
creasingly "classical ", while hanging onto its
essential popular audience (outside of the concert
halls) and to its utterly different System, whereby
every performer is a composer as well, whereby
most of the musical work of the written -down
sort is in the so. called "arranging ", where indeed
the concept of the composer, as we know him in
classical music, does not really exist at all.
Enough said. Listen to this as a hi fi record
if you will. But listen to it as jazz, as classical modern, as 12 -tone music, as dance- derived music;
try it on your ear as a classical composed Concerto, and as an "arranged" piece for jazz band
and hear how all these things are included in one,
unified, over -all style, with astonishing effortlessness.
-
KEY
b
Outstanding recording for the type
of music.
Heavy bass end. (Low turnover ?)
Close-to, sharp-edged, in good live ness.
cc
d
Close -to, in deadish acoustics.
good
Distant, over -all miking,
iveness.
I
dd
o
Distant miking, somewhat narrow
sound, lacks presence.
Highs sharply boosted (NARTB or
more) add roll -off.
Highs less boosted than U. S. normal (RIAA). Use less roll -off.
Good try for hi -fi.
Big, golden liveness.
Good piano sound.
Piano tone rather percussive.
Recorded level rather high.
Solo (s) close-to and loud.
Close-up solo, accompaniment in
background.
Hiss and crackle- under -par sur;
1
P
pp
s
V
faces.
Tape record.
good voice reproduction.
Voice may buzz or blast in loud
parts.
Some distortion- ringing or graininess, harshness.
xx Poor resolution. Lacks clarity.
Y
Solo voices oddly dead acoustically.
And imagine the scene, too, in Chicago. The
Chicago Symphony, in black ties and coats -the
classical tradition. The Sauter-Finnegan "band,"
in fancy uniform -the pops -jazz tradition. All on
the same stage. And chunky Fritz Reiner (uniform or tails ?) who was said to have swung and
swayed on his podium like a shortened Paul
Whiteman! Finally, picture the audience, combining the Symphony's regular classical adherents
and the S -F Orchestra's equally regular enthusiasts. We can wonder just what did happen; for
even the listening -manners of classical and popular audiences are radically unlike. Was there
silence in the aisles during the hottest passages?
Or did people dance in them?
And the "composer ?" Was he applauded afterwards in the classical manner -or did he not exist,
as in the popular? Wish I'd been there.
" Cy Inside Sauter -Finegan. The Sauter Finegan Orchestra.
o*. RCA Victor TP 4
In the Schwalm LP catalogue this is listed, of
course, under "POPULAR. JAZZ, SWING"
along with two LP mates, though one of those
is called "New Directions in Music." It'll have
to be admitted that S -F is not exactly a "pure"
popular band. It has classical- trained musicians in
it and the intention, frankly, is to experiment, to
exploit the assembled talent in every way that
works out. But the vital thing is that the band
is technically pops. It exists under the pops
system, plays, makes money. It doesn't even rate
an RCA Red Seal.
And so the stuff on this tape is very interesting
in the light of the Concerto reviewed above. Some
of this is "straight" popular, juke box, or what
have you. But every piece has something in it
that goes beyond the strict and sure popular conventions. Bits of this and that creep in, from anywhere and everywhere. One crooned songstress
item smacks of ye Sumac, definitely. Another one
smacks just as positively of Hindemith -I'll bet
a nickel I could pass it off as a piece for Winds
by Hindemith in any classical concert. A piece
for marimba sounds purely "pops " -except that
the harmonies are far more complex than usual
and virtually every chord is a dissonance, a major
seventh. etc. And so it goes. All within the
official pops framework. No composers listed, of
course. Not even the arranger(s). The printed
comments merely talk about "making use of the
talent" of the band.
The LP version, on disc, is LJM 1003. The tape
is superb, though levels, as in other pops- orientated
RCA tapes I've tried, seem rather high and there
was an occasional slight overload somewhere in
my system.
2, THE VOICE
Moussorgsky: Songs & Dances of Death;
Duparc: L'Invitation au Voyage. George
London, baritone, Paul Ulanowsky, pf.
Columbia ML 4906
Schumann:
Liederkreis.
Brahms:
Vier
Ernste Gesaenge. Wm. Warfield, baritone,
O. Herz, pf.
Columbia ML 4860
Song cycles by the two biggest baritone sensations of last year, and I'll have to be luke -warm
on both. Warfield's big American voice is not yet
matched by a natural feeling for this German
music -nor should; his style is good, but forced,
learned expertly from a good vocal coach. That's
V
not enough to make a convincing lied singer.
George London's perfectly enormous voice is
superb for the dramatic Russian songs-he does
a famous "Boris," same composer. But he's a
bull -in -a -china -shop in the pastel French music,
in spite of good taste. Biggest difficulty here is in
the voice reproduction; at such close range, the
overtones and transients are so overwhelmingly
potent that few home systems will "take" this
recording even the first time through. A bad
needle will be disastrous.
AUDIO
52
www.americanradiohistory.com
APRIL, 1955
_srrr Songs of Rachmaninoff. Songs of
Moussorgsky. (Assorted Russian singers,
pianists.)
Vanguard VRS 6023
The first two Moussorgsky songs are from
the Songs and Dances of Death -see above -here
sung by leading Russian artists in the home country tradition, and it's a marvelous one, too.
These recordings are Russian, featuring five
artists among whom the two baritones, Boris
Gmirya and Alexander Pirogov, have huge,
wonderfully expressive voices of the sort found nowhere but in Russia. Each sings one of the above
songs; Gmirya also sings two of the Rachnaninoffs. Though the other singers are evidently
celebrated, I found them so -so.
Technically the Moussorgsky recordings are
fairly good, the bulk of the Rachmaninoff songs
are minus
all highs and somewhat distorted.
Quite listenable
more serious fault is the uneven flutter that shows up occasionally in the
piano parts.
-a
"sp4 Songs of Brahms. (Four Serious Songs;
Two Songs with Viola; In Stiller Nacht;
Sandmaennchen.) Nell Rankin, contralto.
Coenraad V. Bos, pf.. C. Cooley, vla.
Cap. P. 8289
The "Four Serious Songs" are the same as
Warfield's "Vier Ernste" above, here sung by a
contralto and so easier to understand. She's an
American too. but extra -well coached -by Mr.
Bos, who played the first performance in 1896 with
Brahms himself present! Rankin makes these,
Brahms' last songs, far more accessible than is
usually the case. She has a gorgeous, Traubellike voice which records beautifully, her musicianship is excellent, her pitch ultra -true, her only
fault here a lack of clear diction. A fine record.
"
Song Recital. (Schubert, Brahms, Wolf,
Faure, etc ) Mattiwilda Dobbs, sopr. Gerald
Moore, pf.
Angel 35094
Here's another recent voice sensation. She is a
wonderfully high, lilting soprano, so high you
can't believe it, her pitch is superbly accurate and
her diction is more natural in the foreign languages than either Warfield or Rankin, above.
Some of the singing is a bit on the cute side, but
most is wonderfully lyric, expressive, unaffectedly
direct. Gerald Moore's piano is arrestingly good,
if a bit in the background. Another fine record.
0spl' Debussy: Fetes Galantes fist Series) ;
Trois Ballades de Villon. Suzanne Danco,
sop. G. Agosti, pf.
London LD 9146 (10 "1
e., Debussy: Proses Lyriques; Chansons de
Bilitis; Ballades de Villon. Flore Wend,
sopr. O. Gartenlaub, pf.
Haydn Soc. HSL 106
Two sopranos tackle the pure French style of
singing, in early and late Debussy -they overlap
in the late "Villon" songs. banco is big, operatic,
though she sings strictly in the colorful French
way; she may blast for you in the loud parts.
Wend has a smaller voice with a slightly "popular" sound to it
French terms, of course.
Nice, and the good diction plus close -to recording
brings out every word. Both are unusually fine
recordings -the pianos are excellent too.
-in
Dvorak: Biblische Lieder; Zigeunerweisen;
Liebeslieder. Hildegarde Roessel- Majdan,
sopr., F. Holetschek, pf.
Westm. WL 5324
ELECTRONIC ORGAN
A formidable set of German titles but the music
simplicity itself, Biblical Songs, Gypsy Songs,
Love Songs, three complete sets, most of which
are unfamiliar, but should not be. ( "Songs My
Mother Taught Me," one of the Gypsy Songs, is
the only one in the collection that is well known.)
These are the merriest, sweetest, most lyrically
rosy- checked songs you can imagine, not of any
great content but written with the wonderfully
direct tunefulness that made the "New World"
Symphony so widely popular, long ago. Don't be
put off by unfamiliarity. The reasons for that
are mostly due to stick -in-the- muddedness on the
part of singers, who never look beyond the ends
of their noses for likely interesting material, outside of the standard publishers' repertory. The
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THE SCHOBER ORGAN CORPORAT ON, Dept. 14,
35
Dail Street, New Hyde Park, New York
Gentlemen:
me your free booklet describing the new Schober Electronic Organ
completely. I understand that this places me under no obligation whatever. and
that the booklet is to be sent to me at no cost.
Enclosed is 52.00. Please send me the Demonstration Record. Also include the
credit certificate good for this amount on my first purchase of any Schober
Organ Kit sections.
NAME (Please print)
Please send
ADDRESS
CITY
APRIL, 1955
ZONE
STATE
53
www.americanradiohistory.com
soprano here is mo.t communicative. if you don't
mind a throaty voice with a fair amount of
wobble, and the pianist is excellent. So is the
recording.
song -and for those who are already experts in
either singing or listening to this kind of music.
"'v
Irmgard Seefried. (Wolf and Brahms
Songs). Erik Werba, pf.
Decca DL 9743
°" Dvorak: Legends, Op. 59. Little Or-
Compare this lady with the American high
soprano, Mattiwilda Dobbs, above -here is a
soprano from "inside" the German long tradition.
She, too, has a high, light voice of extraordinary
expressiveness and wonderfully true pitch. She
sings with an understanding of the music that
gets over the difficult harmonies and melodies of
the Wolf songs to the ear with utter ease -where
many singers flounder in the sudden changes of
key, unable to keep afloat. Sung with musical
understanding, plus real drama, these songs are
pleasurable for anyone (as are the simpler Brahms
songs) and so this is a highly recommended disc
for all who are curious about the lied, the German
These tiny little "symphonies" for full -sized
orchestra-there are ten of them on two LP sides
-were written as piano pieces and, like the
numerous Hungarian Dances, etc., of the period,
were later orchestrated by the composer. The
music is as sweet as butter -each piece is complete, not like a single symphonic movement,
somehow giving a sense of larger span, even in
a few brief moments. There isn't anything quite
like these elsewhere in music. Imagine a Brahms
Symphony in its most lyric moments, lighten it
up, make it more melodic, more artless. and you
have this music. Big. distant recording, highly appropriate.
3.
Sibelius: Swan of Tuonela; Lemminkainen's Return. Danish State Radio Syme
phony, Jensen.
HIGH ROMANTIC
chestra, Scherman.
Col. ML 4920
London LD 9125 (10 ")
unpretentious reading of these
two short works. L's return might be somewhat
more energetic, but the modest accuracy of this
Danish playing is enough in itself. Characteristic
ffrr sound, clean and close-up in a large liveness.
Superb surfaces, that add by their very silence to
the musical atmosphere.
A lovely, mild,
Tchaikowsky: Nutcracker Ballet (complete) . Radio Berlin Symphony, Dobrindt.
Urania URLP 237 12)
i`
Evidently from a radio broadcast, this shows
some uneven ensemble in the strings and some
not -so -good editing. (Could be to remove sudden
applause ?) but generally speaking, the playing is
very musical and on the lyric side. Brass is particularly good. The complete score is, of course,
much longer than the long -familiar pair of Suites
and was mostly unfamiliar until two recent ballet
revivals and Mercury's earlier recording brought
it into popular repertoire.
The Mercury version of the complete score is
much more spectacular as a hi -fi item -for better
or worse depending on your interest. Musically the
Mercury (under Dorati) is a taut, rather hard
and angular version where this one is soft and
lyric, recorded
in a big, warm
liveness. Some
persistent distortion in the string tone on wide range equipment. Very slight for most ears.
'I Strauss: Death and Transfiguration; Till
Eulenspiegel; Don Juan. Bamberg Symphony, Horenstein.
Vox PL 9060
Excellent performances. Horenstein was born
in Russia, trained in Vienna in the twenties; he
is a true late- Romantic conductor. ultra -high.
tension but still very Romantic in expression,
without a trace of the heavy -footedness sometimes
found in Germanic leadership. Very good for Mr.
Strauss's early works, and these playings are
highly dynamic yet beautifully lyric in the appropriate spots.
Vox's hi-fi is too brilliant for me in the louder
parts, though it is lovely in the soft passages.
A gorgeous over -all liveness.
Shostakovitch: Symphony
Symphony, Golschmann.
#5.
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8268
Golschmann has conducted this orchestra for
almost a quarter century and the beautifully bal.
anced ensemble shows it. In some composers his
playing is not exactly ideal -but in the more
Romantic moderns, especially Russian, he is
clearly in his element. No reason why this
Shostakovitch shouldn't rate as high Romantic in
this sort of interpretation! A bit like the Horen.
stein, taut, modern in its intensity, but smoothly
lyric at the same time -no harsh blats and
bumps. Good.
The distant miking is rather narrow in sound,
a bit lacking in roundness of perspective. My copy
has a lot of pops and ticks.
for Wind Instruments
1944/51 London Baroque Ensemble, Haas.
S" Strauss: Symphony
1
Decca DL 9761
The very late Strauss music, written in what
"oldoutwardly seems a very
fashioned" style, becomes more and more fascinating as we get to
know it extensively on records. This long piece
was composed some sixty years after "Don Juan"
above! In place of the heroic brilliance of the
early work, this shows the typically unpretentious,
wise genius of an old man who has settled his
own accounts and lives in complete tranquillity
ta display the unique and wonderful skill that
sixty years of constant creation has left with him.
Such superb wind writing you will never hear
again, such easy fluency, such a wonderfully
casual gift for melody, for lush, enormously complex and utterly simple flowing expression! Forget
-forget entirely -that technically the language
sounds a bit like 1850 or earlier. Of no importance
whatsoever! (Nobody at that time could have
written this anyLow, and in that way it is definitely modern.)
So acquire this one quickly, if you have any
love at all for wind music, if you want to hear
musical craftsmanship in the ultimate sense. Play-
-
AUDIO
54
St. Louis
APRIL, 1955
ing craftsmanship, too, for the performance
matches the music superbly. It's a long piece.
Take one movement at a time.
It would be nice if Decca could get rid of the
sandpaper element in many of its otherwise fine
classical records. In places they hiss like a war.
time 78. Where there's a will there's a way. . . .
'
Sibelius: Symphony
#2.
Members of the
NBC Symphony, Stokowski.
RCA Victor LM 1854
A curious description, this! " \l embers ,,t" is
a term ordinarily used for a half -dozen or a
round -dozen players in a smaller- than. symphonic
work. The Sibelius score presumably called for
every man -jack in NBC who was available. A
sort of members' party? Who knows.
Anyhow, it sounds like a good, fat, full orchestra here. and it sounds very nice, too. This
moody, misty, craggy Sibelius is the kind of
music that becomes harder to play each year, as
the old boys of Stokowski's generation slowly retire from circulation and the young things take
over. You can't play Sibelius with a jazz beat
or a dead -pan face. Listening to this, you'll be
reminded that for all his show, for all his exuberantly lush desecration of older music in the
name of arrangements, for all his flamboyant activity. "Stoky" has been and still is a master
conductor, one- of the most accomplished in the
first half of this century. There's nothing showy,
nothing stunty, nothing sloppy about this -just
a top ranking professional cooperation between
expert players and an efficient and knowing leader.
The "members' party" was held in a very fine
hall with superb acoustics, and /or RCA's "enhanced sound" treatment is better than ever; this
is an impressive hi -fi recording though some of
us would prefer a bit of safe distance between
ourselves and the nearest instruments. Close -up
recording in a big liveness, probably multi -mike.
(P.S. What happened to Stoky's erstwhile performing group of the last few years, succinctly described on record labels as "& His Orchestra ?"
Could it perhaps have been "members of" the
NBC ?)
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The Golden Age of Brass. The Brass En-
(Boston).
Unicorn UN 1003
Here is an authentic "members of" group:
these are brass players from the Boston Symphony,
though the name is naturally not used. They're on
their own. Two of the dozen pieces on the disc
are recorded in Symphony Hall (with big echo) ;
others are in a close -up dead studio acoustic.
The Golden Age extended through the 17th
century and there are three groups here- Italian,
English, and German. The Italian is the earliest
and
the most spendid -double brass choirs,
gorgeously decorative. The English music is
chatty and ceremonial by turns, with bits of very
British jiggy tunes that you can't miss once
you've noticed them. The group includes some ex.
cellent Purcell, hitherto unknown.
The Germans were the big brass people, after
the Italians, right up into the 18th century. The
second side here is all German and the variety
of spirit and expression attests to the great
popularity and wide use of brass music.
This group plays as would be expected
technically with top ensemble and accuracy as
befits a symphony group, but also with a typically
limited conception of style. The music is simply
brass music -not music of this and that composer,
in this and that period; the tone, the phrasing,
the slight vibrato, are those 01 an expert symphony
orchestra group whose experience clearly lies out.
side of this music-that is, they do not know
intimately other types of music from the same
times and composers and so are honestly unable
to play beyond their legitimate brass limitations.
This is common enough among all sorts of top
professional musicians. Only a rare few achieve
a wide enough education and experience to rise
truly above their own immediate professional field.
Listeners on the outside -who take it easy, not
having to spend a lifetime learning technique
can hear these discrepancies quickly enough.
Thus the Purcell work here simply doesn't have
a "Purcell" touch to it
terms of many other
sorts of Purcell, from anthems to harpsichord
works, string fantasias. etc. etc. The earlier
Gabriella are played choppily, non -legato, in what
to my ear is a somewhat anachronistic style.
Relatively minor criticism, in view of the expert playing and the sincere dedication of the
group.
-
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enclosure development entails a
cavity and slot port, to form a resonant
chamber, and a horn coupled to the
slot. The slot is loaded by the horn; the
proportioning of slot, cavity and horn
provide bass response below 100 cycles which corresponds in efficiency
to the front -of -cone direct radiator response above this critical 100 -cycle
point. There are two ways one might
consider the function of this horn. One
is a bass reflex with a horn acting as a resistive load on the
port. System resonances are damped by useful radiation resistance while the horn does not cost anything. It is already
formed by the room corner. Again, if a full horn were added
below the 100 -cycle point bass response would be boomy and
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APRIL, 1955
y
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75 North 11th Street
Brooklyn, N. Y.
55
www.americanradiohistory.com
d
Frescobaldi -Organ Music. Guiseppe de
Dona.
Vox PL 8780
a hi.fi disc for organ sound men,
a source of some lovely music played on
rather juicy "old- fashioned" organ, not at all
in the now popular German classic or Baroque
manner. Frescobaldi was a superbly alive old boy,
flourishing in the early 1600's, one of the first
real virtuoso organists, who played (it says here)
to 30,000 people once in Rome, and was enormously popular in his day, exerted a vast influence on later organ writing.
Frescobaldi is a big composer. Writing in that
peculiar period when modern instrumental music
and modern harmony first developed, he had a
wonderful sense of melody and a grand feeling
for the strange, wandering harmonies, especially
the half -step (chromatic) ones, that had not yet
settled comfortably down into the later major.
minor system of keys. Finally, his music (like
his name) was highly decorative, often very
serious but just as often humorous, whimsical,
dance -like, with a strong feeling for popular tunes.
All of this appears on the record. The first
side has four big, massive Toccatas, masculine,
for full organ; the second side has the softer,
lighter, more whimsical music, written primarily
for harpsichord but equally playable on his own
instrument, the organ.
Very musical playing by Signor Dona.
Not exactly
this is
a
Giovanni and Andrea Gabrieli -Organ
Music. Giuseppe de Dona.
Vox PL 8470
Two famous Venetian relatives, of a slightly
earlier period than Frescobaldi, a generation or so.
Their music is more of a square sort, more impersonal and also very decorative. The harmonies
are less important-the great brilliance of the
passage work, the echo effects, loud and soft, the
clearly treated motives, short ideas, being the
main interest. Wonderful music for long acquaintance, though not as easy first -off as the
Frescobaldi. The organ is evidently not the same;
the reverberation is considerably less in this record than in the Frescobaldi preceding.
Liszt: Prometheus; Mephisto Waltz
#1. Paris Cons. Orch. Munchinger.
Lon. LD 9153 (10 ")
Hindemith, Vol.
1.
Collegium
Musicum, Yale University. (Monteverdi,
Weelkes, Gesualdo, Bach.)
Overtone LR 4
Ohs
Paul
A seldom-heard, pompous and noisy but genuinely musical tone -poem, in the vein of familiar
"Les Preludes," very well played; an orchestral
"waltz macabre." more familiar, to accompany it.
Excellent sound, old- fashioned hi -fi, and a good
conservative demonstration record.
Publicity I Hindemith is the conductor of the
unaccompanied chorus that sings this music and
so he gets top billing, the composers coming last.
Three of the four composers are of the same
times as the above music, given a few decades.
Choral music was still the most expressive and
well- advanced medium, as you'll quickly hear if
you listen to the powerful expression of Monteverdi (a set of tragic madrigals about a lover at
the tomb of his beloved) and the slightly crazy
genius, Gesualdo, who wrote experimentally with
almost Wagnerian harmonies. Weelkes represents
the more reserved English version of the same
kind of intense expression.
If you enjoy amateur singing at its very best,
this is for you. If you have had doubts about
chorus music because of too much fuzzy, wobbly
confusion, then try these accurate, expressive
amateurs, hear every note, every harmony on pitch
and unconfused.
Always remember that, today, few professional
singers can sing ensemble music with other
singers, outside of opera (where competing solo.
ists are intended) ; they don't know how to blend,
can't sing in pure intonation, seldom produce
convincing harmonies, usually wobble so much
that pitch is obscured. Amateurs, in these respects,
are 'way out in front. They sing on pitch
not
at all. They don't wobble, they do blend, they
often are more intelligent, more expressive than
the over-trained professional soloists.
-Especially when led by an outstanding
musician like Hindemith, a composer who has
a remarkably wide knowledge
of all Western
music and is an indefatigable enthusiast at bring.
ing it to life -from the oldest to the newest. See
also Volume Two of this same series.
Schumann: Symphony #3
"Rhenish ").
Amsterdam Concertgebouw, Carlo Zecchi.
Epic LC 3092
Phew! A very odd "axis" here, what with the
(
Dutch orchestra under an Italian, playing German
music ; the interpretation is strong but very odd,
too, heavy -footed, exaggerated in the beginning,
with Italian lightness in the finale, full of Italian style explosive emotion but lacking altogether that
lyric, personal quality that is the essence of Schumann. Fine sound -Epic's problems are now
solved.
or Debussy: Pelleas and Melisande.
Epic
CLASSICS
SC 6003
(3)
A valuable new version of thi, long and unique
French opera, so remarkably conversational yet
so mystic, impressionistic at the same time. The
men are, for once, superb here, notably Pelleas
(Camille Maurane) and Goland (Michel Roux),
the women good. All- French, as is vitally necessary, the voices recorded very close but with
superb naturalism, every word easily audible. Fine
French lesson, incidentally. Big lack -no libretto;
a most unwise economy.
-or
5. LOOKING 'EM OVER
Soloists,
Lamoureux Orch., Fournet.
Handel: Messiah. Soloists, Huddersfield
Choral Society, Liverpool Philharmonic, Sir
M. Sargent.
Angel 3510C (3)
Os
-
This is essentially the same performance as the
older Columbia recording (same British source)
but with radically improved modern sound. The
Sound with Alpine Clarity
That
is the
fidelity that comes with Philips of Nether-
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voice or instrument, with Alpine-air clearness: A perfection resulting from the use of a new construction
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that allows more compact units and outmodes awkward
"woofer" and "tweeter" construction.
Model 9762
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14% at 400 c/s due to use of extra powerful " Ticonal"
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Hi -Fi and other equipment can be raised to a level never
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20 watts
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All list prices subject to the usual audiophile discounts.
Available at leading jobbers or Duotone Co., Inc., Key port, New Jersey. Write for catalogue.
-
-
-8
-4
AUDIO
56
www.americanradiohistory.com
APRIL, 1955
old -fashioned large -scale "Messiah," in the British
tradition, far removed from the newer "authentic"
performances but extremely musical just the same
and of top -notch effect. The best "Messiah" I
know of inn y tradition.
Leonard Radio "Audio Mart"
Your COMPLETE Hi-Fi Headquarters
Mozart: Masonic Music. Soloists, Vienna
Symph., Ch. Choir, Baumgartner.
Epic LC 3062
"
Quad Amplifier & Pre -Amplifier II
Mozart was an ardent 111.:son and in addition
to writing his opera "Magic Flute" about Masonry he did numerous occasion -pieces for his
friends in the movement. here collected together.
Orchestra, male solos and male chorus, and though
outwardly these were intended for such matters
as the dedication of a new building, the funeral
of a member, this includes some of the finest and
most moving Mozart there is -much in the spirit
of Beethoven's "brotherhood of man" in the 9th
Symphony and elsewhere.
A superbly felt set of performances, too, One
piece is all -orchestral, the Maurische Trauermusik,
K. 477, one of Mozart's greatest slow movements.
A top disc for any Mozart lover. Some ringing
distortion in the sound (this is an Epic from
scme months back), won't l oti t-r the mn.irnl car.
"lw Mozart: Fantasia in
Sonatas in C mi.,
Badura -Skoda, pf.
A.
You need not be an engineer to know that you are on a
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button equalization -Col. LP, AES, FFRR 78, Std. 78, and
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Elcctro -Voice PATRICIAN:
mi. K. 475;
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Westm. WL 5317
Badura Skoda is about the hest Mozart pianist
alive. But the strange and difficult (interpretation,
not fingers) Fantasia strikes me as nut too successful here; the sonatas are better. Piano recording is so -so. Percussive. Not B -S's best record
to date.
Gluck: Orpheus and Eurydice, Act II.
Soloists, NBC Symph., Shaw Chorale, Tos-
canini.
RCA Victor LM 1850
"His mastery of the Gluck .talc is overwhelming," say the record notes of Toscanini. Yes-if
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you remember that this opera was first written
in Italian (for Viennese audiences), then re -done
into French, in which version it is far better
known. This is, of course, sheer Italian in style
(in Italian) and an interesting contrast to French
versions of the music. Amazing how the same
music can sound so different.
From a broadcast, the sound is somewhat dead
and strident, the solos sing in padded closets into
private mikes
so it seems. Odd effect. (Com-
-or
$119.95
NET
mon enough in radio announcing.) The orchestral
ballet music is best. Nan Merriman is the contralto Orpheus.
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obr
Haydn: Trumpet Concerto in E flat;
s Harpsichord
Concerto in D. G. Eskdale,
tp., Erna Heiller, hps.; Vienna State Opera
Orch., Litschauer.
Vanguard VRS 454
The two best -known Haydn Concertos, aside
ftem the Cello Concerto, in warm. beautifully
recorded performances. The trumpet work was for
the first chromatic trumpet that could play all
the notes, not just the overtone series. Justly
famous for its easy tunefulness over a fine structure. Its odd that Haydn's harpsichord music,
though evidently not intended for the then undeveloped piano, is nevertheless really pianistic in
style, makes the harpsichord sound tinny and tiny
-where Bach's and Handel's harpsichord writing
is big, impressive, only a generation earlier. A
rapid shift in composing technique that seemed
to get ahead of the actual development of the
instruments themselves. briefly.
e,.,.
St. Paul's Cathedral Choir.
works, from the repertory
l
(Assorted
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Angel35I6B (2)
A wonderful visit "inside" a famous British
working choir, with a big cross- section of the
typical Church of England choral repertory and
the English singing style. Lovely older music,
seasonal carols, a brace of modern British anthems,
very British and most impressive but a wee bit
empty under the surface, a batch of madrigals
sung by too many voices but nicely -and, the
unexpected and stunning item, a superb long excerpt from Haydn's great "Nelson" Mass, most
movingly sung.
AUDIO
RADIO, INC.
York
7,
N.Y.
COrtlandt 7-0315
New! "Audio Reference Guide" 160 page book all about Ili Fi
Write for your free ropy today, A -4
.
. 25% deposit, balance C.
Mail and phone orders filled, 24 hour service
APRIL, 1955
.
O.
D.
57
www.americanradiohistory.com
er/rArrIPPrAPPrAII4/4/4.
Your Higher, More Rigid Specifications Demanded ALL
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NEW
GRAMPIAN
azwiected"
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flux correcting feedback
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top transient response
precision balanced armature.
to 20 kc
...
REEVES -GOTHAM
sapoble of delivering ISO watts fat low
on,ptifier
distortion) necessary for high level phonograph
recording. Includes oll equalization for all of
... for
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today's standard recording curves
... at all speeds.
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better sound recording, motion picture and TV everywhere
Reeves Equipment Corp.
10 EAST 32ND STREET,
NEW
YORK, NEW
l4 keep
The First Christmas in Carols. Societas
Musica Choir (Copenhagen
Hansen.
Haydn Soc. HSL 150
o
I
,
Never too late for this .sort of Xmas singing.
Danish choirs, we're beginning to find, are extremely good. Funny thing about this is that the
music is strictly in the EnglishAmerican tradition
--no doubt it was chosen for export purposes
and is sung in remarkably faultless English, too.
Just a trace of "foreignness" that lends a piquant
touch.
-
Famous feedback disc recording cutterhead delivers
wide frequency range
Chaste choir -boys' voices, of course, smooth,
non- wobbly singing, beautiful blends of harmony,
excellent diction and phrasing. Taken for granted
in British singing. Two whole LP's.
YORK
4f/fa/toted- -
to read
ELECTRONIC
MUSICA L
INSTRUMENTS
By
6. ODDITIES
kleinsinger- marquis: archy & mehitabel.
carol channing, eddie bracken, d. wayne,
narr., orch. cond. kleinsinger.
col. ml 4963
far be it front me to break a forty.odd year
tradition that all material concerning archie the
cockroach should be 1.c., lower case. (archy
couldn't bump typewriter keys hard enough to
write in caps.)
this is the recent comic opera (plus an extra
piece added/ that wowed a portion of off- b'way,
ny, and will probably wow a bigger piece before it
ends. a very nice evocation of the archie story,
complete with mehitabel the cat's alley adventures,
reform, return to aileydom. excellent acting-singing
be mehitabel- channing and archie bracken, conventional narration, ok, by david Wayne.
music? sorry i can't rave. the kleinsinger tunes
stick archly around one or two tones, back and
forth, hack and forth, with the melodic subtlety
and sophistication of trained seal music. it's the
same time everywhere, if you can call it a tune.
his orchestra, on the other hand, is far more engaging with lots of bright ideas, good color,
rhythm. why? very nice recording, ultra clear
vocals.
Edgar Allan Poe. (The Raven, Annabel
Lee, etc.; Masque of the Red Death; The
Black Cat.) Basil Rathbone.
Caedmon TC 1028
Solo reading (poems and two complete stories)
by the well -known Basil, and very easy listening
if you enjoy his brand of British speech. An interesting experiment Itere in acoustics -the voice
speaks against a faint but golden liveness, surrounding and in the background. Personally I
prefer a "dead" voice. so that it may take on
the color of whatever room it reads into from the
record. Absolute recording. But this is an interesting alternative.
Richard H. Dorf
Passion in Paint. Famous Paintings Set
to Music. Henri Réné and His Orchestra.
RCA Victor LPM 1033
If RCA put on its own paint a little less thickly,
l'
In one big volume, you can now learn
all about the intricacies of commercial electronic
organs, including the Allen, Baldwin, Connsonata, Hammond. Minshall -Estey, Lowrey Organo, and others, together with
many smaller instruments. Constructional details on the author's Electronorgan
and the simpler Thyratone show you how to build one of these fascinating
instruments for yourself. A compilation in book form of the author's articles
in Radio Electronics, brought up to date and with many additions. Price $7.50
(Foreign, $8.001.
Customary discounts to dealen and distributors
RADIO MAGAZINES, INC., Book Division
P. O.
Please send me
Box 629, Mineola, N. Y.
copies of Dorf's ELECTRONIC MUSICAL INSTRUfor $7.50 each
money order
enclose check
MENTS.
(Foreign, $8.001.
I
Name
Address
City
......
.
Zone
State
things like this might find their way to their own
happy level of usefulness.
Here we have a dozen real masterpieces (paint)
tonally matched by a dozen fussy salon pieces,
described as music in a "continental" style, I
suggest that the connection between this slithery
stuff (wonderful hi -fi) and the works of Leonardo,
Goya, Manet. Renoir, Botticelli, et al, is -shall
I put it -exaggerated. If you must match it to
equivalent art I'd - uggest the nearest over-decorated cafeteria.
"Here, as far as I know," say the notes, "is
the first attempt to link popular paintings with
what is usually called popular' music. I'm not
sure I know precisely what popular music is: I
am certain that (this is music] which everyone
can enjoy
understand, and from which everybody can experience an emotional lift."
OK, try it and see. I'm not sure what popular
music is either- -see the beginning of this Revue.
But maybe I should pass on a hot tip. The
popular Italian composer Respighi wrote a piece
called " Trittico Borticelliano," which sets three
Botticelli paintings to music. (Two LP versions
available.) Come to think of it, ('m not so sure
I'd like it any better than RCA's torte- painting.
I'm not exactly a Respighi fan.
Let's leave Botticelli & Co. alone with their
paint for awhile. If you want hi -fi mood music,
...
this is it.
AUDIO
58
www.americanradiohistory.com
APRIL, 1955
Danses Concertantes; DumOaks Concerto; Concertino and
Three Pieces for String Quartet. Rochester
Chamber Orch., Hull; the Gordon String
Quartet.
Concert Hall CHS 1229
For Stravinsky likers this is an interesting
disc, with two of the lateay le choppy orchestral
works with their foot-tapping heat and short,
jagged, jazzy music -hall bits of tune, plus two
early and dissonant bits for string quartet. Fine
recording-especially the Gordon Quartet, in view
of the fact the Jacques Conlon died nine or ten
years ago, if I remember rightly. A transfer from
the old Concert Hall Limited Edition 78's, disc
made, and you couldn't tell them from new tapes.
Stravinsky:
barton
new performance
always!
41,0361r.»rigJ6.OL'!tttu&.1f
-
e
Anna Russell's Guide to Concert Audi Eugene Rankin, pf.
Columbia ML 4928
Volume Three of this zany lady's musical takeoff acts, with audience, and its another party
stopper if you know your way around singing well
enough to appreciate her many- l:mguaged double
talk -and the musical double -talk in the parody songs she has invented. Wonderfully recordedshe's right in your room with a beaming pussonality, and the audience loves it.
0l Greek Folk Songs and Dances. Royal
Greek Festival Company I Dora Stratou
Esoteric ES -527
Made in New York by a traveling road company (untrained), this record is a beautiful example of clean recording with superb close-up
mike presence, ultra -silent surfaces. The folk
music is what the British call "traditional" -i.e.
current folk music, still in free active circulation,
without benefit of collectors and restorers. Such
music is, Of course, entirely free to absorb what1
.
ever influences that come its way and so it is
generally pretty up to date in sound, using whatever modern instruments or styles may have
happened along to catch the local fancy.
Thus the Greek music here is a mixture, with
plenty of "authentic" semi- oriental stuff, exotic
scales and the like, but also with a strong dose
of recent Western influence. quite casually. Some
of it is pure barber -shopharmony stuff and don't
be surprised to hear a good old guitar, American.
style, going oompah -pah, oompa h-pah. Side 2 has
the more pure native sounds on it, for my ear.
Pure or mixed, the whole is very natural, musical,
unforced, and pleasurable ir: the listening.
Complorment Rey4rdteit
*Positions
FAIRCHILD 260
50 watt
PROFESSIONAL
AMPLIFIER
....t`°-'-"!}ttwt4+.
lyas'4
l'nwtMn,pnrsn}tWratsiMrWWYM6V- ---- ---_
sgr.rMlt%tsrl.
s.
HeR'few+y".neys111441,;drV.rwnwwM+tsrMrtisl
Many amplifiers work well when new, but as tubes age unequally,
distortion sets in. With ordinary amplifiers you accept this distortion or throw away the tubes and buy another matched pair
for the all- important output stage.
But, with the Fairchild 260, you can be your own test engineer.
By turning a single control shaft, you can easily restore full distortion -free 50 watt performance yourself. No instruments are
required. Proper balance for minimum IM distortion is assured
at any time as often as you wish. See this important, practical
feature at your dealer's. Try it yourself.
-
$144.50
Open
Positions Wanted.
E. B .-Audio equipment and transformer design engineer. Six years experi-
includes diversified background in
audio amplifier, broadcast audio, and recording system design, and a.f. transformer design. Presently engaged as consultant on audio transformer and amplifier
application. Desires permanent, responsible position in NYC or vicinity with a
progressive company that seeks the services of a dependable, versatile engineer,
with experience in any or all of the above
fields. Box 401 AUDIO.
*Design Engineer. Long established manufacturer in New York area is looking for
a radio engineer with 3 to 5 years experience in tuner and amplifier design.
Responsibilities and remuneration will be
in keeping with what the individual has
to offer, and the opportunity will be
limited only by his personal capabilities.
Box 402, AUDIO.
Radio Engineer. B.A. degree physics
plus some engineering. 3 yrs. AM -FM
broadcast engineer; I yr. TV. Redesigned
WE 1 -kw transmitter to use AX9902 output tubes; built remote control for AM
transmitter; operated small recording
studio for several years. Have designed
and built preamplifiers, line amplifiers,
power amplifiers, and FM receivers. Desire position in audio-design, development, recording, or FM broadcasting. Box
403, AUDIO.
isles Executive- Engineer. Position
wanted with manufacturer or representative. Experience includes selling components, HI -Fi, sound equipment to distributors and Industrials. Box 404, AUDIO.
ence
AUDIO
FAIRCHILD model 280 arm
Frequently overlooked is the important role played by the pickup
arm in a high fidelity system. A poor arm impairs listening quality
due to its lateral and torsional resonances, uneven tracking pressure
because of bearing friction, lateral instability and distortions from
numerous other causes.
The Fairchild 280 Arm, incorporating
remarkably rigid square aluminum
tubing, separation of lateral and vertical
mass, low -friction gyro bearings and
other expertly engineered features, assures you of only the sound you were
meant to hear.
9th AVE
&
154th ST.. WHITESTONE, NEW YORK
APRIL. 1955
59
www.americanradiohistory.com
NEW PRODUCTS
Pickering Miniature Cartridges. The
Model 220 and 240 pickup cartridges recently announced by Pickering and Com-
pany, Oceanside, N. Y., are the identical
reproducers which make up the company's
famous Model 260 turnover pickup. The
220 cartridge, for use with 78-rpm records,
is available with either diamond or sap-
Build-It-!ourself Electronic Organ.
Lovers of organ music will find great
interest in the fact that they may now
enjoy the performance of a full concert
organ in their home within the framework
of modest income. The Schober Electronic
Organ can be built by even a complete
novice, yet is a two -manual instrument
with 32 pedals, 19 stops, t nd 6 couplers.
It is entirely suitable for uas In the home,
church, or auditorium. In aperation it is
entirely electronic, with nc moving parts
except keys and controls. Among the
low-distortion tone controls, and special
tape recording facilities. Front panel controls include scratch- and rumble -filter
a
phire stylus. The 240 cartridge, for use
with both 45- and 33 -1/3 -rpm microgroove
records, is available with diamond stylus
only. A simple clip -type universal adapter
permits installation of the cartridges in all
standard makes of changers and tone arms.
The 220 and 240 cartridges are finished in
gold and silver, respectively.
A-8
Speaker-Headset Control Box. This unit,
known as the "Maestro," permits the use
of headphones or an extension speaker
with any hi -fi system. Two jacks are
mounted on the front panel of the control
box; use of one cuts out the main speaker
of the system, while use of the other
leaves the main speaker' in operation
switches, Housed in a handsome cabinet
which measures but 4" x 14" x 101 ", The
"Music Center" is available in several
finishes including mahogany, black, and
white gold- tooled leatherette. Descriptive
sheet available on request.
A -13
Compact AM -FM Tuner. Notwithstanding the fact that it measures only four
inches in height, the new Kauland "Golden
Gate" AM -FM tuner offers an exceptionally
high standard of performance. The FM
section includes Armstrong circuitry with
sensitivity of 5 microvolts for 30 db
quieting and frequency response of 20 to
20,000 cps within + 0.5 db. AFC defeat
position is included- on function switch.
features which make construction simple,
and technical knowledge unnecessary, are
130 printed circuits. Kits for the separate
components, such as each of the 12 tone
generators, preamplifiers, stop filters, and
the like, may be purchased separately to
make budgeting easy. For descriptive
booklet write Schober Organ Corporation,
35 Dail St., New Hyde !'ark, N. Y.
A -11
Tune -A -Port Speaker Enclosure. Characteristics of this enclosure may be varied
from the outside simply by adjustment of
two external knobs which alter the port
opening to meet the requirements of the
speaker enclosed. The cabinet accommodates 12- or 15 -in. single, coaxial, or triaxial speakers. It has an internal volume
of 10,000 sq. ins. and is constructed of
%-in. mahogany veneer stock. Internal
reflections are minimized by means of
simultaneously with an czteusiou speaker
or headphones. A volume control is provided for adjustment of signal level to
extension speaker or headset. The "Maestro" cabinet is finished in mahogany with
a gold -finished perforated front panel.
Permoflux Corporation, 4900 W. Grand
A-9
Ave., Chicago 39, III.
Deep -Drawn Aluminum Chassis. Many
applications will be found in the audio
equipment industry for various models
among the more than 500 types of deep drawn aluminum enclosures now being
made by Moorlee Manufacturing Company,
515 DuPont Circle Bldg., Washington 6,
D. C. Available with matching covers, the
enclosures arc seamless, single piece, light
All circuits are drift -compensated. The
AM section has a tuned r -f stage and requires a 5- microvolt signal for 1.5 -volt
output. Frequency response is 20 to 5000
cps. Cathode- follower output permits location of the tuner up to 200 feet from
the amplifier with which it is used. Tuning
control is of the counter-weighted flywheel
type. For full details address inquiry to
Rauland -Borg Corporation, 3515 W. AddiA -14
son St.. Chicago I8, Ill.
Compact Signal Generator. Availability
of a new compact signal generator which
acts as a secondary frequency standard
with a short -time accuracy of one part
per million was announced recently by
D & R. Limited, 402 E. Gutierrez St., Santa
Barbara, Calif. Generating twelve selected
standard frequencies between 20 cps and
100 ice, the Model FS -1 has a long -time
I
al ' #
:r
War
t
1
44
.
Ill
wei,
q ruggedly
,, structed. Included tuuong standard sizes are units
ideally suited for amplifier or tuner chassis, record changer and turntable bases,
and preamplifier housing. A complete catalog detailing all sizes and shapes will be
mailed on request to interested designers
and manufacturers.
A-10
in
t
acoustic padding. Overall size is 36 "h x
Available in mahogany,
24 "w x 17 "d.
blonde, or walnut finish. Manufactured by
Standard Wood Products Corp., 47 W. 63rd
St., New York 23, N.
Y.
A -12
Twenty -Watt Hi -Ft Amplifier. Designated as the Model S -1000 "Music Center,"
this new amplifier manufactured by Sherwood Electronic Laboratories, Inc., 2902
W. Cullom Ave., Chicago 18, IIL, features
push -pull 6L6GB's in a wide-range ultra linear circuit designed to handle 40 -watt
peaks. Other unique features include pushbutton control of record equalization,
speaker damping selector, center -set loudness control, Z729 low -noise preamplifier,
accuracy of 20 parts per million over normal ambient room- temperature range.
Eleven sine -wave frequencies, available
at approximately 1 -volt level and selected
by front -panel controls, are: 1, 3, 5, 10, 15,
20 kcs, and 20, 60, 100, 300, 400 cps. In
addition, a constant 100 -kc signal may be
used for reference to aprimary standard
or to WWV for precise correlation. Full
technical information is available on reA -15
quest.
AUDIO
60
www.americanradiohistory.com
APRIL, 1955
The NEW
REK -O -KUT
The NEW
SCOTT
(')?(/V)/O
Model 310
3- Speed, 12 -inch
FM TUNER
PRECISION TURNTABLES
An unusual FM circuit featuring 2 me bandwidth for more effective quieting
on weaker stations and more reliable, drift -free tuning without the need
for AFC. Single sweep tuning mechanism permits rapid location of desired
station on dial. Calibrated tuning meter insures precise station selection.
Adjustable suppressor reduces characteristic FM interstation noise. Employs
three cascaded limiter stages.
Sensitivity is 2 us for 20 db quieting and 4 uv for 40 db. High capture
ratio permits noise -free reception of stations only 2y, db stronger than
interfering stations on some channel. Two low distortion, feedback stages
Represented to be the result of more than 5 years study, these new record
playback units ore offered as the closest approach to perfection in turntable
performance. Like oll Rek O Kut units, the turntable is cast Aluminum and
exerts no pull on magnetic cartridges.
The following new features have been included:
single selector knob for
setting speed: 331/4, 45 and 78 rpm.
built -in retractable hub for 45 rpm
permanently affixed 3 -speed strobe
records -requires no external adapter
disc for instantaneous speed checking neon pilot light as 'on /off' indicator
special cork -neoprene mar material to eliminate record slippage
rectangular deck to fit conventional record changer boards.
Two identical Rondine models are available which differ only in the type
of motor employed.
Rendine Delux Model B-1211 hysteresis synchronous motor.
Rendine Model B -12 with 4 -pole nduction motor
$1
of audio amplification provides 4 volts maximum output voltage. Low
impedance permits long interconnecting cables between tuner and other
units. Power supply is built -in. Aluminum cabinet measures only 133/s"
wide, 10" deep and 41/4" high.
Complete with tubes
$ 149 50
1995
74.95
:
New
McINTOSH
50 Watt
PILOTROL
AUDIO AMPLIFIER
Model
Model PA -913
5C W -2
A professional-type front -end control featuring
circuit design
employed to provide 50 watts
of continuous power (100 watts
peak) with amazingly clean, dis
torsion -free reproduction. Fre-
-.
-
quency response extends from 20 to 20,000 cycles, ± .1 db, and from
10 to 100,000 cycles, ±3 db. Distortion is less than I% over the entire
audible spectrum at full 50 -watt output. Phase shift is negligible. High
domping factor and other features contribute much to the outstanding
listening quality of the 50 W -2.
$249.50
Complete with tubes
New PICKERING
TURN -OVER CARTRIDGE
Model 260DS with Diamond
and Sapphire Styli
PORTABLE
MagneCordette
identical.
Combines the famous PT6 -A1X mechanism,
the PT6 -G recording amplifier together
with the 91X742 speakers -amplifier -case
unit. features include: separate erase and
record -playback heads, fast forward and
rewind speeds. Frequency response: 50 to
15,000 cycles ±3 db at 15 inches /sec.,
and 50 to 7,000 cycles ±2 db at 71/2
inches /sec. Mechanism is driven by hys
teresis motor, and induction motor is used
for rewind. The 91X742 unit hos two wide.
range loudspeakers. Separate bass and treble controls provide means for
continually variable boost and attenuation. May be used with microphone,
phono pickup, or tuner, and os PA system. Power output is 10 watts with
less thon I% distortion. Power requirements: 117 volts, 60 cycles AC,
85 watts.
Response is smooth and clean from 20 to 20,000 cycles. Lower moving mass
and higher compliance provides excellent tracking at low stylus pressure,
and good transient response. These and other design features result in lower
harmonic and intermodulation distortion. The Model 260DS fits most pickup
arms and operates directly Into conventional low -level prsamp inputs.
,,___...,$4800
......_
_...__._
60.00
JIM LANSING
SIGNATURE SPEAKER SYSTEM
Model D -31050
One of the few truly front - loaded horn enclosures,
augmented by two Independent Helmholtz resonators to provide unusual realism of response to
extremely low frequencies. Equipped with two
Model 130B 15 inch low frequency units, one
Model 175DLH high frequency driver, horn, and
Kousticol lens assembly, together with a Model
N -1200 dividing network, the entire unit operates os an effective three.
way system with balanced, clean response over the entire audible spectrum. Height 50 "; Depth 28 "; Front Width 37 ". Shipping Weight 215 lbs.
HARVEY
552900
Complete pertoble MagneCerd.tte
PT6 -AHX Recording Mechanism only
PT6 -G Recording Amplifier only
91X742 Speakers -Amplifier -Case Unit
HARVEY SHIPS EVERYWHERE. Use
I-
$53925
Model D- 31050M (mahogany)_
Model D- 310506 (blonde)
NOTE, Prices Net, F.O.B.. N.Y.0
- -
-
-
Following the enthusiastic acceptance of the Model 260DD Dual Diamond
Cartridge, Pickering now announces the Model 260DS with Sapphire stylus
ter standard and Diamond for microgroove. Both cartridges are otherwise
Model 260D5- Diamond Sapphire...........
Model 260DD -Dual Diomond ....... ..._
a
sensitive, calibrated meter for indicating output level.
There are 4 inputs: phono, radio, tape, and auxiliary, operated by push.
button selectors with illuminated indicators plus an additional input channel for high impedance microphone. There are 5 push -button controls for
treble roll -off and 5 for base equalization. Other features include separate,
continuously variable boss and treble controls providing 19db boost and
attenuation at both 20 and 20,000 cycles
microphone volume control
master level control
loudness compensator
meter switch and meter
sensitivity range selector.
Convenient AC outlets are provided for auxiliary equipment, and is controlled by power switch. Microphone channel may be mixed with any one
of the other 4 channels. Cathode follower output permits up to 100 feet
of connecting cable. Cathode follower recorder output is independent of
volume, loudness and tone controls. Power supply is self -contained. Cabinet
is finished in mahogany and measures 6" high, 131/4" wide and 9t/" deep.
$11950
Complete with tubes.
....
_...
A novel and unique
is
PILOT
Preamp- EqualizerAudio Control
HARVEY RADIO CO., Dept.
A -4, 103
299.00
99.50
160.00
this handy coupon
W.43rd St., New York 36,
Subìect to change without notice
ESTABLISHED 1927
RADIO COMPANY, INC.
103 W. 43rd Skeet, New York 36
JU 2 -1500
I
enclose
check
money order for S
shipping charges. Unused surplus will be refunded.
New FREE High Fidelity Catalog
Send,
Details of your TIME PAYMENT PLAN
I
NAME......................._......._..........._..............__.........._.....................__..........
including estimated
_..
ADDRESS.._._........._..._ .. .................._.,......_.._ _........
Ciry.._......._......_ ................ ..........................................Zone................
AUDIO
N.Y.
Please ship the following.
546.75
APRIL, 1955
State
61
www.americanradiohistory.com
Do you know
you can own
Three -Speed Professional Turntable. Al- on both AM and FM. A built -in powerthough similar in design and construction
line antenna provides excellent reception
to the original turntable manufactured by
In normal locations. Essentially a basic
Components Corporation, Denville, N. J., tuner, the 850 is virtually identical in all
this new model is considerably reduced in respects with the well -known Pilot Model
size without any sacrifice in performance.
860, except that the 850 does not include a
The new unit occupies a space 19^ long,
preamplifier or tone controls. Pilot Radio
Corporation, 37 -06 36th St., Long Island
A -18
City 1, N. Y.
Heathkit High- Pidelity Amplifier Hit.
the
critical
to
satisfy
most
Features
listener are inherent in the new 25 -watt
Model W -5M amplifier kit recently announced by the Heath Company, Benton
Harbor, Mich. Frequency response is
within 1 db from 5 cos to 160 kc at a
reference level of 1 watt. Noise level is
99 db below rated output. Incorporated in
SPEAKER
for only $49.50
c
eiíe,
"the little speaker with the big Poire"
1:11_" deep, and 8" high, at the same time
providing ample room for ni punting any
standard pickup arm, including 16 -in.
transcription arms for broadcast use. The
"Professional" features a 25 -lb turntable
which is belt -driven from a three -step motor shaft pulley. Rumble Is down 70 db
and wow is negligible.
A-16
Mood Tapesoriptionc Pre-recorded tapes
featuring Robert Elmore, prominent organist, performing on a large cathedral
pipe organ, are now available from Electrosonie Specialties, 7230 Clinton Road
Upper Darby 3, l'a. The tapes are equalized
to achieve a close, intimate sound quality
You won't believe it, but
011
Audio Response -55 to 16,000
Speaker Components -8 inch
cps.
the amplifier is a new -type balancing circuit which results in closer dynamic balance between the KT -66 output tubes.
Intermodulation and harmonic distortion
are reduced, and low- frequency response
is extended a full octave below that of
present Heathkit Williamson-type amplifiers. Further technical information will
A -20
be mailed on request.
Twelve -Watt Hi -Pi Amplifier. Many features normally found only in more expensive units are included in the new Model
LA -54 12 -watt amplifier recently introduced by Lafayette Radio. Frequency
bass
driver in 36 inch exponential horn.
3'2 inch tweeter and specially designed crossover network. Impedance:
8
ohms.
Construction
-
Korina veneers finished in Blonde, Walnut, Mahogany
or
rubbed lacquer.
Ebony hand
Wrought iron legs.
Unique Features -Curled, not folded, exponential horn (1% of formula).
Multiple Flare formula (patent applied
for). Passive phasing chambers. 24db/
octave acoustical crossover. Distributed
throat characteristic (not found else-
where).
Size -19
x 12
9 inches.
x
Other Stan White Cabinet Speakers
LeSabre -24" x 15" x 12 ", Frequency
Response: 40 to 16,000 cycles
79.50
Esquire -30" x 24" x 16 ", Frequency
Response: 30 to 16,000 cycles 194.00
x 30" x 20 ", Frequency ReHi -Fi
sponse: 20 to 16,000 cycles
645.00
-4'
4 -D -5'
x
3'
2',
x
which lends itself particularly well to
sustained listening. Merchandised under
the trade name "Fidelivox," the tapes are
sill muse, interrupted only by a 30- second
break once each hour. They are available
in 2 -, 4 -, 6 -, and 8 -hour lengths, dual track.
Fidelivox tapes are sold direct by mail.
Inquiries should be directed to the address
A -17
shown above.
Pilot PM -AM Tuner. Extreme sensitivity
is principal among features of the new
Pilot Nlodel AF -S50 tuner. FM and AM
sensitivity are 1.5 and 2 microvolts, respectively. Circuitry includes an Armstrong limiter-discriminator circuit on FM
with continuously -variable AFC. Provision
response is 20 to 20,000 cps. Incorporated
in the amplifier are: a record equalizer
system with individual controls for bass
turnover and treble roll -off; separate bass
and treble tone controls, and a special
take-off Jack for tape recording. Written
request will bring technical specifications.
A -20
Compact Speaker System. Equally at
home on a table, in a bookcase, or on as
wall, the new Electro -Voice "Skylark"
incorporates two horn ports which properly load an E -V Model SPEC low- and
mid -frequency reproducer from 79 to 3500
Frequency Re994.00
sponse: 15 to 16,000 cycles
See your high fidelity distributor or
r
geelv
St.
727 S. LaSalle
Dept. A -4,
S, Illinois
A Division
ps. :l 'Type 'l'151í tweeter
3500 cps and extends the
Chicago
Enterprises
of Eddie Bracken
takes uv er at
range of the
system beyond the limit of audibility.
Dimensions of the Skylark are 33" w x
14" h x 10%" d. Finishes available are
mahogany and Korina blonde. Complete
specifications of components as well as
the complete system are described in Bulletin No. 219 which will be mailed on
request.
A -41
.
INC
-
wss.
+e u
is made for broad or sharp I -F' bandwidth
on AM, with 10 -kc whistle filter to elimi-
nate heterodyne interference. The exclusive
Pilot "Micro- Meter" assures precise tuning
AUDIO
62
www.americanradiohistory.com
APRIL, 1955
i
AROUND- THE -WORLD PORTABLE
(from fa<(,' 20)
some low frequency, feedback which becomes positive in sense and makes the
entire system unstable. Fortunately this
condition did not develop except at such
high average power levels that heavy
clipping was taking place within the
amplifier. The acoustical feedback problem could probably have been lessened
by a more elaborate shock-mounting of
the turntable. but the trouble was not
severe enough to justify the extra expense and time in experimentation. The
only deficiency of the Bogen turntable is
that no shock mounts of any sort are
provided. There was no noticeable
acoustical fedback. through the amplifier
principally because it was mounted on
in. rubber cylinders. and the first two
tubes of the amplifier were separately
isolated from the chassis by rubber grommets.
The final testing of the unit involved
tuning the port, using the system de-
scribed in the Audio Anthology. After
completing the tuning, a qualitative
check of the amplifier and enclosure was
made by driving the unit with an audio
oscillator and observing the output of
the loudspeaker by means of a microphone and amplifier connected to an
oscilloscope. The output was reasonably
level to about 70 cps, and then fell
sharply. There was no doubling, however, and the fundamental was clean
until the limitations of the 8 -in. cone
itself were reached, at about 50 cps.
After it traveled the first time a buzzing resonance developed at a certain
frequency, and on close inspection two
loosened screws were found in the
speaker mounting board assembly. After
reseating these the resonance cleared
away. A test trip seems to be in order
with equipment of this sort to show
flaws in either design or construction.
This unit has already traveled two thirds
across the country by railway express,
Fig.
11.
TRANSFORMERS
cally demolished, and only sheet -metal
screws holding the two halves of the
chassis together were loosened. This
condition was corrected by using four
bolts long enough to pierce the chassis
box completely to clamp the two halves
together.
PARTS LIST
electroly-
C,
20- 20 -20- 20/450,
C,, Cs, C,, C.
.02 pf, 400 y, paper
.001 pf, 400 y, paper
.01 .f, 400 v, paper
.002 pf, 400, y, paper
0.1 pf, 400 y, paper
50 pf, 50 v, electrolytic
15 Hy at 75 ma
10,000 ohms, 1 watt
0.1 meg, 1 watt
1500 ohms, 1 watt
0.47 meg, % watt
0.1 meg. % watt
2200 ohms, % watt
1500 ohms, % watt
tic
Cs
Cs, CIS
Cr
C,, C,.
C
L,
R,, R,
Rs
R,
R,
R.,R,,
R,
R,., R,,,
R,,,
R,,,
R,,, R,.
R
R
R
.
ILABLE FROM STE
47.00) ohms, 1 watt, 5%
1000 ohms, % watt
0.27 meg, % watt
30 ohms, 2 watts
250 ohms, 10 watts
0.25 -meg potentiometer,
R,s
R.
YOUR TRIAD JOBB
olation Transformers
cially designed for is
ry test equipment ..
audio toper
R
rn of line disturbanc
0.5 -meg potentiometer,
of undesired grou
audio taper
10,000 ohms, % watt
0.47 meg, '/a watt
1200 ohms, % watt
12,000 ohms, '/z watt
250 0 250, y at 75 ma, 5 v
at 2 a, 6.3 y at 2.5 a.
Universal output, 20 -watt.
R
R-F
T,
T,
ideal for use in s.
.nstruction featur
reatment, liberal
limat
quality
insure opt
erials and static
m
performance._
In VI
ng
d long fe.
I
5Y3GT
v,, v.
12AX7
6AQ5
Altec 755A loudspeaker
3 -cet phone jack
Bogen DB -50 turntable
and arm, ceramic cartridge.
Type
No.
List
Price
Input
Volts
V. A.
Output
Output
Volts
$ 5.95
35
115
115
N-52M
32.50
With switch
and meter
350
115
95- 100.105110.115-120-
N -51%
MEP
111=
í
Curves
ISOLATION
having just been slipped into an outer,
protective, cardboard box. At the end of
the trip, the cardboard box was practi-
125.130
N.53M
12.75
85
115
115
N -54M
14.30
150
115
115
N-55M
25.30
115
115
N -57M
40.75
250
500
115
115
N -59M
87.20
1000
115
115
130.00
2000
230/115
230;115
TN-60
tSpecial case.
;%N//
#1/iY/,G,'l,'OO//////
%
showing tone control range.
Writt for
'!'1,1'0ii % A
Cab1og TR -$4F
-25
s
No
NsE
FREQUENCY
AUDIO
IN
N.n
MOO
CYCLES PER SECOND
APRIL, 1955
TTRAPISPOPPAiR
COPP
1
63
www.americanradiohistory.com
Emergency Expedients
COMPARE
this performance!
FAIRCHILD
I220
'
DIAMOND
CARTRIDGE
($37517
1`.orsluid s 2 20 Set as cartridge guarantees this distortion -free reproduction in
the entire audible range!
Just look at these frequency response
curves of the Fairchild 220 and two other
leading cartridges. See how Fairchild
alone gives smooth, even reproduction
completely uniform to 17,000 cycles
with only slow roll -off beyond. This
means no unnatural harshness, no distorted
sound! With Fairchild, you have only
the sound you were meant to hear!
-
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FREQUENCY
IN
CYCLES PER SECOND
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the RIGHT sound always
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FAIR('IIILD
24O
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PREAMPLIFIER
Highest performance and operating simplicity in this attractive Fairchild 240
Balanced Bar Preamplifier give you the
world's finest sound equalization.
Also, the Fairchild 240 features Listening Level Control. Operating independently of volume control, LLC provides
pleasant low -level listening and correctly
all
balanced normal listening levels
easily, without complex adjustments.
-
ge5o
#11101149
AVE. &
154th ST.
U
="7
WHITESTONE. NEW YORK
METER SCALES
(from page
3.?)
be produced rather rapidly, and at a
relatively low cost. Samples of special
scales other than those for use in conventional panel meters comprise Fig. 6.
At right is a GMT dial, for use in a
24 -hour "tinge of day" panel clock. At
left is the dial for a self -computing
anemometer timer. Outer scale is calibrated in seconds. Next inward scale is
calibrated in miles per hour of wind,
for use with a 1/6 -mile contacting
anemometer. Innermost scale indicates
numerical significance of intermediate
markings on the wind-speed scale, and
was designed to reduce interpolation
blunders.
Several very complicated multicolored
scales have been made by an extension
of this general technique, color printing
being done by use of wash off relief
film. Use of a second calibration in red
is quite satisfactory, but additional calibrations in other colors are difficult to
read unless overall illumination is quite
rigidly controlled. Yellows become unreadable under ordinary incandescent
lighting. and most blues "drop out"
under fluorescent lights.
A special meter scale, made by any
ordinary method, is likely to cost at
least as much as the meter in which it
is installed. Relatively simple scales,
such as those shown in Fig. 5. require
from one to two hours of drafting time
if made as single jobs. Ten or twelve
scales. of about the sanie dimensions and
complexity, can be drawn up in a single
working day if the entire group is assigned at one time as a single job ; and
provided the instructions are both adequate and simple.
Copying of scales entails only a few
minutes of actual work, but also requires
a considerable time for developing, fixing, washing and drying. Most commercial photographers can produce
copies in 24 hours as "straight run"
work ; and in three hours, at a higher
price, as "rush" work. Copy negatives
cost from one to five dollars each, with
three dollars for an 8 x 10 negative being fairly standard. Five 3 -in. diameter
meter scales, all to the same reduction,
can be copied on a single 8 x 10 negative.
Contact prints cost from ten cents to
two dollars, with one dollar for an
8 x 10 print being a common charge.
Usually, if a number of prints from the
same negative are ordered at the same
time. the cost of additional prints is
considerably less than that of the first.
When more than about 25 copies of a
scale are wanted, multilith reproduction
may be economical ; and when much
more than 200 prints are needed within
a year, printing from a line engraving
should be considered.
Mounting of the scale on the scale
plate, and installation in the instrument,
takes from 10 to 45 minutes, depending
upon the mounting method used. Mounting of a dozen scales, however, all done
at the same time, requires only slightly
more than two hours.
Uthough makers of trans -adhesive
art aids have regular outlets in most
large and medium -sized cities, there will
be times when a single symbol, or group
of them, cannot be' obtained. When this
occurs, or when material cost is more
important than labor cost, symbols cut
from printed texts can be cemented onto
a scale, in suitable alignment, with gratifyingly satisfactory results. In one "war
emergency" situation, a complicated
meteorological computing scale was
completely numbered and lettered with
type cut from pages of the Saturday
Evening Post.
Coloring Scales
When scales in several colors are desired, construction may become somewhat involved and difficult. The most
common need, the red line accompanying
instructions "Set to red line," is also
the most easily applied. Clean the surface of the print with carbon tetrachloride or clean (not motor) ether,
and draw in the desired line with red
drafting ink using a clean ruling pen.
If the need is for a scale with black
lines and letters on a colored field, a
standard black and white print can be
made, and the field (the white portions)
dyed any desired color by use of photographic dyes (available at most photographic supply houses) or high -grade
colored drawing inks (K and E or Craftint) applied by immersing the entire
scale, or painted on with a clean brush
or cotton swab. Use of cheap "easter
egg" dyes leads to fading and ultimately
blotchy appearance of the scale. Application with a pen usually plucks the
paper surface, producing nonuniform
coloring.
Colored zones on a meter scale, like
those commonly used in tube checkers,
can be produced by outlining the areas
to be colored with a thin black line in
the original print, and then filling in
the outlines with the desired color. using
dye or ink applied with a brush or
swab, not with a pen. Large areas can
also be colored by application of solid
color Zip -A -Tone.
When multicolored scales are needed
in moderate numbers, such as 25 or
more at one time, excellent results can
be obtained by two -color multilith. For
this, the lithographer requires one
original for each color used, and register
marks, so that the various prints will
superimpose properly in the finished
scale. This process is usually too costly
for only one or two scales, as almost
the entire cost is the making of the
separation plates and setting them up
for multilithing. Cost of a single scale
Fig. 6. Special timer scales made by combining
standard drafting and trans -adhesive lettering.
AUDIO
64
www.americanradiohistory.com
APRIL, 1955
is likely to run around $25.00, but 100
scales will only cost $30.00.
As a last resort, and then only when
costs don't matter, a complex scale in
color can be photographed in color, and
Kodachrome or equivalent prints cemented onto the meter scale plate.
î
=
-tTHR ORIGINAL
By use of the methods here outlined
combination of line drafting and
"stick up" lettering-workmanlike special instrument scales can be made
quickly at reasonable cost. Quality of
scales produced by these methods will
usually be superior to that produced by
"direct drafting," but will not equal
that of scales printed on the special
dividing machines used by a few of our
-a
The name
GENALEX on the
tube and carton is
your guarantee
that you are buying
the original
KT66... world famous power
tetrode, often
referred to as the
finest audio tube
ever made! The
better instrument manufacturers.
In many plants, all processes of making a special meter scale can be performed within the plant, eliminating the
involved and costly purchase order procedure needed-to get a special scale from
the instrument manufacturer. Likewise,
local manufacture of special scales eliminates the prevalent delay in delivery,
which currently ranges upward from 30
GENALEX KT66 is
the hallmark of the
finest amplifiers.
It is supplied as
original equipment
in amplifiers
of the highest
quality. Identical
pins and
connections as
days.
tubes.
Only $3.50 net.
6L6
` John L. Ridgway "Scientific Illustration," Berkeley, 1938, 101 -103, 108 -111.
'R. L. Ives, "Fabricated diagrams,"
For complimentary
fact sheet,
write Dept.
Journal of Geology, Vol. 47, 1939, 517 -545.
° J.
R. McDermott, "New electronic
drafting tools and techniques," Electronics,
Vol. 27, No. 8, August, 1954, 121 -125.
' Craftint Mfg. Co., 1615 Collamer Ave.,
Cleveland 10, Ohio.
Fototype, 1414 Roscoe St., Chicago 13,
Illinois.
° Monsen- Chicago, Inc., 22 East Illinois
St., Chicago 11, Ill.
Artype is manufactured in Chicago. but
is marketed in the New York area by
Trans-Art Incorporated, 15 Park Row,
New York 38, N. Y.
°R. L. Ives, "Special Symbols from
Standard Type," School Science and
Mathematics, Vol. 50, 1950, 567-569.
°Para -Tone Co., Inc., 343 S. Dearborn
St.. Chicago. III.
Quality endorsed
product of the
British Industries Group
BRITISH INDUSTRIES CORPORATION
164 Duane Street New York 13, N. Y.
C! -100
Nat price. $4.50
The highest
overtones of
the piccolo
AMPLIFIERS
¡,
,
"
discrimination for such inaccuracy. The
main sources of distortion in sound reproducing systems are the electromechanical and electro- acoustic transducers
-pickups and loudspeakers -but even
here amplification helps matters. When
the efficiency requirements of the passive
transducers are reduced by virtue of
the amplifier it is easier to subdue annoying mechanical resonances, a step
that improves performance considerably.
The possibilities of securing amplifi-
cation from new types of devices have
by no means been exhausted, nor have
current amplifying devices been fully
covered here. Research in basic amplifier units and in applied circuitry is
continually going on. The amplification
of oscillatory or otherwise variable
stimuli occupies a central position in
modern applied physical science. Although the popular drama of nineteenth
century gadgets may be missing, revolutionary work is being performed.
AUDIO
Centralab's
Senior COMPENTROL'
The deepest tones
of the bass tuba
Senior Compentrol -with special
Printed Electronic Circuit'
is no ordinary compensated
control. There's nothing else
like it, for improving the tone
performance of hi -fi amplifiers or
pre -amplifiers! Leuel -set lets
you control compensation to
suit yourself. Ask your Centralab
distributor
or service man.
Write Centralab, Dept. 934D,
Milwaukee 1, Wisconsin for
Compentrol booklet.
h......
-
ct
Cen
-
.tpralab
APRIL, 1955
65
www.americanradiohistory.com
HI
-FI FANS
and CRITICS AGREE:
EQUIPMENT REPORT
"GEORGE WRIGHT
plays the
MIGHTY WURLITZER
PIPE ORGAN"
(irons page 49)
9000, 5000, and 3000 cps respectively. This
is useful in eliminating scratch or high -
frequency distortion occasionally found in
some of the poorer records. The filter
curves are shown in Fig. 10.
Figure 11 shows the circuit of the filter.
Note that there are three separate controls
-the low- frequency cutoff at the left, the
compensator at the center, and the high frequency cutoff at the right. The left control introduces a series capacitance of 4,
2, or 1 sf, together with a shunt inductance
oIIIIIIIsiumilmIIng
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.
f'?
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Praised like This in
High Fidelity, Audio,
SPRAY
.
IIIÌÌIIIIIIIIIII
deserves its fine
..:'
reputation
"...of
-.of considerable
Your Best Defense
Against DustEnemy of Records and Needles
effectively
Absolutely Safe'Bmt product!"
Non -Residual
+
Contains No Soaps or Detergents
Adds Years to Record Life -With No
Loss of Presence or Brilliance
Laboratory Tested. Unconditionally
1
..:
-
Guaranteed
Nothing stops dust as safely and effecNo other
tively as STATI- CLEAN.
cleaner has the permanence of STATICLEAN one quick spray stops dust for
months! Chemical-impregnated cloth
cleaners are temporary and become useless after dirtying, washing, or short exposure to air... but with STATI- CLEAN,
you use the free applicator cloth indefinitely. It may be washed repeatedly, is
continually restored by use! Further, unlike clip -on devices that reduce static but
do not clean the record (and are dangerously radioactive), and brushes that
just generate more dust attracting static
in use STATI -CLEAN does the whole
job, sensibly and safely.
Ask for STATI -CLEAN the original
anti -static spray cleaner next time you
visit your record dealer.
-
-
-
BY THE MAKERS
Of
-
THESE OTHER
FAMOUS RECORD PRODUCTS:
WALCO
WALCO
Contoured Bottom
I
I111111111111111111`111111\\
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Review of Recordings and American Record Guide:
Sal.
ec
Fig. 10. Low- and high- frequency cutoff curves
for the filter section.
and a suitable terminating resistance for
the three positions of the switch. The two
2-µf capacitors are paralleled to make 4
µf, one is used singly to make 2µf, and the
two are in series for the 1 -0 position.
Similarly, the high -frequency cutoff control
introduces shunt capacitors with suitable
terminating resistors to provide 12- db -peroctave cutoffs at the desired frequencies.
The two sections of the compensator control vary the series capacitance together
with the terminating resistance to provide
the desired curves.
The audible effects from this filter unit
are quite satisfactory, and it serves well to
make the simple UPX -003A preamplifier
nearly as flexible as many of the more
elaborate -and more expensive- preamplifier control units. This filter is designed
for use with the G.E. pickups, and would
not provide the indicated compensations
for other makes.
We are especially pleased to note one
line in the instruction book accompanying
phrase we have often used
this filter
in these pages in the nature of advice about
Provide adequate
phono equalization:
flexibility in the reproducing system controls, and then adjúst the controls so the
reproduction sounds best.
for Records
e4t)
FREE
9
A
Angela Mia
Roller Coaster
ADVANCE ORDERS
ACCEPTED NOW
s 4.95
12" L.P. Hifirecord
$12.95
2. 15 I.P.S. full track Hititape
S 8.95
3. IS I.P.S. half track Hifitape
$ 8.95
4. 7Ií= I.P.S. full track Hifitape
$ 6.95
S. 711/2 I.P.S. half track Hititape
all
12
selections.
include
Above album prices
post paid and tax free.
DEALER PRICES UPON REQUEST
1.
To order
simply enclose check or money
order for correct amount with reference to above numbered High Fidelity Recording you want -orders
will be filled following March 20th
in the order they are received.
HIGH FIDELITY
RECORDINGS, INC.
6087 Sunset Boulevard
Hollywood 28, California
IF YOU ARE
MOVING
Please notify our Circulation Department
at least S weeks in advance. The Post
copies sent to you once. To save
yourself, us. and the Post Office a head
ache, won't you please cooperate, When
notifying
dress
and
us.
please
your
new
give
your
old
ad
address.
Circulation Department
PRODUCTS, INC.
RADIO MAGAZINES, INC.
60 AFranklin St., East Orange, N. J.
AT LEADING RECORD SHOPS
Boogie
cate
Write for free sample DISCOVER,
plus free S1 book on record core,
indexing, etc. Enclose 25c to cover
postage and handling.
UKJ
Caminito
Office does not forward magazines sent
to wrong destinations unless you pay additional postage. and we can NOT dupli.
for all
cartridges
and players
The Boy Next Door
Brazil
Stella by Starlight
Love for Sole
Dancing Tambourine
Stars and Stripes Forever
Ebb Tide
.
NEEDLES
/
MR. WRIGHT PLAYS
Jealousy
-a
REPLACEMENT
Protective Polyethylene Sleeves
High Fidelity Recordings, Inc.,
takes pleasure in announcing a
limited issue new release for theatre organ enthusiasts.
George Wright is best known as
Organist of the New York Paramount Theatre where for several
years his artistry entertained
throngs of New York theatregoers.
More recently he's doing Radio and
TV work in Hollywood. The organ
recorded is among the largest theatre pipe organs ever built by Wurlitzer with five manuals. An 8"
x 10" photograph of both Mr.
Wright and the Organ will be included with each order.
available about March 20th
on "HIPTTAPE" pre -recorded
tapes and "HIFIRECORD" long
playing 12" records
Fig.
il.
P.
0. Box 629 Mineola N. Y.
Schematic of the Al -901 Record Filter
AUDIO
66
www.americanradiohistory.com
APRIL. '955
Acclaimed Coast to Coast!
PATENTS
MIRACORD XA -100
(from page 4)
of Fig. 3, the middle and treble tend to roll
off somewhat as level drops. How much
real difference this is we do not know.
Figure 3 is the same as Fig. 1 in operation except for a couple of points. The tube
is a variable -mu pentode connected as a
triode. Instead of making the cathode resistor Rr a potentiometer, a second, probably much larger resistor R, is shunted
across the cathode, and this becomes a pot.
The d.c. the arm carries to the grid is
filtered by a double time-constant network.
That the extra components are worth while
seems doubtful.
It should be mentioned, by the way, that
this circuit is also very good for use as
a non-frequency- compensating remote volume control. The usual method of remote
control is to use a variable -mu tube. However, for highest -quality audio work these
gadgets often introduce some distortion.
In the circuit here the characteristics of
the tube can introduce no distortion since
the signal doesn't go through the tube.
Possibly the only disadvantage would be
that you can't reduce level to zero. To
remove the compensating feature, simply
proportion C, so that turnover takes place
at 10 cps or less; in other words, put in
the biggest convenient value you run across
in the junk box. If you use a very low -mu
triode so that C, might have to be inconveniently large for this, you can probably
get out of it by using a value with reactance
small with respect to R,, then connecting
the left end of C4 (Fig. 1) to the tube
plate. The tube in any case should be something like a 6J5 rather than a high -mu
triode like a 6SF5 or dual equivalent.
E
"The Mircrord ¡;
"The bsence of
the serfcce n
al' others riel ro so far superior h
comparisons
pansons cc
be nade"
- Boston
ineease
Mas.
v
bra nmde
and
f1i r button greatly
istdrpttpleasura'
- Hartf:rd, Conn.
'How tie 'vagic Wo
changes recoras -d aindle
without a
pusher arse is
reoll, magic"
Philadelphia. Pa.
%cc/1i, Fla.
Has everything
xaul of sound,
convenience of operatior, compa..t
in size, at .c dive in cesigi"
of Angeles, Ca .
"Choice of parse lengths
betwee
r
records with the 'pausamat,
,ompact end eFident
oed"
"TI-e most
is remat t ok le' _
trave e vet DV. Po.
Seattle, Wash.
reca -J cluing 'r
Pittsbsrgt,
it can
'A-rswers al ny needs because
Ily"
be operated aJlematically or mane
-
-
-
-
:
all
"I could net Jel eve it would do
you claimed j-rtil I bought one"
"Fcr ti.' first tine my
raso
-is are
real!, bei ig treated
£entfa egre,
tha-ts te the Magic with
Wand"
- Dallas, Texss
- Chi :ago, Hl.
truly o miracle
pulls
The Miraccrd is
automation. a wonderc'J1
u1
is
modern
N. Y.
button operation New York,
cQ4wen
n
ate"
See and
Hea
-
o Warned
So Pfesed
Iwi h
[email protected]
Y
Mira
o MY`nFriend
cord
St. Lc vi s of
c'PPorttrni
-
AUDIOGERSH CORPORATION
23 PARK PLACE, NEW YORK 7, N. Y.
EXCLtSI'E DISTRIBUTORS IN
Inventions Wanted Department
At this writing the last issue has just
barely got to the customers, so we have
no response yet to our call for ideas for
inventors. We would just like to start the
ball rolling, however, with one desire of
our own.
Something this writer would like to see
(or invent) is an artificial reverberation
circuit in which there would be no resonances and transmission response would be
flat so that controls could select which frequency ranges should reverberate the most.
There must also be a control for reverberation time. About the only good way of doing
this so far is with a tape recorder acting
as a delay line with feedback from playback
head to recording head. Any chemists it
the audience who can come up with a sub
stance that will transmit audio slowly but
without distortion? We need a delay of
about 1/16 ,:f a .cc::nd in a small space.
Mo.
lt at Yon' Hi -Fi Dealer.
THE AIS.
FOR
+'
'LAC RECORD PLATERS
control prearplifier-equcMier
Ouclity De:iattrd
v
maranlfz
Owners of he Marva:: audio C.nsoiette inea-ably
comment 3M the ihnei to imp-ovenent in s,un3
quality of their systena. Sa_h a fine iasrulne-t- emit
he produca1 by the -hxsir ids, hut only through :aw-
assenthlyand thcrcu3h:esting of _a_h t=it.
its comp -ears are unconIprome.mgj/
chosen for superior quality. This and tie dscmc:zr of
ful
Naturally
DON'T MISS
its workmanship make; .t the obvious choice for rhos_
who wish to mprove their p -esent installations. Cktssis
suitable kz nstallati)n SH12.50, w.th cabinet S155.0(.
The 2nd Canadian Audio Show
Prince George Hotel, Toronto
April
AUDIO
27 -28
i'ritr Tor Cim¡,ctr
Details:
S.
b. mazantz u ts7ernon Bvd
APRIL, 1955
,
:,.I.C, NewYo-k
67
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4
AUDIO ETC.
Postpaid
REK-O-KLEEN
LASTS
-
A
-
LIFETIME
IT'S NEW!
IT'S
-
(from puye
No question about it-the lower prices,
even with the golden possibility of higher
sales, even with the possible aid from profit- making popular sellers, even with all
the aid available from outside enterprises,
still are painful for small business, favorable to large business.
I think that if in the next year in spite
of the price cut we find the majority of
the reputable small companies still in business with their quality musical offerings
still intact and new offerings still coming
forth, then we will have witnessed a minor
miracle of business adjustment. There are
dire predictions that the mortality will be
high, that it takes six or eight months (that
is, from Jan. 1st when the price cuts went
into effect) for the results to be felt and
that the worst is yet to come. I hope not,
and I have a certain sneaking feeling that
maybe things will come out OK, after all.
Financial predictions, like voting pre
dictions, are likely to go haywire, as we
know. The more statistics we have to
prove our predictions, the more off -base
we may be. Let's see what happens.
P. S.' Note that the price cuts have been
staggered in many companies, the full
RCA Victor price level ($3.98 list for
12 -inch LP's) applying only in some cases,
-'
DUSTFREE PLAYING
WILL
INCREASE YOUR RECORD
AND STYLUS LIFE A
HUNDREDFOLD
The OWN Record Brush
With All These Features:
*
Record
and Stylus
Automatically
Kept
Dustfree During the Entire
Play
To Fit All Automatic
Or
Manual Players, in One Inch of Space.
Designed
Adjustable
Width Turntable
Any
Height
*
Fully
*
Never Interferes with
*
Finest Grade Camel Hair Cleans Thoroughly. Lasts A Lifetime.
*
Pre -Set Brush Eliminates Constant Brush
To
Or
Speed or Opera-
tion Of Turntable
Re- Setting
-Tip Control Swings Brush In or
* Finger
,ut of Use Instantly
* Easily Attached Or Removed In A Few
Seconds. No Hardware
To
other records being priced higher according
to their type. Even Columbia has taken on
this policy, where RCA's prices go across
the board. An excellent idea. Better to pay
more for a specialized item any day than to
find it unavailable, priced right off the
market. Never forget the fabulous sums
that collectors will pay for "rare" recorded
items, not regularly available. Better on the
market at $5.05 than off the market at $10.
Fasten.
*
Its Self- Contained. Operates Indepen-
*
Brush
dently of Tone Arm.
Width Adjustable To Any Size
Record
KRAL PRODUCTS
1704 WALNUT STREET
PHILADELPHIA 3, PA.
2. VERIFIED.
Well, now we can have our high fidelity
verified. One of the large one -piece phonograph makers offers this service and suggests that there is no substitute for verified
high fidelity. You can duplicate it only by
being in front of the performers themselves.
The company has set up an independent
panel of experts and, it says, your assurance
and proof of the highest fidelity is in the
panel's verification of it.
The members of the panel are Milton
Cross, Yehudi Menuhin, Hoagy Carmichael,
Guy Lombardo, James Melton, and Sir
Cedric Hardwicke. The phonograph line
that is in question starts off with a model
offering "highest fidelity for your fonograf
dollar," which sells for $29.95.
Wasn't it a year or so ago that the AES
was considering setting up some official
categories for high fidelity standards, beginning with plain "high fidelity," then going
upward through "super high fidelity"
(SHF) and "ultra high fidelity" (UHF) ?
Looks to me as though, verification being
what it is, these days, they'd better consider a couple of extra categories ; UHF
.51)
couldn't rate much higher than $99.95. How
about Very Ultra and beyond that maybe
Astronomically Ultra? For. real top -quality
we should have something with a proper
tone to it, say Galaxial High Fidelity.
That's it That'll be the name of my next
audio. Verified GHF.
book on, ugh .
(Verified by whom? Canby, of course.)
!
.
.
A special virtue of this department, I
insist, is its lateness. While others jump to
get in reports on new equipment before it
hits the market, this column just waits and
waits, to see what happens. And it's well
rewarded. Any number of gadgets that have
arrived here in too -hasty defective form
have been replaced, later on, with de- bugged
models of very much better performance.
An early report would have been unfortunate.
Indeed, I hafta laff, as the funny papers
say, at the surprising number of defective
articles I've been sent and the red faces
that have resulted in many a company's
sales office! I don't mind ; I'm used to it
and I know that this is quite normal and
to be expected in the complex and anguished business of launching new products.
Pressure of competition is unbearably high
and the. urge to rush the first models out
quick to the press and the experts is irresistible. Or, to put it another way, it's easier
to advertise than to produce and invariably
the publicity department gets ahead of the
production department and has everybody
excited long before there is anything to sell.
With ads flying right and left and orders
piling in, the production people are often
forced to send out anything they have, half baked or no: It happens in the best manufacturing circles.
Just to show you how impartially I am
thinking, let me say that my first early Garrard changer was a lemon (the second was
excellent), I've had one defective arm and
two defective cartridges from a reputable
cartridge maker-nameless since we're trying again with a new set -my first Collaro
changer wasn't up to being written about
but a new one of later vintage is a different
story (to come), my first try at an Ampex
600 disclosed a faulty output circuit with
bad hum, I got an early GE cartridge minus
damping blocks (probably damaged in
transit), and finally
I did have some trouble with both the
Miracord changer and the Miraphon manual
player. Yet I'm about to record myself as
recommending these last two, and very
worthwhile machines they are.
-
3.
MIRACORD, MIRAPHON.
The Miracord -Miraphon pair share the
same basic drive mechanism, which shows
every evidence of solid German engineering.
My first one had serious wow in it, but as
might be guessed this was purely temporary,
an early -type defective rubber idler wheel.
AUDIO
68
www.americanradiohistory.com
APRIL, 1955
When it was replaced, in a few seconds,
I got extremely steady performance-no
complaint left. Same for the manual -play
Miraphon. (If you have a wobbly one, you
can make the same change very quickly.)
The Miracord changer has the much touted "magic wand" spindle which does a
variety of tricky changing functions at
the center of the record. Unfortunately for
the ads, it was right here that another
difficulty cropped up, now entirely conquered. The earlier models of last season
had a spindle that was slightly too thick
and wouldn't change some brands of records.
Naturally I got one of those. It flubbed
about half the records I fed to it. But the
replacement spindle is OK. I've watched
it change every brand of record I could
find to try. (And if you have one of the
early ones the company will give you a free
replacement spindle at once if you just
ask.) So that's fixed too.
The present well- broken -in Miracord,
then, is an excellent machine, steady, so
quiet in operation that I keep leaving the
table turning by mistake. It rates surely as
one of the best of the middle -de-luxe
changers. I have only a few negative reactions. The push-button controls include
a scratch filter and a pause control. The
filter on mine is set for crystal cartridge
and will do odd things to a magnetic's output unless you change the components,
underneath. Not a very important gadget,
these days.
The pause control may be fine for those
who want intermittent music, for dancing
and the like, but its mechanism is diabolical -you can't stop it. Or rather, you can't
start it. Once the thing is pushed, there is
absolutely no way to cancel its action and
in the extreme position at LP speed you
may have to wait a full five minutes before
you can get a sound out of your changer!
Of course, you can switch to 78 and speed
up the process. The pause feature is evidently popular in Europe ; the Paillard
changer I described on my Swiss visit in
the summer of 1953 had exactly the same
thing. The timing, on that one and on the
Miracord, is perhaps intended for 78 -rpm
usage ; at the long play speed the intervals
are much too long.
One more suggestion. The Miracord, and
the Miraphon as well, combine an automatic motor shut -off with a manual provision for disconnecting the rubber idlers to
avoid flats not unlike the system used in
many Webcor models-positions marked
78 --0-45 -0-33. A basic flaw in thinking out
the design leaves it up to you to change the
setting from 33 to 0 after the changer has
turned off its own motor. If you don't, the
drive remains engaged. Hours -or weeks.
Now any reasonable soul can manage to
set the knob to 0, I know. But most of us
are unreasonable and absent minded. I am,
anyhow. Three times out of four I leave
the thing in gear. Haven't got a flat yet,
but I'm expecting it any day.
AUDIO
Twit to the,fAMOUs
WI L L I A M S O N Specification
PARTRIDGE WWFB
Output Transformer
Built to the famous Williamson specification,
the PARTRIDGE WWFB covers full A.F.
range with lowest distortion. Secondary windings are brought out to eight separate sections
of equal impedance. Power Rating
continuous
steady
Stork
tone.
types comprise 0.95, 1.7, 3.6 and
7.5 ohm sections.
16 watts
$27.75
Net
Pri,r
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Available in
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EXCLUSIVE DISTRIBUTORS
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For .peeiflcat Ions. prices, and the name of the
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23 -03 45th Road, Long Island City 1, N. Y.
By arrangement
TYPE C.F.B.
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at 43
of turne. See June issue **Audio Engineering
Leads the way in '-C" Core technique. Power up to 60
units front 22 cf. to 30 Eels. Distorsion less than
with no S.F.B.
$43.75 Net Price
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A p.p. Transformer
signed for really high
Each half primary is
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$27.30
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PARTRIDGE TRANSFORMERS LTD
T O
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presenting present -day knowledge of
TRANSISTOR Ilttaorv, fu idlioning.
ntunuluciuring. applicationsHere's practical help on transistors-to enable you to understand clearly the operation of these important circuit components.
In straightforward terms, this manual provides theoretical and
practical knowledge of the properties and applications of transistors.
Tii.ANSISTORS:
Theory and :lppliratiotts
By ABRAHAM COBLENZ and HARRY L. OWENS
JUST
PUBLISHED
Transistor Products Co., Inc.,
Waltham Mass., formerly with
Signal Corps Engineering
Laboratories
Chief, Solid State Devices Branch,
Signal Corps Engineering
Laboratories
313 pages, 6 x 9, 115 illustrations, $6.00
Transistor design, functions, and
The book presents valuable information on such important topics as cascadperformance are fully explained at a technical- engineering level. Theory is kept to
a minimum -and stressed only in its relation to practical needs. Manufacturing techniques, practices, and precautions for both
silicon and germanium transistors are included, detailing fundamental metallurgical
and production aspects.
ing of transistors, silicon and germanium
preparation, the intermetallic compounds
and criteria for their selection as transistor
materials, power transistors, high frequency
transistors, and a host of related subjects.
Technicians, engineers, and advanced workers in electronics alike will find this book of
positive and practical help.
RADIO MAGAZINES, INC.
P.O. Box 629, Mineola, N. Y.
APRIL, 1955
69
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CLASSIFIED
Rata: l0e
per word per Insertion for noncommercial
advertisements; 2ie per word for commercial advertisements. Rates are net, and no discounts will be
allowed. Copy most he accompanied by remittance In
full, and must reach the New York office by the
first of the month preceding the date of issue.
The
THE AUDIO EXCHANGE has the larges
selection of new and fully guaranteed used
equipment. Catalog of used equipment on request. Audio Exchange, Dept. AE, 159-19 Hillside Ave., Jamaica 32, N. Y. OL 8 -0445.
AUDIO EXCHANGE EXCHANGES AUDIO
Record
TUBES -70% to 90% DISCOUNT.
ment, manufacturers, jobbers. etc.,
Guaranteed 1 year. Free catalog on
Cadillac Trading, Dept. A, 231 -07
Blvd., Jamaica 11, N. Y.
Changer
Governsurplus.
request.
Linden
HERE'S A $2000.00 VALUE FOR $1100.00
Two Presto tape mechanisms- RC-10 -24 and
RC- 10-14, one 900A2 three -channel amplifier,
and SA -9 transfer switch for continuous recording. Everything is in top condition and
will demonstrate to prove it. Modified Olson
disc cutting head (50 to 15,000 cps) $200.00.
RECO -ART, 1305 Market St., Philadelphia 7,
With
Pa.
FM YAGI Antennas. Sharply tuned and
broad band types. Installation accessories.
Wholesale Supply Co., Lunenburg 10, Mass.
25 -50% DISCOUNT. Factory -fresh guaranteed LP records, 690 and up send 200 for
catalogue. SOUTHWEST RECORD SALES,
Dept. A, 4710 Caroline, Houston 4, Texas.
HI- FIDELITY BARGAINS : English 71/4
and 3% ips TAPE DECK. Push button operation. electronic braking, silent drive with three
4-pole shaded motors, fast forward and rewind
position breaks oscillator circuit, accidental
erasure impossible. YOUR COST $59.50. Pre amp with connecting harness for above, only
$39.75. Authorized distributors of the finest
hi- fidelity lines. Changers, turntables, baffles,
amplifiers, tuners, speakers, etc. Write today
concerning your requirements. All shipments
Diamond
sppeard foRPX
stylus
only $10.50. Heavy
simulated leather covered base for Garrard,
Collart or blank base with hinged covers to
protect your changers, only $9.50. Free audio
consultation service. Write today. FIDELITY
UNLIMITED, DEPT. AE, 63-03 39th Ave.,
Woodside 77, N. Y.
rÓ
-0,
py
LEAK Dynamic Pickup, transformer, arm.
Sargent -Rayment 20 -watt Acro Ultra $39
Linear amplifier. $49. R. Balzer, 435 E. 74th
St., New York 21, N. Y.
;
IT'S FUN to SPLICE TAPE with GIBSON
GIRL Cutter -Splicers. At your dealer or write:
Robins Industries Corp., 82-09 251st St.,
Belleroso 26, N. Y.
REK-O -KUT M -5 -S master pro 15 -in. overhead recording mechanism. Brand new, $100.
Original cost $210. Alex Siegel, 1516 Shakespeare Ave., Bronx 52, N. Y.
SALES -SWAP -SERVICE
On all types of new and used audio equipment.
ARGUS SERVICE COMPANY
235 Lyons Avenue
Newark, N. J.
WAverly 3 -3025
;
PRE -RECORDED high -fidelity tape of 9
AUDIOSPHERE,
leading
libraries -A -V,
ATLANTIC, LIVINGSTON, CONNOISSEUR,
etc. -We also have the. largest available
supply of binaural tape releases. Retail by
mail only. Complete listings and prices on
request. Satisfaction guaranteed. THE TAPE
SHELF, Box 214, 22nd St. Station, St.
Petersburg, Florida.
-
CfAcivey.
FOR SALE One 6-N two-speed Presto Disc
recorder in carrying case. Perfect condition.
Price $450, f.o.b. Glendale. P. O. Box 729,
Glendale, California.
RC -54 3 Speeds
Fully Automatic
RCA professional studio to
recorder, and
Presto SR-950. Both 7% and 15 ips. Best offer.
Rosenthal. 215 E. 88th St., New York, N. Y.
PRESTO RC -10 -14 Tape Recorder and
900-A2
Recording/Playback AMPLIFIER,
$525 comp. Rek -O -Kut D -16 transcription
turntable, 33/78, G.E. Hysteresis motor, $75.
120-watt power amplifier, push -pull 211 final
stage, twin 13 x 18 custom chassis, $275. J.
J. Lash, Box 8716, Crenshaw Station, Los
Angeles 8, California.
Diamond needles $9.95, Sapphires 98e. Guaranteed re- tipping service. (Free Literature.)
STYLUSCO, Box 322(A), Mt. Vernon, N. Y.
:
WA 9 -2981.
MANUFACTURERS' REPRESENTATIVE
opening new agency in Michigan, desires lines.
Long experience in audio and with a good record of consistent coverage with proven results. Box CA-1, AUDIO.
ALTEC 820 Speaker System for sale, $395;
also Altec 400 -B speaker (new). $17. Both
excellent condition. Shipped f.o.b. Carson, B-10
North Brunswick Gardens, New Brunswick,
N. J.
WOULD LIKE to cooperate with other
Ampex 350 owners in the Los Angeles area in
dubbing tapes. Box CA -3, AUDIO.
FOR SALE : Radio Craftsmen C -800 tuner,
$95.00 C -500 amplifier, $65.00. Electro -Volee
SP-12B speaker, 8-ohm, $15.00. University
4402 tweeter, $12.00 ; 4410 network, $12.00;
4420 network, $10.00. Ralph Ashworth, Charlton City, Mass.
:
WANTED: Price on Jensen G-610 Triaxial
speaker or Altec-Lansing 604C 15 -in. speaker.
George Ljutic, 618 Broadway, Kingston, N. Y.
WILL SELL one Miller Cutterhead, In excellent condition. Make offer. Box CA-4,
AUDIO.
NEW PEERLESS S-265 -Q output transformer $23. Rek-O -Kut B -121I turntable, $99.
B-16H. $195. Craftsmen C -1000 tuner $139.50.
Altee 820 system, $399. Box CA -2, AUDIO.
r
ge
Get the whole story
ROCKBAR CORPORATION, Dept. RD -I
215 East 37th Street, New York 16, N.Y.
Tell me about JPF and the Cellaco
RC
Zone.- ._....- Stata........_
L
-54
CORDS
Fidelity Records.
YOUR TAPES on
Highquality,
service,
33
78's.
yyE
IiR
3
reasonable 5cost
E. Broad St., Columbus 15, Ohio.
FOR SALE : Crestwood 401 recorder, 402
amplifier -speaker, new, both $210. Fisher
Master Audo Control, new $70. Weathers FM
pickup, sealed carton, $30. Harman Kardon
Festival, like new, $125. Meissner FM tuner,
like new, $30. Magnecordette, many extras. $225. Federal Disc Lathe, amplifier,
tuner, $125. Converted BC348, $100. Masco
recorder, many extras, $80. Hickok oscilloscope, sweep generator, $90. Hickok tube checker, $35. Hickok shutterspeed meter, $100.
Stephens coaxial speaker, $20. National cash
register, $75. Camera. enlarger, other items.
No swaps, need cash for medical bills. Sherzer,
Stone Harbor, N. J.
70
The New York office of PYE, Ltd., of
Cambridge, England, has announced the
appointment of British Radio Electronics,
Ltd., of Washington 6, D.C. as nationwide
distributor of PYE high-fidelity products,
which will be Imported into the United
States in the near future.
The equipment manufactured by the
high -fidelity division of PYE consists at
present of a professional- quality amplifier and control unit, loudspeakers, and
speaker enclosures. These will soon be
supplemented by a low-cost amplifier, an
AM /FM tuner, and other items. A record
player is also being distributed.
A program is presently in operation for
appointing sales agents and establishing
distributor outlets throughout the United
States.
AUDIO
www.americanradiohistory.com
APRIL, 1955
yoto7tirsbuy
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P. O. Box 629, Mineola, New York
AUDIO
...
...
HIGH -FIDELITY HOUSE
KIE
Albert Kahn, Howard Soother and Lawrence LeKas1iman, top executives of Electro- Vuise, inc., joined in hosting at an
exhibition of the new Electro -Voice line
of high -fidelity components. Showing,
which took piace in the company's
quarters at Buchanan, Mich., Marchhead2 to
b, was attended by representatives of the
press as well as by executives of leading
Jobbers and dealers from all parts of the
country
Another introductory showing
of a new hi -fi line was conducted on March
lb in New York by Dictograph Products,
inc., pioneer in the manutacture of hearing aids and other specialized audio devices. Host was Stanley Osserman,
graph board chairman, who was Dictomore
than ably assisted by the charm
Mrs.
()merman, present in an unofficial ofcapacity...
Morton D. Goldman has resigned from
the sales staff of Manhattan's Harvey
Radio Company to join Thurow Distributors, Inc., Miami, Fla. He will concentrate
on sales of audio components and hi -fi
equipment
John Colvin, former president of the Audio Engineering Society,
has re- re- located and, much to the delight
of his many friends, is back in the New
York area in his new association with
The Daven Company, Newark, N. J.
Another former AES president,
Sumner Hall, has been engaged by the P.Library
of Congress to develop and establish a
laboratory whose function will be research
directed toward the use of audio devices
in aiding the blind. Preliminary reports
.
indicate remarkable accomplishments are
in the offing
Joseph Martin has resigned as music editor of The Billboard
to
become Eastern representative of Mercury
Records, Inc.
Prod Steiner, formerly assistant
manager for the audio departmentsales
of
Arrow Electronics, Inc., New York, has
Joined the sales staff of University Loudspeakers, Inc.... Eugene P. Grant is the
newly- appointed director of engineering
for National Company, Inc. Formerly an
engineering manager for W. L. Maxson
Corporation, New York. Another executive
appointment at National finds Vincent P.
Crowninshield, formerly personnel manager for Tithe Deutschmann Corporation,
assuming the title of Technical Placement
Director ... Marvin O. Grossman has been
named assistant sales manager of Hermon
Hosmer Scott, Inc. Formerly a sales engineer with the company, his new duties
will include sales promotion and sales administration.
Michael Mnckley, formerly sales manager of the Espey phonograph division,
has been appointed sales manager for the
entire line of audio equipment made by
Espey Mfg. Co., inc., New York. He has
organized a national trade and consumer
advertising program which will break
soon
. W. Walter Jablon, veteran of
the electronics industry, has joined
Radio
City Products Co., Inc., and its affiliate,
Reiner Electronics Co., Inc., both of
Easton, Pa., as sales manager-will direct
all sales and advertising of commercial
products and will manage a new division
for special industrial contracts.
Alexander M. Ponlatoff,
was
elected chairman of the boardfounder,
of
of Ampex Corporation at its directors
March 1
meeting; he will be succeeded as
dent by G. L Long. T. Kevin Mallonpresinamed vice -chairman of the board was
Appointment of Robert V. Holton to general manager of the electrical products
division has been announced by Minnesota
Mining & Manufacturing Co. He
will be
assisted by Leonard A. Johnson
as general sales manager .. A. D. Adams
was
re-elected executive secretary of the Phonograph Manufacturers Association, Inc.,
at its first meeting for 1955; bulk of the
gathering was devoted to a general discussion on new parts and accessories recently introduced for phonograph manufacturing.
Smart merchandising is paying
in a
big way for Leon and Rene Grove, off
of the High Fidelity Music Center,owners
lyn, Pa., who have just announced Rosthe
opening of their Sound Studio No. 2. Their
"High Fidelity News," which is mailed
periodically to prospective customers
throughout the Center's sales area, might
well be emulated to advantage by other
audio equipment dealers
Gone Smith.
feature writer on high fidelity
for The
New York Herald Tribune, has transferred
his hase operations to the business news
denartment of The New York Times .
John R. McDonough, formerly general
manager of Sylvania's radio and television
division, has joined General Instrument
Corporation as vice -president of its F. W.
Sickles division.
simplify
custom
installation
.
.
The 4200 Sound Effects Filter and
4201 Program Equalizer are now avail-
able in component form, as illustrated,
for the custom builder.
In addition to the flexibility of instal
lotion, all the features and character-
istics of the standard models are
retained.
The high and low sections of either
model may be obtained separately.
Complete wiring instructions included.
Send for Bulletin 18.4
Model 4200 Sound Effects Filter
(Send for Bulletin S
a
9
I
Q-wi?wL
Model 4201, Program Equalizer
(Send for Bulletin E)
Representatives in
Principal Cities
.
APRIL, 1955
Subsidiary of International
Resistance
Campant
11423 VANOWEN STREET
NORTH HOLLYWOOD 3, CALIF.
71
www.americanradiohistory.com
Measurements
Corporation
ADVERTISING
INDEX
MODEL 59
MEGACYCLE
METER
5I
Allied Radio Corp.
Altec Lansing Corporation
4, 35
Cover
Ampex Corporation
Audak Co,
Audiogersh Corporation
Belden Mfg. Co.
Bell Telephone Laboratories
Bogen, David Co., Inc.
British Industries Corp. facing p.
5
16
41
43, 65
1, 3,
Cabinart
Carter Motor Co.
Centralab, Division of Globe -Union
Classified Advertisements
Collaro Record Changers
Cousino,
Duotone
55
12
65
70
70
Inc.
Co.,
71
Inc.
56
I,
Electro -Voice, Inc.
Electro -Voice Sound Systems
Fairchild Recording Equipment
13,
27
71
Corp.
59. 64
Fenton
WORLD FAMOUS QUALITY
At All Leading Hi -Fi Dealers
Wrte for Complete Information
KINGDOM PRODUCTS, Ltd.
23 Park Flace, New York 7, N. Y.
\\\
\\11111II!11
INSIST
WOrth
Ip,piIl///%////,
4 -8585
/
ON EMITRON
KT66
WORLD FAMOUS QUALITY
Hi -Fi AUDIO Tubes
At All Leading Hi -Fi Dealers
Write for Complete Information
45
Company
Electric Co.
Goodman's Industries,
General
Ltd.
....
Cover
2.2 Mc.
to
400 Mc.
FREQUENCY CALIBRATION:
±2%
For determining the resonant
frequency of tuned circuits, antennas, transmission lines, bypass condensers, chokes, etc.
For measuring inductance and
capacitance. May also be used
as an auxiliary signal generator; for signal tracing and many
other applications.
Complete data on request.
3
61
49
71
66
71
2
71
Mfg. Co.
31
Kierulff Sound Corporation
71
Kingdom Products Ltd.
Kral Products
72
68
Leonard Radio,
57
Inc.
Marantz, S. B.
Measurements Corp.
McIntosh Laboratory, Inc.
Minnesota Mining and Mfg. Co.
67
National Company
37
Partridge Transformers, Ltd.
Permoflux Corp.
Pickering G Company, Inc.
Pilot Radio Corp.
Presto Recording Corporation
69
Rauland -Borg Corporation
Reeves Equipment Corp.
Rek -O -Kut Company
50
58
Schober Organ Corporation
Scott, H. H., Inc.
Sonotone Corporation
53
cancer
strikes
72
54
1
9
in
6
15
29
4
33
11
7
8
Triad Transformer Corp.
63
United Catalog Publishers, Inc.
United Transformer Co.
University Loudspeakers, Inc.
71
Walco
covering the
wide ronge
of
47
Harvey Radio Co., Inc.
Heath Co.
High Fidelity House
High Fidelity Recordings, Inc.
Hollywood Electronics
Hughes Research and Development
Laboratories
Hycor Co.. Inc.
Jensen
only
grid -dip
meter
The
2
10
67
Cover 4
Products, Inc.
White, Stan, Inc.
of your friends
give to
39
66
62
AMERICAN CANCER SOCIETY
KINGDOM PRODUCTS, Ltd.
23 Pork Place, New York 7, N. Y.
WOrth 4-8585
AUDIO
72
www.americanradiohistory.com
APRIL, 1955
U
w
S
O
SIMPLE AS
>
W
Z
î
O
W
O
W
Ñ
it just as easy as possible for AUDIO's readers to subscribe, order books, get
further information about the new products and the new literature mentioned in the pages
of the magazine, or to get catalog sheets and brochures describing articles advertised, we
provide herewith three cads. Wa know that many readers are loath to cut coupons from
the pages of their favorite magazine because they have told us so. And we know that many
times one would like to have complete and thorough data about something he sees in these
pages, yet he considers it too mt.ch trouble to hunt up paper and envelop -not to
mention the stamp -and write a long letter detailing what he wants
to know. This is just as simple as we know how to make
it with the exception of stenciling each subscriber's name
and address on each of the aostcards -an operation
which would be highly impractical from the printing
standpoint. But from new on, when you want more
information about something you have seen advertised
or mentioned in AUDIO you need only indicate it on
the appropriate card, prirt your nome and address, and
drop it in the nearest postbox. We pay the postage, and it goes
without saying that we wouldn't include these cards if we didn't welcome your
use of them. And, for the first time, you can enter your subscription without sending a penny
with your order-we'll bill you Icter. For books, we'll have to ask for the money in advance,
but only for books.
To make
Z
O
N
O
LA-
Readers have told
know more about
tioned in the New
ture pages of the
us
that they often want to
of the items menProducts and New Literamagazine, but that they
do not want to take the time and effort to
write to each one of the sources individually
to get all the information they need. As o
matter of fact, in an overage issue there
ore usually ten items in the New Literature
column, and between tdn and fifteen on
the New Products pages. It is conceivable
that the average reader might wont information on at least ten of these items, since
they ore selected with the interests of most of
AUDIO's readers in mind. Thus one would
have to have ten envelopes, ten sheets of
paper, and ten three -cent stamps, together
with the need for writing the ten letters
and inscribing each with name and address.
We do it all for you, assuming that you are
willing to circle the items obout which more
information is desired and to write your name
and address once. We will forward your
inquiries to the organization involved, and
you will receive the data you wont with only
one inquiry. Isn't that as simple as A B C?
scme
0
Postage
No
Will bePaid
Postage Stamp
Necessary
by
If Mailed in the
United States
Addressee
BUSINESS REPLY ENVELOPE
First Class Permit No. 142, Mineola, N. Y.
AUDIO
P.
O. Box
629
Mineola, N. Y.
No
Postage Stamp
Necessary
If Mailed in the
United States
just the some way you con get more information about any product that is advertised in the pages of AUDIO. But there is
a little more work involved in this, since
you must indicate the item in which you are
interested and the name of the manufacturer.
However, you still have to write your name
and address only once for all the information you want about advertised items from
a single issue -unless you wart to know all
about everything. If your cards indicate that
this is likely to be the case, we will make
them larger to fit your requirements. In the
meantime, if you do need more space, you
might subscribe to two copies.
In
BUSINESS REPLY ENVELOPE
First Class Permit No. 142, Mineola, N. Y.
AUDIO
P.
O. Box 629
Mineola, N. Y.
www.americanradiohistory.com
BOOK ORDER
checked below,
money order
me the books
Please send
postage paid. I enclose check
in full payment.
for $
the 2nd audio anthology
Board cover, $3.00
the 2nd audio anthology
$2.00
Paper cover,
Electronic Musical Instruments
Dorf. $7.50 Foreil;n $8.001
I
Wear and Care of Records and Styli,
Weiler. $1.00
To start receiving Audio monthly without
any effort on your part to locate one
on the newsstands or at your jobber's,
mark the appropriate boxes with crosses,
tear out the card, and drop it into a
handy postbox. If you are one of those
who always pays in advance, we will
accept your check or money order -we
do not recommend cash to be sent
through the mails -enclose the card in
an envelope, and mail. This will cost
you an extra three cents, so if you wait
until we send you a bill, we'll enclose a
business reply envelope for your convenience. We try to make it as easy for
you as we know how.
Unfortunately, we do have to have money
with your order in the case of books, for
many of those our readers order are those
which we must purchase from other
sources. And even with our own publications, we do have to pay the printer if
we expect to have him print the next
book we put out. But we can help in
you want any book from
this fashion
any publisher, just list the name of the
book and the author and we'll get it for
you. It helps if you know the name of
the publisher, but that isn't necessary.
If you aren't sure about the price, make
a good guess and enclose that amount
we'll mail the book COD for the difference, or we will refund the overpayment
if you are too generous. In any case, we
pay the postage on the book, although
you will have to pay the postage on the
envelope you use to send us the order
card. Try it once and see how easy it is!
-if
--
-
O
IIIIIIIIIIIIIIII
AUDIO,
Please
P.
0.
send me
Box 629, Mineola, N. Y.
further information
on
the items circled as listed in New Products and New Literature
A
l
A2
A3
A4
A5
A6
A
A
8
A
9
A 10
A
11
A 12
A 13
A 14
A 16
A 17
A 18
A 19
A 20
A 21
A 15
7
At the end of each item of New Literature or New Products you will notice a
letter and a number -the letter indicates
the month and the number indicates
which item it is. All you have to do to
get full information about the product or
to get the literature described is to circle
the appropriate number, add your name
and address -printed if possible, so the
information doesn't end up in the Post
Office at Washington -and mail it to us.
We'll do the rest, and you may
that we'll be prompt because we
be sure
are just
anxious for your inquiries to get to
their destination as you are -and behave room enough
sides, we don't
around the office to accumulate a lot of
cards. Circle one item, if you wish, or
all of them -we'll carry on from there.
This whole system breaks down if there
is a charge for the New Literature described, so if you can suggest any improvements in this service, we would
appreciate hearing about them.
as
NAME
ADDREi,
CITY
AUDIOabout-
ZONE
Please
send
me
STATE
We can't think of any way to simplify
this card without actually listing every
product mentioned throughout the magazine, and this becomes an impossibility
we don't always get the ads sufficiently
far in advance of printing time to make
it possible to plan such an elaborate card.
So if you want to know more about any
product advertised-except from the
Classified section -just write down the
product and the name of the advertiser as
well as your own name and address. We
can't promise that no salesman will call,
but we think it highly unlikely, because
very few manufacturers have enough
salesmen to answer all the inquiries individually in person. But we are sure
that each manufacturer will be glad to
send you the information you want without any obligation. If we find that this
card doesn't have enough room for all the
information you want, we will have to
enlarge it, but let's try this one for size.
complete information
advertised
-
by-
NAME
ADDRFtc
CITY
ZONE
STATE
www.americanradiohistory.com
-Sr
Especially...
What can be said for the Axiette among high
quality loudspeakers generally, is one thing. But, more
significant is the fact that the Axiette has become the
ideal solution to the limited space problem
and who
hasn't such a problem!
Many would -be high fidelity enthusiasts have
been discouraged by the lack of available space. While
there are smaller tuners and amplifiers, little has been
done to relieve the speaker situation. Most smaller
speakers and enclosures don't quite have `what it takes'
for good high fidelity systems.
The little Axiette has changed this. Used in a
suitable enclosure and operating at normal living room
volume, it is doubtful whether a group of critical listeners
could consistently distinguish between the 8 -inch Axiette
and a costlier, larger system. This listening quality has
never before been achieved in a loudspeaker of such
small proportions.
If you are being denied the enjoyment of high
fidelity because of space limitations, you have the answer
in the Goodmans Axiette ... the good little speaker
that was designed to be heard - not seen.
...
Complete Service Facilities maintained for your convenience
A N S
G O O D
$2320
M A D E
I
N
Slightly Higher
ENGLAND
on West Coast
Sold by Leading Sound Dealers
For Compfere Literature write to
R
O C K B A
R
C
O
R
P
O
R
A
T
I
O N
2
1
5
East 37th Street, New
www.americanradiohistory.com
York
1
6, N. Y.
OUR MILLIONTH FILTER SHIPPED THIS
YEAR...
FILTERS
FOR EVERY APPLICATION
TELEMETERING
FILTERS
I
wide variety of
band pass filters for multi-channel
telemetering. Illustrated are a group
of filters supplied for 400 cycle to
40 KC service. Miniaturized units
have been made for many applica.
lions. For example a group of 4 cubic
inch units which provide 50 channel;
between 4 KC and 100 KC
UTC
manufactures
a
C
1,
1
466.
4682E
'1'
1
1
4682G
2990 CPS
3890 CPS
4582
46e21
111
5400 CPS
7550 CPS
46e2Ú
.
I
Dimensions,
2
(4612A) 11/2
sous
VOLES
a
2
3834
6
4e.
o
o
200
U)
4
IFS
50.`.
70
100
200
150
250
FREQUENCY
REQUISO'
o
oe
o
_o
20
09
filters are
produc!d the bulk (...l filters
aircraft -quipment 'or over
Jive at tha left is
decade. The
used in
that of a minia Irzed (1)2) cycles)
range filter prod cing high attenuation between v1ice and ranee frequencies.
Dimensions:
(3134) 11/4 x 15/4 x 2-3/16'.
(2000, 1) 11/4 X 13/4 x 1574".
A wide variety of carrier
o
UTC has
-^
K;
CARRIER
FILTERS
2
AIRCRAFT
FILTERS
a
1/4
X
Curves at the r'fht are that of our
miniaturized 90 aid 150 cyde filters
for glide path s7stems.
9049
available for specific applications.
This type of tone channel
40
filter can
be supplied in a varied range of band
60
widths and attenuations. The curves
shown are typical units.
80
40
3,
45
4.5
5
N
6
MAIMS
(7364 series) 144
e
FREQUENCY
FREQUENCY
09
6173
4
134 x
)1V2x2xl".
25h".
6174A
.30
DISCRIMINATORS
discriminators provide
exceptional amplification and linearity. Typical characteristics available
are illustrated by the low and higher
These high
420
Q
4q
5
p
frequency curves shown.
20
5
30
13004.
1440
1500
full data on stock UTC transformers,
reactors, filters, and high 0 coils, write
for Catalog A.
For
U N I T E D
Dimensions:
(6173) 1-1/16 x 154 ( 3 ".
(61741) 1 x 11/4 x 21.-e
ars
1600
FREQUENCY
FREOEENCY
TRANSFORMER CO.
150 Varick Street, New York 13, N. Y.
EXPORT
www.americanradiohistory.com
DIVISION:
13
E.40th St., New York 16,
`L. Y.
CABLEi: "ARLAB'
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