Audio - May 1959
1
1111
IN
1959
500
MAY,
dveepsea6/62fre ahled4li,614-./
www.americanradiohistory.com
40 Watts MONOPHONIC...
20 Watts STEREOPHONIC...
with RCA -6973 TUBES
tell you very confidentially...
the 6973's got POWER...real power for such a small "bottle ". Four of them,
in twin, push -Full class AB' circuits, put 20 watts of power into each of
two output- transformers to give you the brilliant stereo sound you dream about.
With the flip cf a switch, you can parallel the twin circuits for 40 husky
watts' monophonic power output. B:g on power.. small in size...long on
low -cost design possibilities...everything about RCA's 6973
See her sitting there so neat. And
I
beam -power tube makes sweet news.
Whether you'-e designing for monophonic or stereo high fidel ty, you'll want
to hear the many other facts your RCA Field Representative car give you
on the RCA -6773. For technical data, write RCA Commercial Engineering,
Section E91 CE, Harrison, N. J.
RCA tubes for H.gh Fidelity also avail ble from your
local Authorized RCA
Tube
Distributor
RADIO CORPORATION OF AMERICA
Electron Tube Division
Harrison, N. J.
www.americanradiohistory.com
RCA FIELD OFFICES
EAST:
MIDWEST.
WEST:
744 Broad 5t.
Newark 2, N. J.
HUmboldt 5 -3900
Suite 1154,
Merchandise Mart Plaza,
Chicago 54, III.
WHiteholl 42900
6355 E. Washington Blvd.,
Los Angeles 22, Calif.
RAymond 3.8361
MAY, 1959
VOL. 43, No. 5
Successor to RADIO, Est. 1917.
AU D Io
ENGINEERING
4
MUSIC SOUND REPRODUCTION
C. G.
Henry
Harrie
Linda
McProud, Editor and Publisher
A. Schober, Business Manager
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K. Richardson, Associate Editor
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Edgar E. Newman, Circulation Director
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64
79
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COVER PHOTO -Music wall built by E. L. Phillips, Jr. for his home in Odessa,
Texas. In the upper compartments are two McIntosh MC -60 power amplifiers
and a Fairchild 411 -H turntable with Grado arm and stereo cartridge and a
Calrad viscous damped arm with an ESL Concert monophonic cartridge. The
center row contains a Garrard RC -88 changer with E -V stereo cartridge, a
McIntosh C -20 stereo preamp (serial No. 6), Magnecordette stereo tape recorder
and amplifier, Grundig TK -820 tape recorder (for background music), and
drawers for tape storage, tools, spare cables, microphones, etc. Two Bozak 305
speaker systems at the bottom flank a record storage compartment. Cabinet cost,
only about $450.
(title registered U. S. Pal. Off.) Is published monthly by Radio Magazines, Inc., Henry A. Schober, President;
C. McProud, Secretary. Executive and Editorial Offices, 204 Front St., Mineola, N. Y.
Subscription rates -U. S.
Possessions. Canada and Mexico, $4.00 for one year, $7.00 for two years, all other countries,
$5.00 per year. Single
copies 50t. Printed In U.S.A. at Lancaster, Pa. All rights reserved. Entire contents copyrighted 1959
by Radio Magazines,
Inc. Entered
Second Class Matter February 9, 1950 at the Post Office, Lancaster, Pa. under the act of March 3, 1879.
AUDIO
C.
u
RADIO MAGAZINES, INC., P. O. Box 629, MINEOLA, N. Y.
Postmaster : Send Form 3579 to AUDIO, P. O. Box 629, Mineola, N. Y.
MAY, 1959
www.americanradiohistory.com
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Letters
Speaker Phasing With an Oscilloscope-Bob E. Tripp
Audio ETC -Edward Tatnall Canby
Editor's Review
A Compatible Stereophonic Sound System-Floyd K. Becker
Moving Magnet Stereo -The new horizon of stereo disc reproduction
Herbert Horowitz
Negative- Supply Outboard Codan-Ronaid L. Ives
The Amplifier Distortion Story- Norman H. Crowhurst
The Tape Guide-What Kind of Tape Machine for your Audio System
Herman Burstein
Equipment Profile -Lafayette KT -600 Stereo Control Amplifier
Standard Methods of Measurements for Tuners -The Complete text of
IHFM -T -100, adopted in December, 1958
Record Revue-Edward Tatnall Canby
Jazz and All That-Charles A. Robertson
New Products
New Literature
Coming Hi Fi Shows
About Music -Harold Lawrence
Industry Notes & People
Advertising Index
N>.
Á
Midwest Representative
W. A. Cook and Associates
161 East Grand Ave., Chicago 11, Ill.
West Coast Representative
lames C. Galloway
6535 Wilshire Boulevard, Los Angeles 48, Calif.
CONTENTS
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GRADO
AUDIOCLI N IC??
JOSEPH GIOVANELLI
Deemphasis and Time Constant
"Truly
the
world's
finest..."
STEREO CARTRIDGE $49.50
COMPATIBLE WITH
Monaural
Stereo
Lateral
Westrex
Vertica
Mime
STEREO TONE ARM $29.95
Finest Wolnul Woo'`
4 Wires and Shlel
:
Q. I have a Browning RJ48 tuner which
which has given exemplary service since
1954. Its FM response has a rising characteristic to 10,000 cps, which snakes it
slightly on the bright side, which is not
too objectionable; but I have lately added
a tape recorder and the high- frequency
boost in the tuner together with the high frequency boost in the recording equalization causes a most unpleasing sound on
playback. The de- emphasis network at the
discriminator of the tuner consists of a
series 7.5,000 -ohm resistor, followed by a
620 µµf capacitor to ground, with the
signal taken off the capacitor.
1. How can I change this network to give
me flat response?
2. What is the method used to calculate
the time constant? John A. Roberts,
Quebec, Canada.
A. The values in the de- emphasis network of your Browning RJ48 tuner should
be a 75,000 -ohm resistor and a 1000 µµf
capacitor. However, the a.c. resistance of
the discriminator is approximately 10,000
ohms and is in series with the de- emphasis
network. Therefore, the actual value of
the external resistor to be used is 65,000
ohms since this value plus the 10,000 ohms
inherent in the discriminator itself is equal
to 75,000 ohms, the correct value needed
for the time constant of the de- emphasis
network, 75 microseconds.
The time constant in microseconds of
a resistor and capacitor in series may be
figured by assuming the capacitor to be
in micro- microfara.ds and the resistor to
he expressed in terms of megohms. By
multiplying resistance by capacitance, you
will then have the time constant of the
network in microseconds.
when connect c,i as .amplifiers.
This results partly from the direct connection to the power line and partly because of poor grounding in such circuits.
Poor grounding is made necessary in order
to isolate these circuits from the line. This
isolation, in turn, is made necessary to
minimize the shock hazard and to conform
to U. L. requirements. The first of these
outlined conditions may be remedied by
placing an isolation transformer between
the set and the power line. One side of
the primary of this transformer should be
bypassed to B minus with a 0.05 -µf
capacitor, of 400 volt d.c. rating.
If this procedure proves unsatisfactory,
we must improve the grounding. This is in
addition to using the isolation transformer.
(Use of this isolation transformer eliminates the shock hazard which might otherwise result after the readjustment of the
ground lead.)
1. Connect B minus directly to the chassis.
2. Connect the return for the tuner input
to the point at which the first audio amplifier stage is grounded.
blesome
The Pickering Stereo Cartridge
Q. tlfy original monophonic setup worked
very well. After I switched io stereo, I
experienced difficulties with my Pickering
stereo cartridge. When I connected this
cartridge to the input terminal (specifically marked "Pickering ") of my preamplifier, I obtained almost no gain.
I noticed, also, that the cartridge when
tracking at 2 -4 grams, has considerable
distortion, especially at the high end.
How may I correct these conditions?
Harry Hausman, Weirton, W. Va.
A. The new Pickering stereo cartridge
has relatively low output as opposed to the
older monophonic cartridges for which the
Pickering terminal on your preamplifier
Interconnecting a.c. Equipment with
was designed. The cartridge, therefore,
AC -DC Receivers
should be plugged into the high -gain input,
Q. My problem concerns strong hum normally used for GE inputs and the like.
The original Pickering stereo cartridge
after connecting an FM tuner into an ACDC receiver which has the input specifically cannot track at 2-4 grams, because this is
marked: "for FM tuner, TV sound, phono." not sufficient force to push the stylus shank
This sounds as though it was meant for parallel to the face of the disc and, thereconnecting a.c. devices. The receiver has fore, in line with the polepieces. A 6-8
push -pull output and a phase inverter, and gram tracking force should provide the
..+.......
GRADO
IABORA'ORIES, INC.
4614 7th Avenue Brooklyn 20, New York
Export- Sirnonlrice, 25 Warren St., N.Y.C.
the usual series-connected filaments. It also
has a shunt resistor-capacitor connected
from B minus to chassis ground. Its tuner
input has a 0.01 -µf capacitor connecting
the signal lead and its shield and a 0.01 -µf
capacitor connecting shield and B minus.
The input shield does not connect to
chassis. Everything seems in order according to the manufacturer's schematic. Can
you kindly give we an idea of what is
happening to cause hum? Can it be eliminated or reduced? I would like to use the
receiver as a handy, quick check for tuners
and other equipment. S. W., New York,
N. Y.
A. AC -DC receivers are normally trou3420 Newkirk Ave., Brooklyn 3, N. Y.
best results. There is a new T -bar stylus
assembly, however, which will track at the
lower force, and it is interchangeable with
your present one.
Aging of Power Tubes
Pots in Filament Circuits
1. I should like very m itch to learn. how
the power output and distortion characteristics of such tubes as KT88's, EL34's, and
so forth, vary with age. I am unable to find
anything on the subject in the literature
available to me.
2. I should also like to know why, in
hum -balancing circuits across filament
windings, 100 -ohm potentiometers are used
instead of 1000 -ohm or higher valued units.
A. J. Steen, Los Angeles, Calif.
1.
2.
AUDIO
2
www.americanradiohistory.com
MAY, 1959
THE
PAGE
-
Serving the owners of Garrard
world's finest record play ng equipment
and other discriminating listeners
in high fidelity.
monaural
Stereo and
... most people ready to buy high fidelity components seek advice from friends who own them. Generally you will find that these
knowledgeable owners have a Garrard changer. And if you ask experienced dealers,
they will invariably tell you that for any high fidelity system, stereo or monaural, the
world's finest record changer is the.
Here are the reasons why
people who will not compromise
with quality insist upon a
GARRARO CHANGER
for playing stevea records:
It's QUIET
actually u superb
turntable. No matter how
precisely you check wow, flutter,
and rumble content-you will find
Garrard Changera comparable to
the best professional turntables.
The Camard is
It's "CLEAN.'
The esclusi re aluminum tone
arm on every Garrard Changer is
non- resonant, non -distorting...
thus superior to most .separate
transcription arm a.
it's CORRECT
Precision-engineered to track
cartridges at lightest pro
weight, the Garrard Changer to
arm insures minimum friction
and record wear.
CCNTLE
Carrard'.s r'r!ustre, foolproof
pusher platform actually handles
records more carefully than by
your own hand -far more
Ca refit
than by any oth
changer or tutraitubl
Its CONVENIENtq
Garrard affords all the features
of a manual turntable, with the
tremendous added advantage of
automatic play when wanted/
Pre-rvi red for stereo-a
installed in ininnt
It's ECONOMIC
Despite its many ad sa stages
Garrard Changer costs less that
turntable with separate ar'
Backed by Garrard's 36 -yea
record of perfect, trouble -free
performance.
-.
Carrara is
a quality -endorsed
mponent of the
British Industries Corporeilon
(BIC) Group.
Your n ame below will bring you the
GarrattYl6amparator Guide
Nome
Address
Cita
Stale
Dept. Ga-19.
Carra
-Corporation
Division of British Indust -ies Corp.
Port Washington, N.Y.
Canadian Inquiries lo
6 Alcina Ave., Toronto.
other thon ri S.A. and Canada to
Terril Garrard Engineering 8 M!g. Co., ltd..
Swindon, Wilt:., England
Chai. W. Point on, lid.,
i
r
www.americanradiohistory.com
A. 1. There can be no data given as to
what happens to power tubes as they age.
This is because the change in characteristics
varies with the manner in which the tubes
are operated and the manner in which the
aging occurred. In other words, the tube
will have a far longer life when voltages
are conservatively applied than when voltages at or near the tube's maximum ratings
are applied. Much also depends on the
operating cycle -whether the amplifier is
operated continuously or sporadically for
if it's
short periods.
2. Low impedance potentiometers are
used in hum-balancing circuits because they
will draw sufficient current from the filament winding to make their effects felt.
The potentiometer serves to ground the
filament supply to the exact electrical center of the circuit. This will cause the hum
voltage to be symmetrical, thereby keeping
hum to a minimum. If the resistance of the
potentiometer is high, the resistance between this electrical center and ground
will also be high. A high resistance is a
poor ground.
worth
recording,
it's worth
putting on
Input Voltage and Signal -to-Noise Ratio
Q. A certain preamplifier, with a tape head input of 0.5 mv, has a signal -to -noise
level of 50 db. What would be the noise
level for an input signal of 1 mv? For $
mv? H. S., New York, N. Y.
A. If the signal -to-noise ratio of a preamplifier at 0.5 mv is 50 db, it will increase
to 56 db with a 1 mv signal applied, and
will increase to 62 db with an applied signal
of 2 mv. Of course, it is assumed that the
input impedance is equal in all three instances.
It might at first be supposed that by
doubling the input signal voltage the improvement in signal -to -noise ratio would
also double- thereby providing an improvement of only 3 db. Doubling the voltage across a constant impedance, however,
causes the power to increase as the square
of the voltage -in this case 4 times. The
basic formulas for calculating the amount
of gain or loss in db are based upon power
rather than upon voltage. Since the power
has increased 4 times, the signal -to -noise
ratio will increase by 6 db as already
mentioned.
A tape recording is no better than the tape used to
make it. You can't get first -class sound from second -
Amplifiers at High Power Levels
class tape. When you buy Audiotape, you know
you're getting the truly professional quality recording tape ... no matter which of the eight types you
choose. Remember, there's only one Audiotape quality -the finest obtainable anywhere. And this single
quality standard is consistent within each
reel, uniform from reel to reel, type
to type. It's your assurance of getting all the sounds -from the tuba's
lows to the highest highs.
Manufactured by AUDIO DEVICES, INC.
444 Madison Ave., New York 22, New York
Offices in Hollywood & Chicago
HIM
MAN
Q. I would like to test the sound quality
of my amplifier when it is operating at
levels up to 20 watts, its nominal capacity.
I presently have a $0 watt capacity, 16ohm speaker, and would like to listen to
it at normal levels while the amplifier is
working hard. What kind of arrangement
can be used under these circumstances to
drain most of the power from the amplifier? A VTVM, wattmeter, and audio generator are available. Irwin B. Margiloff,
Syracuse, N. Y.
A. AH you need to do to lower the
power fed to your speaker is to connect a
16 -ohm L pad to the system. Instructions
for so doing are usually furnished with the
pad.
Be sure the L pad has a power- handling
capacity great enough to handle the maximum power you will feed into the system.
Æ
AUDIO
4
www.americanradiohistory.com
MAY, 1959
}
Amperex® tubes
are making music in the
world's finest
§fll®
systems ..
POWER AMPLIFIER TYPES
/EL34- Exceptionally linear, high-power output pentode with low- voltage drive requirements.
Up to 100 watts in push -pull.
EL84/6B05- Unique AF power pentode combining
high gain and linearity with 9 -pin miniature construction. Up to 17 watts in push -pull.
EL86 /6CW5 -Low voltage, high current version of
6CA7
AMPEREX `preferred' tube types have proven
themselves in the world's finest monophonic amplifiers. Now AMPEREX is paving the way with tubes
for the world's finest Stereophonic systems. Developed in the research laboratories of Philips of the
Netherlands. and applications- engineered by
Amperex for the American electronics industry, these
ultra -advanced tubes have proven their reliability and
unique design advantages in late model amplifiers
and tuners of the world's leading high fidelity manufacturers. Sold by franchised dealers everywhere...
available for off- the -shelf deliveries in any quantity.
Detailed data and applications engineering assistance available from Semiconductor and Special
Purpose Tube Division, Amperex Electronic Corp.,
230 Duffy Avenue, Hicksville, Long Island, N. Y.
in push -pull.
8
watts in
50v) version
16v) version
VOLTAGE AMPLIFIER TYPES
EF86/6267- High -gain pentode with exceptionally
low hum, noise and microphonics. Particularly
suitable for pre -amplifier and input stages. Similar
.
the type E184/6805. Up to 20 watts
ECL82/6BM8- Triode-pentode. Up to
push -pull.
UCL82 /50BM8- Series string (100 ma.
of ECL82 /68M8.
PCL82/16A8- Series string (300 ma.
of ECL82, 68M8.
to the Z739 and the 5879.
ECC81 /12AT7- Medium-gain dual triode with low
hum, noise and microphonics. Replaces the 12AT7
without circuit changes.
ECC82 /12AU7- Low -gain dual
triode with low hum,
noise and microphonics. Replaces the 12AU7 without circuit changes.
ECC83 /12AX7- High -gain dual triode with low hum,
noise and microphonics. Replaces the 12AX7 without circuit changes.
ECF80/68L8
-
High -gain triode -pentode
hum, noise and microphonics.
with low
RF AMPLIFIER TYPES
6018/ECC88- Frame grid, sharp cut-off twin triode.
Particularly suitable for cascode circuits, RF & IF
amplifiers, mixer & phase inverter stages. Features high transconductance and low noise.
6ES8- Similar to 6018 /ECC88. Has remote cut -off
characteristics.
6ER5 -Frame grid shielded triode with remote cutoff characteristics. Suitable for RF amplifiers in
TV & FM
tuners. Features high transconductance
tECC85/6AD8 -High gain dual triode for FM tuners
with shield between sections for reducing pscil-
lator radiation.
EBF89 /6DC8 -Duo diode -pentode with remote cutoff characteristics. Suitable for RF & IF amplifiers.
ECF80/6B1.8 -High gain triode -pentode for RF amplifiers.
RECTIFIER TYPES
-
Indirectly heated, full -wave rectifier
with 6.3 v, 0.6 amp. heater, 90 ma. output capacity and 9 -pin miniature construction.
E281/6AC4- Indirectly heated, full -wave rectifier
with 6.3 v, 1 amp heater, 150 ma. output capacity
and 9 -pin miniature construction.
E280/6V4
and low noise.
6234/5ÁR4- Indirectly heated, full -wave rectifier
with 5 v, 1.9 amp heater and 250 ma. output
capacity. Octal base. Replaces the 5U4G without
circuit changes with the advantage of lower
tube voltage drop because of the unipotential
cathode.
Also Available: INDICATOR TUBE TYPES
EM84 /6FG6- Indicating pattern is a varying length
bar. For use in broadcast receivers and tape
recorders.
DM70 /1 M3- Subminiature type with "exclamation
mark" indicating pattern. Features low filament
consumption (25 ma.).
GERMANIUM DIODES
------
ask
Amperex-
1N542- Matched pair. Replaces 6AL5 In
tector circuits.
.foot Al -!l frfos for Al-11 stoma elrerlfry
FM
de-
1887A-High RF rectification efficiency diode. Suit able for AM detector circuits.
300,
t300,
www.americanradiohistory.com
450 & 600 ma series string versions availably.
750 & 100 ma series string versions available,
for less work and more play
LETTERS
GET THE TURNTABLE
THAT CHANGES RECORDS!
MIRACORD XS-200
No turntable and no record player,
in the history of high fidelity, gives
you more quality and more features
than the famous MIRACORD XS -200!
heavyweight, professional -type turntable -and a fully- automatic changer!
plays both stereo and monophonic!
push -button controlled throughout!
Magic Wand spindles eliminate
pusher platforms and stabilizing
arms!
intermixes 10" and 12"; plays all
4 speeds: has a 4 -pole motor!
even as a turntable it shuts off
$6 a
audiophile net
the stereo cartridge that
ELIMINATES HUM!
the perfect magnetic
hi -fi cartridge for stereo and monaural! It fits all record changers and
standard tone arms. And thanks to
special construction and MuMetal
shielding, it eliminates hum! Instant
stylus replacement, too.
STEREOTWIN is
$4450 audiophile
of an oscilloscope amplifier is
the LEFT CHANNEL PHASE switch. It requires one additional capacitor and two
resistors, as shown in Fig. 1.
rather
as stated,
net
decibels.
Power amplifiers with input impedances
of the order of 100,000 ohms or more are
often rated in db. Is this power gain?
so, changing the input resistor will change
the "gain" of the amplifier. We don't
match impedances at the input, but usually
(hive the amplifier from a fairly low source
impedance. The input power is of no concern to us; all we care about is what
voltage it takes to drive the amplifier to
full output. Here, decibels should not be
used at all. I suggest the use of the expression:
/E15, or watts output per volt
i,Iput squared. Now if an amplifier is
rated at 40 W /Pr, this means that 1 volt
input will give us 40 watts, 0.5 volt will
give us 10 watts, and so on. Thus we CRn
get the information we want from the
expression.
If
P
Staff Consultant,
University Loudspeakers, Inc.,
80 S. Henske Ave.,
White Plains, N. Y.
VICTOR BROCINF"R,
AHEAD)THE FINEST BY FAR
Available at selected dealers.
A.
AUDIOGERSH CORP.
Yak 12, N.Y.
WORTH e -0800
a
divided by input voltage, and the voltage
definition of db should be applied.
In the paragraph relating to noise and
hum rating, a manufacturer is quoted as
stating that his amplifier has a hum level
90 db below 20 watts. If it is 90 below
20 watts, it trust be 90 db above 20 watts.
Although this is a common form of expression, it is wrong. The hum level should be
stated as being 90 db with respect to 20
watts, or 90 db below 20 watts, but certainly not 90 db below 20 watts. Later
in the same paragraph, the statement is
made that "the hum is found to be down
80 db." One would not say that the
temperature dropped 15 degrees, and I sec
no more reason to apply this practice to
FAR
514 Broadway, New
This circuit revision eliminates a loud
"plop" which accompanied operation of
good one. A cathode-ray tube is driven by
voltage and not by power, and when the
specification says "response is down only
3 db at 200 he," it means that the voltage
gain of the amplifier at 200 kc is not one
W
For Free catalogue, please write Dept.
provement.
There are many eases where we are
interested in this figure and not the power
ratio. Mr. Westphal's own illustration of
the use of the decibel in the specifications
a given deflection on the oscilloscope screen.
In this ease, gain is purely output voltage
STEREOTWIN 200
NOW
was described in the August, 1958, issue.
One inquiry has led to a slight circuit im-
but 0.707 of its gain at mid -frequency.
The specification is not concerned with
the power output as such but only with the
amount of voltage that is required to get
rest position.
costs only
-
half of its mid- frequency gain,
automatically when record is
finished and tone arm returns to
-yet it
More About the Decibel
Sla:
Mr. Westphal's article "The Decibel
Fact or Fable ?" correctly states that the
decibel is defined in terms of a power
ratio and then concludes that it cannot be
used to express voltage ratios except for
equal impedances. J agree with Mr. West phal's contention that some specifications
using the terni "decibel" should be made
more definite, but I do not see why a
voltage ratio cannot be expressed in decibels, regardless of impedance, as bug as
it is properly defined, purely as a voltage
ratio. In this case, the formula n = $0 log
E, /E, is applicable.
Stereo Compatibility Translator
SIa:
requests for additional
information indicate increasing interest in
my Stereo Compatibility Translator, which
Several
recent
6
Fig.
As to the power requirements, let it be
said that any supply delivering 100 to 250
volts d.c. at 10 nia can be used without
If other than
nominal +75 -volt bias
deteriorating performance.
150 volts is used, the
will adjust properly to the correct mid -
value, using the series 100 k resistors shown
in the original schematic.
The translator can be used for many
different applications. For general use it
should be inserted between a pair of preamplifiers and power amplifiers. It is not
recommended that it be used directly at
the output of a stereo cartridge. For FM
Multiplex, the translator can be used following the output of a sub- carrier filter
and detector.
the translator is incorporated as part
of a preamplifier with direct wiring to
succeeding circuits, the cathode followers
may be eliminated.
HERBERT M. HONIG,
If
127 Lake Street,
Englewood, N. J.
Acceptable or Not?
SIR:
After careful study of specifications and
using the greatest care in the selection of
components, I bave a stereo system which
all the local critics pronounce the best that
they have heard.
You can well imagine my dismay upon
rending our (mis)leading* consumer organization's reports to find that most of
the components used are "unacceptable."
Should I destroy this system and build
anew using "Check-Rated" components or
go on enduring its "Wowing" turntable,
"Shattering" pickup, "Groove- jumping"
arm, and its $700.00 worth of "Unacceptable" speakers?
T. H. KUYKENDALL,
535 Daytona Ave.,
Holly Hill, Florida.
(e Italics ours. By all means, replace
crerything i,n r), ediately. Don't over trust
your own ,judgement. Be regimented like
everyone else. ED.)
AUDIO
www.americanradiohistory.com
1
MAY, 1959
I'
Ea4r-bui&L
style
performance
quality
STEREO EQUIPMENT CABINET KIT
casfid you,
64.0
MODEL SE -1 (center unit)
$14995
MODEL SC -1 (speaker enclosure)
Shpg. Wt. 42 lbs.
$3995
each
Superbly designed cabinetry to house your complete stereo system.
Delivered with pre -cut panels to fit Heathkit AM -FM tuner (PT -I),
stereo preamplifier (SP-I Sc 2) and record changer (RP -3). Blank
panels also supplied to cut out for any other equipment you may now
own. Adequate space also provided for tape deck. speakers, record
storage and amplifiers. Speaker wings will hold Heathkit SS -2 or
other speaker units of similar size. Available in unfinished birch or
mahogany plywood.
World's largest manufacturer of
electronic instruments in kit form
MONAURAL -STEREO PREAMPLIFIER
KIT (Two Channel Mixer)
MODEL SP -2 (stereo) $56.95 Shpg. Wt. 15 lbs.
MODEL SP -1 (monaural) $37.95 Shpg. Wt. 13 lbs.
MODEL C -SP -1 (converts SP-1 to SP -2) $21.95
Shpg. Wt. 5 lbs.
Special "bLilding block" design allows you to
purchase instrument in monaural version and add
stereo or second channel later if desired. The SP -I
monaural preamplifier features six separate inputs
with 4 input level controls. A function selector
COMPANY
HEATH
Benton Harbor, 25, Michigan
bsldiary of Daystrom, Inc.
switch on the SP -2 provides two channel mixing.
A 20' remote balance control is provided.
HIGH FIDELITY
RECORD CHANGER KIT
MODEL RP -3
.
PROFESSIONAL STEREO -MONAURAL
AM -FM TUNER KIT
MODEL PT -1
$8995
The 10 -tube FM circuit features AFC (automatic
frequency control) as well as AGC. An accurate
tuning meter operates on both AM and FM while
a 3- position switch selects meter functions without
disturbing stereo or monaural listening. Individual flywheel tuning on both AM and FM. FM
sensitivity is three microvolts for 30 db of quieting.
The 3 -tube FM front end is prewired and prealigned, and the entire AM circuit is on one printed
circuit board for ease of construction. Shpg. Wt.
20 lbs.
AUDIO
$6495
Turntable quality with fully automatic
features! A unique "turntable pause" allows
record to fall gently into place while turntable is stopped. The tone
arm engages the motionless record, and a friction clutch assures
smooth start. Automatic speed selector plays mixed 33!:i and 45
RPM records regardless of sequence. Four speeds available: 16, 33':x.
45 and 78 RPM. Changer complete with GE -VR -II cartridge with
diamond LP and sapphire 78 stylus, changer base, stylus pressure
gauge and 45 RPM spindle. Shpg. Wt. 19 lbs.
"EXTRA PERFORMANCE" 55
WATT HI -FI AMPLIFIER KIT
work horse packed 'sith top quality
features, this hi -fi amplifier represents a
remarkable value at less than a dollar per
A real
watt. Full audio output at maximum
damping is a true 55 watts from 20 CPS
to 20 kc with less than 2'; total harmonic
distortion throughout the entire range.
Featuring famous "bas -bal" circuit. push pull EL34 tubes and new modern styling.
Shpg. Wt. 28 lbs.
MAY, 1959
MODEL W7 -M
$55495
7
www.americanradiohistory.com
HIGH FIDELITY AM TUNER KIT
32695
MODEL BC -1A
Designed especially for high fidelity applications
this AM tuner will give you reception close to
FM. A special detector is incorporated and the
IF circuits are "broadbanded" for low signal
distortion. Sensitivity and selectivity are excellent
and quiet performance is assured by a high
signal -to -noise ratio. All tunable components
are prealigned before shipment. Your "best buy"
in an AM tuner. Shpg. Wt. 9 lbs.
"BOOKSHELF"
MODEL EA -2
12
WATT AMPLIFIER KIT
$2895
There are many reasons why this attractive amplifier is such a tremendous dollar value. You get rich, full range, high fidelity sound
reproduction with low distortion and noise ... plus "modern styling".
The many features include full range frequency response 20 to 20,000
CPS
db with less than 1% distortion over this range at full 12
watt output -its own built -in preamplifier with provision for three
separate inputs, mag phono, crystal phono, and tuner -RIAA equalization- separate bass and treble tone controls-special hum control
and it's easy -to- build. Complete instructions and pictorial diagrams
show where every part goes. Cabinet shell has smooth leather texture
in black with inlaid gold design. Shpg. Wt. 15 lbs.
t
1
"MASTER CONTROL" PREAMPLIFIER KIT
$1975
MODEL WA -P2
All the controls you need to master a complete high fidelity system
are incorporated in this versatile instrument. Features 5 switch selected inputs each with level control. Provides tape recorder and
cathode -follower outputs. Full frequency response is obtained within
± 11/2 db from 15 to 35.000 CPS and will do full justice to the finest
available program sources. Equalization is provided for LP, RIAA,
AES, and early 78 records. Shpg. Wt.
7
lbs.
HIGH FIDELITY TAPE
RECORDER KIT
MODEL TR -1A
$9995
Includes tape deck assembly. preamplifier and
r011 01
MODEL TE -1
Stipp. Wt.
tape.
10
$3995
lbs. (Tepe Preamplifier Only)
The model TR -1A provides monaural record /playback with fast
forward and rewind functions. 71/2 and 3% IPS tape speeds are
selected by changing belt drive. Flutter and wow are held to less than
0.35%. Frequency response at 71/2 IPS t2.0 db 50- 10,000 CPS, at
33,4 IPS
±2.0 db 50-6,500 CPS. The model TE -1 record /playback
tape preamplifier, supplied with the mechanical assembly, provides
NARTB playback equalization. A two -position selector switch provides for mike or line input. Separate record and playback gain
controls. Cathode follower output. Complete instructions provided
for easy assembly. Signal -to -noise ratio is better than 45 db below
normal recording level with less than %a total harmonic distortion.
(Tape mechanism not sold separately). Shpg. Wt. 24 lbs.
HIGH FIDELITY FM TUNER KIT
MODEL FM -3A
$2695
For noise and static -free sound reception, this FM
tuner is your least expensive source of high fidelity material. Efficient circuit design features
stabilized oscillator circuit and broadband IF
circuits for full fidelity with high sensitivity. All
tunable components are prealigned before shipment. Edge -illuminated slide rule dial. Covers
complete FM band from 88 to 108 mc. Shpg.
Wt. 8 lbs.
"UNIVERSAL"
12
WATT
AMPLIFIER KIT
MODEL UA -1
$2195
Ideal for stereo or monaural applications, this
I2 -watt power package features less than 2%
total harmonic distortion throughout the entire
audio range (20 to 20,000 CPS) at full 12 -watt
output. Use with preamplifier models WA -P2
or SP -I & 2. Taps for 4, 8 and 16 ohm speakers.
Shpg. Wt. 13 lbs.
YOU'RE NEVER OUT OF DATE
WITH HEATHKITS
Heathkit hi -fi systems are designed for maximum flexibility. Simple conversion from basic to complex systems
or from monaural to stereo is easily accomplished by
adding to already existing units. Heathkit engineering
skill is your guarantee against obsolescence. Expand
your hi -fi as your budget permits ... and, if you like,
spread the payments over easy monthly installments
with the Heath Time Payment Plan.
1
AUDIO
8
www.americanradiohistory.com
MAY, 1959
CONTEMPORARY
Model CE -1B Birch
Model CE -1M Mahogany
CHAIRSIDE ENCLOSURE KIT
*4395
MODEL CE -1
each
Control your complete home hi -fi system right from
your easy chair with this handsome chairside enclosure in either traditional or contemporary models. It is designed to house the Heathkit AM and
FM tuners (BC -IA and FM -3A) and the WA -P2
preamplifier, along with the RP -3 or majority of
record changers which will fit in the space provided.
Well ventilated space is provided in the rear of the
enclosure for any of the Heathkit amplifiers designed to operate with the WA -P2. The tilt -out
shelf can be installed on either right or left side as
desired during the construction, and the lift -top
lid in front can also be reversed. All parts are precut and predrilled for easy assembly. The contemporary cabinet is available in either mahogany
or birch, and the traditional cabinet is available in
mahogany suitable for the finish of your choice.
All hardware supplied. Shpg. Wt. 46 lbs.
No Woodworking Experience
Required For Construction.
All Parts Precut
&
Predrilled
For Ease of Assembly.
TRADITIONAL
Maximum Overall Dimensions:
18
Model CE -1T Mahogany
"W.x24 "H.x35 "D.
%,,
"BASIC RANGE" HI -FI SPEAKER SYSTEM KIT
IT'S EASY
. IT'S FUN
AND YOU SAVE UP TO
WITH DO -IT- YOURSELF HEATHKITS
.
.
The modest cost of this basic speaker system makes it a spectacular buy for any
hi-fi enthusiast. Uses an 8' mid -range
woofer and a compression-type tweeter to
cover the frequency range of 50 to 12,000
CPS. Crossover circuit is built
in with balance control. Impedance is 16 ohms. Power rating 25 watts. Tweeter torn rotates so that the speaker may
be used in either an upright or
horizontal position. Cabinet is
made of veneer -surfaced furniture -grade plywood suitable
for light or dark finish. All wood
parts are precut and predrilled
for easy assembly. Shpg. Wt.
Putting together your own Heathkit can be one of the most
exciting hobb,'es you ever enjoyed. Simple step -by-step instructions and large pictorial diagrams show you where
every part goes. You can't possibly go wrong. No previous
electronic or kit building experience is required. You'll
learn a lot about your equipment as you build it, and, of
course, you will experience the pride and satisfaction of
having done i! yourself.
MODEL SS-2
Legs: No.
DIAMOND STYLUS HI -FI
PICKUP CARTRIDGE
super
tweeter to extend overall response of basic
speaker from 35 to 16,000 CPS ±5 db.
Crossover circuit is built in. Impedance is 16
ohms, power rating 35 watts. Constructed of
V4' veneer- surfaced plywood suitable for light
or dark finish. Shpg. Wt. 80 lbs.
SS -2
MODEL HH -1
SEND FOR FREE CATALOG
Describing over 100 easy -to -build
kits in hi -fi, test, marine and ham
radio fields. Also contains complete specifications and schematics.
AUDIO
26 lbs.
*29996
The startling realism of sound reproduction by the Legato is achieved
through the use of two 15' Altec
Lansing low frequency drivers and a
specially designed exponential horn
with high frequency driver. The special
crossover network is built in. Covers
25 to 20,000 CPS within ±5 db. Power
rating 50 watts. Cabinet is constructed
of ty4' veneer- surfaced plywood in
either African mahogany or white
birch suitable for the finish of your
choice. All parts are precut and pre drilled for easy assembly. Shpg. Wt.
195 lbs.
HEATH
MODEL SS -1B
*9995
*S995
Shpg, Wt. 3 Ib. $4.95
LEGATO HI -FI SPEAKER SYSTEM KIT
*2696
MODEL MF -1
Replace your present pickup with the MF -I
and enjoy the fullest fidelity your library of
LP's has to offer. Designed to Heath specifications to offer you one of the finest cartridges
available today. Nominally flat response from
20 to 20,000 CPS. Shpg. Wt. I lb.
"RANGE EXTENDING" HI -FI
SPEAKER SYSTEM KIT
The SS -IB employs a 15' woofer and
91 -26
COMPANY
pioneer In
bs/dlary of Deystrom, Inc.
"do-lt-yourself"
Please send the Free Heathkit catalog.
electronics
Enclosed find s
Please enclose posted
for parcel post- expres
orders are shipped de
livery charges collect
All prices F.O.B. Bento
Harbor, Mich. A 20%de.
posit is required on all
C.O.D. orders. Price
subject to change with
out notice.
BENTON HARBOR 25, MICH.
name
address
city 6 state
QUANTITY
MAY, 1959
ITEM
MODEL NO.
PRICE
9
www.americanradiohistory.com
Speaker Phasing
With an Oscilloscope
BOB
CLAUDIO ARRAU
tapes his own
recordings on
Here's why
you should use
It's the best -engineered tape in the world
...gives you better highs...better lows...
better sound all around! Saves your tape
recorder, too because the Irish FERROSHEEN process results in smoother tape
...tape that can't sand down your mag-
-
netic heads or shed oxide powder into your
machine. Price? Same as ordinary tape!
of multi-speaker
systems and stereophonic
sound the proper phasing of
speaker systems has become an everyday problem for the hi -fi dealer, the
service man and the broadcaster. In order to realize the full advantages of
stereophonic sound it is important that
the speakers be properly phased, and
from the broadcaster's point of view it
is desirable to transmit both stereophonic and monophonic signals with
the proper phasing to permit in -phase
reception on a commercially built hi -fi
ITH THE ADVENT
hi -fi
installation.
Proper phasing can be accomplished
by the usual listening tests with connections being correct when the multiple
speakers present a smooth wall of sound
with no sharp transition point as the
listener walks between the speakers.
However, this method of phasing is often slow and laborious, and in some
cases it is quite difficult when the physical location and characteristics of the
speakers do not permit easy checking.
A foolproof, quick and positive
method of phasing speakers is readily
available by the simple use of an oscilloscope and two inexpensive crystal
mikes. In operation, it is necessary only
to place the two mikes in front of the
speakers to be phased and observe their
output patterns on the oscilloscope while
the speakers are in operation on a monophonic program. With identical mikes
connected to the vertical and horizontal
amplifier inputs of the oscilloscope, inChief Engineer, Station KIXL, 1401
S. Akard St., Dallas, Texas.
O
OSCILLOSCOPE
(A)
Available where've quality tape is sold.
ORRadio Industries, Inc., Opelika, Alabama
Export: Mo chan Exporting Corp., New York, N. Y.
Canada: Atlas Radio Corp., Ltd., Toronto, Ontario
TRIPP'
The same principle used for years by builders of two -way speaker
systems to determine the proper phase relation between the units
can also be employed to check the two channels of a stereo system.
W
That alone is not
the reason why
you should use
E.
Fig.
OSCILLOSCOPE
(B)
(A), In -phase pattern on 'scope
and (B), out -of -phase pattern.
1.
Fig. 2. Method of connecting oscilloscope
and microphones to check speaker phas-
ing.
phase operation of the speakers will be
indicated when program material produces an oscilloscope pattern which is
predominantly along the line A-B as indicated in Fig. 1. If the speakers are out
of phase, program material will produce
a pattern which lies along the line C -D
as indicated in Fig. 2.
Referring to Fig. 3, an in -phase signal on the speakers is picked up by the
crystal mikes which in turn apply inphase voltages to the X and Y axis. On
the positive peak of the cycle mike #1
produces a voltage o-a' and mike #2
produces the voltage o-a'. The resultant
of these voltages is at point A on the
diagram. On the negative peak of the
cycle, the voltage o-b is produced by
mike #1, and o -b' is produced by mike
#2, with the resultant of these voltages
being at point B on the oscilloscope.
Program material will fall on a line between A and B.
If the speakers are out of phase, mike
*1 will produce a voltage o-a and mike
#2 will produce a voltage o-b' with the
resultant C. On the opposite half of the
cycle mike #1 will produce voltage o-b
while mike #2 produces voltage o -a'
(Continued on page 47)
AUDIO
10
www.americanradiohistory.com
MAY, 1959
NOT
1961
1960
Today'
ear"°T
This Gray tone arm has to
built in... to give you the finest
ow's stereo requirements
nd reproduction from the
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THE FINEST SOUND WITH THE LEAST WEAR ON YOUR RECORDS
MI Grams tracking
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force for cartridges whose compliance measures 5 x 106 cm /dyne. Tracks at minimum force required by leading cartYidge manufacturers.
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ing error in degrees per inch radius. Lowest distortion factor
FLAT
ARM
RESPONSE
attained by Gray among 10 others tested.
... Dynamic control through linear fluid damping smooths. out
resonances in the critical areas -of the audio spectrum. GRAY keeps
the needle in the groove during heavy low frequency passages. Only
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groove without damage to the most compliant stylus assemblies.
Get all the extras with a Gray tone arm!
El
roll.®
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See
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and let him show
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G EIAy
Gray High Fidelity Division
Gentlemen:
- Hartford,
Conn.
new fact sheet on the Gray
Please send me, free, your
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Complete descriptive literature on turntables, turntable
kits, tone arms, and tone arm kits.
Name
Street Address
City State
I presently own.
High Fidelity Division
DEPT.
H
www.americanradiohistory.com
16 ARBOR STREET, HARTFORD
1,
CONN.
di
Well, I hooked it up. But not before I
had got my wires so tangled up, halfway
through, that I had to unplug everything
and put labels on the ends of the cables so
I could figure out which was which 'mid
the developing maze of wire macaroni
that quickly grows out behind your units
as you prepare them for operation! You'd
U
Now what
¿dward
1. DYNA STEREO
That high -powered kit company, Dyna
of Philadelphia, lent me a Mark III system last year, complete with power amplifier and the separate preamplifier that
takes its power out of the main unit. This
year, in line with the ever- present stereo
development, Dyna has sent me two complete Mark
outfits -and, much more
important, along with them, the Dyna DSC1 stereo control unit.
(Also a dual power
supply unit, for the two preamps, to free
the main power amplifiers for placement
where convenient -more of that in a
moment). And now I have had a Dynakit
stereo conversion in action to see for myself what happens when one Dynakit system turns into two, for stereo. Very interesting, and it works, by golly, as far as
the sound is concerned. Sound, after all, is
the basic intention.
The way to approach this Dyna system
is (as the scholars would put it) in its
context. What is its purpose, intent; what
gave rise to its designi Where does it fit
in the picture? And the answers would
seem to nie quite forthright. The Dynakit
stereo conversion is exactly that
specific
means of converting present monophonic
Dynakit systems to stereo by (1) duplicating the components for a second channel and (2) -the big trick -adding a
joint control unit, to operate both systems
as one in all the desirable ways.
Of course you can buy two complete
Dyna systems right from scratch if you
want, and join them with the DSC-1 stereo
III
-a
control unit. But frankly, I don't think
this was the basic idea in this development, even though such a system would
work and work well. If you start from the
beginning, you are likely to want not two
separate systems, joined, but a complete
integrated, designed -for -stereo outfit. It'll
be simpler, involve less duplication of
parts and functions, and above all it will
be less complicated in the outward aspects.
Dynakit stereo, then, is Dyna's concrete
answer to that nightmare cry now heard all
over the
land-"WHAT
I Do WITH MY
SYSTEM?" The
fancier the old system is, the more agonized the screetch! The Dyna people are in
a very neat position to answer it, for the
Dynakit system ranks high in the quality
scale but, thanks to kit -form economy, may
be duplicated at a cost in dollars that is
PRICELESS
MONO
it
to believe it.
am unfolding here is not a
criticism but an observation. Remember
that every system of this sort is set up
according to a purpose, an aim, a design
objective; though other purposes may be
encompassed too, they are side -lines. The
purpose here, in Dyna stereo, is as already
stated and-given these units, including
the two separate preamplifiers
can't
really see how the wire macaroni could
have been avoided, granted the standard
stereo functions were to be well served.
Complications lead to complications, the
more switches and wires and inputs and
outputs you have, the more difficult is it to
make a neat, simple affair out of the wires
and plugs that go with the system. Given
the basic premise, the Dyna conversion
just had to be complex in its external facilities and wiring. Let's look at it.
My earliest hi -fi home amplifiers, a
dozen years ago, generally had one input
on the rear, and one output, to speaker.
There were soon two inputs -PHONO and
RADIO-and them three, when the magnetic
cartridge and the preamplifier came along.
The complexities were setting in, and they
increased when we got to HI MAO and Lo
MAO, then TAPE, TAPE HEAD, and so on.
Now I've just taken a look at the rear
of my Dyna stereo system. I counted up
the RCA -type phono jacks to be seen, and
to be plugged into: they add up to no less
than twenty -six
the one basic system!
And all but two are on the rears of the
two matched preamps and the joint control
unit, mounted in serried ranks, like cavalry, four to a rank. Looks like a telephone
exchange, to mix my metaphors.
To hook up your stereo for disc only,
you must make use of ten RCA -type plugs,
eight of them on the ends of four short
cables (provided) from the preamps to
the stereo control unit and back; the other
two are the usual pair from the stereo
phono cartridge. For FM -AM radio you'll
need four more plugs, on two cables from
tuner to system. That's fourteen.
I went no further than this, though
there are numerous other things you may
do, of course. You can play stereo tape, or
mono tape (through both channels), record
on tape and all the rest -everything is
possible; but the resulting cable macaroni
is inescapable.
(The only way to get rid of it, you see,
is to build a single stereo chassis with all
the wiring inside and immovable. That is
another kind of system, altogether.)
your plugging job has been done right,
e-eryning works fine. But if you've pulled
a faux -pas, plugged
a boo -boo, made
something where it doesn't belong, your
macaroni is in the soup. Even the simple
net of removing two phono cables, to plug
in another pair, is apt to get you tangled
in wire-and the odds are that you'll pull
the wrong plug. Then when you try to find
your soup is in
which one you did pull
]nave to see
SHALL
HI -FI
at least possible, if not exactly chicken feed money. You CAN convert your Dynakit
to stereo, you CAN use every bit of Dyna
equipment you already have and all this
can be done without quite breaking your
local bank. Moreover, if you were able to
put together your first Dynakit, the second will go a lot faster.
In these words, I think, you'll find
enough to justify the Dyna stereo conversion in the face of every conceivable criticism. It does what it aims to do.
Ztnall Canby
if
The joker,
any, could be that joint
stereo control unit. That's the spot where
most of us would tend to look with deep,
deep suspicion. 'There aren't many problems
involved in setting up two separate amplifier systems for stereo, each controlled on
its own, independent except for the common stereo origin of the signals. Two
Dynakit Mark
systems work more or
less like one, in this respect at least, if you
III
don't mind fussing with two different
control panels, keeping things balanced,
plugging and unplugging for changes in
function and so on.
Unfortunately, most people do mind, and
that includes me. So-let's have a ganged,
joint control. But the instant you start to
,join up your two. systems electrically you
run into dire problems. You're positively
yelling for trouble. Dyna, then, stepped
bravely into a. potential morass when it
set out to develop its DCS-1 control to join
up two of its systems for stereo. If hairs
turned gray, then it was worth it. For,
though I wouldn't have believed it possible,
the darned thing works. That, I suggest, is
the understatement of the year!
I am at this point, then, able to state a
gratifyingly positive conclusion, a semimiracle.. On direct AB test in my home,
two separate Dynakits vs. the same two
hooked into the DSC-1 stereo control, I
found no significant difference in sound,
either way. There were slight, minor differences in the background noise at top
volume setting, to be sure; but I could not
possibly express a preference for one over
the other. As far' as I ant concerned, then,
the stereo sound out of this joint control
unit is ,just as good as that from two
separate Dyna systems, controlled individually from two preamps. And this, in
spite of an outward wiring complexity that
would suggest the system couldn't possibly
work without some sort of hum or something. No such thing.
The only complications you'll run into at
all, aside from the normal ones of kit building, are those of the outward hooking up and controls. These, however, are so
utterly typical of stereo today that I can't
help going into them at some length, even
though I am aware that they are superficial, not fundamental, problems and
should cause minimum worry to the man
who can put together his own amplifier kit.
Macaroni
First, you finish your Dynakits for
stereo, all six units. Two power amps, two
preamps, the small PS-1 dual power supply unit (for convenient feeding of the
two preamps) and the DSC -1 stereo control box. Everything is in order, we'll
assume, and you are ready to go. All you
have to do is book up the system. That's
where I came in, for as always, I was a
sissy and got mine ready -assembled, fac-
tory- built.
I
-I
-for
If
...
(Continued on page 73)
` Mr. Canby called it "spaghetti," whieh
already has another connotation in electronic circles. We changed it to "macaroni." ED. OK! It's that enough. ETC.
AUDIO
12
www.americanradiohistory.com
MAY, 1959
NEW STEREOPHONIC EQUIPMENT
HFBS: Stereo Dual Preamplifier is a complete stereo Control system in "low silhouette" design adaptable to any
type of installation. Selects, preamplifies, controls any
stereo source-tape, discs, broadcasts. Superb variable
crossover, feedback tone controls driven by feedback
amplifier pairs in each channel. Distortion borders on
unmeasurable even at high output levels. Separate lolevel input in each channel for mag. phono, tape head.
mike. Separate hi-level inputs for AM & FM tuners & FM
Multiplex. One each auxiliary A & B input in each channel.
Independent level, bass & treble controls in each channel
may be operated together with built-in clutch. Switched.
in loudness compensator. Function Selector permits hearing each stereo channel individually, and reversing them:
also use of unit for stereo or monophonic play. Full-wave
rectifier tube power supply. 5.12AX7/ECC83, 1.6X4. Works
with any high-quality stereo power amplifier such as
FICO HF86, or any 2 high -quality mono power amplifiers
the
experts
STEREO
AND
M ONAURAL
such
as
EICO
HF14, HF22,
..
HF35,
HF30.
-
HF50.
HERO.
HIFI REVIEW.
a bargain"
"Extreme flexibility
Kit $39.95. Wired $64.95. Includes cover.
HF66: Stereo Dual Power Amplifier for use with HF85
above or any good self- Dowered stereo preamp. Identical
Williamson -type push -pull EL84 power amplifiers, conservatively rated at 14W, may be operated in parallel to
deliver 28W for non -stereo use. Either input can be made
common for both amplifiers by Service Selector switch.
Voltage amplifier á splitload phase inverter circuitry
feature EICO- developed 12DW7 audio tube for significantly
better performance. Kit $43.95. Wired $74.95.
HFgt: Stereo Dual AmplifierPreamplifier selects. ampli
fies 6 controls any stereo source
tape. discs, broad.
casts-& feeds it thru self- contained dual 14W amplifiers
to a pair of speakers. Monophonically: 28 watts for your
speakers; complete stereo preamp. Ganged level controls,
separate focus (balance) control, independent full -range
bass & treble controls for each channel. Identical William.
son -type. push -pull E184 power amplifiers, excellent out.
put transformers. "Service Selector" switch permits one
preamp -control section to drive the internal power ampli.
fiers while other preamp.control section is left free to
drive your existing external amplifier. "Excellent"
SATURDAY REVIEW; HI.FI MUSIC AT HOME. "Out
RADIO & TV NEWS
ing quality
extremely versatile"
say...
in HI -FI
the best buys are
.
,
-
World- famous
EICO advantages
guarantee your complete satisfaction:
-
-
...
Kit 569.95. Wired $109.95. Includes cover.
for Stereo) HF -6S: superb
Inputs for tape head, microphone, magphone cartridge & hi -level sources. IM distortion 0.04%
HF65A
l 12V out. Attractive "low silhouette" design
Kit $29.95. Wired $44.95. HF65 (with power supply) Kit
$33.95. Wired $49.95.
MONO POWER AMPLIFIERS
LAB -TESTED.
Advanced engineering
Finest quality components
"Beginnèr- Tested," easy step -by -step instructions
LIFETIME service & calibration guarantee
IN STOCK
Compare, then take home any EICO
equipment -right "off the shelf" -from 1900 neighborhood EICO dealers.
MONO PREAMPLIFIERS (stack 2
new design,
-
(use 2 for STEREO)
HF60 160W), HUSO 15OW), HF35 (35W). HF30 (30W), HF22
ß2W'. 1014 (14W1: from Kit $23.50. Wired $41.50.
MONO INTEGRATED AMPLIFIERS
(use 2 for STEREO)
HF52 (50W). HF32 (30W), HF20 120W), HF12 (12W): from
Kit $34.95. Wired $57.95.
SPEAKER SYSTEMS (use 2 for STEREO)
HFS2: Natural bass 30-200 cps via slot -loaded 12-ft. split
conical bass horn. Middles á lower highs: front radiation
from 81
edge- damped cone. Distortionless spike- shaped
super-tweeter radiates omnidirectionally. Flat 45. 20,000
cps. useful 30-40000 cps. 16 ohms. HWD 36". 151/x".
"Eminently musical" -Holt, HIGH FIDELITY. "Fine
for stereo " -MODERN HI FI. Completely factory- built:
111 /x ".
Mahogany or Walnut. $139.95; Blonde, $144.95.
Stereo Preamplifier HESS
Bookshelf Speaker System, complete with factory.
built cabinet. Jensen 8" woofer, matching Jensen compression- driver exponential horn tweeter. Smooth clean
bass: crisp extended highs. 70. 12,000 cps range.
Capacity 25 w. 8 ohms. HWD: 11" x 23" x 9" Wiring
NFSM:
FM Tuner HFT90
AM Tuner HFT94
time
15
min. Price $39,95.
the first time, makes practical
building of an FM tuner kit equal
to really good factory wired units. No instruments
needed. Pre. wired, pre aligned temperature- compensated
"front end" is drift free -eliminates need for AFC. Precision "eyetronic" DM70 traveling tuning indicator, supplied pre wired, contracts at exact center of each FM
channel. Pre -aligned IF coils. Sensitivity 6X that of other
kit tuners: 1.5 uy for 20 db quieting, 2.5 uy for 30 db
quieting, full limiting from 25 uv. IF bandwidth 260 kc
at 6 db points. Frequency response uniform 20. 20,000
cps
db. Has 2 output jacks: cathode follower output
to amplifier, plus Multiplex output for FM Multiplex
Stereo adapter; thus prevents obsolescence. Flywheel
tuning, AGC, stabilized low limiting threshold for excel.
lent performance from weaker signals. broadband ratio
detector for improved capture ratio á easier tuning, full.
wave rectifier & heavy filtering, very low distortion.
"One of the best buys you can get in high fidelity kits"
AUDIOCRAFT. Kit $39.95. Wired $65.95. Cover $3.95.
Less Cover, F.E.T. incl.
FM TUNER HFT90: For
even for the novice the
Stereo
Amplifier- Preamo
HF81
:I
Bookshelf
w
Monaural Integrated Amplifiers:
50, 30, 20, and 12 -Watt
(use 2 for Stereo)
Speaker System
-
HFS1
NEW AM TUNER NF794: Matches HFT90. Selects
wide (20c
Omni -directional
Speaker System HFS2
Monaural Preamplifiers:
H165, HF65A
(stack 2 for Stereo)
(20c
36"
H
x
-
9kc
Q
-3
RF
selectivity
Built -in ferrite loop, prealigned
RF & IF coils. Sensitivity
30% mod. for 1.0 V out, 20 db S /N. Very low
distortion. High-CI 10 kc whistle filter.
Kit $39.95. Wired $69.95, me) Cover 8 F.E.T.
3 uy
151/4" W s 11Vz" D
noise
1P1
&
EICO, 33.00 Northern Blvd., L.1.C.
I
Monaural Power Amplifiers:
i0, 50, 35. 30. 22 and 14 -Watt
ruse 2 for Stereo)
Stereo Power Amplifier HF86
"hi -fi"
db) or weak- station narrow
stage for high
- 5kc á@ sensitivity;
-3 db) bandpass. Tuned
precision "eye -tronic' tuning.
I
I
1,
N.Y,
A -5
SHOW ME HOW TO SAVE 50% of 65
models of top-quality:
Test Instruments p "Ham" Gear
HiFi
Send FREE catalog & name of neighbor.
hood EICO dealer.
NAME
....
ADDRC55
Over
1
MILLION EICO instruments
In New
AUDIO
in
use throughout the world.
York hear "The EICO Stereo Hour," WBAI -FM, 99.5 mc, Mondays, Thursdays and Saturdays, 7:00 P.M.
MAY, 1959
13
www.americanradiohistory.com
EDITOR'S REVIEW
THIRTEENTH YEAR
THIS ISSUE, AUDIO becomes a teenager, since
it enters its thirteenth year of publication.
Starting twelve years ago without any organized industry to represent-and, in fact, with practically no industry at all, organized or not-this
magazine started life with no professional publishing
experience behind it. It did have, however, a wholehearted interest in what then was just a hobby for a
small group of experimenters who were not satisfied
with the sound reproducing equipment which was
available to them on the consumer market. In 1947,
you either bought a Brook amplifier or you scrounged
around and found some way to get your hands on
some broadcast or motion- picture theatre or studio
equipment.
But in addition to that whole- hearted interest in
sound reproduction of quality, there was one other
precept in Ammo's favor -the magazine was to be run
for the reader, and the material chosen for its pages
was selected with considerable thought to make sure
that the reader would never be given a "bum steer"
about equipment of all types-amplifier circuits,
WNTH
speaker cabinetry, and general audio information.
The Musician's Amplifier, a modification of the British- designed Williamson was one of the first to be
copied in both kit and completed form by manufacturers. The loudness control-which, in our opinion,
did more to take high fidelity out of the hobbyist's
"shack" than any other single advance -first saw
light in May, 1948, in these pages. Remember how the
early high fidelity "bug" was always criticized for
playing his system too loud? The rear -loaded corner
"horn" was first described here-in January and
February, 1949 -and that design, too, became a
standard.
Little by little the industry began to assemble itself.
The experimenter with an exceptionally good idea
often became a manufacturer, and there are many
examples among today's successful companies that
started with one man's tinkering and diligent striving
for still better sound.
We here at AUDIO feel that considerable of the
credit for the entire high fidelity industry falls on
us. We have been extremely fortunate in having loyal
and competent contributors whose articles have actually contributed far more to the industry than they
have received in return, and it is that kind of loyalty
which has made AUDIO the authority on the technical
aspects of high fidelity.
There is another kind of loyalty that is most heartwarming to those of us who attend the hi -fi shows-
the subscriber and constant reader who comes up to
one or the other of us and tells us proudly that he has
every copy from the first issue, or perhaps from the
second, whereupon he bemoans the fact that he
doesn't have one of the first. We are more than grateful for this loyalty, from reader and contributor alike,
for we could not exist without both.
Continuing in our aim to be of definite help to
everyone who wants better sound and more effective
operation of his equipment, we are inaugurating a tape
section this month. Under the heading of "The Tape
Guide," we will present reliable information to guide
you in the purchase and use of tape machines, the
techniques of editing, suggested ideas for recording
microphone placement, maintenance procedures, and
countless tips and aids to the art of tape recording.
While we have lined up a considerable array of material about tape, we know that many readers have independently developed ideas and techniques that would
be of interest to others, so we extend a special invitation to those intrepid tape experimenters who "think
for themselves."
All contributions will be gratefully received, and
all will be paid for. This applies also to photographs
of attractive home installations which you believe
others would like to see. Not everyone may want to
duplicate your home installation, but perhaps you
have some particularly attractive solution to a given
problem in decoration or component placement and
others may glean considerable help from your work.
Hope this doesn't sound as though we are being
boastful, but we are -just a little.
AND NOW, THREE -CHANNEL STEREO
Or at least that's what one company has announced
in the headlines. But in the fine print it says that
there are three speakers -the woofer (probably an
enormous 6 x 9 -inch unit) in the center handles the
combined low frequencies of both channels, while two
separate tweeters handle the highs, one for each channel.
This is a great idea, of course, but it is not new. It
works, and it is a good solution, especially where it
is difficult to find space for two separate full -range
systems. However, we find fault with calling the system "three- channel," and we believe that the manufacturer should reconsider the idea. Three channel
means just that-three separate channels from microphone all the way to loudspeaker. It seems that the
FTC might take cognizance of this kind of misleading
nomenclature.
AUDIO
14
www.americanradiohistory.com
MAY, 1959
The
responsibility of being the finest...
FLUXVALVE AND TGUARD ARE TRADEMARKS USED TO DENOTE THE QUALITY OF PICKERING d COMPANY INVENTIONS.
Truly the finest stereo pickup ever made...
the STANTON Stereo FLUXVALVE is
hermetically sealed in lifetime polystyrene with
all of the precision that has made Pickering
a quality leader in the field of high fidelity
for more than a dozen years.
For instance...only the
STANTON Stereo FLUXVALVE has the
"T- GUARD" stylus assembly -so safe and easy
to handle...so obedient and responsive
to every musical nuance in the stereo groove.
Only the
STANTON Stereo FLUXVALVE has
the parallel reproducing element contained in the
"T- GUARD "...assuring the proper angle of
NEWLY
correspondence between recording and playback
styli for maximum Vertical Tracking Accuracy.
And...because of this the STANTON
Stereo FLUXVALVE reproduces music
with magnificent sound quality...from both
stereophonic and monophonic records...with
negligible wear on record and stylus.
In plain truth...the STANTON
Stereo FLUXVALVE is by far the finest stereo
pickup made...backed by a Lifetime Warranty`,
assuring you a lifetime of uninterrupted,
trouble -free performance -with a quality of
reproduction no other pickup can equal.
We suggest you visit your Pickering Dealer soon
-drop in and ask for a personal demonstration.
REVISED
-"IT TAKES TWO TOSTEREO " -ADDRESS
Toi Mote who coo
Escludlne wearand tear al the diamond stylus tlp and parts
heat
The
DEPT.
Ihivence
R
-59 FOR YOUR FREE COPY.
e..u...
room
..x,.....es....
PICKERING & COMPANY, INC., Plainview. N. Y.
of the related moving system In the '?GUARD" assembly.
AUDIO
2371A
MAY, 1959
15
www.americanradiohistory.com
WE'RE LEARNING
WHY TWO EARS
ARE BETTER THAN ONE
Which speaker is making the sound?
sounds
- observes how two
In
ears operate
echoless chamber at Bell Labs, Robert Hanson measures test subject's ability to localize
in partnership. This and other tests may point the way to better telephone instruments.
in listening to stereophonic music, how
is it that
our ears and brain construct a picture of the
entire orchestra with but two samples (the sounds
from two speakers) to work with?
our neural network connects then with our brain.
The problem: to discover what functions the network performs and to see whether electronic
duplication might enhance understanding.
How is it that our ears and brain are able to
pinpoint one voice in a roomful of talkers -to
listen to it alone and ignore the rest?
The work is under way. Electronic circuits
that simulate the operation of nerve cells have
already been created -and conceptual models
of the neural network are being constructed.
What makes two ears better than one?
Bell Telephone Laboratories scientists are
searching for the answers. For in finding them,
better telephone instruments and better ways of
transmitting sound will surely result.
Our hearing performs feats that no electronic
system can yet duplicate. How? Laboratories
scientists believe the secret lies in the way our
two ears function in partnership and in the way
Alexander Graham Bell's interest in deafness
and hearing led to the invention of the telephone.
Bell Laboratories' current explorations in binaural sound may well lead to important new
advances in the transmission of speech and music.
BELL TELEPHONE LABORATORIES
World center of communications research and
www.americanradiohistory.com
development
A Compatible Stereophonic
Sound System
is to become acceptable, either transmission channel must be
capable of presenting a complete signal to the listener not equipped for stereo presentation. This system is completely compatible for use with any two -channel transmission.
FLOYD K. BECKER
If stereo broadcasting
"NEW SOUND" of high fidelity
stereophonic sound is far from new.
At least as early as 1881 a demonstration of an electrical transmission of
binaural sound, a close cousin of stereophonic sound, was made at the Paris
Opera. That demonstration used two
widely spaced microphones connected to
a binaural headset. In 1925, the New
Haven radio station, WPAJ, made
binaural broadcasts by employing two
separate AM transmitters on different
wavelengths. Two standard studio microphones placed 7 inches apart originated the binaural signals.
In 1933, the Bell Telephone Laboratories culminated a series of auditory
perspective tests in a three -channel
system demonstration. linder the auspices of the National Academy of Sciences, a concert of the Philadelphia
Orchestra was transmitted from the
Academy of Music in Philadelphia to
Constitution Hall in Washington. The
orchestra was conducted by Associate
Conductor Smallens while Dr. Stokowski, the Director, manipulated electrical
controls from a box in the rear of Constitution Hall.
Three microphones were placed before
the orchestra, one on each side and one
in the center at about 20 feet in front
of and 10 feet above the first row of
instruments of the orchestra. The microphone outputs were transmitted to Constitution Hall in Washington by three
separate electrical circuits specially
tailored for the occasion. At Constitution Hall these transmission lines were
connected to power amplifiers. The
associated loudspeakers were placed on
stage in positions corresponding to the
microphones in the Academy of Music
in Philadelphia. The comments of those
who heard this reproduced concert proclaimed the development of a system
with possibilities for even greater emotional appeal than that obtained when
listening to the orchestra "live." Much
of this reaction was undoubtedly due to
the enhanced volume range.
In 1936, the Bell Telephone Laboratories produced disc recordings of two channel stereo. In 1939, Philips of The
Netherlands experimented with stereophonic sound reproduction in large
THE
Member of the technical staff, Bell
Telephone Laboratories.
AUDIO
uuditoriaws. In 1941, the Bell Telephone
Laboratories demonstrated sound motion picture recording using three chamnel stereo.
This chronology of early sterephonic
sound is by no means complete. It only
attempts to place a few of the salient
efforts at stereophonic sound transmission and /or reproduction.
Radio broadcasting of stereophonic
sound programs by two separate channels became popular in 1952-4. In
various experimental arrangements, the
two channels required have been selected
from different combinations of AM, FM,
and TV, the listener spacing appropriate receivers properly in his home. Results have been sufficiently favorable
that more broadcasters are considering
offering stereophonic sound programs.
Many such programs have been originated on the national networks.
The major obstacle to vastly increased
use of this type of stereophonic broadcasting, however, is the person who
listens with only one receiver. If the
broadcaster tries for the full stereophonic effect, the sound the single
channel listener hears comes from only
one of two widely spaced microphone
pickups, and he misses a portion of the
program. The effect in many cases is
similar to listening to one -half of an
orchestra or to one side of a two -way
conversation. What the single channel
listener does receive is poorly balanced,
because of the microphone placement in
relation to the sound sources. The
broadcaster, in order to protect investment and sponsor revenue, has had to
dilute the stereophonic effect in order to
preserve satisfactory reception for the
single channel listeners.
Most of the effort to produce a coinpatible stereophonic sound system has
been directed at single channel systems.
These systems generally comprise a
frequency or time multiplexing of the
stereophonic channels on a single carrier. Most of these systems are, indeed,
compatible with present day singlechannel receivers but require additional
equipment-other than AM and FM receivers-to produce stereophonic sound.
Compatibility Desirable
One solution to the two -channel problem is gained through the use of a compatibility circuit developed at the Bell
Telephone Laboratories. This circuit,
equally adaptable for a two- or three channel system, depends for success
upon a psychoacoustic phenomenon
known as the Precedence Effect. Before
discussing this effect, it would be well
to review the principles of sound localization. The localization of a sound
source with respect to the observer requires three coordinates: the radial
distance, the altitude angle, and the
azimuth angle. Man's auditory perception of distance seems to be primarily
governed by the loudness and ratio of
direct to reverberant sound. There is
little or no altitude perception. Azimuth
localization is extremely good, and accuracies of about 2 deg. are average. The
mechanisms for azimuth detection are
(1) phase differences between sound
waves at the two ears; (2) differences
in the time of arrival of transient
sounds; (3) differences in intensity at
the two ears due to shadowing by the
head, which also has a. frequency dependence and will result in an interaural
quality difference. Azimuth localization
of pure tones is possible only in areas
approximating free -space. In reverberant rooms, even those with optimum
reverberation time for music reproduction, the standing wave patterns destroy
the sense of directivity. Hence the arrival time and intensity differences of
transients assume the predominant roles
in determining azimuth in ordinary
listening environments.
Loudness Differences
It is possible to trade loudness differences for arrival time differences. An
observer seated before two in -phase
loudspeakers which are separated by
several feet will gain the impression of
a single, centrally located source if the
two loudspeakers have the same loudness. If the loudness of one speaker increases while the other correspondingly
decreases, the apparent source will
shift toward the more intense loudspeaker. The amount of the apparent
shift depends upon the sound intensities
at the ears. If the sound levels are the
sanie in both speakers, but a time delay
is introduced in one source, the apparent source will shift toward the undelayed speaker. Time delays as short as
17
MAY, 1959
www.americanradiohistory.com
cross connected through two delay lines,
each with its own buffer amplifier.
Because of these cross connections,
music or voice signals from the left
microphone are transmitted directly to
the left loudspeaker in the listener's
home, while the same signal is slightly
delayed before reaching the speaker to
his right. The stereo listener will hear
the sound as if it came only from the
left loudspeaker because of the Precedence Effect. Conversely, the sound
from the right microphone goes direct
to the right speaker, but is delayed
before reaching the left speaker, and is
therefore unheard in the left speaker.
Thus, the stereo listener localizes the
sound he hears as coining direct from
each of his two speakers, and full
stereophonic effect is maintained.
However, monophonic reception is
completely compatible with this, since a
listener to each single channel hears the
total sound from both microphones in a
balanced reproduction. The slight delay
of one signal does not affect his reception at all.
The three -channel system of Fig. 2
operates in a similar manner. The direct
signal travelling only in the primary
channels while a time delayed replica
of the direct signal is added to the
alternate channels in order to achieve
250 microseconds produce considerable
shifts in the apparent source. These
time delays are of the same magnitude
as the time differences of transient
arrivals at the two ears for a sound
source to the observer's side. When the
time delay in the one speaker system is
increased to 2 or 3 milliseconds the delayed source must be intensified until it
is ten times more powerful than the
undelayed source before the observer
will detect it to be of the same loudness!
This condition holds while the delay is
increased to about 35 milliseconds. In
the neighborhood of 35 milliseconds time
delay, the observer begins to detect a
distinct echo. It is the reaction of the
azimuth localization mechanism in the
region of 1 to 30 milliseconds that is
called the Precedence Effect. In this
region, the localization of a sound source
is determined by the direction of the
first arriving sound. The later arriving
echoes are virtually disregarded. This
may at first seem an amazing phenomenon but a closer examination discloses
that it is at least an every day experience. In the average indoor environment,
the bulk of the sound power reaching a
listener arrives by way of reflections or
echoes. Yet, in this same environment
the listener has no difficulty localizing
the sound source.
Now to turn to Figs. 1 and 2 and an
explanation of this form of a compatible stereophonic sound system. Referring
first to Fig. 1, the circuits between the
microphone pickups and their corresponding radio or TV transmitters are
compatibility.
Observations
Results IC two-channel subjective listening tests with musical material indicate a preferred time delay of about 10
Fig. 1. (below) Block schematic of Precedence
system for two channels. Fig. 2 (right) The same
system may be expanded to permit transmission
milliseconds with the intensity of the
delayed signal equal to the direct signal.
A different set of parameters appear
optimum for speech; e.g., 5 milliseconds
delay and the intensity of the delayed
signal 3 db less than the direct signal. A
tested compromise of 10 milliseconds
time delay and 3 db attenuation yields
very good over-all results. The 8- to
10 -db channel separation due to Precedence Effect added to the 3 -db intensity
difference gives results comparable to a
system with 12 -db channel separation.
It might he of interest here to mention
some desirable side effects of these
circuits. The literature is full of references to the "hole in the middle" and
to the subjective reaction to the reproduction of the music of a full orchestra
from a box occupying some 2 or 3 cubic
feet. The employment of the Precedence
Effect for channel separation causes the
area of the apparent sound sources to
seem quite large. The sound no longer
emanates from the small speaker cabinets but appears to be produced by large
area sound sources. The apparent area
of these sources greatly diminishes the
"hole in the middle" effect and is more
suggestive of the appropriate size of
loudspeakers required to reproduce
orchestral music.
This development should make it
possible for many more broadcasters to
offer double or triple channel stereo
programming without diluting the stereo
effect or penalizing the single channel
listener, who will make up the majority
of their audience.
r
of three compatible channels.
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AUDIO
18
www.americanradiohistory.com
MAY, 1959
Moving -Magnetic Stereo
The new horizon of stereo disc reproduction
A discussion of the design features of the newest stereo pickup to reach the
market with an analysis of some of the parameters which affect performance.
HERBERT HOROWITZ
FROM THE SLOW
first steps towards
new goals, our scientific and engineering progress ereates and accelerates further progress. With stereo disc
reproduction, as in all new moves forward, there have been inadequacies
ranging from crude initial disc- cutting
equipment to doctored and modified
monophonic phono pickups attempting
to make use of the new stereo media.
The design problems of recording cutters and playback pickups have been
the major technical bottleneck to public
acceptance and appreciation of the new
stereo technique.
New and improved stereo cutters have
emerged during the past year, and new
design approaches and principles have
been applied to produce high-quality
stereophonic phonograph pickups to
equal and surpass the standards of
Director of Commercial Products,
Audio- Empire Division, Dyna- Empire, Inc.,
1075 Stewart Ave., Garden City, N. Y.
CARnIDGE TOP COVER
6{¡\/
CONTACINN
TOP
o
COIL
'
RETAINING NUT
SOMN-I.
CARTRIDGE
MOUSING
STYLUS A41CI1ANISM
MIDGE
MAGNET
MOUNTING
LOCATING MAR
SCREW
QUADRATURE
POLE STRICTURE
ELASEOMES
MAGNET
MAGNET
RW'/
STYLUS LEVER
STYLUS
Fig. 1. Exploded view of the pickup.
AUDIO
excellence achieved during the mono-
phonic era.
Initial attempts at stereo pickups
followed the basic established patterns
of ceramic, variable -reluctance, and
moving -coil technical design.
All of these attempts bottlenecked in
the miasma of high cost, high moving
mass, difficult construction, high distortion, and so on.
Any new principle of technology must
move by necessity to newer principles of
technique. Designers of stereo pickups
who were able to visualize the complex
problems began to approach the solution
from a new direction. This approach has
now been formulated to the major
breakthrough needed to give the final
impetus to the bandwagon of stereo disc
the coil structure shown at (B) and
pivoted at its center. Coils A and B in
hum- bucking series opposition form one
coil structure which develops voltage
from inner groove wall modulation
while hum- bucked coils C and D develop
the outer groove wall signal. Force F,
as shown in (C) rotates the poles of the
magnet toward and away from the pole
faces of coils A and B creating a variable flux in the coil structure. However,
force F, has not caused any air gap
variation relative to poles C and D since
the magnet is moving parallel to those
UNIVERSAL CENTER PIVOT
MAGNET
reproduction.
Moving- Magnet System
This new concept is the "Moving Magnet System." Phonograph pickup
designers worked along this approach
at the tail end of the monophonic era.
Although the basic principles date back
quite a while, it has only been the major
technological advances in magnetic materials of the last few years that allowed
the system to he feasible. Widespread
fame eluded the moving -magnet monophonic pickup since it had to. contend
with the giants of variable reluctance
and moving coil. Every new concept
must have a raison d'erre. For the
moving magnet it is Stereo.
The moving- magnet system is the reverse application of the moving-coil
system. The generating magnetic element produces a variable flux which
induces electrical energy into stationary
coils (L dß /dt). The parameter of low
distortion is basic in the moving-coil
system and is therefore true of its converse, the moving magnet.
The operation of this system can best
he illustrated with Fig. 2. At (A) is
shown the basic magnet structure, a rod
magnet of rectangular cross section
magnetized lengthwise and inserted into
MAY, 1959
OUADRATUIE
DIAMOND
ST
STYLUS
POLE PIECES
STYLUS
LE VER
(A)
,,,
"A"
CHANNEL
',,,.
I
R
P
s
Q
04?:1
FI
(C)
\
Tp
Fig. 2. (A) Diagram of stylus assembly
and quadrature pole structure. (B) Relation of coils to moving magnet. (C)
Effect of forces from two groove sides
upon stylus and magnet.
19
www.americanradiohistory.com
(A)
of a typical arm and cartridge. The arm
contains mass Ma and compliance Cg;
the stylus mass is M. and stylus compliance C8, while Cd is designated as the
compliance of the disc under the proscribed stylus force.
Since C, is much greater than Ce,, and
.17 greater than M we find that at very
nc audio frequencies the stylus mass
M, has virtually zero impedance and
the record disc has a very small compliance. This leaves the mass of the arm
M. and the compliance of the stylus C,
as the determining factors of low -frequency resonance.
!r
ACTUAL SYSTEM
a typical system, (A) in Fig. 4, where
a mass is forced to pivot about axis AA.
The inertia of the moving element about
axis AA is given by:
J_W(rt +h')
12
where
IV =
I
MASS OF THE ARM
o
COMPLIANCE
OF THE STYLUS
MASS
OF THE STYLUS
COMPLIANCE-..
OF
fr (low) _
VINYL DISC
MECHANICAL EQUIVALENT
(6)
(C)
ELECTRICAL EQUIVALENT
(3---AR
CONSTANT
CURRENT
SOURCE
O
Fig.
(B)
CD
T
cm
T5
Therefore
J=
J
MA
At the upper end of the frequency
spectrum, the mass of the arm Ma attains too high an impedance to be moved
by the system while the high compliance
of the pickup C, has virtually zero impedance. We can say, therefore, that for
high frequencies
r
3. (A) Typical pickup -arm system,
its mechanical equivalent, and (C) its
electrical equivalent.
pole faces, and therefore there is no
voltage generated in the C and D combination. Conversely force F2 causes a
flux variation in the C and D structure
while isolating A and B.
It is not possible to locate coils A and
D beneath the magnet physically because
of the practicality of stylus lever length.
The Audio -Empire moving magnet
pickup contains four vertical poles
which mount coils as seen in Fig. 1.
These vertical poles are mated with a
quadrature pole structure, (A) in Fig.
2, designed to develop independent outputs from F, and F, modes of motion.
The quadrature pole structure is
moulded into an independent structure;
the magnet -and-stylus -lever assembly is
inserted and mounted to its pivot. This
allows simple stylus replacement by the
complete removal of the moving-magnet
mechanism.
fr(high) =
1
2sVM,Cd
which indicates that the high -frequency
resonance of the system is determined
h')
12
7nDh5
192
- 0.115k'
The radius of gyration of the above
mass is given by the equation :
Radius of gyration
kid.- dr' +h2
12
and when r = h /2, KAA = ß/0.146h=
The effective mass of the system reflected
to the stylus tip being
Effective Mass at stylus = JAA (KA A)1
X
When X equal the pivot -to- stylus distance
or 0.115Dhs
I0.146h' \
.0168Dh7
1`\
//II
The significance of these calculations
lies in the factor h'. This indicates that
in the determination of the effective mass
Fig. 4. Diagram of stylus bar to determine moment of inertia.
by the dynamic mass of the pickup and
the compliance of the record disc.
Parameters of System Dynamic Mass
Any basic element turning about a
pivot has inherent inertia which is reflected to the stylus tip. Let us examine
of the system reflected to the stylus, the
i, factor is overwhelmingly the major
element.
Variable -reluctance systems whose
mass is uniformly distributed over a
long lever are unable to achieve low mass
because of large h factor. It is obviously
necessary to keep the mass of the system
concentrated as close to the pivot center
as possible. Figure 5 numerically and
more pointedly demonstrates the relationship of dimension to dynamic mass
reflected to the stylus tip. The three moving- element systems shown have cross
MASS OF MOVING
ELEMENT,
h
WhNe Mo= JAA
at redsus of gyration
M.. er2h z Density
Moving- Magnet System?
7.6R
The technically minded audiofan has
become familiar with the terms dynamic
mass, compliance, frequency response,
and resonance. These key parameters of
phonograph pickup design are dependent upon one another for the over -all
performance of the stereo pickup with
its need for channel isolation.
y
A
7777A
I
F
L
MASS REFLECTED
TO THE STYLUS
GYRATION
gm,/cm
.0201n. .0501n.
7.7(10)-3 gn,
.020 in.
23(10) -3 gm,
TIP
KAA. ár
12
1.06(10) -1
AA
h
cm
M=W(KX
1
/
.21(10) -3 gee
a
-
V
/_h
RADIUS OF
Density
PHONO PICKUP
MECHANISM
Why the Superiority of the
Mechanical elements in motion have
inertial effects which cause them to have
inherent mechanical resonance at a fre
quency dependent upon the dynamic
masses and compliances of the system.
Figure 3 shows the physical, mechanical,
and electrical equivalent configurations
TLfshD (.3r' +
for a typical case where r= h /2,
1
2AV/M,C,
CONSTANT VELOCITY SOURCE
nrthD
and D = density (7.68 gins/em' for steel).
.0501n.
1.8(10) -1 cm
1.9(10)-3 gnu
A
A
T
r
1.
.020 in. .050 in.
38(10)
-3
gm,
2.3(10)-1
en,
5(10)
3
9,
f
h
A
.a
Fig. 5. Table of parameter
pertaining to stylus assemblies of different designs.
AUDIO
20
www.americanradiohistory.com
MAY, 1959
^.....- -1"--
WITHOf DAMPING
--N-- N--i{-.--
W
.15
M
shown in Fig. 4, let us examine its three
major components, stylus, stylus lever,
and generating element.
The mass of the diamond illustrated
I
fz
\
\
.5
0
is given by
DAMPING
«lo
K
M
o
O
arerl +
- -5.5 -4.0
el
-46
Io
:
-1
IN
'
PRRAVLNCY
'
'
'
lo
'
Iseo
noon
IN CYCLES PER SECOND
Fig. 6. Response of professional type monophonic pickup, corrected
for equipment
response and record deviation.
sections which are identical yet they
differ in the h dimension. Figure 5 shows
the relative differences these systems
exhibit in the parameters of weight,
radius of gyration, and mass reflected
to the stylus tip.
All phonograph reproducing systems
exhibit mechanical resonance at both upper and lower end of the spectrum. A
frequency response pattern of a high quality monophonic system is shown in
Fig. 5. Low -frequency resonance occurs
at 12 cps while upper resonance occurs
at 18,000 cps. The resonant frequency of
the undamped system effectively extends
over the full audible range from 16 cps
to 1.5,000 cps within + 3 -db limits of amplitude.
Introduction of damping to the cartridge system deflates the high -frequency
resonant peak. Damping-which is amplitude sensitive in character but not
velocity sensitive -is a distortion-generating factor and this is especially true
of transient response where the RC time
constant of a damped system does not
allow for sufficiently rapid recovery time
to insure faithful reproduction of musical content.
The effect of mass loading, operating
in several degrees of freedom in mechanical resonance, is a major concern in
stereo pickups because of its effect on
channel separation. Figure 7 compares
the channel separations of a typical
high -mass system with that of an inherently low -inertia moving- magnet pickup.
The high -mass system at (A) shows a
high -frequency mechanical resonance in
the order of 11,000 cps. This pickup is
heavily damped to suppress audible amplitude effects of this resonance. Note
the gradual loss of channel separation
as we approach resonance with the complete loss at 12,000 cps and beyond in
the high -mass system. The moving magnet system shown in (B) can retain adequate channel separation throughout the
audible range. Obviously as resonance is
approached, the generating element mode
AUDIO
of motion is no longer controlled by
groove -wall modulation but becomes a
function of natural resonant vibration.
Introduction of damping with its undesirable incorrect resistance character
is the cause of the high distortion content encountered in many stereo pickups
currently marketed. Pickup inefficiencies
of this nature can no longer be attributed to poor cutterhead design.
The ideal cartridge mechanism is a
virtually undamped system whose dynamic mass is so small that the natural
resonance of the system, 1 /23TVCdM.x,
lies outside the audible range and allows
for flat frequency response and adequate
channel separation.
L
n
3
Density
r5 =
Ibr + e=
12
KAA=
The mass of a rectangular element of
dimensions a, b, and c is
M=ax
b x ex
Density
The effective mass of the moving element referred to the stylus tip is given
by the expression :
Effective Dynamic Mass =
(Lass of the Moving element x
radius of
gyration
distance from
pivot center to
stylus
The Cd factor, compliance of the
dise, has been relatively standardized
5
o
-15
-20
1!
:w111P1111
11 SEPARATION
I1
ICHANNEL
B
MEE
Will
a'b x Density
where X = distance from pivot center to
stylus.
For the case of the Empire "88"
(Continued on page 46)
o
o
:
=
5
5 -5
5
-I
!MIMI'
1NS0111M1i11ai
I.
SEPARATION
1!
IN
20
111111110111EM
I
I
low
FREQUENCY IN
1111111111
15
-25
I
Densit y.
hh
Dynamic Mass of the Stylus
and is a function of disc fabrication
techniques and materials. The only variable parameter of cartridge design capable of affecting high -frequency resonance becomes the dynamic mass of the
system. The smaller the dynamic mass,
the higher the point of resonance.
To calculate the dynamic mass of the
previously
moving -magnet
system,
3
P
radius of cylindrical portion
of stylus
i = length of cylindrical portion
of stylus
h = height of conical portion of
stylus.
With the density of diamond at 3.5
rws/em3 we find for the nude stylus of
.012 in. diameter x .030 in. long the actual stylus mass is 0.2(10) -3 grams or
0.2 milligrams.
The stylus lever, made of aluminum
.005 in. thick is negligible in mass.
The mass of the rectangular generating element pivoting about its center
axis (AA) is concentrated at its radios
of gyration
where
\
-4.0
GRAMS
VERTICAL TRACKING FORCE
GRAMS
VERTICAL TRACKING FORCE
UNFILLED VINYLITE
RECORD MATERIAL
CM/SEC.
RECORDED VELOCITY
CM/SEC AT 20KC
GROOVE VELOCITY
TO 24.5 CM/SEC AT I KC
PICKUP COMPLIANCE -6x(10)-6 CM/DYNE
zz(10)-3 GRAMS
PICKUP DYNAMIC MASS
+
4
lE
MEASUREMENT CONDITIONS
5
LL
B
MINI=
111111
om
CYCLES PER SECOND
(B)
(A)
Fig. 7. Channel separation for typical variable -reluctance pickup (A), and for moving -
magnet pickup described
(B).
21
MAY, 1959
www.americanradiohistory.com
Negative -Supply Outboard
Codan
Although relatively few AM tuners are provided with any form of "squelch," there are times when
it would be of some advantage to have silence in the absence of a carrier rather than modulation.
Interstation noise during tuning can be eliminated by this device, which is simple and effective.
RONALD
L. IVES
of a codan,
squelch, or intersignal noise silencer are well known to most
commercial and amateur radio operators,
yet few commercially-made receivers
incorporate the device. A number of
technical descriptions of the CODAN
(carrier operated device, anti-noise),
have been published in recent years'L2.3,
and all of those cited, as well as a number of others embodying the same general principles, work, and work well.
Chief objections to addition of a
codan to an existing receiver have been
the great amount of circuit change
necessary, the loading of the receiver
OPERATING ADVANTAGES
2075 Harvard St., Palo Alto, California.
' R. A. Heising, "Radio links to the
telephone system," Bell System Technical
Journal, Vol. 19, 1940, 611-646, or Bell
Fig. 2 Connections to receiver.
AVC
injection of
contact potential from the codan into
the receiver AVC system. This latter
difficulty reduces the receiver sensitivity
at low signal levels .(where it is needed
most), and generally messes up the AVC
action, making extensive redesign of
the AVC circuits necessary before
optimum performance is again attained.
Telephone System Monograph, B -1255,
1940, 36 pp.
'R. L. Ives, "Codan elimination of
intersignal noise," QST, Vol. 36, No. 10,
Oct. 1952, 36 et seq.
' U. S. Bureau of Standards, "Handbook
Preferred Circuits" NAVAER 16-1 -519,
1955, 64 -3, N-12 -2, N-12 -3.
1
system, and
the
ILLER 012 -C -2
455 kc
6U8A
pbo
SQUELCH
NE-51
02
.001
I.
-I(
F.
CASE
o
1N547.
91'
.4
l l
.02
=
CASE
w
IN54A
.02
.02
1
I
OPTIONAL
00
2
;
0Öó00
C-1515
_L--
STANCOR
125 v.
117v.
40
CASE
40
M-50C
4700
4
p
PA 8421
STAN COR
i
FIL.
6.3
Fig.
100Iw.
1001w.
44
5
1
Circuit of negative -supply codan.
The principal function of a codan is
to silence the audio system of the
receiver when the carrier amplitude falls
below a specific and usually adjustable
value. By use of a "negative" power
supply, and an I -F "stealer" circuit,
this function can be performed by a
simple outboard device, requiring only
two connections to the receiver, and one
to the power line. This circuit, having
no connection to the receiver AVC system, does not load it or alter its char-
acteristics.
Circuit of this simplified codan is
shown in Fig. 1. This is one of a family
of similar circuits, all of which perform
well, and all require about the same
number of components. Differences between various members of the family
are rather obvious variations in the
location and method of sensitivity and
bias adjustments.
In this circuit, the actuating signal is
tapped off the last i. f. stage through a
small capacitor, and fed to the grid of a
pentode (half of a 6U8A) through a
potentiometer, which provides grid
return and sensitivity adjustment. Amplified signal is tapped off the plate of
the pentode, and fed, through a small
capacitor and glow lamp, to a rectifier.
The pentode plate circuit is tuned, to
narrow the effective frequency range of
the eodan, and the glow lamp provides
AUDIO
22
www.americanradiohistory.com
MAY, 1959
adjusted to exactly zero by use of the
bias potentiometer (Fig. 1). When zero
external voltage is applied to the grid
of an audio tube, any signal applied to
the grid will be amplified, and the
receiver will not be silenced.
How to Connect
Connections of the codan to any ordinary receiver are shown in Fig. 2. Note
here the alternative i. f. connections.
which makes use of the signal frequencies always present in the screen circuit,
has definite experimental possibilities,
but is likely to introduce stability
problems into a pre -existing receiver.
Construction of a codan of this type is
simple and straightforward. Standard
components of almost any brand may be
used, and adjustment is a matter of a
few minutes at most. In the prototype
here shown, a standard 5 x 8 x 2 in.
Fig. 3 Alternate "stealer" circuit.
"snap action ". In consequence, there
will be no audio signal output until the
receiver is tuned very close to resonance.
After rectification and filtering, the
signal, now d. c., is applied to the grid
of a triode (the other half of the OU8A),
which is biased positive with respect to
its cathode when no signal is fed into
the codas.
Power supply is conventional except
that the "ground" is not negative, but
the arm of a potentiometer in the
bleeder, electrically very close to B plus.
When signal at the pentode plate is
too small to actuate the glow tube, triode
bias is positive, and the triode draws
appreciable plate current. In consequence, the plate, and hence the squelch
terminal, will be strongly negative
(about 150 volts) with respect to ground.
This, when applied to the grid of any
audio tube, very effectively silences the
receiver.
In contrast, when signal at the
pentode plate is adequate to operate the
glow lamp, rectified current is applied
to the grid of the triode, cutting it off,
and reducing the plate current to a very
low value (not zero). Voltage between
ground and the squelch terminal is
Fig. 5 Rear
view of outboard codon.
Slight "touching up" of the i. f. transmay be desirable after the
formers
codan is connected.
An interesting alternate "stealer"
circuit, which has no effect on receiver
alignment, is shown in Fig. 3. This,
aluminum chassis was large enough to
permit generous spacing between components. Front panel view comprises
Fig. 4. Parts may be arranged differently, to suit operating convenience or
personal taste, without impairing operation.
Power and signal connections, and
fuses, are mounted on the rear chassis
skirt, as in Fig. 5. Co -axial connectors
are used for both i. f. and squelch outputs for convenience, and because coaxial
connectors and cables seem to furnish
better shielding than "mike cable" and
microphone connectors. Besides that,
they were on hand.
Construction Details
The
power transformer shown in
these figures is a Stancor PS 8415,
whereas that specified in Fig. 1 is a PA
8412. The reason for this discrepancy is
that the smaller transformer, used in
the prototypes, is overloaded about 30
per cent. Even though it runs cool in
this application, a larger transformer is
recommended.
The two-section filter capacitor, a
Mallory FP 214.5, is mounted in a
Cinch socket, to facilitate replacement.
Although this capacitor, rated at 150
Fig. 4 Front panel view of outboard codon.
AUDIO
MAY, 1959
(Continued on page 72)
.23
www.americanradiohistory.com
The Amplifier Distortion Story
NORMAN H. CROWHURST'
Many are the elements causing distortion in amplifiers, ranging from
circuit design to deficiencies in the individual components. The
author points out where some of the pitfalls occur, and shows how
to use the transfer characteristic of tubes to study their performance.
basic
In two parts -Part 2.
next form of distortion we consider is one that is essentially a
feedback- amplifier effect. The instability due to peaking that can occur at
the high- frequency end is only one result
of using too much feedback for the circuit constants involved. The other one
revealed by a linear circuit analysis occurs at the low- frequency end, due to a
low frequency, probably subsonic, peak.
This has been loosely defined by some as
low-frequency transient distortion. While
it is quite true the effect is a transient
one, it might be rather puzzling just
what constitutes a low -frequency transient. Where would a frequency much
lower than 20 cps come from
Usually the phonograph pickup or
radio input doesn't have appreciable output at any frequency below 20 cps, so
the presence of a peak down here should
not cause trouble. That is not quite true.
Although the low frequency is not present as a separate entity, the program
THE
216-1R 40th Ave., Bayside
61, N. Y.
material contains even -order harmonies
and other forms of waveform that produce considerable asymmetry. As has
been mathematically shown, such an
asymmetrical waveform is equivalent to
a combination of symmetrical sine waves,
plus a change in bias, a momentary d.e.
variation in operating condition. This is
what really constitutes the low-frequency
transient.
It is something that normally is not
audible and it should not produce any
audible effects. But its presence in a
feedback amplifier means that any program material with asymmetrical waveform can initiate a high -amplitude low frequency fluctuation. This will not he
audible itself but, being high amplitude,
will introduce the changes in high -frequency response already referred to due
to the changes in circuit parameters,
plate resistance of tubes, and so on, on
different points on this high -amplitude
waveform. This will produce phase or
frequency modulation as well as amplitude modulation of program components
toward the top end of the range.
Feedback will attempt to minimize
such fluctuations in the handling of
individual signals. But still spurious byproducts will occur that will become
Audible and deteriorate the quality of
the program when such asymmetrical
signals are present.
Exaggerated Overload
b
GEOMETRY ON WHICH CURVE
IS
EASED
lo
5
2
.5
iuuiiuull =iiiiuüu rrieMZiiiN
1
M
wen!'
meE1111 MMerS111
MINIM MR111111111111 1111MILIIIII IM
Illlll .111111 111111
11111111IIIIIUIIIIIIUQI
l
iÌl1
iiiiói iiuió
I1111 ririiuiiiiiuii
L1111
EIEIEIEIII
11111111I 1M1111111511rS1111111M
IIIIR! i1IIIIII R9IIIIII
.002 005 .01 .r1
.05
I
.5
I
Measured Harmonic, %, on A erage-Reading Meter
ig. 10. Analysis of true peak -to -peak
relationship for readings obtained with
a normal average- reading meter used
with a harmonic -distortion meter, on
clipping.
Now we return to the overload characteristic question. Here we will consider
three cases. First, a well- designed feedback amplifier which overloads by running into clipping and ceases to overload as soon as the waveform ceases to
go far enough to cause the overload.
Suppose the input exceeds the clipping
level by 10 per cent, which is a little less
than 1 db. This would produce a deviation from true waveform by 10 per cent
of the signal, sounding like a knocking
oz limitation of excursion at this point.
The peak amplitude of the clip or knock
component would he 20 db below the
fundamental signal amplitude, This is
quite audible.
Referred as peak deviation to peak
signal it is a 10 per cent distortion. But
2e.
Ou pu
Low
F
Clipped I. M.
equency Removed
-
Waveform
Module ed Hig Frequency
Low -Frequency Harmonic in Residue
High -Frequency Modulation
-
-
Not Measured
Theoretical
Fig. 11. Graphical analysis of clipping
as shown with an IM test waveform.
Indications on this kind of instrument are
discussed in the text.
measured on a harmonic meter that
averages the waveform over a complete
cycle it will only measure about 2 ptr
cent. A lower level of clipping, for
example, a 6 per cent ratio on a peak to -peak basis, will give an indication of
only 1 per cent on a harmonic averagereading meter. This relation is plotted
in detail in Fig. 10.
An IM analysis of clippings is shown
at Fig. 11. If the filters associated with
the meter to produce the residual components are all perfect in handling the
range of frequencies they are supposed
to, then the relationship between the
indication and its effective value will be
precisely the same as with the harmonic method. But the probability is that
the deviations in amplitude of the modulated high frequency are for such short
duration that the instrument indicates
them at even less than their true value
because of the integrating action of the
rectifier and filter used for separating
out the modulation from the high -frequency component itself.
It has often been observed, looking at
the transfer characteristic on the 'scope
and measuring the output for both harmonic and IM distortion, that quite a
AUDIO
www.americanradiohistory.com
Test
MAY, 1959
Shatterpro
tainer for
protection against dirt,
dust, abuse. Vertical
storage eliminates reel
II
warpage and "Wow."
-ma- Easy access, flip of finger
opens case -tape rolls forward.
INDEXING:
e
V-slot, self
ding Sel
rge write of
surface for
notations.
Fumble -proo
V -slot permit
jiffy -quick
threading.
Unique
Sonoramic
indexing
stem on
(e)
Easy -to -read
Selection Find
numbers permanently moulded
reel. Aligns with tape -time ruler
colorful
pressure
sensitive
labels is
included in
very package.
i
11ualul11l1111N1II11IINl1=
the ultimate in brilliant
reproduction. For magnificent
unsurpassed sensitivity and rich
startling realism, insist upon the best
insist upon Sonoramic
professional recording tape.
e
-
Sonoramic Tape -Time
ruler. Gives you footage
and recording time
on reel. Write Dept. A.3.
FREE
"armed
CORPORATION,
LODI, NEW JERSEY
AUDIO
MAY, 1959
25
www.americanradiohistory.com
f
MAXIMUM
UNDIS.
10%
OVERLOAD
INPUT
//"
/
/WAVEORM
FED BACK\
WAVEFORM
WAVEFORM
AMPLIFIED BY
EARLY STAGES
OUTPUT
WAVEFORM
Fig.
2.
What happens in the "fron
end" of any feedback amplifier when
clipping occurs. This may or may not
cause distortion that is drastically notice
able, depending on various design fac
tors.
visible order of clipping can occur
and certainly an audible order -before
the increase in harmonic or IM appears
to show an overload condition at all on
the meters.
This may be important if you want to
listen to a sine wave, in which case the
knocking effect referred to becomes quite
audible. However, usually the limitation
imposed by this kind of performance is
one of transient short duration only.
For example, the pluck tone of a guitar,
which may be 20 db higher than the
sustained tone, may get lopped off by
this momentary clipping. But tests show
that, subjectively, such losses are virtually inaudible. Maybe progressive
listening education may render them
more audible than they are at present.
But certainly they are far less audible
than one would think from listening to
a great many amplifiers of today.
This is because there is a secondary
-
aspect to the overload characteristics of
many feedback amplifiers, our second
case. Again assume that the amplifier
has 20 db of feedback and that the
input level is 10 per cent higher than
the clipping point. At this point the
feedback ceases to follow the input
waveform. Consequently, the internal
input to the amplifier suddenly shoots
up by 100 per cent instead of 10 per
cent. (Fig. 12).
If the input goes 20 per cent over the
clipping point then the increase in input
waveform will be 200 per cent and so on.
It is evident that a high transient peak
will produce a vastly exaggerated peak
in the front end of the amplifier-in
fact all the way through until something
happens in the nature of clipping.
Usually the clipping occurs at the grids
of the output tubes. However, the drive
stage will probably not have 20 db in
reserve before it too goes into clipping.
This means that a very small overload
will very often cause clipping at several
stages in a feedback amplifier.
These are usually resistance /capacitance coupled and consequently, blocking is likely to occur. Whenever a grid
goes positive, particularly when it is
driven a long way positive due to the
sudden sensation of feedback, the bias
on that stage is knocked back a long
way beyond its normal value, perhaps
four or five times. Then the time constant of the coupling network has to
allow the bias to return to its normal
condition before the amplifier can go on
working.
This means that these very short duration excessive amplitude peaks in pro gram material can cause blocking for an
appreciable fraction of a second, perhaps more than a second, after they
occur. This is then followed by a strangled return of the signal, due to the fact
that the tubes do not suddenly return to
their correct operating condition. The
over -all effect is that the amplifier breaks
up badly on these sudden peaks.
Several independent experimenters,
constructing amplifiers that avoid this
effect, have reported that considerable
clipping can be allowed before the effect
becomes appreciably audible. To achieve
this requires careful attention to the
design of the amplifier so that sudden
removal of the feedback that occurs
when the clipping point is reached does
not overdrive some portion of the
amplifier to produce a blocked condition. Or if such overdrive does occur it
happens at a direct -coupled point where
immediate return to operating condition
follows removal of the excessive peak.
Some amplifiers add insult to injury
by having almost a trigger condition as
soon as maximum output is reached,
which is our third case. This will be
found when testing the amplifier. A
point is reached on its overload characteristic beyond which it goes into
quite drastic or violent distortion, after
which the only way to obtain maximum
output again is to bring the input down
a long way below the maximum point
and then bring it up very carefully,
taking care not to exceed the desired
maximum. Obviously any transient peak
that exceeds this point on program waveform will produce the trigger effect that
careless handling of the oscillator will
cause in making the measurements.
The trigger effect can occur due to
variety of combinations in circuit parameters, but one of them is illustrated at
Fig. 13.
When the input exceeds clipping level
by less than 1 db, such tis to produce 10
per cent beyond the maximum permissible input, the output stage clips. This
removes the feedback at this point and
produces a sharply peaked waveform at
the intermediate stages. In turn this
drives the output stage into considerable
grid current so as to over-bias it. The
resultant over -bias produces crossover
distortion and at the same time increases
the high -voltage supply, which was
previously drooping due to the approach
of maximum output, and thus increases
the gain of the earlier stages. The reason
for this is that the output power actually
drops when this input level is exceeded
due to the pieces taken out of the waveform by the crossover effect. The over -all
effect is that the waveform gets chopped
by clipping and crossover distortion and
stays that way until the input is reduced
to a level considerably below the maximum permissible input.
So
What?
So much for the various items of distortion, some of which are analyzed in
greater detail in the appendix. Now
what can be done about them?
Two steps need to be considered: (1)
how can an amplifier be designed to
avoid these effects? And (2) what test
facilities are necessary to measure an
amplifier, so as to give a more effective
indication of the audibility of the distortion it produces?
Oddly enough the first part seems to
he the easier of the two. It is relatively
easy, once you are acquainted with the
possibilities, to explore an amplifier design and find out whether it happens;
(Continued on page 70)
MAXIMUM
0.9db INCREASE IN INPUT LEVEL
UNDIS.
\
INPUT
WAVEFORM
FED BACK
WAVEFORM
WAVEFORM
AMPLIFIED BY
EARLY STAGES
WAVEFORM
AT ONE
OUTPUT
GRID
'BIAS'
COMPONENT
OF GRID
WAVEFORM
OTHER
PLATE
PUSH -PULL
OUTPUT STAGE
ii'iYFI
OUTPUT
WAVEFORM
Fig. 13. One form of "trigger" distortion
that occurs on some amplifiers as soon
as the input for maximum rated output
is exceeded by the smallest amount.
AUDIO
26
www.americanradiohistory.com
MAY, 1959
two -way
speaker
Frequency response
flat over wide range
Outstanding transient
response
Small enclosure is adequate
Elimination of nonFuHl.fledged
-
linear distortion
High efficiency
Built -in electrical crossover network
world of high fidelity is about to enter the stereophonic age.
The
One after the other, high fidelity equipment manufacturers
are unveiling the outstanding results of their unceasing efforts
in coping with this rapidly evolving situation.
The PAX -20A unveiled by the PIONEER Company is a
full -fledged two -way speaker comprised of a now renowned PIONEER PW -20A 8 -inch woofer and a
newly designed cone type tweeter unit featuring a
built -In electrical crossover circuit, and it reproduces
freauencies ranging from 40 to 20,000 cycles per
PAX-20A
THE IDEAL SPEAKER FOR YOUR STEREO SYSTEM
second at an average efficiency factor of 103db /watt
with extremely low distortion. With o power handling
capacity of 8 watts, the PAX -20A is the ideal 8 -inch
speaker for stereophonic systems.
The PAX -20A, PIONEER's proud contribution to the renaissance of the audio world, will fulfill every fond
expectation.
! ! !
addition to this particular model, PIONEER manufactures more than 170 different types of speakers
of oll shapes and sizes that are exported to close
to 60 different countries of the world.
In
FUKUIN ELECTRIC, TOKYO, JAPAN
US
Agent:
Monarch International Inc.
7035 Laurel
5
AUDIO
Otowacho
Canyon Blvd.
North Hollywood, Calif. U.
6- choose,
S. A
Bunkyoku, Tokyo, Japan.
MAY, 1959
27
www.americanradiohistory.com
NEWto
THE WORLD'S ONLY
STEREO RECEIVER FOR
THE DISCRIMINATING
AUDIO ENTHUSIAST
cabinet available
17" wide, 141/2" deep, 49í6" hi
351
lbs. net.
For those who want the convenience of an
all -in -one instrument... versatility at the heart
of their hi -fi installation... as well as the quality of performance and dependability that
have typified all FISHER high fidelity products
for over twenty -one years THE FISHER
TA -600 is the only possible choice.
-
www.americanradiohistory.com
compact chassis!
Everything you need-on
STEREO FM -AM TUNER
STEREO MASTER
STEREO
AUDIO CONTROL
40 -WATT AMPLIFIER
$34950
7
Slightly Higher
in the Far West
13
THE FISHER
BEST STEREO RECEIVER
Forty watts of power from dual twenty -watt amplifiers (seventy watts peak power.) 2 Cascode RF stage
on FM for extreme sensitivity. 3 Bridge-type, low noise triode mixer on FM. 4 Input and output jacks
for MULTIPLEX reception. 5 Two MICRORAY tuning
indicators to help you tune in the weakest signal as
easily as the strongest. 6 Connections for four, eight,
and sixteen-ohm speakers (rear.) 7 Rotatable, ferrite
loop antenna, for maximum signal power and minimum interference (rear.) 8 Two -position bandwidth
on AM (a must for stereo.) 9 Ten kilocycle whistle
filter to eliminate interferonagrIrom adjacent stations.
10 DC filament supply to reduce hum to complete
1
.
MADE!
inaudibility. 11 Dual bass and treble tone controls.
12 Five -position input selector. 13 Five -position
stereo -monophonic switch. 14 Dual balance control.
15 Master volume control. 16 Tape monitor switch.
17 High and low frequency filters. 18 Loudness contour switch. 19 Five input level adjustments (rear.)
20 Phase -reversing switch to compensate for any improperly phased tape recordings or speakers (rear.)
21 Tape recorder output jacks (rear.) 22 Special input
jack arrangement to permit using an external FM
tuner with the TA -600 for the reception of FM -FM
stereo broadcasts (rear.) 23 Auxiliary AC outlets for
plugging in associated equipment (rear.) Frequency
response, 25 to 20,000 cps, ± 1 db
WRITE TODAY FOR COMPLETE SPECIFICATIONS
FISHER RADIO CORPORATION
21 -29
44th DRIVE LONG ISLAND CITY 1, N. Y.
Export: Morhan Exporting Corp., 458 Broadway, New York 13, N. Y.
AUDIO
MAY, 1959
29
www.americanradiohistory.com
What Kind of Tape Machine for Your
Audio System?
HERMAN BURSTEIN"
-
The first step in buying a tape recorder is to determine what your requirements are
some users want only to play recorded tapes, others to record their favorite music off the -air, and still others want to engage in the most complicated of tape maneuvers.
IF
YOU PURCHASE an FM tuner, it is
quite well understood what you are
getting from a functional point of
view. Essentially you are acquiring a device that will convert a radio signal into
an audio voltage. It remains for other
audio components to amplify this voltage, adjust its tonal balance if necessary,
and finally convert it into sound. Similarly, if you acquire a control amplifier
(often called a preamplifier) or a power
amplier or a speaker, its functions are
quite well defined; you do not expect
a power amplifier, for example, to do
what a control amplifier does (selection
880 Twin Lane E, Wantagh, N. Y.
of signal source, control of gain, adjustment of bass and treble, filtering of
highs and lows, preamplification and
equalization of low -level signals, and so
on), or vice versa.
But the province of a tape machine
is not nearly so well defined. (For the
time being we shall use the term tape
machine in lieu of tape recorder because the device does not necessarily
have to record.) The scope of a tape machine can range from merely transporting the tape to providing a complete
self- contained audio system for the recording and reproduction of sound on
tape.
There are five types of purchase that
one can make in order to bring tape reproduction into the home:
1.
2.
Transport only
Transport and separate playback
electronics
3.
Transport and separate record -
playbaek electronics
recorder proper-transport
and integrated record -playback
electronics.
5. Self -contained tape recorder -including power amplifier and
speaker
The purchase suited to a given individual depends partly upon his wants,
4. Tape
Fig. 1. (left) A typical transport mechanism
-the
Pentron TM
Series.
Fig. 2. (below) Another type of tape mechanism- Viking FF75.
II"1,'"
rlllllpn
AUDIO
30
www.americanradiohistory.com
MAY, 1959
of these Jensen hi-fi speakers
idea...
contain a
all
Mai
DS -1C0
DUAL STEREO
TP-250
...the FLEXAIR* woofer!
P12-NF
...
can
All of the new Jensen speakers illustrated above sound better
give you much more
be housed in small -scaled enclosures
because they use the new Flexair*
performance for the money
woofer developed and perfected by Jensen.
Relative freedom of cone movement is not new but this is only part
of the story. When used in a Bass -Superflex* tube vented enclosure,
the Flexair woofer for the first time gives you ALL these important
performance features for vastly superior, utterly authentic bass
response: (1) Extremely long cone travel; (2) very high compliance
throughout total travel; (3) very low resonance; (4) extremely low
distortion; (5) high efficiency (will drive with a 10 -watt amplifier).
If you'd like to know more about this exclusive Jensen
development, write for free Brochure KF.
...
...
A White dot shows forward, central and inward positions
of Flexair woofer cone during 1" movement. (Perspective
shortens apparent distance between dots for inward travel).
B Diagram shows extreme accordion action of annulus
permitting linear extra -long cone travel.
C shows the scientifically proportioned tube vent used In the
Bass- Superflex enclosure for extended bass and very low
distortion with the Flexair woofer. Except for vent,
enclosure is air- tight. Vent action during large motions
of woofer cone is dramatically illustrated in the two
unretouched photos at the right. Jensen TR -10 TRi -ette
(with grille cloth removed) was used in the experiments.
In D, air filled balloon is kept in suspension by air flow
from vent. Successive high speed exposures show
rise of balloon when signal is turned on. In E a
candle flame is deflected by air motion from
tube vent with same low frequency signal.
T. M.
J. M. Co.
AUDIO
Jensen / MANUFACTURING
38,
6601 S. Laramie Avenue, Chicago
Division of The Muter Co.
In Canada: J. R. Longstaffe Co., Ltd., Toronto
MAY, 1959
COMPANY
Illinois
In Mexico:
Radios Y Television, S.A.. Mexico D.F.
31
www.americanradiohistory.com
,,'i
'i IM.
29
15
r
111.-
10
5
Q
<
NAR
11`
-_\_
20
5
-10
:
!Ii
-p
00
IN
'
FREQUENCY
INS
IN CYCLES PER SECOND
GRID OF
STAGE
Z729,
5879, 6ALI6
OS
pl
>.
TAPE
NARTB
equalization corn pared with RIAA
phono equalization.
INN
:woo
partly upon his standards of audio reproduction, and partly upon the audio
equipment he already owns. Through an
understanding of each of these types of
acquisition in terms of functions performed, quality of performance, limitations, and economy, the audiofan can
decide which acquisition is best for him.
Transport Only
PLAYBACK
HEAD
0.10
LO55ER EOUALIZATION
(A)
GRID OF
1/2
3.
tape playback
NARTB
FOLLOWING
EF86,
Fig.
FOLLOWING
I2AX7, ECC83
STAGE
7025
.
05 pf
TAPE
PLAYBACK
MEAD
LOSSER
As many people know, it is feasible
to purchase simply the transport (Figs.
1 and 2), the mechanical device that
moves the tape from a supply reel, past
the tape heads, and onto a takeup reel.
Transports capable of good performance
can be had for substantially less than
$100, although it is also possible to pay
several hundred dollars for units of
semi -professional and professional quality. Ordinarily, the transport comes with
one or more heads, and in some cases
the unit may provide space and facilities for adding more heads. To illustrate,
if the owner wishes only to play recorded tapes, he can purchase a transport containing a playback head. However, if he plans on recording, he will
need to add at least an erase head; if he
desires the best possible results, he may
wish to add a separate recording head
instead of using one head for both recording and playback. The transport
may contain room for as many as five
heads; considering the diversity of types
of heads -full -track monophonic, half track monophonic, two-track stereo, and
four -track stereo-and taking into account special practices such as sound on
sound recording, some audiofans might
want as many as five heads.
The transport plays a role in the audio system analogous to the phonograph.
It is a mechanical device (like the turntable) incorporating a transducer (like
the phono cartridge) that delivers a
small signal requiring amplification to
bring it up to a usable level and equalization to achieve fiat frequency response.
To be able to limit one's purchase to a
tape transport without electronics, it is
necessary that the control amplifier in
oné's audio system contain preamplification facilities (including equalization)
specifically designed to accommodate
the signal directly from a tape playback
head. This corresponds to the requirements imposed by a magnetic phono cartridge, where the control amplifier must
provide RIAA compensation (equalization for earlier recording characteristics, such as LP and AES, are also usually supplied). In the case of the tape
head, and assuming operation at 7.5 ips,
NARTB equalization is required instead; it is also becoming the practice
to use NARTB equalization at 3.75 ips,
although this is not yet as common as
at 7.5 ips. Figure 3 shows the RIAA and
NARTB curves.
Most control amplifiers made today
contain equalization for the signal obtained directly from a tape playback
head. That is, they have an input jack
marked "tape head." However, they do
not all provide NARTB equalization.
The writer has measured the tape equalization curves of a number of control
amplifiers, and while some follow the
NARTB curve within a decibel or two,
(Continued on page 66)
QUALIZATION
(B)
Frequency
response resulting
from the use of
compensaRIAA
tion for a tape
Fig. 5.
TAPE
PLAYBACK
HEAD
requiring NARTB
equalization.
8200
620
K
15
o
_5
> -10
4
LP
ae
FEEDBACK EQUALIZATION
.005p
(C)
Fig.
4.
NARTB
playback
circuits.
equalization
10
2.N
Imo
I
m FREQUENCY
IN CYCLES
PER
AUDIO
32
www.americanradiohistory.com
20000
SECOND
MAY, 1959
As Professional
As a Stereophonic
Preamplifier CAN Be.
Paola 216 -A
The New, Versatile
THE NEW PILOT 216-A is the professional stereophonic preamplifier
from Pilot dealers by broadcast engineers of some of the nation's
COMPLETELY
PROFESSIONAL
IN CONCEPT,
DESIGN
AND
PERFORMANCE!
purchased in quantity
major radio- television
stations -before the appearance of any publicity or advertising. The uncompromising
quality to which PILOT has been dedicated for 40 years is evident. There Is no other
stereophonic preamplifier on the market for music systems and tape recording, quite
like the 216 -A.
TWO VU METERS
Illuminated, to indicate tape recording output level or to visually
balance both channels of a stereophonic system.
SEPARATE TAPE OUTPUT GAIN CONTROLS
to adjust the gain for tape recording for
each channel independently. The combination of recording gain controls and VU meters
-
-
provides
complete control center for tape recording.
METER FUNCTION SWITCH
to use the VU meters for tape recording, or to adjust
the listening balance without affecting the tape signal in any manner.
TROLOK TONE CONTROLS
exclusive PILOT feature permits treble and bass adjustments for each channel individually or simultaneously.
14 INPUTS
two each for phono record changer, phono turntable, tape head, microphone, FM -AM, Multiplex, tape recorder.
4 OUTPUTS
two audio outputs and two tape recorder outputs. Tape output signals
unaffected by volume or tone controls.
TURNTABLE /RECORD CHANGER SWITCH
enables you to connect both a record changer
and turntable to your system, and use either.
EXCLUSIVE PILOT AUTOMATIC SHUTOFF
permits your record changer to turn off
your complete system when the changer stops after the last record has been played.
LOUDNESS CONTOUR CONTROL
applies Fletcher- Munson loudness compensation to
both Channels A and B simultaneously. Five positions
normal, plus four calibrated
positions to provide increasing amounts of bass boost to compensate for the normal
human low frequency hearing loss at low listening levels.
ELECTRONIC CROSSOVER
feeds low frequencies to Channel A and high frequencies
to Channel B for monophonic bi-amplifier use.
INTERNAL CATHODE FOLLOWERS
to provide low output impedance permitting use
of audio cables up to 100 feet between the 216 -A and power amplifier, as well as to
the tape recorder.
12 FRONT PANEL CONTROLS
Selector, Mode (including Stereo Reverse Position),
Master Volume, Loudness Contour, Stereo Balance, Bass and Treble (optionally used
ganged or separately), Power /Automatic Shut -off, Channel A Recording Gain, Channel
B Recording Gain, and Record Changer/Turntable Switch, Meter Function (Recording
Indicator -Listening Balance.)
SPECIFICATIONS
Frequency Response, ± 1 db from 20 to 20,000 cycles. Audio
Output, I volt. Tape Output, 0 -1.3 volts adjustable for OVU. Harmonic Distortion,
0.2% (2'10 of 1 %) at maximum sensitivity. Hum and Noise, 80 db below 1 volt.
Equalization: RIAA automatically, LP, NAB, AES at calibrated points on tone controls.
NARTB tape equalization and MIC flat frequency response automatically. 10 tubes
including rectifier. Size: 43/4" high x 141/2" wide x 1044' deep.
DRAMATIC DESIGN
brushed brass escutcheon with triple gold plated frame and
heavy duty knobs. Supplied complete with black vinyl -clad steel enclosure.
Slightly higher in the West.
.7
a
-
-
-
-
-
-
-
-
-
-
-
-
Write Today for Complete PILOT
Stereophonic Component Catalog
Pike RADIO CORPORATION
AUDIO
-
37 -04 36th STREET
MAY, 1959
;, p50
L. I. CITY 1, N. Y.
33
www.americanradiohistory.com
EQUI PMEN'r
I__E
O
aoO
PROfi I
LAFAYETTE KT -600
.
STEREO CONTROL AMPLIFIER
The Lafayette KT -600, shown in Fig. 1,
is a stereo control amplifier in kit form.
This is a skillfully engineered unit incorporating almost every mono, and stereo
function of value that has lyet appeared.
Because it seeks to provide the stereofan
with all he may desire, it is necessarily an
elaborate affair. It contains 12 inputs, 5
outputs, 12 switches, 7 front panel continuous controls, 9 rear panel continuous
controls, 7 tubes, 97 fixed resistors, 63
capacitors, and various other parts -calling for 457 assembly steps. There are
about 35 to 40 hours of work ahead of the
constructor, and in the opinion of this reviewer the result justifies the labor. It is an
excellent control amplifier (not a power
amplifier), obviously designed to a standard of performance rather than a price,
and such reservations as this reviewer may
have are only two and relatively minor.
Priced at $79.50 as a kit, it would probably sell in the region of $175 to $200 in
finished form.
Features, Functions, Modes of Operation
The KT -600 provides the following
features and functions hitherto found in
monophonic equipment.
1. Input jacks, on each channel, for six
sources: tuner, tape amplifier, auxiliary
(high -level), magnetic phono, constant amplitude phono (ceramic, crystal, or
capacitive pickup), and tape head.
2. Input level -sets for each high -level
source, and one input level -set following
the preamplifier, which accommodates the
three low -level sources.
3. Tape recorder output.
4. Separate turnover and rolloff switches
for phono and tape -head equalization. The
turnover positions are LP, RIAA, AES,
HEAD
(approximately
TAPE
and
NARTB). The rolloff positions are LP,
o
eOO
N.
E
RIAA, AES, 10.5 (db down at 10,000 cps),
5 (db down), and flat. Altogether, 24 equalization combinations are possible. The roll off switch has a seventh position, which
connects the tape -head jack instead of the
phono jacks to the preamplifier.
5. Bass and treble controls. Separate
controls, rather than ganged ones, are
provided for each channel.
6. Rumble filter (ganged for the two
channels).
7. Scratch filter (ganged).
8. Presence control (ganged).
9. Play- monitor switch. This enables one
to compare the incoming signal with the
signal being recorded on a tape and simultaneously played back, assuming one is
using a. tape machine with separate record
and playback heads.
10. Loudness switch, that converts the
gain control to a loudness control. Only
bass boost is provided.
The stereo features, functions, and
nodes of operation are as follows.
1. Input Stereo Function Switch:.
a. Mono A (Signal A to both channels).
b. Mono B (Signal B to both channels).
c. Stereo (Signal A to Channel A; Signal B to Channel B).
d. A + B (both signals to both channels,
with separation between signals variable
from 0 db to 12 db by means of a bridging
control; with maximum separation, 25 per
cent of Signal A is fed to Channel B, and
25 per cent of Signal B to Channel A).
e. Calibrate (both signals to both channels, with no separation). This has two
purposes. (i) Channel balancing (discussed below) requires a mono source so
that the full audio information can be fed
to both channels.
If
a mono source is
unavailable, the A +B signal simulates one.
(ii) The bridging control (discussed above
in d) is ganged with the gain control for a
center-channel output, on the theory that
center fill will be obtained either by partial mixing of the A and B signals or by
Fig. 1. Panel view
of Lafayette KT600 Stereo Control Amplifier.
use of a center channel, but not both at
once. When playing mono records with a
stereo pickup, it is desirable that both
channels be fully combined in order to
minimize vertical rumble. However, if the
center channel gain control is below maximum position, which is likely to be the
case, then the A and B signals will not be
fully combined, because the bridging control will perforce also be below maximum
setting. However, the calibrate position of
the input stereo function switch permits
complete mixing of the A + B signals.
2.
Output Stereo Function Switch:
a. Reverse Channel, Reverse Phase (Signal A to Channel B output; Signal
to
Channel A output).
b. Reverse Channel (Signal A to Channel B output; Signal B to Channel A out-
B
put).
c. Normal (Signal A to Channel A output; Signal B to Channel B output).
A
d. Reverse Phase (Signal A to Channel
output; Signal
to Channel B out
B
put).
e. Calibrate (signal A B to both channels). If identical signals, as from a mono
disc, are fed to each channel, and if the
input level sets and /or volume controls of
each channel in the KT -600 are adjusted
for equal gain, a null in the sound should
occur. Hence the calibrate position is very
useful for balancing purposes. (This assumes that the power amplifier -speaker
combination of one channel has been balanced against the other, so that equal signals to each power amplifier will result in
equal acoustic output from each speaker.
Such balancing can easily be accomplished
with the aid of the KT -600 by feeding a
signal to one channel and alternating it
between the A and B output jacks by
means of the output stereo function switch
(positions described above in b and c).
3. Center Channel Output. This mixes
Signals A and B in the same proportion
as they occur at the A and B output jacks.
As previously indicated, gain of the center
channel is variable independently of the A
.
and B chanels.
4. Master Gain -Balance Controls. Individual gain controls are provided for each
channel, concentrically mounted and with
a push -pull clutch device so the knobs can
be operated independently or simultaneously. With the inner knob (Channel B
pulled out, the controls can be rotated individually for channel balance. With this
knob pushed in, they operate together as
a master gain control.
A feature considered desirable in a
stereo amplifier is an "AB" switching facility that enables one to balance stereo
program material by alternately listening
to the A and B signals. Although this
feature is not specifically incorporated in
either of the KT -600's two stereo function
switches, nevertheless it exists by virtue of
the fact that the selector switches are not
ganged but operate independently for each
channel. To illustrate, if one is listening to
an FM and AM pair of tuners bringing in
a stereo program, one selector switch ea:
be set to the tuner position while the other
is set to another position; then the procedure can be reversed. The selector
switches are concentrically mounted, which
permits them to be turned together to facilitate the AB balancing process.
Design
Figure 2 is a block diagram of the KT600, which contains many points of interest
from a design viewpoint. Tubes V, - V,
constitute Channel A, and V,- Ve Channel
B. V,, is a phase inverter that changes
V,5 provides a center
Signal B to
B.
AUDIO
34
www.americanradiohistory.com
MAY, 1959
Even on
a
tight budget, you can still enjoy The Very Best in Sound
the finest two -way speaker system made
the
B
-207A adapts to your needs
ing sturdy
cabinet-
handiwork, or
a
in an economical
-or as
a
E -300K
enclosure kit,
a
cabinet of your own design and
you'll choose Bozak
a
space- saving quality music
system-
and compare, note -for -note and dollar-for-dollar
Use it as you
in pairs
component of the larger Bozak three -way systems
- listen
B -207A,
Modest in price, unrivalled in musical sensitivity,
Bozak -built cabinet of Contemporary, Provincial or Urban styling
franchised dealer
AUDIO
the Bozak
Use it where you will: in a wall, built -in enclosure, or exist-
will: singly as the purest voice for
stereo realism
-with
for thrilling
See your Bozak
- if you know music
)
Literature sent on request
BOZAK
MAY, 1959
DARIEN
CONNECTICUT
35
www.americanradiohistory.com
channel consisting of A +B.
Since Channel A is an exact duplicate of
Channel B, except for V,4, comments in
the following discussion about V,- V, apply as well to V,-17,.
Negative feedback, mainly of the plate to -grid variety (over one stage at a time)
is used throughout the KT -600 in order
to: minimize distortion; shape frequency
response (phono and tape -head equalization, presence control, scratch filter, tone
controls) ; maintain high- frequency response; adjust gain to circuit requirements; and enable the tubes to present a
high input impedance and a low output
impedance to other circuit elements,
(phantom)
thereby minimizing loading effects upon
each other, which in turn reduces distortion, maintains treble response, and permits accurate shaping of frequency response (equalization, tone controls, and so
on).
The output stage, V, (and similarly
V, for Channel B and V, for the center
channel), is not the familiar cathode follower but the rather unfamiliar plate follower. The cathode follower achieves a low
output impedance, permitting a long cable
run to the next piece of equipment, by
current feedback via a large cathode resistor. The plate follower achieves a low
the output tube. This raises the possibility
of excessive signal input and consequent
overloading, which is averted in some control amplifiers by placing the gain control
at a very early stage. The problem is solved
in the KT -600 by providing input level sets for each high -level source and another
level -set following the preamplifier V,.
These level sets serve a second very important purpose in permitting one to balance the two sections of a stereo signal
source, such as the two sections of a stereo
cartridge or stereo tape head. By having
the gain control at a late stage, the noise
of preceding stages is reduced as gain is
reduced.
It will be noted that the constant- amplitude phono input is connected to the magnetic phono input by a small capacitor. In
conjunction with the load impedance, this
capacitor acts as a high -pass filter, causing
the signal to rise with frequency in the
same manner as the signal from a constantvelocity (magnetic) pickup. Thus the signal from a constant -amplitude pickup
(ceramic, crystal, capacitance) can be
handled by the preamplifier in the same
way as a signal from a magnetic pickup,
permitting a variety of equalization characteristics. One can use either a constant amplitude pickup or a magnetic pickup,
output impedance by voltage feedback via
a resistor from plate to grid. The designer
of the KT -600 gave the reviewer his reasons for preferring the plate follower: It
permits some gain, according to the value
of the feedback resistor, whereas the
cathode follower operates at a slight loss;
that is, the plate follower enables the
designer to trade the advantages of feedback for gain in whatever proportions he
desires. Distortion is less when operating
a tube on its voltage characteristic (plate
follower) than on its current characteristic
(cathode follower). On listening tests, the
plate follower sounds better to the designer, having a more transparent quality.
Every tube in the KT -600 is a 7025/
12AX7, so that the owner need keep only
one replacement tube on hand. From the
design standpoint, the 12AX7 -type was
preferred as more linear than the 12AU7,
which is often used in some amplifier
stages in order to limit gain; gain of the
12AX7 is about 30 db for each triode, and
of the 12AU7 about 20 db each. To limit
gain where necessary (the six stages in
each channel have potential gain totalling
about 180 db), negative feedback was employed by the designer.
It may be seen in Fig. 2 that the gain
control is at a very late stage, just prior to
G-
GANGED WITH SWITCH FOR CHANNEL
B
ALL TUBES 7025's OR 12AX7's
EQUALIZATION
ROLL -OFF
TURNOVER
LP
RIM
COMBINED WITH
ROLL -OFF SWITCH
10.50
LP
RIAA
50
AES O
TAPE
TAPE
HEAD
CONSTANT
TONE
CONTROLS
AES O
PRESENCE
CONTROL
On
FLATO
i
HOP
TAPE
Op
p
HD.O
Off
PREAMP
^
SCRATCH°
FILTER
OnO
O-
OTAPE
OUTPUT
0
G
MONITOR
ON ITORRG
A
TREBLE
PLAY
BASS
Off
O
AMP.
PHONO
GAIN
MAG.
PHONO
LEVEL SET
TUNER (VtVVYWV'
On O
AUX
LOUDNESS
CONTROL
RUMBLE
FILTER
Off
O"
OnO,
Off O'a
O
COMBINED WITH
GAIN
TURNOVER SWITCH
TAPE
PL.
MON A
CHANNEL
B
MONS
STEREO
O
CALIB.
A.BO
MON A
A
MONS
B
STEREO
A B
A.BO
CALIB.
-
-B
REV CH -REV PH
BO
AO
AO
NORM
REV PH
BO
A
A +BO
I
REV CH
A
A.B
I
OUTPUT SWITCHING
FEEDBACK
INPUT SWITCHING
CHANNEL A
I
p
CALIB.
REV CH
REV CH
I
Ot.
p
Có
BO
°
A. BO
-REV
1
I
I
A
PH
AO
BO
NORM
CH. B
OUTPUT
-BO
REV PH
CAL IB.
i
A-BO
I
CH. A
OUTPUT
I
A
- BO
U
OBRIDGED
OUTPUT
L
O
TAPE
OUTPUT
f-
FEEDBACK
0 0
NOTE: UNLABELED PARTS IN CHANNEL B
CORRESPOND TO THOSE IN CHANNEL A
CHANNEL SEPARATION VARIABLE
FROM Odb TO 12d1,
Fig. 2. Block diagram of the Lafayette KT-600 Stereo Control Amplifier.
AUDIO
36
www.americanradiohistory.com
MAY, 1959
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IM Distortion Less Than .6% at Normal Listening Level
Total Harmonic Distortion Less than .2% at
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Separate Treble Controls for
Each Channel . Separate Bass Controls for Each Channel
. Separate Volume Controls for Each Channel . Master
Loudness Control Provides Gain and Attenuation for Both
Channels Simultaneously . Separate Panel Illumination
Switch
Contour Switch with Provision for Normal Listening,-10 and -20
Slide Switch Affords Stereo, Monophonic
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for Normal Stereo Listening or Reversal df Stereo Channels . Selector Control has Positions for Phono, Tuner
Tuner Plus TV (for Special TV -Radio Stereo Broadcasts) TI
and Tape . Built -in Speaker Phasing
Variable Hum BalInputs for 2 Tuners (Can be Operated SiControl
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AC Convenience Outlet
Luxurious White and Gold Contrasting Front Panel
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Oceanside, Long Island, N.Y.
Dept. A -5
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Volume
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Rumble Filter
Muting Switch
AC Convenience Outlet
Output Meter Reads
Power Output in Watts, Tape Output in Volts
Separate and Independent Tape Output Level Potentiometer
Cathode Follower Tape
Internal Grid Bias, Grid Balance and Hum Balancing Controls
Output
Output Selector for Speakers of Different Impedance
A -AB -B
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OCEANSIDE, LONG ISLAND, NEW YORK
MAY, 1959
37
www.americanradiohistory.com
but not both. It is not advisable to connect
a constant- amplitude pickup to one of the
KT -ß00's high -level input jacks, because
the input impedance is only 250k ohms,
whereas about 1 to 3 megohms is usually
required.
From the selector switch, which is combined with the turnover switch, the signal
goes to a two-stage rumble filter of the
lesser type-the only instance in the KT600 where frequency -shaping
is not
achieved by negative feedback. Below 30
cps, where rumble is apt to be most pronounced, there is an attenuation of 16 db
at 30 cps and 21.5 db at 20 cps. On the
other hand, the filter does take a fair bite
out of the lower audio frequencies. Attenuation measured 4.5 db at 100 cps and 10
db at 50 cps.
The block diagram shows that each of
the remaining frequency-shaping circuits
takes place at a different tube stage, so
that these circuits are isolated from each
other and one control does not affect another. High -level sources feeding into the
KT -600 are isolated from each other by
placing the input stereo function switch
after V,,. The output stereo function
switch comes after the plate followers
(V,s, V,e, V,5,).
A bridged-T network is employed in the
feedback loop of V. to achieve a presence
rise. It should be clear that with the
presence control switched off, there continues to be negative feedback, except that
now it is the same at all frequencies. This
is also true of the scratch filter in V,e.
The presence control is designed to provide
about 5 db maximum boost at 2500 cps,
with a 2 db rise at 1000 cps, 5 db at 2000
cps, 5.5 db at 2500 cps, and 0 db at 5500
cps. Response was down 1.5 db at 10,000
cps and 2.5 db at 15,000 cps with the
presence switch on. With the scratch filter
on, attenuation measured 0.25 db at 1000
cps, 5 db at 5000 cps, 13.5 db at 10,000
cps, and 18.5 db at 15,000 cps.
The bass and treble controls employ a
configuration based on the Baxendall circuit. They are designed to assure the user
of flat response when set to the 12 o'clock
position. One can turn each control about
15 deg. to either side of mid- setting with-
out affecting frequency response at the
extremes of the audio range more than 1
db. Maximum bass boost and bass cut is
somewhat less -about 4 or 5 db -than,
usually encountered; the reviewer measured maximum boost and cut of 13 db at
50 cps. The treble control covers more
nearly the usual range; at 15,000 cps, 16
db of boost and 20 db of cut were available.
The signal from V,1 is fed to the gain
control through a PLAY- MONITOR switch
when the latter is in the PLAY position.
With the switch in MONITOR position, the
gain control is connected to the tape amplifier input jack, permitting one to compare
the tape playback signal (from a machine
having separate record and playback heads)
with the signal that is being recorded.
The play- monitor arrangement of the
KT -600 is unusual because it permits the
output of a tape amplifier to be connected
either directly to the gain control or to
the selector switch; in the latter case, the
signal goes through all the stages and is
subject to the tone controls, etc. However,
this arrangement does raise the possibility
of a feedback loop when using certain tape
machines -those which have one head for
both record and playback, which employ
the same tape amplifier stages for both
modes of operation, and which do not disconnect the tape machine's output jack
from these stages when the machine is in
the record mode. With the output of such
a tape recorder connected to the tape amp-
lifter ínParja ** hé XT -600, if the
machine were in the record mode, and if
the KT -600's selector switch were accidentally set to the tape amplifier position,
there would be a feedback loop from the
input jack of the KT -600 through stages
V. and V,,, to the tape output jack, to
the input of the tape recorder, to the output of the tape recorder, to the tape amplifier input jack of the KT -600, and so on.
The result can be a growl, howl, or squeal.
This is one of the reviewer's minor reservations about the KT -600. The solution
might be to redesign the selector switch to
disconnect the tape output jack from the
circuit when the switch is in the tape
amplifier position.
A more important question involving the
tape output jack of the KT -600 is its location in the circuit. One of the dogmas of
high fidelity has been that the tape output
jack should appear prior to all frequencyshaping controls (bass, treble, filters) so
that the tape recording will have the same
frequency balance as the original signal.
However, as may be seen in Fig. 2, the
tape output jack of the KT -600 comes
after the frequency -shaping circuits. It
may well be that the dogma rather than
the KT -600 bears criticism. For the optimun, combination of high signal -to-noise
ratio and low distortion, a tape should be
recorded with proper frequency balance.
If highs and/or lows are excessive, inordinate distortion may result. If highs and/
or lows are deficient, one is wasting signal to -noise ratio by -not recording these in
sufficient strength. In short, correct frequency balance should be achieved before
putting the signal on tape rather than in
playback. The KT -600 perA,its one to do
so. On the other hand, if one desires electrically flat recording (same frequency
balance as the incoming signal), it is
merely necessary to set the bass and treble
controls to flat position and turn off the
rumble, presence, and scratch filters.
The loudness switch enables one to obtain a relatively moderate amount of bass
boost at low settings of the gain control.
At 50 cps, the reviewer measured 2 db
boost with gain 10 db below maximum; 5
db at 20 db below maximum; 10.5 db at 30
and 40 db below maximum; 9.5 db at 50
db below maximum. These are rather small
amounts compared with loudness compensation reaching as much as 25 or 30 db at
50 cps in some control amplifiers. On the
other hand, this minimizes the danger of
excessive boost, as sometimes happens with
the switched -type of gain- loudness control.
The total of about 23 db bass boost at 50
cps that can be achieved by setting the
bass control at maximum and turning on
the loudness switch should be sufficient in
the great majority of instances requiring
Fletcher- Munson compensation. The availability of individual level sets for each
high -level source and for the preamplifier
section makes it possible to obtain automatic bass boost (with the loudness switch
on) at the correct sound levels.
Performance
In evaluating a stereo preamp, we are
interested in its performance not only in
the usual sense -with respect to frequency
response, distortion, signal to noise ratio,
and accuracy of equalization -but also in
terms of how well matched are the two
channels. On both counts the KT -600 is
essentially flawless, except for the tracking
error which occurs when the gain controls
are not locked at the same point of rotation.
With gain full on and tone controls at
12 o'clock, frequency response over the 20
to 30,000 cps range was between 0 and 1
db on both channels. With gain 6 db below
maximum, where high -frequency loss i
usually the greatest, response at 30,000 cps
was only 0.8 db down on one channel and
flat on the other.
IM distortion measured .08 per cent at
4 volts equivalent sine wave output on one
channel, and 0.1 per cent on the other.
Below 4 volts, IM could not be measured
on the reviewer's meter, which has a residual reading of about .06 per cent. At 10
volts, IM measured 0.3 per cent on one
channel and 0.5 per cent on the other.
Since 1 volt or less is apt to be enough to
drive most power amplifiers, the KT -600 i
highly unlikely to be a source of distortion
in an audio system.
Based on 1 volt input, signal-to -noise
ratio for high -level sources measured over
90 db. Even with the KT -600's gain control at maximum and using the most sensitive scale of the reviewer's VTVM, the
pointer fell so far to the left as to prevent
a precise reading of noise. Based on the
customary 10 mv input for measurement
purposes, signal to noise ratio on the magnetic phono input was 64 db at 1000 cps.
More likely, 20 mv or more will be produced on peaks by most magnetic cartridges, so that in practice the signal to
noise ratio is apt to be 70 db or better. To
measure signal-to-noise ratio for a constant- amplitude pickup, a 1000 -cps signal
of 0.5 volt was used, yielding a figure of
66 db. Based on 5 mv at 1000 cps into the
tape -head input, signal -to -noise ratio measured 55 db, which compares with the top
quality tape amplifiers. The excellent noise
characteristics of the KT -600, practically
identical on each channel, are attributable
to the use of low -noise resistors in the
preamplifier stages, to the use of a premium grade of audio tube, to a d.c. heater
supply, to a hum -balancing pot in addition
(for cancelling 120 -cps ripple), and to the
design and layout in general.
Sensitivity is high. For 1 volt output at
1000 cps, the KT -600 requires an input
signal, as measured by the reviewer, of 93
mv on high -level inputs, 2.2 mv on magnetic phono input, 56 mv on constant amplitude phono input, and 1.8 mv on
tape head input. Requirements were just
about the same on each channel, which
differed a mere 0.2 db in sensitivity, in-
cluding the preamplifier stages.
VIA, which converts Signal B to
for
phase reversal and null balancing, should
have zero gain. Actually, the reviewer
found that the B and
signals differed
by about 0.5 db, which may be considered
negligible in view of the fact that even
the trained human ear cannot detect differences below 1 db on single tones, or
below 2 db on program material.
Magnetic phono equalization was checked
only for the RIAA characteristic and
found very accurate. On one channel the
error was between 0.5 db and 0.3 db over
the 50- 15,000 cps range; on the other,
between 1 and 0.3 db.
Equalization for a constant amplitude
phono cartridge requires a certain amount
of bass cut and treble boost. Most ceramic
and crystal cartridges have built -in treble
boost, achieved through resonance, which
approximates the RIAA requirement.
Hence the equalization for a ceramic or
crystal pickup should provide only bass
cut and approximately flat treble response.
The KT -600 conforms to this principle.
For frequencies of equal magnitude fed
into the constant amplitude phono input,
bass cut measured within 1 db of the RIAA
requirement, while response between 1000
and 15,000 cps was flat within 3 db.
B
B
AUDIO
38
www.americanradiohistory.com
MAY, 1959
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7s/a
Mates easily and quickly to any speaker made
Frequency Response: Full flat, lifelike mid
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Impedance: Designed to match 8 or 16 ohms
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Crossover: Self-contained R/C crossover network; recommended crossover point between
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Sound Dispersion: Full 180° coverage (front and
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Fig.
3.
Above chassis view of
the Lafayette KT-
600.
The KT -600 claims to provide "correct
NARTB tape playback equalization."
Assuming an "ideal" playback head,
namely one without treble losses, the
NARTB curve, using 1000 cps as a 0 db
reference, is +23 db at 50 cps, -7 db at
3180 cps, and -10 db at 15,000 cps. Based
on these check points, the tape head equalization of the KT -600 ;measured about -3
db at 50 cps, +4 db at 3180 cps, and +7 db
at 15,000 cps on each channel. At first
there may seem to be excessive error in the
treble region. However, the designer of
the KT -600 has sought to allow for the
treble losses of the typical tape head;
NARTB equalization specifies that playback losses shall be compensated in playback. A typical head with a gap of .00025"
(intended for speeds of 7.5 ips and higher)
and eddy current losses may increase these
figures by a db or two. Accordingly, what
theoretically has about 2.5 db loss at 10,000
cps and 5 db loss at 15,000 cps. Hysteresis
is in effect 7 db treble boost at 15,000 cps
tends to be in keeping with total NARTB
playback requirements, not merely the
official playback curve. The designer has
stated to the reviewer that the curve of the
KT -600 was based upon test tapes containing NARTB recorded induction and upon
the playback heads of several tape machines in popular use: -For the audiofan desiring exact NARTB equalization, be reeommends setting the treble control to 10
o'clock. The reviewer found that such a
setting brought the response characteristic
to within 1 db of the NARTB curve. In
addition, the 3 -db loss at the bass end can
be overcome by setting the bass control to
about 1:30 o'clock.
The effects of the rumble filter, presence
control, scratch filter, and loudness switch
upon frequency response have already been
noted. It remains to say that in every instance the two channels were matched
within .5 db of each other.
Crosstalk of the KT -600 is rated at
"better than 55 db separation between
channels." This apparently is a natter of
what frequency one is talking about. At 50
cps, the reviewer measured 56 db separation; at 1000 cps, 49 db; -at 15,000 cps, 28
db. Inasmuch as anything in excess of 20
db is considered sufficient for full preservation of the stereo effect, crosstalk should
be no problem.
and cathode circuits; these resistors are
about ten times as costly as the ordinary
molded carbon ones and about three times
as expensive as the deposited carbon kind
frequently employed in home audio equipment for noise reduction. For accurate
equalization and control of gain, 5 per
cent tolerance resistors are generously
used. A large percentage of the capacitors
are mica with a'tolerance of 5 per cent or
ceramic with a tolerance of 5 per cent or
10 per cent. The only component that gave
the reviewer trouble was a noisy cathode
resistor
deposited metal film one at
that-in one of the preamplifier stages.
This is a rare occurrence for the deposited
metal film type. It is interesting to note
that signal -to -noise ratio was reduced about
20 db by the offending part. A temporary
I -watt resistor of the conventional type
while awaiting a replacement low -noise
resistor from Lafayette -recaptured about
14 db of the 20 -db loss.
Locating lugs on all switches and controls eliminates the problem of correct
orientation of these parts, particularly in
the case of tone controls, where it is desirable that 12 o'clock setting shall corres-
-a
-
pond to flat response. The chassis and related hardware are sturdy and fit properly.
The top cover and front panel come together snugly,. without the gaps that sometimes betray Home- assembled equipment.
The front panel is essentially attractive,
although one observer remarked that the
knobs could be more eye -appealing.
Although a lengthy project, the KT -600
is not a difficult one. Assembly instructions
and pictorials are clear, and the reviewer
found no errors in them. Figures 3 and 4
are above- and below -chassis views of the
completed unit. Such errors as previously
existed were corrected by addenda supplied with the construction manual. When
the reviewer completed the assembly, the
unit operated as it is supposed to do, with
the exception of the noisy resistor. The
only error he found in the manual was the
statement on page 71 that the inner knobs
on the front panel control Channel A.
Actually, the outer knobs do so.
Because of the large number of assembly
steps, the statistical probability of error
is naturally greater than in a simple kit.
Therefore the constructor is advised to
proceed at a cautious pace and to recheck
his work after every ten steps or so. If -the
amplifier fails to work properly, Lafayette,
like other reputable kit manufacturers.
stands ready to put the unit to rights at a
standard service charge, provided that the
constructor has followed instructions with
respect to wiring and type of solder. Lead
dress, as shown in the pictorials and photographs, should be followed religiously; a
good many engineering hours have been
devoted to this aspect of the kit in order
to minimize hum, crosstalk, and the possibility of oscillation due to feedback (after
all, there are 180 db of potential gain in
Channel A and 210 db in Channel B.
counting the phase inverter).
There is no excuse for using the wrong
kind of solder, because Lafayette supplies
an ample quantity of the best kind, 60 -40,
with the kit.
Good soldering technique is very important to successful assembly and operation of the KT -600. The neophyte should
read the manual's instructions carefully in
this respect and practice for a while before
going to work on the kit. Excessive solder
flow should be avoided on printed circuit
board connections lest solder bridges forni
between adjacent printed leads, which
often run very close together. A low -wattage iron with a small tip is advisable;
also, it avoids possible damage to the
board through excessive heat. The reviewer
did his soldering with a pencil iron, using
a 231/2 watt tip most of the time. When
soldering connections to ground or when
soldering a group of leads to one lug
situations that quickly drain the heat from
the iron -he switched to a 371/2 watt tip,
which provided ample heat in all circumstances. When soldering on the printed
circuit board has been completed, it should
be cleaned with a brush and one of the
fluids recommended by Lafayette in order
to avoid signal leakage due to rosin flow.
(Continued on page 59)
-
Fig.
4.
Below chassis view of
the KT -600 Stereo
Control Amplifier.
Construction
Components and hardware are of the
quality one expects in a-liigh -grade instru-
ment. The tubes, as previously remarked,
are all 7025's, an improved version of the
12A %7. For low noise, tfoth triodes of the
preamplifier (in each channel) employ
deposited metal film resistors in the plate
AUDIO
40
www.americanradiohistory.com
MAY, 1959
.
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Hum and Noise: Only /1000th of 1% of full rated output!
IM Distortion: Less than 0.08% (European CCIR standards.)
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at
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AUDIO
MAY, 1959
41
www.americanradiohistory.com
Standard Methods of
Measurements for Tuners
The complete text of IHFM -T -100, adopted in December, 1958
IN TWO PARTS -PART
1
1.00 Introduction
Present -day high fidelity tuners vary
considerably in their uianher of operation.
It is difficult to set down a single teat
procedure for each fundamental characteristic and have the procedure include all the
allowances that should be made for peculiarities of different sets.
Reference is made to the following IRE
300 ohms
Standards.
Standard on Radio Receivers, Methods
of Testing Frequency Modulation Broadcast Receivers, 1947, and Supplements.
Standards on Radio Receivers, Methods
of Testing Amplitude Modulation Broadcast Receivers, 1948, and Supplements.
Standards 56 IRE 27S1 and 51 IRE
17S1.
2.00 Definitions of Terms, FM
2.01 Standard Test Frequencies
The standard group of three carrier frequencies for testing is 90, 98, and 106
megacycles. The standard mean carrier
frequency, for use when measurements are
to be made at a single frequency only, is
98 megacycles.
3.03 Test Input Signals
Input signal intensities are expressed in
terms of input voltage measured in microvolts across a dummy load of 300 ohms
when supplied by a generator of internal
impedance of 300 ohms. See Figs. 1, 2 and
3.
5.03 Standard Test Modulation
Standard Test Modulation in tests on
frequency modulation tuners refers to a
signal that is frequency modulated at 400
eps with a deviation of 100% of maximum
system deviation. In this standard, maxi mum rated system deviation is taken as 75
kilocycles.
S'.04 Usable Sensitivity Test Input
The usable sensitivity test input is the
least 100 % -modulated signal input which,
when applied to the receiver through the
standard 300 -ohm dummy antenna and the
audio voltmeter connected through a 400cps null filter, reduces the total internal
receiver noise and distortion to the point
STANDARD
z
FM SIGNAL
GROUND
O
GROUND
o
ANTENNA
-0
FM RECEIVER WITH
UNBALANCED
ANTENNA INPUT
o
GROUND
Fig. 1. Standard 300-ohm balanced dummy antenna and method of connection.
where'the output rises 30 decibels when the
400-cps null filter is removed from the
audio voltmeter circuit. It is expressed in
microvolts. The results are to be given in
X microvolts for 30 db usable sensitivity.
5.05 Standard Test Output, Reference
Level
The standard test output is 1 volt with
the tuner operating into a load of 500,000
ohms shunted by 500 µµf (see also section
8.01). This is a reference voltage only.
306 Standard 300-ohm Dummy Antenna
For tuners with a balanced input, the
standard 300 -ohm antenna comprises a
pair of resistors, one connected in series
with each terminal of the signal generator,
of such value that the total impedance
between the terminals including the signal
generator is 300 ohms. For tuners with an
unbalanced input, the standard 300 -ohm
antenna comprises a single resistor connected in series with the energized terminal
of the signal generator of such value that
the total impedance between the antenna
terminal and ground including the signal
generator is 300 ohms. It is intended to
simulate the mean value of the impedance
of a typical transmission line connected to
an antenna. See Figs. 1 and 2. For those
tests requiring the use of two signal generators see Figs. 4 and 5.
2.07 Standard De- Emphasis Characteristic
The standard de- emphasis characteristic
has a falling response with modulation
frequency the inverse of the standard preemphasis characteristic equivalent to that
provided by a simple circuit having a time
O
Z
Z
UNBALANCED
DUMMY ANTENNA
O
ANTENNA
L
O
STANDARD
FM SIGNAL
GENERATOR
-
~vv.
STANDARD 300 -ohm
GENERATOR
150 ohms
O
O
O
.
STANDARD 300-ohmo
BALANCED
DUMMY ANTENNA
150 ohms
FM RECEIVER
BALANCED
GROUND WITH
ANTENNA INPUT
O
ANTENNA
Fig. 2. Standard 300 -ohm unbalanced dummy antenna and method of connection.
constant of 75 microseconds. The standard
de- emphasis characteristic is usually incorporated in the audio circuits of the
tuner.
5.08 Frequency Deviation
Frequency deviation is the difference
between the instantaneous frequency of the
modulated wave and the carrier frequency.
5.09 Maximum System Deviation
Maximum system deviation is the great eat deviation specified in the operation of
the system. It is expressed in kilocycles. In
the case of frequency-modulation broadcast
systems in the range from 88 to 108 megacycles the maximum system deviation is 75
kilocycles.
3.00 Definition of Terms, AM
3.01 Standard Test Frequencies
The standard group of three carrier frequencies for testing is 600, 1000, and 1400
kilocycles. The standard mean carrier frequency for use when measurements are to
be made at a single frequency only is 1000
kilocycles.
3.03 Test Input Signals
Antenna input voltages are to be measured in microvolts. Loop antenna input
field intensities are to be measured in
microvolts per meter.
3.03 Standard Test Modulation
Unless otherwise specified, standard teat
modulation is an amplitude modulation at
30% at a rate of 400 cpa and applied to
the receiver through a standard dummy
antenna or through a standard loop generating a field of known intensity at the
location of the loop antenna of the receiver.
3.04 Usable Sensitivity Test Input
The usable sensitivity test input is the
least 30 %- modulated signal input which,
when applied to the receiver through the
standard dummy antenna and the audio
voltmeter connected through a 400 -cps null
filter, reduces the internal receiver noise
and distortion to the point where the output rises 20 db when the 400 -cpa null filter
is removed from the audio voltmeter
circuit. The results are to be given in X
microvolts for 20 db usable sensitivity.
AUDIO
42
www.americanradiohistory.com
MAY, 1959
O
O
STANDARD
FM SIGNAL
GENERATOR
Fig. 3. Method of
VOLTMETER
300 -ohm
INPUT IMPEDANCE
STANDARD 300 -ohm
DUMMY ANTENNA
(DUMMY LOAD)
o
O
the internal impedance shall be negligible
compared to the standard AM dummy antenna. The generator shall be capable of
being amplitude modulated at rates from
30 to at least 15,000 cps. The generator
shall provide an amplitude-modulated signal at 400 cps and be capable of being
modulated in amplitude up to the required
modulation percentage for the individual
test with leas than 2% distortion. Residual
noise and hum shall be at least 40 db below
30% modulation.
5.03 Output Dieter
A vacuum -tube voltmeter is required for
testing of high fidelity tuners.
The vacuum-tube voltmeter shall cover a
frequency range of at least 20 to 20,000
cps with less than 1 db error. It shall
possess average rectifying characteristics.
The output meter shall be capable of measuring over a dynamic range of at least 60
measurement of input signal intensities and method of connection.
3.05 Standard Test Output
See 2.05 above.
3.06 Standard Dummy Antenna
A standard antenna is taken as an open
single wire antenna (including the lead
wire) having an effective height of 4
meters. A dummy antenna which closely
approximates such an actual antenna over
the frequency range of 540 to 1600 kilo c-veles is a capacitor of 200 .q.f.
300 ohms
at least twice the rated system deviation.
The generator shall provide a frequency modulated signal at 400 cps with less than
2% distortion at rated system deviation.
Generator frequency deviation shall be
calibrated to an accuracy of 5 %. Residual
noise and hum shall be at least 60 db below
rated system deviation.
5.02 AM Signal Generator
An amplitude -modulated signal generator
-
db.
5.04 Audio Generator
An audio generator is required for modulating the signal generators.
The audio generator shall be capable of
modulating the signal generator to at least
full system deviation or up to the required
amplitude-modulation percentage for the
individual test. The distortion of this generator shall be less than 1 %.
5.0.5 Distortion Meter
A distortion meter is required for testing
of high fidelity tuners.
The distortion meter shall be capable of
measuring distortion over a frequency
range from 30 to 15,000 cps. It shall be
capable of measuring either total distortion
or the amplitude of each frequency component.
ANTENNA
Z
STANDARD
FM SIGNAL
GENERATOR
I
FM RECEIVER
WITH BALANCED
ANTENNA INPUT
ZI
GROUND
150 ohms
o
ANTENNA
GROUND
300 ohms
STANDARD
FM SIGNAL
GENERATOR
-Z2
STANDARD 300 -ohm
BALANCED
Z2
DUMMY ANTENNA
2
O
GROUND
6.00 Test Procedures, FM
6.01 Normal Control Settings
Unless otherwise specified, all controls
on the tuner shall be set to their normal
settings. The volume or level control shall
be set to the position of maximum audio
output (see also section 8.01). The automatic frequency control shall be set to the
condition of minimum frequency control.
The squelch control shall be set to the
condition of maximum sensitivity, providing least suppression of tuner noise. All
other controls affecting audio frequency
response shall he set to the condition of
flattest frequency response as indicated by
FOR
TWO- GENERATOR
TESTS
Fig. 4. Standard 300 -ohm balanced dummy antenna for two-generator tests. Generator open -circuit voltage must be increased 2x over connection of Fig. 1 for same
input signal intensities.
4.00 Operating Conditions
4.01 Power Connections
The normal test voltage is 117 volts root
mean square, 60 cps, with less than 2%
harmonic distortion. One side of the power
input to the tuner is to be grounded.
4.02 Shields and Covers
Shields and covers are to be in place and
securely fastened.
4.03 Electron Tubes and Semi -Conductors
The electron tubes and semi-conductors
shall have standard rated values for those
characteristics which most affect the performance of the tuner.
5.00 Requirements and Character?stics
of Testing Apparatus
5.01 FM Signal Generator
A frequency -modulated signal generator
is required for testing of frequency -modulation tuners.
The signal generator shall cover at least
the carrier -frequency range from 88 to 108
megacycles.
The generator output shall be controller'
by a calibrated attenuator and the output
shall be adjustable over a range of at
least 1 microvolt to 100,000 microvolts.
The output meter and the attenuator of the
signal generator shall indicate the open circuit voltage at the terminals. The generator shall be capable of being frequency
modulated at rates from 30 to at least
15,000 cps and at deviations from zero to
AUDIO
is required for testing amplitude-modula-
tion tuners.
The signal generator shall cover at least
the carrier -frequency range from 540 tr
1600 Ice. The generator output shall be
controlled by a calibrated attenuator and
the output shall be adjustable over a range
of at least 1 microvolt to 100,000 microvolts. The output meter and the attenuator
of the signal generator shall indicate the
open -circuit voltage at the terminals and
panel markings.
6.02 Tuning Control
A tuner for frequency -modulated waves
is tuned accurately to a desired signal
when the tuning indicator shows correct
tuning. The tuning is to be performed at
600 ohms
-
Z1
ANTENNA
STANDARD
FM SIGNAL
GENERATOR
rI
FM RECE IVER
A
GROUND
GROUND
600ahms
STANDARD
FM SIGNAL
GENERATOR
WITH
UNBALANCED
ANTENNA INPUT
- Z2
STANDARD 300 -ohm
2
r2
UNBALANCED
DUMMY ANTENNA
FOR
GROUND
TWO -GENERATOR
TESTS
5, Standard 300 -ohm unbalanced dummy antenna for two -generator tests. Gen erator open- circuit voltage must be increased 2.. oevr connection of Fig. 2 for some
input signal intensities.
Fig.
MAY, 1959
43
www.americanradiohistory.com
a signal level corresponding to the test
input for 30 db usable sensitivity.
If a tuning position different from the
one above is found giving minimum undesired noise, the frequency difference shall
be stated. If no tuning indicator is incorporated in the tuner or if no usable
indication is obtained, minimum undesired
noise shall indicate proper tuning. A third
possible tuning position may he found at
which the harmonic distortion of the demodulated desired signal is a minimum.
In this case, the frequency difference shall
be stated.
6.03 Performance Tests
The performance of an FM tuner is determined by measurement of the several
individual characteristics. The foregoing
sections have specified the setup of measuring apparatus and the tuner under test;
in addition, it is necessary to follow
standardized test procedures in order that
measurements made in different laboratories will be comparable. These test procedures serve to measure the individual
characteristics of the receiver.
6.03.01 Tuning Range and Frequency
Calibration
The tuner tuning control is set for
the respective minimum and maximum
carrier frequencies in each tuning range
which the tuner is capable of receiving
with normal operation. At each setting, the
signal generator is tuned to the resonant
frequency of the receiver and the carrier
frequency recorded. This procedure maybe
extended to obtain a frequency calibration
of the dial, if this is required. If an error
in frequency calibration is found, the
maximum error in megacycles shall be
stated.
6.03.08 Usable Sensitivity
This test is performed at each of the
standard test frequencies with the signal
generator connected to the tuner under
test through the standard 300 -ohm dummy
antenna. The signal generator shall be
frequency modulated with standard teat
modulation. The controls of the tuner shall
be set to the normal control settings. The
signal intensity shall then be reduced to
the least value which will produce a 30-db
rise in indicated output with standard test
modulation as compared with the indicated
output with standard test modulation
measured through a 400 -cps null filter; This
test serves to indicate the relative freedom
of the tuner from objectionable internal
receiver noise during pauses in modulation
when receiver noise is least likely to be
masked by modulation. This test also
serves to indicate the relative freedom of
the tuner from objectionable distortion
during periods of maximum modulation.
The results are expressed in microvolts.
6.03.03 Volume Sensitivity
This test is performed at each of the
standard test frequencies with the signal
generator connected to the tuner under
test through the standard 300 -ohm dummy
antenna. The signal generator shall be
frequency modulated with standard test
modulation. The signal generator shall be
adjusted for an output of 100,000 microvolts. The output voltage of the tuner
shall be recorded in decibels with respect to
1 volt. Then, the signal generator output
shall be reduced to a value at which the
audio output of the tuner has been reduced
by 20 db.
The results of the volume sensitivity
test are expressed in microvolts.
The rated sensitivity of a tuner shall
be equal to the highest number of micro-
volte obtained in all tests of sections
6.03.02 and 6.03.03 with the controls set to
their normal settings.
6.03.04 Capture Ratio Test
This test is intended to show the
effect of an interfering signal of the same
frequency as the desired signal, and includes the inherent effect of the detector,
the limiter, and the automatic volume
control.
Two signal generators are required,
only one of which need be capable of
frequency modulation. The outputs of both
are applied simultaneously to the receiver
under test at the mean carrier frequency
of 98 megacycles (see Figs. 4 and 5). The
tuner controls are set to the normal control
settings. With the desired signal frequency
having 100% modulation at a 400 cps rate
and an intensity equal to the test input
giving 30 db usable sensitivity, the output
control of the unmodulated signal generator is advanced until the audio output has
fallen by 1 db. This value is to be recorded. Then the output control of the unmodulated signal generator is advanced
further until the audio output of the tuner
has fallen a total of 30 db. This value is
again recorded.
The ratio of the two values recorded is
to be converted to decibels, and the number
of decibels is to be divided by 2. This last
number is defined as the capture ratio for
100% modulation. It gives the ratio of
desired to undesired signal required for
30 -db suppression of the undesired signal.
The same test is repeated but with
30% modulation. The results will be the
capture ratio for 30% modulation.
These tests shall he repeated at input
levels of the desired signal in steps of 20
db above signal level of the previous tests.
The rated capture ratio shall he the
highest number of decibels measured with
the 100%-modulated signal generator set
to produce a 1000- microvolt input into the
tuner at each of the standard carrier frequencies.
6.03.05 Selectivity Test
This test is intended to show the effect
of an interfering signal differing in frequency from the desired signal, and includes the inherent effect of the selective
circuits, the limiter, the automatic volume
control, and the detector. This test is
useful in describing adjacent- channel and
second- channel interference.
Test conditions are the same as those
described in Section 6.03.04 except that the
interfering signal generator is separated
in frequency from the desired signal by
one standard channel separation (200 kc).
The desired signal, unmodulated, is applied
at the value providing 30 db usable sensitivity and the output of the receiver is
recorded as the level of the interfering
signal, frequency modulated with 100%
modulation, 400 -cps rate, is varied from
zero to a value corresponding to an output
30 db below the output obtained with 100%
modulation.
The output voltages of both signal
generators are recorded and the ratio of
both voltages is expressed in decibels. The
result is the 100 %- modulagon adjacent channel selectivity.
The test is repeated with 30% modulation and the result is the 30%-modulation adjacent -channel selectivity.
The above tests are repeated with the
interfering signal separated from the de
sired signal by twice standard channel
separation (400 kc). The results are the
alternate 100 % - and 30%-modulation
channel selectivity.
These tests are repeated with the desired signal increased in steps of 20 db.
The rated selectivity shall be the 100 %a modulation alternate -channel selectivity
with a desired input of 100 microvolts at
the standard mean carrier frequency.
6.03.06 Amplitude Modulation
Suppression Test
This test measures the suppression of
amplitude modulation which may be present in a frequency-modulated signal. It is
carried out at the standard mean carrier
frequency. The frequency modulation is at
a 400 -cps rate with a deviation of 100%
of maximum system deviation. A signal 10
db higher than the value giving 30 db
usable sensitivity is applied to the tuner
in the usual manner. The output voltage of
the tuner is recorded and a 400 -cps rejection filter is inserted between the output
of the tuner and the meter. The input
signal is then amplitude -modulated at 30%
modulation with frequencies between 30
and 15,000 cps. The intensity of the undesired output of the tuner is measured and
is expressed in decibels below the normal
output obtained above.
The rated amplitude suppression is
the ratio of the undesired output to the
output with standard test modulation
when the amplitude modulation is at 1000
cps.
The above tests are to be repeated at
input voltages in steps of 20 db above the
main and initial test.
It should be assured that no incidental
frequency modulation be obtained when
the signal generator is amplitude modulated. It may be desirable to use an amplitude modulator connected in the output
lead of the signal generator.
6.03.07 Frequency Response
This test shows the manner in which
the audio output of a tuner depends on the
modulating frequency. It takes into account
all the characteristics of the tuner. The
tuner is tuned to a signal at standard
mean carrier frequency and a signal level
of 1000 microvolts, frequency modulated
with standard test modulation. The tuner
output is measured with all tuner controls
set to the normal control settings. The
output variation is observed while the
modulation frequency is varied continuously from 30 to 15,000 cps. The results
are to be compared to the response of the
standard de- emphasis network and are to
be expressed in db in reference to the
400 -cps output.
It may be desirable to repeat these
measurements with 30% system deviation
and at input signals in steps of 20 db
above the previously used -input signal. If
the results are plotted, semi -logarithmic
paper shall be used and a 20 -db change on
the ordinate shall correspond in length to
one decade of frequency variation on the
abscissa.
If the frequency response changes
with the volume control setting, this teat
should be repeated at selected attenuations
differing in steps of 10 db from the position of maximum output.
6.03.08 Distortion
The test is intended to evaluate the
spurious audio -frequency components which
appear in the audio output of the tuner
during normal operation. Care shall be
taken to avoid appreciable harmonie distortion occurring in any part of the signal generating equipment or in the output measuring circuit. Distortion- measuring
equipment is required in the output circuit
which shall not appreciably affect the
output load conditions. This equipment
AUDIO
44
www.americanradiohistory.com
MAY, 1959
may measure each frequency component
individually or may measure all frequency
components collectively. The proper tuning of the tuner is important in making
distortion teste. For this test only, proper
tuning is indicated by a minimum reading
of the distortion meter. No one complete
set of conditions can be prescribed for this
test because distortion depends on so many
details of tuner design and operating
conditions. Distortion is caused by overloading and by many other phenomena and
is present under various operating conditions, especially at high degrees of modulation. The following series of tests is intended to show the effect of operating
BACH
OR
BE-BOP
parameters on distortion.
(a) Variation of Output
The receiver is tuned to the standard mean carrier frequency and a
1000 -microvolt signal with standard
test modulation is applied. The
harmonic distortion is noted as the
output of the receiver is varied by
means of the volume control.
(b) Variation of Modulation
At the standard mean carrier frequency with the above signal input
and a 400 -cps modulating signal, the
modulation is varied from a deviation of 10% to 100% of maximum
rated system deviation and the distortion observed. The volume control
is left in its maximum position.
(c) Variation of Input Signal
The distortion is recorded as the signal input level at the standard mean
carrier frequency, deviated at 400
cps, is varied. The test is made at
both 30% and 100% of maximum
rated system deviation. The distortion shall be recorded as the signal
input is varied over the entire range
of input voltages in steps of 20 db
starting with an input corresponding
to 30 db usable sensitivity. This
test indicates distortion due to inadequate bandwidth.
(d) Variation of Modulation Frequency
To disclose the effect of the modu-
lation frequency on distortion, tests
in Paragraphs (a) and (b) shall be
repeated at several modulation frequencies throughout the audio -frequency range. The maximum modulation frequency at which harmonic
distortion can be detected by this
method is one -half the maximum
frequency which can appear in the
output.
In making distortion tests at the
higher frequencies, special apparatus and
special test methods (such as simultaneous
application of two modulating tones) are
required.
Harmonic distortion measurements are
useful and significant up to modulation
frequencies of approximately 1000 cps. At
higher frequencies the de- emphasis characteristic of the tuner will attenuate the
higher distortion products severely and will
give rise to considerable errors in measurement.
Measurement of distortion at the
higher modulation frequencies will show up
deficiencies such as caused by inadequate
bandwidth or phase shift of the selective
circuits in the tuner, or an inadequate
limiter or detector. Here the distortion
product of most interest is the difference
tone obtained when the carrier is 'modulated by two audio frequency signals differing by less than 500 cps.
Here the signal generator is modulated to identical deviations by the two
different audio-frequency signals and the
AUDIO
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Depth: 20 ". Shpg. wt., 72 lbs. User net: $150.00.
For complete details, write for brochure.
Desk R- I, University Loudspeakers, Inc.,
80 South Kensico Ave., White Plains, N. Y.
-
-
;45
MAY, 1959
www.americanradiohistory.com
arithmetic sum of both deviations is recorded as the signal deviation. This total
deviation shall be 30% and 100 %. The
level of the difference tone between the
two frequencies is measured in the audio
output of the tuner and its value is recorded in decibels below 30% and 100%
rated system deviation at 400 eps.
The rated harmonic distortion of the
tuner shall be the percentage of distortion
measured with the signal generator modulated to full system deviation at 400 eps,
the receiver tuned to the standard mean
carrier frequency, and the signal generator
set to produce a 1000 -microvolt input into
the tuner.
The rated intermodulation distortion
of the tuner shall be measured at the same
input level and signal frequency as above
and the total instantaneous maximum system deviation shall be 100% with the signal generator modulated with two signals
of identical amplitude and frequencies of
15,000 and 14,600 cycles per second. The
400 -cps output of the tuner shall be measured and shall be expressed in per cent of
the output of the tuner obtained with 41111
cps at rated system deviation.
(To Be Continued)
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pickup shown, X = 0.2 inches. In this
pickup, to achieve an effective dvnanIle
mass of the magnet referred to the
stylus tip of 0.5(10) -' grams, we find
the maximum electromagnetic sensitivity of the system occurs when the moving magnet is made of Alnico V and its
dimensions are .040 x .040 x .100 in. long.
The total dynamic mass of the system
is calculated to be
Mtafal= }Ietnlae +í ellectlre of magnet
= 0.2 + 0.5 = 0.7 x10-3 pins
= 0.7 mg.
These dimensions allow from frequency
characteristics surpassing those shown
in Fig. 6. Thus the overwhelming
strength of the moving magnet system,
and the ability to use a moving element
of very small dimension-thereby minimizing the effect of the h factor on radius of gyration and weight and allowing for extremely low dynamic mass reflected to the stylus tip -will produce
relatively high output with coils of moderate impedance.
Superiority of Moving System
The moving-magnet stereo pickup system inherently allows for low -cost production and replaceable stylus assembly
(long the problem of moving -coil systems). The system is rugged yet fully
compliant, virtually indestructible, and
with no service problems of delicate rubber bearings and fragile moving coils.
The very small magnetic flux densities
required are fully shielded and offer no
magnetic attraction to steel turntables.
Hum -bucking construction and magnetic
AUDIO
MAY, 1959
! ag-lvsx.;f.,9.;-sr,
shielding prevent pickup of motor and
transformer field radiation and there is
no audible hum produced in the system.
This coupled with high output creates a
pickup of outstanding signal to noise
ratio.
The moving -magnet stereo system has
become the prime mover of stereo disc
reproduction. With its arrival, stereo
has arrived, and will not take a back
seat to any other method of sound reproduction. We can now look forward to
future growth, expanded repertoire, and
greater appreciation of musical and
Æ
sound experiences.
SPEAKER PHASING
(from page 10)
with the resultant of these signals being
at point D. Program material will produce a pattern lying along the line C -D,
and will thereby indicate out -of-phase
operation of the speakers.
Methad of Operation
In using this phasing system, it is
necessary to place the mikes immediately in front of the speakers, and it is
desirable to use program material containing a predominance of low frequencies, or better still a low- frequency test
record. At the higher frequencies, the
distance between the speaker cone and
the mike becomes an appreciable part
of the wavelength of the note being reproduced and difficulty may be encountered in making a correct analysis of the
phasing. This difficulty is overcome if a
major part of the program material is
in the low -frequency range.
Before using this equipment, it is desirable to make sure that both mikes are
phased alike. This is readily indicated
by placing both mikes side by side in
front of the same speaker. Correct
phasing will be indicated by a line on
the oscilloscope in the direction A-B.
If phasing is incorrect, leads to one of
the mikes should be reversed to give the
correct pattern before proceeding with
tests of speaker phasing. The angles of
slant of the line should be adjusted by
balancing the vertical and horizontal
gain controls of the. oscilloscope, to give
a pattern as indicated.
As a substitute for crystal mikes, a
pair of high-impedance magnetic headphones with individual earpieces connected separately to the oscilloscope has
been found to give a workable pattern.
although a high-output crystal mike
works much better. In professional uses
where it is necessary to phase speakers
located at considerable distances from
each other, the user of this system will
probably find it desirable to feed the
mikes through identical amplifiers in
order to avoid excessive hum pickup on
the long high-impedance mike leads. IE
AUDIO
STEREO CAN BE HIGH FIDELITY.
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MAY, 1959
www.americanradiohistory.com
N.
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A DIVISION OF THE SIEGLER CORPORATION.
EDWARD TATNALL CANBY
1.
ONWARD AND MOSTLY
UPWARD
Delibes: Sylvia (complete ballet). London
Symphony, Fistoulari.
Mercury SR2 9006 (2) stereo
This is one of the finest all- around stereo
recordings I've ever heard and strikes me as
a real winner from Mercury. It has everything, but in modest good taste-fine music,
fine performance, excellent recording and the
most utterly suitable and natural stereo sound
imaginable -plus bi -fi virtues that are the
better because they don't shout at you.
Many a hi-fi man has picked Delibes'
"Sylvia," "Coppella," and "La Source" as his
favorite music, in the short orchestral suites
often recorded in the past. But "Sylvia" gains
enormously from being played complete as
one score
whale of a lot of music, too.
My respect for the piece has gone 'way up
since a long, appreciative dinner spent with
this recording all .,a Closely- attended background. The piece'tipally got me.
True. the sound is solidly old -fashioned for
our ears and there are some items that tend
towards corn, taken by themselves -the
famous pizzicato for instance, which you've
heard a million times. Yet as part of the
dramatic whole, these bits gain a dignity that
you wouldn't have expected. Delibes soon has
your admiration for the way that he can
contrast a long succession of short pieces.
keeping your attention ever more easily, maintaining complete freshness. You listen and
listen-and listen; yet (in this playing. at
least) "Sylvia" keeps you happy and contented, side after side without pause. I've
found that the similarly long Tchaikowsky
ballet scores are pretty wearing on the ears
after a side or two ; Tchnikowsky's music is
too high- pressure, too blatantly dramatic, for
such sustained listening interest. On records,
I have seldom been able to keep my mind
on Tchaikowsky for a full ballet. But "Sylvia"
got nie increasingly excited, and notably during the last two sides where the music becomes deeper, more compelling.
"Sylvia" dates from 1875 in Paris and so
you'll also hear echoes of "Carmen," of the
same time and place, though this music is
less showy, more sweet, often more thoughtful
and expressive than "Carmen" itself.
Lovely, melodious, musical playing, under
Fistoulari. Soft, ingratiating stereo sound,
the orchestra set in its normal manner and
every instrument clearly where it belongs in
an unassumingly natural balance. Lhrness
big enough for stereo presence, but not too
big. And for you technlciüps, you'll find behind all this sweetness nii(, light, a big dynamle range, ultra -quiet.' 4it,faces, enormous
bass (when needed), .sharp percussion and
clean strings, plus almbat distortionless inner
grooves in spite of the length of play. That's
Mercury's "Sylvia," and ,mere power to the
company.
-a
The French Touch (Dukas: Sorcerer's Aprentice. Saint-Saëns: Omphale's Spin-
780 Greenwich St., New York 14, N. Y.
ping Wheel. Ravel: Mother Goose.) Boston Symphony, Munch.
RCA Victor LSC 2292 stereo
If I'm right, this is a re -do of an earlier
album, now in RCA's impeccably good tripletrack stereo. The sound is really lovely.
though not of the hi -fi spectacular sort
smooth strings, a bit distant and beautifully
blended (they are about the best in any
orchestra, to begin with), the brass rather
pronounced and sharp, the echo just right.
The "Mother Goose" music of Ravel is the
standout value here, filling side 2. The Sorcerer's Apprentice wórks away with his multiple brooms In a precise but not very exciting
manner and "Omphale's Spinning Wheel" is
similarly well played but lukewarm. (Of
course it may simply be that I wasn't inspired
by the sound of these familiar works. Or
could it be that M. Munch wasn't ?)
-
heard filling the great space. as of a great
man speaking to a vast audience.
Now I don't mean to suggest that he necessarily was there. He could have been. But
in these days, most such narrations are recorded separately, to the playback of the
music, then mixed in for the final version.
The trick here is in the echo, so beautifully
tailored to fit Sandburs s voice. It could be
the natural ball echo -hut it might just as
well be straight out of those two famous stair
wells, at either end of the Columbia building
in New York, which serve as a pair of stereo
echo chambers in many a Columbia recording.
Who knows? The real point is that it
doesn't really matter. The proof of this pudding is in the listening. Here, you see, we
have Art in the most timeless sense, a high
skill, a persuasion, a trick that creates the
Illusion of reality, maybe even more convincingly than reality itself. It doesn't matter
bow Columbia did it, whether Sandburg spoke
the words right out in Carnegie Hall or in a
studio miles away and perhaps months away.
too. The effect is what counts and the effect
here is brilliant, new, perfectly suited to this
work beyond any possible mono recording
far beyond any concert ball presentation.
Incidentally, Sandburg is terrific here, in
these short, simple, laconic bits of Lincoln lana, just enough narration to give him play
for his most persuasive tones, not enough to
lead him into garrulousness. Kostelanetz, too,
is good for this type of music -indeed. be
originally commissioned the piece a good
many years ago.
The rest of the program? Schuman's three
'short pieces based on our New England musical bard of the Revolutionary period, William
Billings, are brash, expertly orchestrated,
generally ugly to my ear. The "Vanessa" excerpt, from the recent opera, is short, sweet,
nostalgic. Copland steals this show, decidedly.
Copland: A Lincoln Portrait. Schuman:
New England Triptych. Barber: Intermezzo from "Vanessa." N. Y. Philharmonic, Kostelanetz; Carl Sandburg, narrator.
Columbia MS 6040 stereo
Here is a striking recording of a piece that
was uncannily well designed for stereo long
before stereo was ever heard of in home
reproduction. "A Lincoln Portrait" is very
impressive in this version -more so, I'd say,
than ever before in any form -and the credit
goes not only to Copland (and Lincoln) but
to Carl Sandburg, Kostelanetz, and, in particular, to the intelligent Columbia engineers
who saw how this thing was just waiting to
be done -after all these years.
The Copland music is of his most angular
sort. On its own (as in the long introduction)
it Is just about self -sustaining and no more.
Bartok: The Six Quartets. Fine Arts
But with the first words of the narrator.
speaking of Lincoln and in Lincoln's own
Quartet.
words ( ".. and he said this:"), the whole
Concert -Disc CS -207, 208, 209 stereo
piece suddenly takes on shape and sense. The
narration, clearly, is the crux of the work
The Fine Arts Quartet is just too much to
and it has seldom been done so well, espebelieve. This foursome is the most public cially in view of the symphonic character of
relations- minded quartet extant -you'll recogthe orchestral framework.
nize theta as the outfit, for example, that
Yes, the piece can be done "live" in the
played in the recent and well- publicized New
concert hall, the voice unamplified. The orYork live -vs.-stereo comparison, sponsored by
chestration is expertly tailored so that the three leading hl -fi companies. I get a publicity
unaided voice may have its say even without
release about them practically every week and
the services of a master control.
even receive an occasional "Dear Edward"
But the piece is inherently more successful
letter, of the sort that- anywhere else
via recording or broadcast, for then the voice drives me into a tizzy. Not from them.
can easily dominate the music and the audiBut these fellows can play. True, they were
ence at normal speaking volume. And now, in
about the first quartet to dabble in stereo and
stereo, the work finally comes fully into its
almost the first performers of any sort to
own and is heard as it never before has apcome out on stereo tape, in the original Con
peared -with the advantages both of the concertape (once Webcor) recordings, 'way back.
cert ball and 6f recording. That's the effect And any way you look at it,, they were pioneers
you'll get on this record.
in getting themselves, as musicians, tangled
After the long musical introduction, first up with audio and with audio's publicity
slow and then fast, the sudden entrance of
media. Yet, against every conceivable exCarl Sandburg, to one side and right close
pectation, these sharply enterprising fiddlers
to you, is absolutely startling- you're likely
are, together, one of the best quartets in the
to jump with astonishment. But what is best,
U.S.A., from anybody's point of view.
as you will quickly realize, is that he is
Their Bartok, I say, is the best on records.
close -up, to one side, but he is also in the hall
To tackle all six Bartok quartets is roughly
along with the orchestra; his voice can be
like producing all the plays of Shakespeare
-
.
-
48
AUDIO
www.americanradiohistory.com
MAY, 1959
ro,,,?N
WM ROBlR
u
III
ILARCReS FROM OPERAS
0.3( -11, I I,., .1. a
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www.americanradiohistory.com
a throw-or maybe I'd better say Eugene
O'Neill, just to be modern. They n:e gorgeous,
difficult, exultant, superhuman quartets, timeless and timelessly difficult, their expression
far beyond the bounds of anybody's quartets
except Beethoven himself -who also knew
how to make four men sound like four hundred or four million.
These playings -as far as I've gone, which
is not all the way through -are at the same
time strong, vital and superbly accurate.
These men hear the music and play in tune
-which makes things simple for us, the
listeners. They are clean players, but they
also have gusto and they react to the incredibly- wild, raw. raucous Bartok -the
grunts and slides and swoops, the bangs,
twangs, screetches -just as handsomely as
to the steely precision that is also part and
parcel of Bartok's incredible writing. A rare
combination, to put it mildly.
Best of all, for all audio hounds, the stereo
recordings bere are as good as claimed, no
less, and they make the best quartet stereo I
have heard. Distortion is nowhere evident,
the balance between the four instruments
happily separates them just far enough to be
natural, and the liveness- possibly artificial
-gives the music just the requisite bigness
for easy home listening (where other quartet
recordings are either too live, or too dead in
sound for those who aren't already chamber
music specialists). Top quality stereo disc and
no less.
The recordings were done in conjunction
with a Ford Foundation project that took
down these same six quartets complete for
TV, on film. That, too, represents some canny
publicity work on the part of the Fine Arts
at
boys.
What of all the other quartet groups, these
days? They're too busy with music to spend
time on hi -fi and public relations. They prefer
to stick to one thing at a time. Not the Fine
Arts!
Mendelssohn: Symphony #4 ( "Italian ");
Trumpet Overture in C, Op. 101. London
Philh., Goossens; Vienna State Opera
Orch., Swarowsky.
Urania USD 1013 stereo
Mendelssohn: Symphony #4 ( "Italian ").
Haydn: Symphony # 104 ( "London ").
N. Y. PhiIh., Bernstein.
Columbia MS 6050 stereo
The two versions of the "Italian" Symphony
make an interesting contrast, representing
musical points of view poles apart -and
equally legitimate. The recording itself in
both cases represents the best of current work,
in somewhat different respects..
Leonard Bernstein's "Italian" is, first of
all, a passionate, Romantic playing -but
modern Romantic, full of anxiety and tension. It's odd that a young, twentieth century
conductor should express himself (with the
cooperation of his orchestra) through such
an old -fashioned war horse of a piece but,
obviously, the music brings out a powerful
set of feelings in Bernstein. It tears its hair
for him, so to speak, and -speaking of hair
I keep seeing a TV close -up of Bernstein in
action as I listen. So will you. no doubt
As for Goossen's British version, it comes
from a senior conductor of an earlier generation, a musician who is inevitably closer to
the continental Romantic tradition of music
than Bernstein -and yet his concept Is strictly
a classical one, in the truest sense of that
word. That is, Goossens does the "Italian"
with marvelously accurate polish and shaping,
every note, every phrase beautifully balanced
and a delight to hear ; the music speaks for
itself and the outward passion is restrained,
so much so that though his two outer movements are almost exactly the same steed as
Bernstein's they seem to be much plower,
more leisurely.
The inner movements are actually slower.
The Goossens slow movement tells an ohl
fashioned fairy tale, slightly mysterious, relaxed but expressively shaped in detail;
Bernstein's slow movement is a Hebrew lament
(and, after all, Mendelssohn was Jewish).
Goossens' third movement is a true minuet,
slow, rich, wonderful in detail ; Bernstein's
-
50
faster, an allegretto like those in the
Brahms symphonies.
The Haydn on Bernstein's other side shares
similar qualities with his Mendelssohn. On
the extra band of Urania's disc there is a
seldom -heard late overture of Mendelssohn,
well worth the space and played well (but
not too accurately) by the Viennese orchestra
under Swarowsky.
As to recording, Columbia's is both louder
and more economical, thanks probably to
variable groove control in both dimensions.
Plenty clean, too, even in those last difficult
loud inner grooves that end each symphony.
Urania couldn't have squeezed Goossens'
slower "Italian" on one side in any case ; so
the music is spread out comfortably on Side
2. For my ear, the sound of the London Symphony on this Urania is close to the ideal for
natural, effective orchestral stereo. It is clean,
unpretentious, marvellously balanced as to
the parts of the orchestra, the music at n
fair distance and the surrounding space just
perfect for enhancing realism, without Intruding too much liveness. Never heard a
better set-up for stereo. The Viennese sound
on the other side ( "Trumpet Overture ") is
considerably more live and there is incipient
confusion in the music, as n result; the liveness tends to blur the details n bit and
muddy- up the harmonies. A common fault.
is
Mendelssohn: Octet in E Flat, Op. 20;
Sinfonia #9 for String Orch. Arthur
Winograd String Orch., Winograd.
M -G -M E3668
Two very pleasant Mendelssohn recordings,
the Octet, in a version for string orchestra by
the conductor (parts of it have long been
played in orchestral form by other conductors)
and a newly launched early string symphony,
composed by Mendelssohn in his early 'teens
for the famous Mendelssohn family show-off
concerts -where the young genius did his
stuff for Berlin society. Nice playing in both
pieces and parts of the little Sinfonia are as
pleasant as any later Mendelssohn.
This is one of the excellent Winograd
series that the conductor produced for M -G -M
before moving on to Audio Fidelity's First
Component stereo, where lie turned out the
best music in the initial release -the record
of Marches from Operas.
Dvorak: Serenade for Strings in E, Op.
22. Israel Philharmonic, Kubelik.
London CS 6032 stereo
I'm happy at last to report out this pleasing
disc from my waiting list. It was one of the
first batch of London stereos and, time after
time. I found it musically lovely but technically fuzzy in the sound. My helpful sixth
sense kept saying-wait, and try again. I
did, and now at last I can safely say that
it isn't distorted. Not more than a wee trace,
at least, even in the tight, inner grooves.
And so this record for me is a sort of symbol
of continuing stereo progress -even though
it hasn't itself changed.
The sweet, passionate string music has an
Israeli intensity to it but the conductor is
Czech in background and knows the style. A
lovely piece, a good complement to the other
Dvorak Serenade, the one for wind instruments, that has had several impressive recordings lately. (Best is on Boston stereo.)
Brahms: Symphony #1. Southwest Radio
Symphony, Horenstein.
Stereo Vox ST -PL 10.690
Brahms: Double Concerto; Tragic Overture. Pierre Fournier, cello, D. Oistrakh,
violin, Philharmonic Orch. Galleria.
Angel S 35353 stereo
Here are two different approaches to the
grand musical problem of today -how to keep
late Romanticism alive and natural.
Horenstein's Brahma First is a big, blowsy,
outgoing version, rather untidy in detail, full
of gusty emotions that aren't very subtle. It
often lacks the big line and shape of Brahms
but, nevertheless, puts over a great deal of
the power of the music, especially in the last
movement, which is very good. Perhaps the
orchestra is simply not up to following
Horenstein's no doubt somewhat impatient
directions-he is a very positive conductor,
as anyone who has followed his recordings in
the past can say. More rehearsals needed?
Maybe, but this is always a moot question,
unanswerable by the record reviewer.
The Vox stereo sound is here quite convincing, still a bit strident in climaxes but
generally clean and big; solo instruments
within the orchestra still are oddly highlighted within the big liveness
sudden
close -up oboe, a distant clarinet for no observable reason.
-a
As for the "Double Concerto," with
the
British orchestra. French cello, Russian fiddle,
and Italian conductor, the mixture comes out
with a British chasteness, every note played
in exact place, a fine over -all shape and impeccable phrasing but, somehow, never anything but warmth, rather than heat. Odd,
with these top-rank soloists it just might
be the conductor's fault. Who knows?
The Brahms "Tragic Overture" follows so
quickly on the heels of the Concerto. with
scarcely a decent pause, that many a listener
will play it quite by accident as an unwitting
fourth movement to the Concerto I almost
;
!
did, m'self.
It blends very nicely. Surely
another five seconds in between wouldn't have
been too much. Angel's stereo is of the tastefully mild sort, perhaps a product of the
M -S double-mike technique. I find I miss the
more flamboyant American stereo approach,
with all its faults. It is, at least, progressive.
ours, barging brashly into new territories of
aural experience. In the end, we'll get more
good timan bad out of our exaggerations over
here.
Schumann: Concerto for Four Horns; Cello
Concerto. Shapiro, Afanasiev, Starozhilov, Krivnetsky, horns; Rostropovitch,
cello; Moscow Philharmonic, Samosud;
State Radio Orch., Gauk.
Monitor MC 2023
Well, what with all those performers and
two different orchestras, it's easy to mix up
the names a bit the Moscow Orchestra plays
the "Cello Concerto," the State Radio does the
horn piece. Monitor's Russian imports just
bristle with long names but among them,
keep in mind, are the top performers and
composers of the U.S.S.R. Keep your eye out
for these.
Schumann would seem to be far removed
from Russia at this point but he seems to be
as popular there as he is -with equal incongruity-in France, where he is played
and played. The Russians do an old -fashioned, all -out Romantic job on this sort of
music, which is more than a lot of Western
outfits can do any more. All in all, Schumann
from Russia is apt to be a good bet.
My main memory of this horn work is a
sad mistake I made on an earlier recording
(this is not the first, as claimed) when 1
ascribed a terrific buzzing and blasting to the
violent acoustic intermodulations set up by
four potent wind instruments in close harmony. It can happen -but this disc will
quickly prove it doesn't, here. The horn parts
are outlandishly difficult yet in this performance they pour forth with utter ease and
polish, minus a trace of distortion. Nice music
and an unusual item. The "Cello Concerto" is
one of those over -intense Schumann works
where you'll tend to think, every so often,
that the old man really was trying too hard.
(But on the next hearing you may be carried away. Nobody can say for sure.) It is
very cello-ish, if you know what I mean.
;
Horace Fitzpatrick Plays Music for the
Hunting Horn on Instruments of the
Period. (with piano accpt.)
Golden Crest 4014
Just how Golden Crest got involved in this
unusual recording project I could not tell
you -it's distinctly not in the usual G.C. line!
Nor is it clear where the job was done, since
the horn player himself does notes on the
album signed "Vienna, 1959" yet the technical
notation mentions the new Golden Crest
studio, which I would suppose is in the good
old U.S.A.
Anyhow, the hunting horn is the forerunner of the present "French" horn and its
final form was the valveless horn used in
AUDIO
MAY, 1959
orchestras right up until the middle
of the nineteenth centry. It could play lots of
notes, due to a wide overtone series and the
stopped effect, one hand inserted in the bell;
but its basic melody always had that overtone- series sound. This recording project reminds me of the Vox "Spotlight" series concerning musical instruments. Also of the Saul
Goodman lone -wolf percussion record for
Angel.
No narration. Side 1 begins with IT ultra short bands each with n fine hunting flourish
on It and you'll probably be lost in confusion
by the second or third example. They all
sound more or less alike. are very bucolic and
quitee pleasing to hear -but, alas, are not at
all in the proper locale since most were intended to he sounded out of doors from afar,
via horse power.
Now if Golden Crest had only been able to
hire a hunt, complete with hounds and maybe
a fox, plus a fine big horse (like on the
record cover) to mount the hornist on top
of . . . but I don't suppose Mr. Fitzpatrick
Is the riding sort. He plays from n chair,
081881Ca1
probably, and he's definitely indoors in this
performance.
This fa intended as an indirect criticism.
The examples are of scholarly and historical
interest but they don't make much of a record
for listening. And the samples of classical
music for valveless horn should be done with
orchestra, if at all, and not with piano
except for the nice little early Beethoven
Sonata for Horn and Piano, Opus 17, which
is the musical high point of the disc.
Unfortunately, even this piece runs into
trouble, for it is hopelessly mixed up in a
gross labeling blunder of the kind only a
musical ignoramus could let pass. It's not on
bands 1, 2 and 3 of side 2, as both the record
label and the jacket notes say, but on bands
6. 7 and 8. Which implies that Golden Crest
needs n musician or two to help out around
the office.
-
Haydn: Cello Concerto in D, Op. 101
(original). Wagenseil: Cello Concerto in
A.
E.
Mainardi; Münchener Kammeror-
chester, Mainardi.
Archive ARC 3110
It gives me pleasure to re -write these
Archive titles to make sense. In the usual
standard format, this one starts out, like an
address given backwards, with the general
historical period, set forth in large letters,
"Mannheim and Vienna, Series C, From the
'Galant' to the 'Bledermeier'"; then, just
to be perverse, the record lists the unknown
concerto first, followed
last-by the real
item of significance on the record, which
should have been posted in HUGE letters:
the first recording of the famous Haydn
Cello Concerto in its original, unrevised form
Nothing like getting to the point hindside
foremost.
You can forget about the Galant and the
Biedermeler, (I've never heard of the latter
though I can tell you about the former) and
take this as of great interest to an those who
habitually listen to cello music
play
and who, therefore, obviously know the Haydn
Concerto in its usual amplified version,
whomped up for turn -of- the -century taste
(1890) by one Gevaert, from Belgium. The
original is far more tasteful for our ears,
though this performance isn't exactly n
dazzling one.
Herr Wagensell, on the other side, was one
of those worthy musicians who work like
beavers -be turned out, in his busy life, a
mere 87 symphonies and 32 piano concerti,
not to mention this somewhat interminable
but very melodious trifle, a cello concerto
that turned up as recently as 1953 after a
long life in total darkness. The style 1s 1752
and this guy was one of the founders of the
German symphonic way of writing. Well
worth hearing, for from such as he came the musical style of bigger men. including
Haydn, Mozart, Beethoven. The Haydn concerto came thirty years later but you can
hear how much they are alike.
-at
;
it-
-or
Music of the Bach Family, Vols.
Zimbler Sinfonietta, Burgin.
1
and 2.
Boston BST 1006, 1007 stereo
This pleasant collection of works by n
batch of different Bache has appeared and re-
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MAY, 1959
51
www.americanradiohistory.com
appeared in carious furors. Last time I ran
into It was on Livingston stereo tape, via
arrangement with Boston -this was before
stereo disc, of course.
The stereo is excellent. even today. and the
tousle is beautifully played by a group in
part out of the Boston Symphony---maybe in
the whole. Of the two doses. Volume 2 is
m ueh the most interesting, with lovely music
by the three great suns of "the' Bach, written
in what for most of us is roughly the Mozart
manner. 'l'he earlier volume has a somewhat
stuffy suite by a 141111 empura ry of old Johann
Sebastian and it slight-bodied sextet for winds
by the last of all the Buchs, one Wilhelm
Friedrich Ernst, who lasted until the mid
nineteenth century. Neither is much to listen
to purely as musie.
-
Mozart: Symphony »34 in C. Haydn:
Symphony :t.:104 ( "London "). Philharmonia Orchestra,
Kempe.
Capitol -EMI
This is no
stereo disc.. l'd
groat
SG
musical
7150 stereo
b:i 1._a
say. The !nosh. is
iii
s
a
plae.I xcìtii
,
surprisingly lard, nrg,nt cric,, souu11iag as
though done with too big an orchestra, the
temp( hurried and excitable where the music
should be p"et i.- I didn't enjoy either side
a
very much. though the famed l'hilhnrmuiia
is technically accurate enough.
There's a curious lack of feeling here for
the subtleties of phrasing and of harmony,
especially in the Haydn, where Haydn's tricks
of express ion, his wonderful play of harmonic
tension tuml color, are largely ignored as
thought the notes were .lust so many notes.
Nope, not for me,
l'un utterly confused. al this point, as to
the changing significance of Capitol's various
brother-labels. under EDI I. Until now. CapitolEMI has been strictly mono, EMI's stereo
going to Angel with Capitol producing the
American stereo on its own FOS label. Now,
Capitol -EMI goes stereo and where is Angel?
We shall see. As far as we are concerned
there's only 11111. valid distinction in the EMICapitol family of labels, 111111 that is between
with joy at the slightest excuse. when a new
recording arrives. That is, if it's a good one.
This is good in many ways, but especially
recordings made by Capitol in the U.S. and
bp EMI ln England and an the continent.
good in the choral parts, even though the
soloists are of high calibre anti better than in
Debut -John Browning.
Capitol
P
8464
many n performance. The trouble, as far as I
can figure it, seems to he squarely with the
conductor. Ile has tine performers throughout but he doesn't give his good soloists half
a chance.
What happens is this. In the grand, powerful choral numbers, the huge well -disciplined
assemblage of performers simply t at kes over,
within the conductor's fairly rigid bent- and
the music soars in spite of him. So I hear
it. .\ rigid bent, of course, has its Valor when
large amasses of tone must be Pout rallyd and
cuorolivated. Good musicianship, high sincerity of purpose, enmtional fe rear. be:uittful time and remarkable nccuraey are assets
here, both in the chorus anti in the instrumental ensemble, and nothing can stop their
effectiveness.
But when the solo numbers come oolong- often just a single solo voice and iw acconipanying solo melody, to light figured -bass
harmonies-the conductor's feast. rigid beat is
devastatingly bad. You can hear the soloists
struggling; you can feel that their conductor
k simply not waiting for them, giving tlutti
no play, allowing their melodies and phrasings
little chance for alive and huuuuu expression.
1 don't
like it and I'm sure the participants
All
call say is that I Un.u_ht this uetc
young piaalst did a creditable job with the
hit teh Of repertory standard pieces he records
here Chopin. I.iszt, Schubert, Debussy, even
that old finger- twister, the "Flight of the
litinible Bee," hut one New York critic thought
he was lousy. Same critic thought the same
thing about another recording of repertory
music float
found very good, the series of
Chopin reun rdings in stereo by the German
pianist. Kempif, on Loudon. I thought them
1
.
1
terrific.
Who is right? Remember, criticism Is never
absolute. The other critic Is a top man ; his
main concern is the standard repertory and
the daily recital concerts in Nu.' York City:
he is an expert from that point of view. Myown Is more of tut outside viewpoint. outside of New York and onside of the regular
concert repertory, too. Our standards of
ttalue are Undoubtedly somewhat differnu t.
and but legitimately so.
I found Dir. Browning quite musical,
granted an early stage in lois career, emphasizing linger brilliance. I fount( Mr.
Kempff's Chopin musical and gracious, too,
if perhaps unexpected and "different."
Too bad that we aut liuritles can't agree.
(tut, yon know, the lurid really isn't that
shop],.
didn't either.
The recorded sound, like musli of \'ox's
stereo, is big, very live, impressive, but with
curiously illogical details, the claw -up elements /Intl distant ones oddly mixed. Why
are the two lady solo sing "rs close to the mike
on one side, but the solo tenor, in the center,
at a considerable distance? (Could have been
the exigencies of a concert performance, but
that doesn't excuse it for us.t In spite of
these oddities, the general sound is very
pleasing and especially that of the chorus,
which is beautifully picked up and, incidentally, produces a smooth tonal blend that
should be the envy of any choral argutn¡zut.
2, VOICES
Bach: Mass in 5 Minor. Sailer, Wunder lich, Bence, Wenk; Swabian Chorale,
Orch. of 35th German Bach Festival,
Grischkat.
Stereo Vox STPL 511.282 (3)
'l'lr
Bach glass was our of the big things
switched colin my early life
I practically
leges in order to get mixed up in it Iuotleg,
glee clubl- and s.. t ate pr.gci nd 11. swou11
tion, amateur or professional.
'l'eehnically speaking, the reearded stereo
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AUDIO
52
www.americanradiohistory.com
MAY. 1959
cut is adequate and no more, like other recent stereos from Vox. It has a gentle, but
also a veiled sound, not really as crisp and
clear in the highs nor as forceful in the lows
as it should be. (Oddly, the Vox discs themselves have o veiled. grayish appearance; but
this could be a coincidence.)
I admit that I'd prefer not to say the
above, since the entire process of producing
for all concerned and the people at Vox no doubt work
as hard at it as plenty of others in the
business. I sympathize, but can't help myself,
since this is supposed to be my business.
Indeed
feel so strongly about things like
good stereo discs is n headache
just
-I
this that I find myself rooting passionately
for every company that has Iruuhle -and I
practically whoop for joy when success does
come, at last! Vox has improved no end since
its first slightly unfortunate stereo discs and
nobody could be happier that I about it. Not
even Vox.
Mozart: La Finta Giardiniera, K. 196
¡highlights). Soloists, Cam. Acad. des Salzburger Mozarteums, Paumgartner.
Epic LC 3543
Lovely ! This seldom -heard early Mozart
opera is here recorded as an extension of the
excellent Epic Mozart Year keries, which was
mostly under l'aonrgartner. The music is
from Mozart's 18th year and it Is wholly
mature, marvelously complex and wonderfully entertaining, even when the story is
lost in the confusion-and it is, mostly, on
this excerpt record.
Paumgartner is a curious Mozart specialist.
His all -instrumental recordings haven't been
particularly successful. But give him any
sort of Mozart vocal music with orchestra and
he is positively incandescent in his ability to
understand the essence of Mozart's expression
and to get it over to his performers and so,
to you also. You won't need to know too much
about the plot in this piece in order to feel
the drive, the sweep of musical humor and
passion that is in the music.
The story of the opera, if you want it, is
boiled down to a couple of close-packed
-
columns here that actually make sense
which is something to marvel at! Perhaps
you have rend some of the usual synopses of
operatic plots.
Haydn: Theresa Mass. M.I.T. Choral Society, Graunke Orch., soloists, Liepmann.
Music at M.I.T. CS-5B
Several points of interest here. First, of
is the mere fact that this entire
project is part and parcel of n leading .American school of technology. M.I.T. has been
turning things inside out, these last years,
by adding various arts and letters to its engineering coverage, to the astonishment of
many. The M.I.T. Choral Society includes
everybody in the 111.1.T. fancily, down to the
secretaries, but it is conducted by the Music
Department-yep, there is a Music Department. You elderly M.I.T. graduates won't
know your junior colleagues pretty soon.
They'll be reading this column and telling me
where to get off, musically.
The recording was made on tour, in Munich
the orchestra was local, the soloists imported
from the U.S.A. along with the chorus. The
music is, of course, European, and more
power to M.I.T. for resisting the inevitable
pressure on traveling choruses to stick to
American music, come II. or high water.
This is fine music and why shouldn't we
Americans sing it -even on tour?
Performance? Enthusiastic on the part of
the chorus and quite good. too competent
on the orchestra's part. considering they
probably didn't have much rehearsal time.
What bothers me. though. is the group of
four imported American soloists, who spoil
the recording ns far as I ant concerned. Why
do our singers have to bellow their wrsemble
solo parts, as though the high water would
freeze over if they didn't yell? Why so
strident, why so competitive?
This happens again and again, on U.S.
records and in U.S. concerts. Soloists in our
big choral performances act like spoiled
movie stars, or maybe Ilke scared puppy dogs;
they seem mainly interested in getting out
the loudest possible volume on their own
more hysterical than
; each one sounds
the next, and nobody, but nobody, ever seems
to listen to the piece as a whole. European
soloists, in the same music, are very noticeably more musical, more thoughtful, more
aware of the whole as well as its parts
their parts.
Don't ask me why, especially since some
of these soloists with M.I.T. are excellent
singers. Just that old American competitive
urge, I guess.
parts
-
course,
;
;
This Is the Mass. Dick Janaver, narr.
Carmelite Fathers Guild,
(Englewood, N. J.)
The words of the ages -old Catholic Mass
have been the inspiration for vast quantities
of top -quality music during centuries ; thus
everyone who does any singing or music
listening has long since become familiar with
them. It is an oddity of our artistic expression that these wonderful works of music
convey a powerful emotional inspiration to
vast numbers of people who are very largely
unaware of the original (and continuing) Intent of the Mass itself -music aside.
Some of the greatest of musical Masses
weren't even intended for Catholic use in the
actual service, notably the Bach Mass in B
Minor. A large number of fine musical Masses
are no longer usable by Catholics due to
changed practices-most particularly, those
of Mozart, Haydn, Schubert, and others of
recent times.
All of which is the background for my
own curiosity about this disc, which, I
thought, might add perspective to my purely
musical knowledge of this religious rite. It
did, to an extent. There is quite a lot of interesting information included in the commentary which helped to relate the familiar
words of the musical texts to the actual
Catholic Mass itself, as now practiced, and in
its long history over the centuries.
But for those who are not Catholics the
record will not he easy to appreciate. Its
intention would seem to be primarily to educate Catholics In their own faith and, point -
(Continued on page 77)
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MAY, 1959
53
www.americanradiohistory.com
shine, the soloist who started it all, for Hall
is a much hotter player, easily the most
incendiary around today. Better yet. forget
about the title tune altogether and concentrate on an Ellington medley. of more than
nine minutes duration, and Hall's two original blues. They are played by a sextet in
which he is joined by Emmett Berry, trumpet,
and trombonist Vic Dickenson. On four numbers, Hall solos with the rhythm section of
Ellis Larkins, piano, Milt Hinton, bass, and
drummer Jimmie Crawford. His Louisiana
origins are recalled on Good Cook, and Don't
Give Me Sympathy. Nat Hentoll produced the
date and the engineer was Lewis Merritt.
amcì
af fiat,
CHARLES A. ROBERTSON'
STEREOPHONIC
Harold Farberman: Max Roach With The
Boston Percussion Ensemble
Mercury SR36144
Known in previous recording to most audio
fans who delight in percussion displays,
Harold Farherman's Evolution, in this expanded version, now has parts in each of the
three movements for Max Roach. A colorful
work. originally written to show the capabilities of this section of the symphony orchestra,
it becomes even more revealing of the contemporary percussionist's art by the addition
of cadenzas invented by an extraordinary Jazz
drummer. lie settles into the strange setting
with characteristic ease and, in his capacity
to swing. is certainly not inhibited by the
surroundings. Everette Firth, Charles Smith,
Arthur Press, Harold Thompson, Walter
Toknrczyk. Lloyd McCausland, and Irving
Farberman comprise the ensemble. It enlists
an awesome number of accessories, including
n nail file to strike the triangle. Corinne
Curry and Al Portch join in an interlude for
soprano voice and French horn.
The scene of the recording last August was
the Music Barn of the Music Inn, and Farberman, besides conducting, was impelled to
write n suite especially for his guest artist.
It is composed of eight brief sketches, each
inspired by some place, or person, connected
with the summer school at Lenox, Mass. By
way of n warmup, variations are played on
Pop! Goes The Weasel, designed by Farberman to demonstrate in turn how Bach,
Beethoven, Debussy, and Stravinsky might
score it for the ensemble. The final episode is
in Roach's own distinctive style. The fine
performance is well- realized in stereo.
Rex Stewart: Rendezvous With Rex
London SJA2001
Two varied groups are concerned in this
production by the English critic Stanley
Dance. and the contrast between therm is as
broad in mood and style as the talent of Rex
Stewart. On the first session, the cornetist
indulges in an outing with n loosely knit
septet. playing in the free -swinging style of
the 30's. The accent is on the blues. and they
are well represented by George Stevenson,
sounding like a younger Higginbotham on
trombone, and Haywood Henry, alternating
on clarinet and baritone sax. George Kelly, n
newcomer on tenor sax, lives up to Coleman
Hawkins' recommendation and aided in arranging Stewart's themes. But much of the
drive comes from n spirited rhythm section,
in which the vigorous Willie "The Lion"
Smith, on piano, is abetted by Leonard Gnskin. hnss, and drummer Art Trappier.
The second session is an example of what
Stewart is doing today and another instance
of his collaboration with Dick Cary. who
doubles on piano and trumpet. The three
originals are graceful vehicles for Hilton
Jefferson's attractive alto -sax passages, with
the embellishments of Garvin Bushell. playing
bassoon and clarinet, and of guitarist Everett
Barksdale. Joe Benjamin is on bass and the
`782 The Parkway, Mamaroneck, N.
Y.
drummer is Mickey Sheen. The compositions
carry mainstream jazz to the furthest point
reached on any of the recordings made under
Dance's aegis. and are an extension of the
work Cary did with Bobby Hackett. Stewart
will be returning Dance's visit this summer,
leading a group of tourists on a Jazz junket
through England and the continent, via
Sabena Airlines, from July 11th to August
8th.
Coleman Hawkins. The High And Mighty
Hawk
London SJA2005
The theme of this date. another produced
by the English critic Stanley Dance, is set on
the opening ad -lib Bird Of Prey Blues, which
ends Coleman Hawkins taking as many
choruses as he pleases. He stops at seventeen,
Buck Clayton, trumpet, Hank Jones,
pinno. and Ray Brown. bass, stretch it out to
a total of eleven minutes. The tenor sexist is
in rare forni, and his marvellous tone sounds
bigger and fuller than ever when given the
depth of stereo. He plays two ballads against
boned bass. rhapsodizing over My One And
Only Lore, and You've Changed. Mickey Sheen
is on drums, and Jones contributes two bright
originals in Vignette, and Get Set.
The Kingston Trio: Stereo Concert
Capitol ST1183
Harry Belafonte: Love Is A Gentle Thing
RCA Victor LSP1927
The production facilities at Capitol finally
have caught up with stereo and current releases are appearing at the same time as the
monophonic versions. This concert seems to
be something special for stereo though, and it
presents Dave Guard, Bob Shane, and Nick
Reynolds in Liberty Hall at El Paso, Texas.
during a recent tour. All but one number are
contained in their two previous albums and
the exception, Raspberries, Strawberries, is
enjoying popularity as a single. New are the
personable introductions, the ready audience
reaction, and the you-are -there presence of
stereo.
Harry Belsfoate's program of folk songs Is
finely wrought, encompassing the Italianate
Bella Rosa, Green Grow The Lilacs, Delia's
Gone, and Times Are Gettin' Hard. As is the
case with Frank Sinatra, his voice becomes
more intimate and immediate to stereo. Both
of these albums will sell and sell, and they
will sell quite a few people on the value of
stereo.
butt
Monday Night At Birdland
Roulette SR52015
The musician's traditional night off is ohserved at Birdland by the engagement of a
group of his fellows. ranging front a corps of
Afro -Cuban drummers to
fair portion of n
big band, who happen to be nt liberty. For
the purposes of recording one of these informal gatherings. the conventional small
hand lineup is followed, with Hank Mobley
and Billy Root on tenor sax. Lee Morgan,
trumpet, and trombonist Curtis Fuller. On
Welkin' and Bag's Groove, the solos Pow unrestricted and unedited. All The Things You
Are and There Will Never Be Another You,
two shorter melodies, fill out each side. The
rhythm is Specs Wright, d:unns, Tommy Bryant. boss, and Ray Bryant, an agreeable
pianist. Syd Toxin, who selected the players,
announces them briefly.
Bell Sound Studios is responsible for the
stereo setup and, as one who was present
during part of the proceedings can attest, it
conveys a better impression than can be
found in some sections of the club. It provides a sent midway back and in the center.
Two microphones, placed to register audience
reaction in stereo, find the relatively sophisticated crowd saving its response until n
number ends. But they do make use of the
hall as n natural echo chamber. giving the
horns a depth which few studios can attain
without an artificial effect. A second set of
fanr numbers front the session is due under
the billing, "Another Monday Night At Bird -
land."
Edmond Hall: Petite Fleur
The
United Artists UAL4028
hit parade status of l'etite Fleur.
popularized by Chris Barber's hand, has re-.
turned clarinetists to favor and given Edmond Hall his first LI' as n leader. You can
forget about comparisons with Monti Sun-
Stewart- Williams & Co: Porgy And Bess
Revisited
Warner Bros. WS1260
With the release of the film, the Gershwin
melodies from his folk opera are due for n
bounteous reprise on records. Among the first
to arrive is a setting, arranged by Jim Tim which aims at preserving the work's
operatic aspects in the medium of jazz. This
is accomplished by assigning roles to the most
vocal of jazz instrumentalists and supporting
them with strings and woodwinds on the
ballads, switching to a big studio hand for
such lively excursions as There's A Boat Dat's
Leavin' Soon For New York. Trumpeter
Cootie Williams is cast as Porgy, and Rex
Stewart swings his cornet into action as
Sportin' Life. As Serena. Lawrence Brown
sadly intones My Man's Gone Now, and employs his opulent trombone to sketch the
beauties of Summertime.
Hilton Jefferson, alto sax, plays Bess. and
Pinky Williams' baritone sax is heard in
Jake's A Woman Is .4 Sometime Thing. With
so many alumni
participating, a distinct
flavor of Ellington, front one of his best
periods, permeates the ten selections. The
soloists occupy the renter of the stereo stage.
mens,
Si
Zentner: Swing Fever
Bel Canto SR1014
Organized to participate in the revival of
big band sound on Its first date for this label.
the Si Zentner unit now is filling engagements
on the West Coast. In an encouraging reversal
of the trend that sent bands into the studios,
it also employs a manager who believes,
"stereo recordings-like this album
have
to be the medium to sell the youthful public
to the point where they'll want to go out and
dance again." The formula seems to he working for Zentner who, playing in the Dorsey
style, lends one of the best trombone sections
in the business. Engorde, one of the four hand
originals among the dozen numbers. spots
Don Lodice and Modesto Briseno in stereo
on a tenor sax duel. Other soloists nre pianist
Bruce McDonald, Vince Fnlzone. trumpet,
and Mel Pollan on bass. Danceable qualities
are stressed on Beautiful Friendship, The
Song is You, and Bye Bye Blues. And Bel
Canto, which started with stereo tapes and
jumped to stereo discs, branches out into the
monophonic field by also issuing a brilliantly
recorded version on single channel.
-will
AUDIO
54
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MAY, 1959
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Henri Rene: Compulsion To Swing
RCA Victor L5P1947
With every mood master from Jackie
Gleason to Michel Legrand sticking a thumb
into the jazz pie, it was inevitable that Henri
Rene also would try to pull out n plum. By
depending upon musicians deft enough to
make them swing. he loads his arrangements
with musical pleasantries and often voices
the brasses and saxes like a string section.
They are nicely grouped around the soloists
in stereo, with Ilymie Shertzcr's alto sax
featured on Cry Mc A River, and clarinetist
Walt Levinsky describing Nature Soy. Urbie
Green, trombone, and Doc Severinson, trumpet, appear at frequent intervals. If Don't
if can A Thing If It Ain't Got That Swing Is
defined by Al Caiola, Arthur Godfrey's favorite guitarist. And when is Arthur going to
take time from affairs of state to prepare a
jazz album?
Robert Prince: Western Sunset
Warner Bros. WS1259
Jack Fascinate: Palm Springs Suite
Capitol ST1157
Admirers of Robert Prince's Opus Jazz,
written for Ballets U.S.A., may be disappointed to find him arranging a mood album,
but it turns out to be a mood with 'a difference. A lonely harmonica and a soulful guitar
are balanced against a string section, hended
by an admirable cellist. His writing is always
tasteful and close to the folk song tradition.
The tunes have all worn well, and include
Colorado Trail, Cool Water, Red River Valley,
and Streets of Laredo. After using considerable space trying to trace song origins, the
liner writer neglects to mention soloists.
Jack Fascinato depicts a newer West, one
tamed into a desert playground for the tired
personnel of Hollywood studios and drive -ins.
His scenes are gaily colored and more animated than some of the native chamber jazz
groups. In fact. John Grans plays a livelier
French horn than he does on his own LP's.
John Williams, piano, and Bob Gibbons.
guitar, solo among strings, woodwinds, and
marimba. Both sets are well contrived in
stereo.
June Christy: The Song Is June
Capital Sil11AIrene Kral: The Band And I
United Artists UASS016
Always noted for the ability to project her
warm personality-, :tune Christy embraces half
a dozen ballads with the maturity which
comes from experience. Most young singers
pick up a set of mannerisms, loosely known
as a style. to make n quick impression on the
listening public. Those adopted by Miss
Christy hit the mark and were widely copied,
but the time came when they hampered her
further development. Now they are integrated
into a larger frame, to he accentuated only
when essential to a song, as may be witnessed
on Saturday's Children, and Spring Can Really
Hang You Up The A lost. Among the four contrasting jump tunes are The One I Love. anti
de Long As I Live. Pete Regolo affords n
backing that emerges brightly in stereo.
Irene Kral, still -very much a band singer
after a tour with Maynard Ferguson, credits
Miss Christy as being her first inspiration. In
recording with a band which has never hind a
vocalist, she proves that n temerity to enter
where others have feared to tread will never
prevent her from gaining experience. She prefers fast tunes, plunging recklessly into Detour Ahead. and Comes Love, but relaxes on
Lazy Afternoon, and I Let A Song Go Ont Of
My Heart. Boston's pride, the Herb Pomeroy
band, is also less tense than on some of its
own LPs, and engineer Ray Hall set it up for
stereo. If you wonder where the good songs
are, after listening to _mho and T \', try looking into these albums.
Ray Martin: Parade Of The Pops
RCA Victor L5P1960
A visit to a college football game, or one to
see the local high school team in action. will
disclose that the music of the marching hand
is being invaded by a new sound and bent.
The top tunes of the day nre featured in nr-
rangements which stem from rock and roll,
jazz, gospel song, and country and western
music. Ray Martin captures the spirit of this
new approach on a dozen numbers, making
exciting display pieces of Manhattan Spiritual, Peter Gunn, Red River Rose, Gotta
Travel On, and The Children's Marching
Song. Designed to serve as models for music
educators, they will influence an estimated
three million young musicians in 60,000
bands. If you want to know what you will be
hearing at the game next fall, here it is in
the fdll impact of stereo, with irresistible
tempos played by a crack baud.
MONOPHONIC
-
Elektra Folk Song Kit
William Loughborough: Bongo Drum Instruction
Folkways FI8320
Everything that falls within the scope of
the folk song kit seems to be accounted for,
and the painstaking care of its preparation
results in an ideal for other fashioners ofinstructional guides to aim at. To withstand
repeated playing, the record itself is pressed
of a special hard material. The level of the
guitar is kept high in relation to the vocals
and the accompaniments are clearly heard.
At the start of the basic course, which occupies one side, Billy Paler explains various
tuning methods, including one using the
Standard A note sounded on the first band.
On the second side, Milt Okun sings twenty
songs, slowing fast tunes to a walk for the
first verse. Besides the manual containing
exercises and texts, there is a separate chord
chart.
Although Paler stops just when things become complicated and Okun barery'touches
on the blues, an effort is made to help the
student in further progress. Lee Hayes writes
a personalized and informative review of the
subject. In addition to a bibliography and
discography, there is a directory of where to
go in principal cities across the country for
advice, the purchase or repair of instruments,
and the all- important association with other
aspirants. For the student removed from
these centers, a sequel might attempt an
analysis of various guitar styles, including
blues artists, and give hints as to how some
effects are accomplished.
Already on the market with fete Seeger's
guitar guide, Folkways moves on ' to offer n
rhythm primer for the beginner on bongo
drums. William Loughborough, a West Coast
percussion expert, demonstrates the rudiments and gradually lends into more complex
patterns. lie concludes with a startling exhibition of the tones it is possible to extract
from two -octave chromatic tympani, bass marimba, and a chromatic log drum set. His
manual is limited to the required exercises,
and the pupil wholnasters the fundamentals
may want to consult the Elektra directory.
It should help him meet a rhythmically-insecure folk singer.
'
Ross Sings A Song With Mulligan
World Pacific WP1253
Peggy Lee: Like Men
Capitol T1131
If you have waited twenty years, as I
have, to witness as close n marriage between
vocalist and instrumentalist as the one which
existed between Billie Holiday and the late
Lester Young, be advised that for me the
wait is over. The association of Annie Ross
and Gerry Mulligan is surrounded by the
same magic and, even though it should prove
not to be as productive, this record will be
spoken of twenty years from now. Her experiments in vocalese, so well realized with
Jon Hendricks and Dave Lambert, appear but
briefly to frame Leonard Bernstein's I Feel
Pretty. The uncanny sense of timing gained
from this training, however, leads to her remarkable phrasing of such ballads as All Of
You,-Let There Be Love, and This Is .4ltcaye.
The blend of her voice and the leader's baritone sax is a deeply emotional experience.
Because two sessions were held, the quartet
varies between Art Farmer or Chet Baker,
trumpet, Henry Grimes or Bill Crow, bass,
with drummer Dave Bailey.
Perhaps this sort of emotion is too much
to expect from female vocalists when so few
of them can manage humor without seeming
Annie
I
coy or cute. Peggy Lee, an exception, treats
her men with -a -largesse that is witty and appealing, and one can only wonder what she
will say next to My Alan, Bill, Good For
Nothing Joe, or Charley, My Boy. Jack
Marshall's settings are jauntily played.
George Lewis: Concerti Blue Note 1208
In his prefnctory remarks to this concert,
held in California in 1954, George Lewis
makes the comment that "After a year or so
you may not hear this music any more." On
his second successful tour of England, at this
writing, he is still going strong at fifty -eight
and plans to pay his first visit to the continent. But it marks the last time banjoist
Lawrence Marrero recorded with the band,
and pianist Alton Purnell is now settled In
Los Angeles. The performance is relaxed and
uninhibited, with no advance notice to the
musicians that it was to be taped. Ten of the
familiar tunes are played, including Gettysburg March, Red Wing, Ice Cream, Burgundy
Street, and Walking With The King. Kid
Howard and Joe Watkins share the vocals.
The circumstances limit the recording quality
and Jim Robinson's trombone is off mike at
times. The brilliant Lewis tone is favored,
however. and his clarinet is heard clearly as
it weaves in and out of ensembles. And that,
after all, is the reason for buying the record.
Cannonball Adderley: Things Are Getting Better
Riverside RLP12 -286
In one of his all too rare appearances
away from the Modern Jazz Quartet, vibist
Milt Jackson joins Julian Adderley on a
blues- studded album calculated to show their
respective talents as improvisors supreme.
They experience the sanie instinctive reactions to the blues and hold views on the subject which lead to complete rapport on Adderley's two originals, and on Jackson's Bisce
Oriental. Included is Budd Johnson's Serves
Me Right, and Jackson illuminates his present position on Gillespie's Groovin' High.
They stray lightheartedly into the pop field
for tuneful invention on Sidewalks of New
York, and Just One of Those Things.
Percy Heath, also on leave from the MJQ,
underscores the vibes with a well -timed bass
line. The pianist is Wynton Kelly, and Art
Blakey shows the subdued side of his drumming: As to the sound, Jackson's vibraharp
has rarely fared better than in this recording
by Jack Higgins. But it is Adderley, playing
with emotion and fine conception, who captures the imagination by reaffirming his newly
acquired stature as a major figure on alto sax.
Cecil Taylor: Stereo Drive
United Artists ÚA55014
Ornette Coleman: Something Else!
Contemporary C3551
Now that n large portion of the jazz public
is busily absorbing Thelonious Monk, those
individuals who like to consider themselves
in the vanguard are looking for more abtruse
subjects. On the East Coast, they are already
learning to cope with a challenging pianist
who studied at the New England Conservatory of Music and is quoted on the liner as
stating, "The object of any jazz musician
who has had this background is to bring it
to jazz- combine it with jazz, anti see what
happens." Another youngster who picked up
a few classical devices to glibly pad out pop
tunes? Not a bit of it. Sample any of Cecil
Taylor's choruses and you will find him
working entirely within the framework of
jazz, using his knowledge to create new
rhythmic and harmonic lines. His originality
is such that the difficulty of finding compatible instrumentalists is at once apparent.
Possibly because John Coltrane worked so
well with Monk and because Taylor is most
often compared with Monk for want of -a
better example, he is used on this date.
playing tenor sax under a pseudonym. As
valid as this theory may seem, there is no
great meeting of minds until Taylor subjugates his personality to that of accompanist
for Coltrane and trumpeter Kenny Dorham.
By adapting to his plastic rhythm patterns,
Chuck Israels, bass, and drummer Louis
Hayes come closer to his concepts. Neither
of the originals is his own and his style is
AUDIO
56
www.americanradiohistory.com
MAY, 1959
w
best typified on Like Someone In Love, and
Just Friends. The producer, Tom Wilson, first
brought Taylor to light on the defunct
Transition label. That record soon may be n
collector's Item. If you can find a copy, hang
on to it.
Ornette Coleman, his counterpart on the
West Coast, has n strikingly similar harmonic approach and is equally evasive of a
stated heat. A self- taught alto saxist from the
Southwest, he played in territorial bands
before settling in Los Angeles. Finding musieioIs willing to accept his style is among
his troubles also, one leader even paying him
not to play. On the nine originals chosen
for his debut, he heads n disciplined quintet.
with Don Cherry on trumpet. Bassist Don
Payne. pianist Walter Norris and drummer
Billy Higgins, form an exceptionnl rhythm
section. If these two unique figures meet some
day in their travels, they are likely to find n
common ground and it should be interesting
10 "see what happens.'
The Other Side Of Benny Golson
Riverside RLP12 -290
An intent to give Benny Colson the free-
dom to emphasize his playing ability, rather
than make the usual demands on his talent
as an arranger and composer, explains the
album title. Its significance seems somewhat
diminished in the presence of the three originals he prepared for the Cite. not to mention
several other LP's on the market with examples of his skill as a tenor. saxist. But It
does grant him more extended solo space
than before, and presents him with different
musicians. Pianist Barry Harris is brought
in from Detroit, and Curtis Fuller plays
trombone. Drummer Philly Joe Jones and
bassist Jymie Merritt are old friends from
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As Golson's natural tendencies are toward
form and order, he would not seem comfortable playing some of the empty phrases
current today and it is just os well that his
own compositions are included. They reflect
an Interest in the work of John Coltrane and
indicate, to these ears. an endeavor to
render its substance into more digestable
portions. Other numbers are Fuller's Slimptona..Junior M incé s Jubilation, and Richard
Evans' 7'his Night.
Randy Weston: Little Niles
United Artists UAS5011 (stereo)
Mal Waldron: Ma1-3 /Sounds
Prestige 8201
Contrary to the impression conveyed in
the popular press, many jazz musicians are
reasonably domesticated and willingly forego
lucrative road trips for the comforts of
home. Being dependent upon the festive
nature of dancers and nightclub crowds, the
opportunities to express this aspect of their
social life are scant in the normal course of
events. The LP audience has proven more
receptive, however, even developing to the
point where it demands a fuller portrait of
the artist than the convention,. of entertainment permit. Perhaps more than any other
factor, this outlet has encouraged the artist
and broadened the base of jazz. Without it.
these two young composers and pianists
would hardly venture to go on record so
firmly as heads of households and write so
tellingly of the joys of parenthood.
Randy Weston's seven vignettes, all In
three -quarter time, revolve around his two
children and their playmates. Ills followers
already know them from piano versions of
the title tune and Pam's Woltz, bait, they are
reintroduced here in Melba Liston's arrangements for a sextet, in which she plays trombone. Ray Copeland. trumpet, and Johnny
Griffin, tenor sax, seem to regard children as
boisterous imps and are inclined to be disruptive of Weston's intentions. They are
best realized on a trio number, Let's Climb
A Hill, with bassist George Joyner and
drummer Charlie l'ersip. Stereo gives the
piano a little clearer definition.
Mal Waldron, in pieces dedicated to his
daughter and wife, is more fortunate iii his
choice of companions. His sexte: includes
flutist Eric Dixon. cellist Cato Scott, and
Art Farmer, whose muted trumpet adds
(Continued on page 58)
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www.americanradiohistory.com
LARRY ELGART at, the CONTROL CONSOLE of his RECORDING STUDIO
(Note the AR-1 monitor
loudspeakers, in stereo)
greatly to the beauty of Portrait Of .4 Young
Mother. The subject joins In with a wordless
lullaby and also sings Harold Arlen's For
Every Man There's A Woman. Familiar jazz
paths are traced In two of Waldron's compo
*tithing. but there is much in both albums to
Intrigue anyone who is seeking something off
the beaten track.
Prestige Blues- Swingers: Outskirts Of
Town
Prestige 7145
Eddie Barclay: Americans In Paris
United Artists UAL3023
Jerry Valentine, all arranger who started
with Earl H Ines and Billy F.cksti ne. indulges
in fond remembrances of their sound to help
introduce Prestige's new policy of recording
studio bands under n house name. By way of
updating, Jerome Richardson's flute is
where Omer Simeon's clarinet once
would he heard on Blue Flute, and Jelly,,
Jelly. The hearty tones of Jimmy Forrest's
tenor sax are a feature of the title tune. and
two Valentine blues originals. Other soloists
are Art Farmer, Buster Cooper. Pepper
Adams. Ray Bryant and Tiny [:rimes. In
their revival of big bands, other labels have
scarcely touched these freewheeling Chicago
groups and this healthy example may impel
one of them to place Earl Hines at the helm
scored
once more.
Quincy Jones, on arranger who enlivened
various European bands during his recent
stay on the continent, attempts to confer a
like favor on the works of such composers as
Henri Salvador and Michel Legntnd. That
he succeeds in lifting these polite tunes above
the level of mood music is due mainly to the
presence in the Eddie Barclay orchestra of
jazz expatriates Don Byes, Lucky Thompson,
and Kenny Clarke. The relief they show when
pe.ndtted to attack Nat and Julian Adder ley's Sereaonette, the most successful number
of a dozen, is quite joyous. Among the
French soloists is violinist Stephatne Grappelly.
Ravi Shankar:
LARRY ELGART, RCA VICTOR RECORDING ARTIST
One
of the most exacting jobs for
a
speaker system is that of studio monitor
in recording and broadcast work. Technical decisions must be made
on the basis of the sound coming from these speakers, which will affect,
for good or for i
he quality of a record master or FM broadcast.
ion speaker systems, although designed primarily
acoustic s
for the home, a e idely employed in professional laboratories and studios.
Below is a partial list of companies using AR speakers (all models)
as studio monitors:
AR
Dawn Records
Concertapss- Concertdisc
Elektra Records"
WGBH
Mastercraft Record Plating,
Canterbury Records
WPFM
Raleigh Records
Concert Network stations
WBCN, WNCN,
WHCN, WXCN
WXHR
Counterpoint Recordings
(formerly Esoteric Records)
Magnetic Recorder and Reproducer
'. Dubbings
AR speaker systehts, complete with enclosures
-the
AR -1,
AR -2,
and AR -3 -are priced from $89 to $225. Literature is available
for the asking.
ACOUSTIC RESEARCH, INC.
24 Thorndike Street, Cambridge 41, Mass.
India's Master Musician
World Pacific WP1248
timed to coincide with Ravi
This release is
Shankar's second concert tour of the United
States and needs no recommendation as far
as his earlier audiences are concerned. They
will welcome n refresher course in the
principles behind his music before meeting
him again. And those persons who plan to
observe his remarkable troupe in action for
the first time will benefit from a modicum of
preparation before attempting to unravel
the mystery of a Raga, or the rhythmic
cycle known as Tala. The exciting climactic
passages of one of his sitar improvisations,
however. speak a universal language and
require no introduction, especially when his
accompanists make their entry. They are
Nod,' C. Mullick, playing the dronelike tambour', and Chntur Lal. whose responses on
tabla comprise some of the most accomplished drumming ever recorded. The sound is
excellent, but you may wonder in passing
why ASCAP's protective seal is considered
necessary on this difficult Indian music.
Italiano
Audio Fidelity AFLP1893
Renato Carosone!
Capitol 710163
Jo Basile: Cafe
Aldo Conti, in joining his tenor voice to
the accordion of Jo Basile. defines the romantic side of Italy, singing a dozen tunes
much as any armchair tourist might expect
to hear them after n meal at a small cafe.
Aided by a chorus and complement of strings.
he is warmly sentimental and creates a
mood reminiscent of n sunny land. Included
in the fine recording are Domenico Modngno s
Lazaarcila, and Renato Cortisone's Marty:-
retie.
When the armchair dreamer actually makes
the trip, a phonograph most likely will displace the live tenor of his imagined cafe and
the voice will be that of one of these popular
singers. A dozen of Carosone's hits. recorded
in Milan, find him borrowing a boogie -woogie
beat from this country, and going to Spain
for Torero! His style, as spirited or humorous as the latest novelty song, can also be
romantic.
AUDIO
58
www.americanradiohistory.com
MAY, 1959
dirvear;e_
EQUIPMENT PROFILE
(from page 40)
Special care should also be exercised in
soldering the switch lugs. The danger is of
solder flowing into the switch contacts and
preventing operation; one will only damage the switch by forcing it. When soldering, the lug should be oriented sideways or,
better yet, downward, to prevent solder
from flowing into the contacts. Again, use
of a low wattage iron with a small tip and
avoiding excessive solder flow will minimize the danger. Should solder get into
switch contact, apply the soldering iron
close to the contact until the solder melts,
and immediately rap the switch on a hard
surface, which should shake out all the
solder. Guard your eyes.
Lest these cautions on soldering frighten
away the would-be constructor, it should
be noted that a fair amount of the soldering in the reviewer's kit was done by his
9% -year old son, with no damage to either
party.
When inserting the tube sockets into t'r
printed circuit board, make certain that all
nine of the pin lugs and the ground lug
have gone through their respective holes;
there is a possibility of one or more of the
lugs being bent so that they remain on top
of the board instead of coming out on the
under side. Be sure that each lug has gone
through as far as possible, making a snap
fit with the under side of the board.
Finally, be sure to solder each lug to the
board. There is a possibility of misunderstanding the instructions and assuming
that the snap fit between the socket lugs
and the board is sufficient. The reviewer
understands that at least one constructor
who sent his amplifier to Lafayette for
service came to grief because he failed tt
solder the socket lugs.
In one respect this reviewer does not
agree with the soldering instructions,
namely that "a good mechanical connection
should always (reviewer's italics) be made
before soldering, by crimping the leads on
the terminals with your pliers." Not that
Lafayette is wrong, but the reviewer belongs to the school of thought that crimping is unnecessary unless its purpose is to
hold a component in place while awaiting
soldering at a later time. A good mechanical connection is not sufficient in itself,
whereas a good electrical connection (a
well -soldered one) is This means inserting
a lead straight into a lug without crimping
and then soldering. The advantages are
quicker assembly and greater ease of removal of a component should the need
arise. If the lead is crimped around the
lug, heat must be applied while the lead is
unbent, possibly long enough to damage
other components soldered to the same lug.
Moreover, in the process of wrestling with
the crimped lead one may physically damage the component in question, other components, or the lug. To illustrate, the reviewer made an error in mounting a resistor
of incorrect value to a switch, and it happened that one of the lugs involved had
two additional leads soldered to it. The
process of removing the wrong resistor and
putting in the right one was greatly facilitated by the fact that the leads were not
crimped. A little heat briefly applied to
the lug enabled one lead to come right out
and the other to slip right in. Even if a
lead is not to be soldered immediately, the
reviewer avoids crimping it. Instead, he
uses just enough solder to hold the lead
in place, without filling the lug. When all
the other leads are in place, he fills the lug
with solder.
E -23
IIB.
AUDIO
MAY, 1959
FOR THE AUDIO PERFECTIONIST
!
Highest quality, easiest assembly, compatible stereophonic
and monophonic equipment in money -saving kit form.
NEW DYNAKIT STEREO 70
independent power amplifiers -35 watts
continuous, 80 watts peak on each channel.
* Unconditional stability using new DYNACO
A-470 Super -Fidelity output transformers.
* All the features of the renowned Dynakit
Mark III, including exclusive Dyna Biaset,
highest quality conservatively rated components, superb listening quality and hand-.me appearance.
* Can be assembled in 4 hours through use
of factory wired printed circuit assembly.
*2
* Only $99.95° net including cover.
DYNAKIT STEREO CONTROL
* Adds complete stereo control
to two
preamps without noise or distortion.
* Unique blend control fills in "hole
in middle."
* Level, balance, loudness, channel reverse, and dual tape monitor controls.
*Only $12.95' net.
* PM -2S
Stereo panel mounting kit
makes integrated package from two
preamplifiers and Dynakit Stereo Control Unit $5.95.
DYNAKIT PREAMPLIFIER
* Finest quality available
of circuitry and components.
*Lowest distortion and noise.
* Easiest assembly using pre- assembled printed circuit.
* Handsome styling selected for
display at Brussels World's Fair.
-
Power supply available for
2
* Only $34.95s net.
$8.95` net
pre- amplifiers PS -1 Kit
DYNAKIT MARK
* Ease
III
uniquely
simple circuitry and printed circuit
construction with factory-mounted
parts.
of assembly due to
* Dyna
Biaset (patent pending) for
simplified adjustment and complete
freedom from effects of unbalanced
components.
* Dynaco Super- Fidelity output transformer. This is the finest available
transformer of its type for the most
critical audio uses.
*
60 watts
$79.95° net.
DYNACO
INC.
611
I
l l
Iii
Available from leading Hi -Fi
brochure available on request.
EXPORT DIVISION
Mark
Mark III also available with added 70 volt
Mark
-70 584.95° net
output.
N.
FORTY -FIRST
dealers
STREET
everywhere.
Descriptive
'Slightly higher in West
PHILADELPHIA
25 WARREN STREET
NEW
4,
PA.
U.S.A.
YORK 7, N.
Y.
59
NEW PRODUCTS
CBS- Eytron Preamplifier Tube. This
new tube, designated Type 7247, is a dissimilar- section double triode which combines in a single envelope the first two
stages of preamplificatlon for a high fidelity amplifier. Section one is a hi -mu
triode with low hum and noise levels. It
is intended as an amplifier for low -level
Wharfedale Speaker System. To meet
the demand for a small full -range speaker
system, G. A. Briggs has designed the new
Model WS /2, a complete two -speaker assembly in a sealed, patented enclosure. It
requires no additional speakers to achieve
a wide frequency range, and will operate
efficiently when driven by an amplifier of
only moderate power. Measuring only 11"
x 10y," x24 ", the WS /2 is finished on all
sides and can be used singly or in pairs,
horizontally or vertically. It is an ideal
unit for adding stereo to any existing
high- fidelity speaker system. For full information write to Dept. 50, British Industries Corporation, 30 Shore Road, Port
inputs. Section two is a medium -mu triode
having characteristics similar to those of
a GC4. It is suitable for cathode -follower
or large -signal phase splitter service.
Twin 150 -ma heaters may be connected in
serles or parallel for operation from 12.G
or 6.3 volts. Complete technical data for
the 7247, including typical circuit diagrams, can be obtained by writing to CBS Hytron Advertising Service, Parker Street,
Newburyport, Mass., and asking for Bulletin E -317.
E -1
Stereo Record Demonstrator. Record
dealers, as well as others that have use for
stereo listening without distraction, will
welcome this Permofiux development.
Providing as it does binaural auditioning
of stereo records, it frees the dealer from
such chores as placing speakers, adjusting
volume, etc., for each individual listener.
The demonstrator consists of a hi -fi stereo
amplifier with total output of 12 watts, a
transcription -type turntable with 4 -pole
motor and pickup arm, diamond- stylus
cartridge, and two sets of headphones
which may be switched independently
from binaural to monophonic listening
when desired. The unit can be used to
demonstrate monophonic records as well
as stereo records, and is equipped with
jacks for feeding external speakers. Individual tone controls are incorporated for
each channel. Further technical information will be supplied by Permoflux Products Company, 4101 San Fernando Road.
E -2
Glendale 4, Calif.
60
Washington, N. Y.
E -3
Dynaco Triple-Function Amplifier. The
Stereo 70 contains two independent 35watt amplifiers which can be used for
stereophonic or monophonic reproduction,
or as a. dual -channel unit when desired.
Based on the use of patented circuitry
and a newly -developed output transformer,
the Dynaco A -470, the amplifier provides
full rated output from 20 to 20,000 cps at
less than 1.0 per cent total harmonic distortion. Intermodulatlon ranges from .05
per cent at normal listening levels to 0.5
per cent at rated power. A dual printed circuit assembly, supplied factory wired,
simplifies construction and permits completion of the amplifier in less than live
hours under normal circumstances. Detailed information on the Stereo 70 is
available from Dynaco Inc., 617 N. 41st
E -4
St., Philadelphia 4, Pa.
Stereo Cartridge. Made in England by
Acos Laboratories, this turnover cartridge
has been added to the line of phonograph
accessories manufactured and merchandised in the U. S. by The Duotone Cotn-
output, and contains built -in RIAA equalization. Frequency response is flat within
± 1.5 db from 40 to 15,000 cps with a roll -off
of 10 db at 18,000 cps. Channel separation
is said to be better than 25 db at 1000 cps.
The special "lok -tite" turnover mechanism
is designed to maintain the stylus at a
perfect 45 -deg. vertical- lateral angle to
the record grooves, thus assuring balanced
stereo reprcducti'.r..
E -5
Bulk Tape Eraser, More frequently than
not, the average tape recordist finds that,
after tape erasure, there is enough residual noise remaining on the tape to make
itself heard over a new recording. By
simply placinga reel of tape on the Robins
Model 99 bulk eraser, and rotating it a
couple of times, complete erasure takes
place and background noise level is
lowered by as much as six db below that
achieved by the average erase head. The
device handles reels up to 10 ins. in diameter, and erases tape up to one -half inch
in width. It operates on regular 117 -volt
60 -cycle line voltage. Manufactured by
Robins Industries Corp., 36 -27 Prince St.,
E-s
Flushing, N. Y.
Transistorized Power Supply. The EICO
Model 1020 serves ideally as a universal
power supply for operating transistor
radio receivers, hearing aids, preamplifiers. instruments, and other transistor
devices under repair, development, or
study. It is also intended for use as a
variable bias supply to bias transistors or
vacuum tubes in circuit development.
Ripple is 0.5 per cent at full load. Two
Type 2N256 power transistors are incorporated in the circuit to permit output
voltages up to 30 volts. Output is continuously variable and is monitored by a
dual -range voltmeter (0 -6, 0 -30 volts
d.c.). Maximum output current capacity is
150 ma from zero to 12 volts; 200 ma
from 12 to 24 volts. and 300 mn from 24
to 30 volts. The 1020 is available in either
kit or wired form. Manufactured by Electronic Instrument Company, Inc., 33 -00
Northern Blvd., Long Island City 1, N. Y.
EA
pany; lCeyport, N. J. Built .around a piezoelectric element, it delivers 0.8 to 1.0 volt
Harman-Kardoa Stereo Receiver. Like
its predecessor, the monophonic "Festival," the new H -K stereo "Festival," Model
TÁ230, is a complete electronic center on
a single compact chassis. It is supplied
with optional copper -finish or hardwood
enclosure. Incorporated in the Stereo
Festival areseparate AM and FM tuners
for simulcast reception, dual preamplifiers
AUDIO
MAY, 1959
!,:rrx'.:..::.,.,,
4,--
with input facility and control for every
stereo function including FM multiplex,
and a 30 -watt dual power amplifier. Features include the new H -K friction -clutch
tone controls to adjust bass and treble for
each channel separately. Once used to adjust system balance, they may be operated
as conventional ganged controls. Preamp
filaments are d.c. heated to insure freedom
---tiw.
.
:
.
..rar ,+....- -..._-
:
.-
1
WORLD'S FIRST AND ONLY
15- TRANSISTOR FM -AM
PORTABLE RADIO
!
TFM-151
from hum. Separate electronic tuning bars
are provided for FM and AM. Controls include AFC. contour selector, rumble filter,
scratch filter, mode switch, and record tape equalization switch. Two high -gain
magnetic inputs are provided for each
channel. Ideal for those situations where
unsurpassed performance and compact
size are of equal importance. the Festival
measures but 15- 13/16 "w x 6%s "h x 123/4"d,
including enclosure. Full technical information will be supplied upon request
by Harman -Kardon, Inc.. 520 Main St.,
Westbury, N. Y.
E -8
Silicone Record Spray. Developed as an
effective means of shielding records
against dust and grime, Sil -Spray is a
new silicone "mist" recently introduced
by Jensen Industries, Forest Park, Ill. A
si
:spray
Look What
AUDIO Magazine
Says About It:
(issue of 1/59)
"The TFM -151 sets
a heu, standard for
quality performance"
"Sony deserves
praise for both its
design and construction"
Now, for the first time, you can enjoy delightful FM music wherever
you are in your car, while you travel, at home even in fringe areas!
Plus, of course, all AM broadcasts! And SONY TFM -151 works on
ordinary flashlight batteries, lias built -in telescopic antenna, weighs
only 5% pounds! Enjoy it for good living. And as a special gift, it
makes rare good giving!
$149.95
-
-
-
concentrated solution, it comes packed in
an aerosol container complete with its
own cloth applicator. The silicone mist
may be applied directly to the record
grooves or sprayed first on the ejoth, then
rubbed lightly on the disc. Sit-Spray also
serves as a static eliminator.
E-9
Program Equalizer. Developed for use
with broadcast, motion- picture, recording,
television, and industrial audio equipment,
the StudioSound Equalizer has input and
output impedances of 600 ohms and an
insertion loss of 14 db. It provides up to
16 db attenuation and 12 db boost at 90
and 100 cps, and at 3, 5, 7, 10, and 15 kilo-
FOR HI -FI you can use SONY TFM-151 as an FM -AM TUNER in
your Hi -Fi system! And as AUDIO SAYS "It could not be told apart
from a high quality standard FM -AM tuner."
15 transistors, including SONY super -diffused grown
transistor, 4 germanium diodes, 1 germanium varistor, built -in 4" x 6" high-
SOME OF THE SrrCIFIcATIONS
fidelity oval type dynamic speaker Output power is 180\1N, frequency response
is 20 to 20,000 cycles plus or minus 1 db,
signal to noise ratio is 50 db.
SONY also stakes the WORLD'S SMALLEST TRANSISTOR RADIOS
SONY TR61O
/
World's smallest,
most powerful
AUDIO
I
SONY TRESS
World's smallest,
most powerful
6- transistor,
cycles. The unit is available on a standard
rack panel with all keys, knobs, and jacks;
or component parts and dials may be
purchased separately. The equalizer is designed for use In individual microphone
or program circuits. For further information write Studio Supply Company, 711 S.
Victory Blvd., Burbank, Calif.
E -10
'
8. transistor,
pocketportubte
radio. Size 1"
s 23'," s 44/5"
pocketportable
539.95
$19.95
rodio. Size
.5
mfg. by the
/,"
2s
Oh" z1 %"
SONY CORPORATION
THE PEAK OF
ELECTRONIC PERFECTION"
distributed nationally by Delmonico International,
Division of Thompson-Starrett Co., Inc., 42.24 Orchard Street, Long Ill9nd City 1, N. Y.
At fine radio stores and department stores, or write Dept. d- jar name of nearest store.
MAY, 1959
61
www.americanradiohistory.com
THE ONE BOOK FOR THE
AUDIOPHILE'S LIBRARY
Sargent- Rsyment Stereo Tuner. Designed with the fastidious user in mind,
the Slt -1000 stereo tuner leaves virtually
nothing to be desired In its outstanding
performance characteristics. Use is made
of the Sargent- Rayment -developed 2 -tube
AM detector which is capable of reproducing AM signals with an absolute minimum of distortion. A specially engineered
10 -kt. whistle filter allows maximum frequency response, yet provides infinite suppression of inter- station interference.
Broad- and sharp -bandwidth AM reception
cascode circuit which provides
high sensitivity and maximum signal -tonoise ratio. The AM section consists of a
high -gain r. f. stage, a pentagrid mixer
and oscillator, and an i. f. stage which
neered
provides either broad- or sharp -bandwidth
louve.
switch controlled. The FAI channel utilizes an advanced gold- plated frame grid
easende tube, permitting FM sensitivity of
is
i
microvolts for 20 db of quieting. For
maximum gain and stability, the SR-1000
uses the new low- voltage i -1' tubes, followed by limiters and a fully -balanced
broad-band 1:íl io detector. FI audio response is within ± 1.11 dl. from IS to 22.000
,ps. AM response is flat to S2110 cps hi the
broad- bandwidth tuning Position. Special
I,t'ovisions are incorporated for PSI- multiplex operation, including output jacks for
adapters and wiled -in automatic switchMg. The SR -1000 is fully described in a
new 12 -page catalog which is available on
request from S:,rgent- itnynieut hump:uty,
4926 1:. 12t1í St.. Oakland 1, Calif.
8 -11
Stereo Balance Indicator-'che vtrs:tti lit y
of this instrument promises to make it of
distinct interest to every owner of a
stereo system. Featuring two Separate
coils set in IL single magnetic field, each
stereo channel feeds an individual coil
through a full -wave bridge rest ifler. When
both signals are equal and balanced, the
resultant deflection on the meter scale will
0.S5
NEW
FROM HOWARD W. SAMS
The AUDIO Cyclopedia"
by HOWARD M. TREMAINE
Greatest Single Compendium of
Knowledge On Audio and Hi-Fi
1280 fact -packed pages
Covers over 3400 topics
Over 1600 illustrations
Seven years in preparation
Includes latest on Stereo
JUST OUT! 'I'he one single book with the
moat comprehensive coverage of every phase
of Audio. Gives you concise. accurate explanations of all subjects in the fields of acoustics, recording and reproduction...each subject instantly located from index by unique
section and paragraph numbering system.
26 SECTIONS! Contents include: basic principles of sound; acoustics and studio techniques; constant -speed devices. motors and
generators; microphones; attenuators;
equalizers; wave filters; transformers and
coils; sound mixers; VU meters; tubes transistors and diodes; amplifiers; disc recording; cutting heads; recording and reproducing styli; pickups; magnetic recording;
optical film recording; motion picture projection equipment; speakers, enclosures and
SPECIAL PRE -PUBLICATION
SAVINGS ORDER FORM
Howard
2201
E.
W. Sams a Co., Inc., Dept.
46th SI., Indi
Hs 6, Ind.
E
-59
Please send me
Enclosed is S
copies of THE AUDIO CYCLOPEDIA at the special
prepublication price of $16.95 each. understand books are returnable within 10 days for
full refund.
Pre- publication pries u/ $16.95 is nosed until May
31, 1969; thereafter the price will be 919.96.
I
Name
Address
City
Zone
State
,t
the dual
,
to. While it is most effective when directed
against a plain wall ur ceiling, ,lo"dlite
may be used in any other nonuser which
sails the momentary moodd
the user. It
may also be used as a co us,ution:tl fixture
for general room illumination by removing the lens- pattern insert. .I:tnufactured
br \Inndlite ('tnup:uly, 2115 Griffith l':u'k
Bled., Los Angeles :la, Calif.
E -14
New Precise Line. \larking its entry
into the high fidelity field, Precise Development Corp., Oceanside, X. Y., has just
introduced two new stereo amplifiers and
a tuner. The Integra, Mark XXIV, incorporates two 20 -watt channels, which
may be a
biped for monophonic use.
This unit, pictured, accommodates phone,
tuner, TV, and tape inputs in ali arrangement which permits switching to two tuners, love TV sets, or tuner and TV for
certain types of stereo broadcasts. In the
Piton. position it will accommodate long-
l'
headphones; power supplies; test equipment;
audio -frequency measurements; installation
techniques; stereophonic recording and reproduction; special charts and tables. It's
the vital, complete reference book for the
serious audiophile.
PRE -PUBLICATION OFFER! Available for
limited time only at the special pre- public
tion price of only
$16.95
Order today -save $3.00. Pre- publication price good only until May 31,
1959. Thereafter, price will be $19.95.
Pro,yuoney range
watt amplifiers is within 1.0 db fr
211
to 20,000 cps. A total of 14 input and output jacks is provided, including connections for :ni FM multiplex adapter. The
front panel contains 13 operating controls and switches. Connections for 4 -, S -,
and 10-ohm speakers are provided on each
channel.
For full information, write
Fisher Radin Corporation, 21 -21 44th
Drive, Long Island City 1, N. Y.
E -13
"äoodlite." This i s a ucw onoept in
decnr:tttvt h,:me lighting. Essentially a.
portable lighting fixture, it permits the
use of partially colored light in a darkened
room to achieve startling effects. It is designed to establish a visual stood in keeping with the type of music one is listening
read zero. Individual channels may be
measured by means of two slide switches.
Stable meter action and protection from
peak voltages are afforded by damping
networks. Maximum meter sensitivity of
120 microamps may be varied by a 7-step
range aunt col. By properly positioning this
control, the movements may he used as
\'l' meters when connected across a 600ohm load. t 'a to loped Model TM -66, this
instrument is distributed by Lafayette
R:ulio, 165-OS Liberty Ave., Jamaica 33,
E -12
Fisher Stereo Receiver. The Model 000
Receiver costa ills separate FM and AM
tuning sections, a stereo audio control
with 1'I operating controls and switches,
and two power amplifiers providing 40
watts continuous power in stereo operatin, all on one integrated and compact
chassis. Only the addition of speakers is
required for the unit to function as a
high -fidelity system for the reception of
FM -AM stereo programs, as well as for
standard FAt and AM programs. In addition, associated equipment may be plugged
into the 600 to make it a complete sound
center utilizing all available program
sources, such as records, tape and FM
multiplex broadcasts. The r. f. stage in the
FM tuner employs an especially-engi-
netic, ceramic, and crystal cartridges, and
slide switches vary loudness contour,
select between four modes of operation,
reverse channels, and control a.c. power.
The Eclipse Mark XIV amplifier is a
highly simplified amplifier of lower power
output accommodating tuner and phono
inputs. The Perfecta AM -FM tuner employs cathode follower output, and incorporates a tuning meter. The function
switch permits connecting a TV set and a
ceramic pickup for a magnetic pickup
through a preamplifier) with full front panel control. Full information will be
sent upon request.
8 -15
AUDIO
62
www.americanradiohistory.com
MAY, 1959
NEW LITERATURE
General Electric Company, West Genesee St., Auburn, N. Y., has prepared an
entirely enlightening 24 -page booklet
titled "Fifteen Minutes to Stereo." Directed strictly to the layman, this publication does an excellent job of filling the
demand for a succinct statement of just
what stereo means to the average home.
In all respects it lives up to its subtitle,
"A Basic Guide to Stereo Hi -Fi." Available at G -E component dealers for 25
cents.
Developed and
Guild- crafted
by
Philips
of the
...the
Netherlan
we/co
co
Sargent-Raymnt Co., 4926 E. 12th St.,
Oakland 1, Calif., displays its complete
line of high quality tuners, amplifiers and
audio accessories in a handsome new
12 -page catalog which has just been released. Colorfully illustrated and replete
with technical specifications of all items
discussed, including the new S-R multiplex adapters, this brochure should be
read before making final decisions in
assembling your stereo music system. It
is available on request.
E -16
University Loudspeakers, Inc.,
.80
new line
profaalonat
rigid trams
construction
of
4 posts
-way binding
5
i
LOUDSPEAKERS
S.
Kensico Ave., White Plains, N. Y., announces a new product catalog containing
.
full information, illustrations and specifications of all new and current University
public- address speakers and components.
Grouped together are the following main
categories of speakers and accessories:
Trumpets; Paging and Talk -Back; Submergence -proof speakers; Ht -Fi Weatherproof Dual -range Systems; Super Power
Projectors; Portable Soundcasting Systems, and Drivers and Accessories. The
final two pages of the catalog contain hi -fi
speakers and enclosures suitable for commercial installations- Available free, on
written request.
E -17
Amplifier Corp. of America, 398 Broadway, New York 13, N. Y., is now distributing a six-page brochure describing and
illustrating the new line of TransMagnemites, a series of transistorized, battery operated, spring -motor portable tape
recorders designed for professional field
applications. Single- and multi-speed
models with or without VU meters are
available and are listed with their respective recording characteristics tabulated
for easy reference. The recorders' operations are concisely explained and complete
technical specifications, recommended accessories, and direct factory prices are
included. The brochure will be mailed
free upon written request.
E -18
French Electronic Directory. The second
issue of the buyer's guide to the French
electronics industry has just come off the
press. Completely brought up to date and
considerably augmented, this directory
provides the most comprehensive comparative source of information of every
industrial product manufactured by the
French Electronics and allied products
industries. It contains addresses of all
French electronics firms, 600 pages of
short -form technical catalogues listing all
available products, over 100 pages devoted
to manufacturers and sub -contracting
firms, as well as a description of the industry itself, its structure, and a corn plete professional directory.
The directory is in two volumes, solid
cover, with 1100 pages, and weighing two
Pounds. Expensively produced, with some
750 color pages, the two -volume set costs
6100 Fr., (approximately $17.50), and will
be found of exceptional value to those who
either buy from or sell to the French
market. It is the first four -language reference work, (French, English, German,
Italian), devoted to a single industry to
be compiled specifically on a Common
Market basis for the benefit of engineers,
procurement departments, and civilian and
military users of electronic equipment.
The directory may be obtained from Pub licité et Editions Techniques, 161, Blvd.
St. Germain, Paris VI °, France.
AUDIO
featuring new magnets
of 4000RIAL
Tlconal -7
alloy
magnet
(30% more powerful than alnico)
Standard E.I.A.
mounting holes
This new line of 5" to 12" loudspeakers is designed
to match the quality requirements of the discriminating music lover
at a surprisingly moderate price.
The world's greatest buys on the basis of listening
quality, the T -7 series incorporates voice coil magnets
of Tlconal -7 steel, the most powerful of modern magnet alloys, for maximum efficiency and damping .
constant
dual cones for wide frequency response
impedance resulting in an extremely straight response
curve
longer effective air -gaps and extra high flux
density to provide exceptional transient response and
to eliminate ringing and overshoot.
-
.
A0-5277M
.
.
...
...
AD-3800M
'twenty
Pow./
f I fineeice Toll nu.
l.m,.l
Model
I10-2690M
Sit
C61818 6681 Peck
o 5277M
J^
20
30
O,6277M
,2^
20
80d87764
8^
6
AO 3800M
8^
m
ae,penu
audlepEde
(,p,
400,p, (uo..eu,)
Me,
,.'/.
,34.000
35,8.000
572 50
30
)°/.
08.000
35.18.000
3000
l0
I0/.
58.300
50.20.000
76.00
IO
6%
26.200
75.10,000
0.00
60.3500M
5"
3
5
%
26.200
30.10,000
8.34
AO 3600M
6.0^
6.0
6
0
55y.
26.200
PO.. 8.000
6
0
757.
15.200
70-,0.000
705
675
AO 2600M
,ro re
/Co'EXHIBITION'
SPEAKER ENCLOSURES
Available in three sizes in hand- rubbed Mahogany, Walnut,
Blond or Cherry finishes. The "Rembrandt," (26" x 214z"
1744" deep) Walnut or Cherry $99.50; Blond $94.95; Mahogany $91.00. The "Van Gogh," (233/4" x 133/4" x 113/a"
deep) Walnut or Cherry $59.95; Blond $55.50; Mahogany
$51.00. The "Vermeer," (1842" x 12" o 6- 15/16" deep')
Walnut or Cherry $35.00; Blond $33.25; Mahogany $31.00.
May be placed horizontally or vertically.
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The "HAGUE "; Completely integrated quality speaker system. Two high -efficiency T -7 loudspeakers in an acoustically
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For further descriptive literature write to:
NORTH AMERICAN PHILIPS CO., INC.
High Fidelity Products Division. Dept. 3A5
230 Duffy Avenue, Hicksville, L. I., N.Y.
MAY, 1959
63
www.americanradiohistory.com
Sound
Talk
What's in an Audience?
by John K. Hilliard
HAROLD LAWRENCE'
Director of Advanced Engineering
WHAT SPEAKERS FOR STEREO?
Sound engineers agree that the finest
stereo reproduction can be achieved only
by two identical speaker systems of exceptional quality. Short of this ideal, however,
the premise is muddled by an ever- increasing number of unfounded claims ... most
of them based on sales philosophy rather
than scientific fact.
Actually, the proper selection of stereo
speakers is quite clear. Due to certain
psycho- acoustic effects, one exceptional
speaker system and one of moderate abil-
ities will provide better stereo than matched
speakers of intermediate quality. This is
only true, however, if the lesser speaker
meets certain requisites.
The two speakers must be similar in frequency response and character. In the high
end of the spectrum they must have the
same limits. At the low end, they must be
similar down to 100 cycles. Below that point, the performance of the lesser
speaker is relatively unimportant.
If the lesser speaker goes down to only
300 cycles or has major irregularities in its
response,
a
phenomenon called the
"orchestral shift" will occur. This shift
results from the fact that the sound from
any given instrument is reproduced from
both speaker systems. The comparative
loudness determines the auditory location.
If an instrument is "placed" in the lesser
speaker and then plays into a frequency
range where that speaker is inefficient, it
will then be louder in the better system
and will appear to shift to that better
system.
Speakers that are inefficient below the 300
cycle point will not provide true stereo.
This is obvious because the 300 cycle point
is above middle C on the piano, 70 cycles
above the primary pitch of the female
voice and nearly 200 cycles above primary
male pitch. For full stereo it is therefore
imperative that the lesser speaker efficiently reach at least 100 cycles.
All ALTEC
speaker systems are similar
in their exceptional smoothness of fre-
quency response, have a high frequency
limit of 22,000 cycles, and are efficient
below 100 cycles in the lower range. This
regularity in response, range, efficiency
and quality is the reason why ALTEC
speaker systems are noticeably superior
for stereo reproduction.
For further information concerning the
best elements for stereo, write ALTEC
LANSING CORPORATION, Dept. 5A
1515 S. Manchester Ave., Anaheim, Calif.,
a_ -..
161 Sixth Ave., New York 13, N. Y.
its inhabitants
nearly as many varieties of musical
fare as there are flowers in the Botanical Gardens. This abundance of musical activity often makes it impossible to
avoid missing some fine concerts, especially
when, during the height of the season, the
Metropolitan Opera House, Carnegie Hall,
and Town Hall each may be presenting important attractions on the same evening. A
critic like Irving Kolodin (music editor of
The Saturday Review) can overcome this
hurdle by shuttling between 39th and 57th
New Yonx CITY offers
Streets to see part of each performancein anticipation of the schedule conflict, he
has probably seen a dress rehearsal of the
Met's production. But non- editors will have
to content themselves with reading the
reviews, hoping to catch the missed concert the next time around. However, the
likelihood is that only
a
tiny minority of
music lovers will be upset by the duplication for, as any eclectic concertgoer will
inform you, the audience overlap between
different musical events is lower in quantity
than is generally assumed. In fact, for each
kind of concert, there is a corresponding
audience.
The Debut Audience
First, let us consider the audience attending the debut of a pianist. The artist
in this case is not a protégé of Sol Hurok,
has made no recordings, and has won
neither the Leventritt Award, the Brussels
Competition, nor the Moscow Tchaikovsky
Prize. He is merely one of numerous young
musicians who plan to mark the beginning
of their concert careers in the usual manner- namely, by means of a New York
recital: With the proper financial backing,
he has rented Town Hall, paid for the
printing of tickets and programs, and seen
the notice of his forthcoming recital duly
listed in the programs -of- the -week page of
the Sunday papers. He does not expect to
sell many tickets; indeed, his chief concern is to get enough free tickets into the
hands of friends and relatives so as to
have a respectable -looking, even if "papered," house.
If he comes from a large family, the
chances are that a sizeable crowd will be
in attendance. On these occasions, the hall
takes on the festive atmosphere of a
wedding reception, as cousins who have not
seen each other in years exchange noisy
greetings. There is much hand -waving,
cries of recognition and boisterous conversation. Here and there one notices an
oasis of silence in the form of a husband,
father, or uncle who has been dragged
X26 W. Ninth St., New York 11, N. Y.
against his wishes to listen to a piano
recital when lie would prefer to remain
home and watch television.
The house lights dim and the audience
tears itself away from its animated social
activity to focus attention on the stage. It
betrays a lack of familiarity with concert
decorum by the nature and timing of its
applause. From the initial ovation that
accompanies the young performer's entrance, to the final round of applause after
the last bow, the intensity never varies. It
is no exaggeration to say that this audience
will clap at the slightest pause, for example,
between variations, movements of a sonata,
preludes and fugues, and at the deceptive
close near the end of Invitation to the
Dance, while the more knowledgeable members of the audience (probably fellow students) loudly shush their less sophisticated
neighbors. By the time the slow movement
of the "Pathétique" Sonata has arrived,
not a few bored male relatives will have
fallen asleep, ,only to be nudged awake at
regular intervals by their indignant spouses.
The
Intellectual Audience
There are no drowsers in the intellectual
audience. Intense concentration is the order
of the day. Gatherings at intermission time
are more subdued than those at debuts;
politics, the theätre, art, books, and psychoanalysis are the principal topics of
conversation. To be worthy of the intellectual audience, music must provide a
sound basis for discussion of ideas. Here
is a partial list of the most "verbalized"
composers and types of music favored by
this audience:
Stravinsky -Close association with poeta,
choreographers,. painters (Cocteau, Diaghilev, Picasso, Chagall, Bakst, Nijinsky,
Auden, and so on).
Weill-Between -the -wars German political and social degeneration a fascinat-
ing backdrop for Weill's bitter musical
commentary.
Schoenberg- Irresistible attraction to intellectual audience due to radical implication of serialization (12-tone system).
Harpsichord recitals, "musica antigua,"
madrigal groups, and so on- Automatic
exclusion of music of the Romantic Era.
Webern -A fascinating miniaturist ; also
called musical counterpart of Paul Klee,
Swiss abstract painter.
The above examples do not include Fire bird, Petrouchka, and Transfigured Night
because these pieces have become "popular"
works in the symphonic repertoire. This is
the kiss of death. For when the general
public takes a work to its collective bosom,
you can be sure that the intellectual audience will abandon it sooner or later.
AUDIO
64
www.americanradiohistory.com
MAY, 1959
The Lieder Audience
Coolness gives way to warmth, theorizing
to sentiment, in the case of the lieder
audience. Imported from Europe before
World War II, this is one of the most
attentive audiences in the world of music.
The word "attentive," though, is too weak
a description; rapt is better, especially
when referring to a Lone Lehmann recital.
The overflow audiences that attended this
great artist's performances shortly before
her retirement transported Town Hall from
43rd Street to the Musikverein in Vienna.
The hush that filled the hall was almost
palpable, handkerchiefs daubed at misty
eyes, and the applause rolled in ardent,
emotional waves. The magic of Lehmann
and her audience has never quite been
duplicated in recent years, though the same
audience gives such artists as Dietrich
Fischer -Dieskau, Elisabeth Schwarzkopf,
and Irmgard Seefried warm receptions.
The Controversial Audience
The audience drawn by controversy normally contains a large percentage of nonmusical elements. The postwar appearances
in New York of politically- tainted German
artists turned Carnegie Hall into a political
arena, while the arrival of the cream of
Russia's musical and terpsichorean talent
set New York agog. But after the smoke
of controversy has cleared away, and the
artists' intrinsic values calmly appraised,
the political element diminishes in size and
importance.
Opera Audiences
Although the Metropolitan Opera is a
tea room in comparison with some of Italy's
boisterous opera bouses, the claques, official
and otherwise, give Met audiences their
special flavor. Everyone is familiar with
the more flamboyant bravo -shouter, but
there are more subtle examples of the
species. For example, take the case of the
young lady who attended a performance of
Lucia di Lammermoor in which ber favorite soprano sang the title role. When Lucia
dies in the opera's penultimate scene, leaving the stage to the tenor,. the fan saw no
point in remaining for the rest of the
performance, and walked out of the house
looking like a "this is where I came in"
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The Folk Song Audience
Youth is the most noticeable ingredient
in the folk song audience. Many of its
members play guitar or recorder, collect
discs by the Weavers, Alan Lomax, and so
on, and congregate around the fountain in
Washington Square Park to listen informally to bearded modern troubadours.
A comprehensive survey of audiences
would have to include the subscription
night at the Philharmonic, opening night
at the Metropolitan Opera House, benefit
audiences, and many others. The next time
you attend a concert, look around you and
try your hand at audience analysis.
.
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ELECTRONICALLY PATTERNED
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others fall significantly wide of the
mark, usually in the direction of inadequate bass boost, causing the sound to
be definitely on the "thin" side.
Therefore if one intends to use his
control amplifier for equalizing the signar from a tape head, it is a good idea
to have the control amplifier checked
out by a technician aganist the NARTB
curve. This can be done by playing back
a test tape and checking for flat response
at the output of the control amplifier,
of by feeding signals from an audio oscillator into the tape -head input and
checking whether the response at the
output of the control amplifier conforms to Fig. 3. If response does not
deviate more than 3 db from the NARTB
curve between 50 and 15,000 cps, it is
acceptable.
For those having older control amplifiers without an input for tape head, it
is fairly simple to convert one of the
phono positions -such as LP or "European"-so that the equalization will instead be NARTB. Thus one can accommodate the signal from a tape head
which is fed into the magnetic phono
jack. But one must then of course remove the phono plug from the jack. On
the other hand, some control amplifiers
have two magnetic phono jacks that can
be used simultaneously, and in this case
one of the jacks can be converted to
tape head use. Or, if there is an input
jack marked "microphone," this can be
converted. Figure 4 shows some typical
circuits that will produce NARTB playback equalization; parts A and B show
losser type equalization, while C shows
feedback equalization. If none of these
circuits is suitable for the particular
control amplifier, information can generally be obtained from the manufacturer of the amplifier in question on
modifying the phono equalization circuit to produce NARTB equalization
instead.
If no other alternative is available,
one can simply feed the signal from
the tape head into the magnetic phono
input jack. Amplification will usually
be sufficient, but because of the difference between the RIAA and NARTB
curves frequency response will be as
shown in Fig. 5; bass will be insufficient,
there will be a slight hump in the middle range, and the upper treble frequencies will suffer. Some degree of correction can be achieved by using the bass
control for bass boost, but there is still
apt to be a significant departure from
flat response in this region because it is
AUDIO
66
www.americanradiohistory.com
MAY, 1959
Fig. 6. Tape playback amplifier -Pentron
CA -11.
unlikely that the characteristic of the
bass control will exactly complement the
bass deficiency shown in Fig. 5. It is not
feasible to compensate the hump in the
mid- range, because attenuation by means
of the treble control would aggravate
the treble deficiency at the high end.
Recording
Unlike a phonograph, the tape transport is also capable of recording, given
suitable electronics. But recording elec-
tronics differ significantly from playback electronics in two vital respects:
1. An oscillator is required to furnish
high -frequency bias current to the record head, in order to bring distortion
Fig. 7. Another type of tape playback
amplifier- Viking
PB60.
down to acceptable levels and to increase
the amount of signal recorded on the
tape. Bias current is also used to energize the erase head, so that the previous
signal on the tape will he erased before
it reaches the record head. (However,
this is not a strictly necessary feature,
although it is virtually universal; one
could instead use a bulk eraser (a large
a.c. electromagnet) to erase the tape,
which is often done by those seeking
maximum results.)
2. A record level indicator-meter,
magic eye tube, or neon lamp
required to indicate whether the signal
being recorded is too great, breeding excessive distortion, or whether it is too
small, resulting in a poor signal -to -noise
-is
ratio.
that some manufacturer will eventually
bring out such a unit.
But as things stand, by purchasing
only a transport the audiofau limits
himself to playing tapes recorded by
others-either commercial tapes (that
are considerably more expensive than
phono discs of equivalent playing time)
or tapes recorded by friends. If one does
not own an FM tuner, or if the content
and quality of FM programs in one's
locality offer no incentive to preserving
them on tape, the absence of recording
facilities may not be missed. On the
other hand, many use their tape recorders extensively for copying discs
they have purchased. With proper care
of the machine and the tape, the latter
can be played thousands of times without suffering blemish (such as scratches,
ticks, and pops in the case of discs) and
without significantly undergoing change
with respect to frequency response and
distortion. Hence the disc can be played
once in order to record a tape and then
he put aside, and the tape can be played
as often as wished instead. In the event
of misadventure to the tape-loss, accidental erasure, damage to several feet
because of a tangle, or the like -the disc
can be brought out again for making a
new tape.
It is very important that the cable connecting the playback head on the transport to the control amplifier be as short
as possible. The head is customarily a
high impedance affair, and 200 µµf or
less capacitance across it produces a
sharp drop in response close to or within
the audio range. The greater the capacitance, the lower is the frequency at which
treble droop begins. A major factor in
this shunt capacitance is that of the cable. Therefore one should use cable of
minimum capacitance per foot (about
25 µµf per foot is available) and of min-
imum length.
Because the signal from the tape head
is very small, just a few millivolts, it is
subjected to tremendous amplification.
Moreover, as shown in Fig. 3, a great
deal of bass boost is applied to it. Hence
any hum picked up by the cable will be
amplified to the extent where it is apt
to be audible. Accordingly, one must be
careful to route the cable from the head
to the control amplifier so that it does
not encounter magnetic fields produced
by motors or transformers.
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Transport and Electronics
Those desiring only
the
playback
These additional requirements mean
PB
that it is far from simple to modify the
Ó MEAD
TAPE
POWER AMPI.
electronics of a control amplifier so that
CONTROL
PB
z
AMPL.
AND SPKR.
AMPL.
__they will be suitable- for- recording- as well as playing a tape. To date, the
writer has seen no control amplifier in
corporating complete tape electronics, Fig. 8. Use of a separate
tape playback
although there is always the possibility
amplifier in an audio system.
AUDIO
FREE
MAY, 1959
LUMBIAl9
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Cost $24.25
CBSHYTRON, Danvers, Massachusetts
A
Division of Columbia Broadcasting System, Inc.
67
www.americanradiohistory.com
4
iú
Fig. 9. Record and
playback tape am-
plifier
-
Webster
Electric.
t)
tl
Q
O
w
â
function, but not owning a control amplifier with proper equalization for a
tape head, can purchase a tape playback
amplifier separately (Figs. 6 and 7) and
use it with the transport of one's choice.
Thus the signal is fed from the playback head to the tape playback amplifier, and from the latter to the control
amplifier, as illustrated in Fig. 8. Again,
if such a course is followed, one must
guard against excessive cable length between the head and the playback amplifier, and one must route the cable to
avoid hum pickup.
If one plans to record as well as play
tapes, it is possible to purchase a complete tape amplifier separate from the
transport, that is, a unit containing both
playback and record electronics. (Figs.
9 and 10). Or one might build a complete tape amplifier on the basis of an
article appearing now and then in the
literature. In either case, one must proceed with greater care and caution than
when purchasing tape electronics that
are integrated with the tape transport.
By an integrated unit we do not necessarily mean that the electronics is physically part of the transport; instead we
refer to a tape amplifier specifically designed for use with a given transport,
whether or not they are on one chassis.
An integrated transport and tape amplifier are apt to have the following advantages:
1. Length and routing of the cable
will minimize high -frequency losses and
hum pickup.
2. The oscillator circuit will be designed to supply the correct amount of
bias current required by the particular
record and erase heads used on the transport. Requirements for optimum performance differ by at least slight
amounts and sometimes by major
amounts among heads of different manufacture.
3. The record -level indicator will sup-
ply a proper reading. The correct
amount of audio recording signal depends not upon the signal (electrical)
delivered to the head but upon the signal (magnetic) delivered to the tape.
For the same amount of signal fed to
two different heads, different amounts
of magnetic flux may be applied to the
tape, resulting in different levels of recorded signal and therefore different
amounts of recorded distortion.
4. Provision for switching from the
play mode to the record 'mode will be
at the transport rather than at the tape
amplifier, accompanied by an interlock
feature to prevent accidentally putting
the machine in the record mode and erasing a valued tape. Usually the interlock
Fig. 10. Record and playback tape am-
plifier- Viking
RP61.
consists of an auxiliary button or lever
that one must actuate in order to bring
the record electronics into use.
5. Equalization will be more specific.
Depending upon construction of the
head, particularly gap width, high -frequency losses will differ somewhat from
one make of head to another. Also, the
frequency response at the very low end
may vary among heads. In an integrated
tape machine, the equalization will probably take into account the deviations of
a particular make of head from ideal
response, so that over -all frequency response is relatively flat.
The term tape recorder should prop-
11. A tape
recorder properiMagnecord S-36B.
Fig.
.
AUDIO
68
www.americanradiohistory.com
MAY, 1959
2
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2 different MODELS
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2
Fig. 12. Complete tape recorder, including power amplifier and speaker.
erly he applied to a unit (for example,
that in Fig. 11) comprising a transport
accompanied by record and playback
electronics, with the playback electronics limited to delivering a signal voltage
capable of driving a control amplifier or
power amplifier -about 1 volt on peaks.
Many tape machines, however, particularly the so- called "home" units, which
are mostly relatively low in price, also
include a power amplifier and a speaker,
as in Fig. 12, so that one does not have
to rely on external facilities for playback. Such a machine may be referred
to as a self -contained tape recorder. The
advantages of a self -contained unit are
obvious enough to require no more than
a few words of comment. The machine
can be taken anywhere-school, church,
friends' homes, etc.-and one need not
wait until returning to one's high fidelity system to hear the results of a recording session. One can check on the
spot whether the recording is satisfactory by playing back the recording. If it
is not satisfactory, circumstances frequently permit one to re- record.
However, there may be some disadvantages. To offer more functions at the
same price or even lower price, there
must be a sacrifice in quality somewhere
-in the transport mechanism, in the
electronics, or both. There is a substantial likelihood that the oscillator will be
a single-ended rather than push -pull
affair. Typically in a tape machine including a power amplifier, the output
stage is a single tube such as a 6V6 or
6AQ5. In the record mode, this tube is
switched to serve as an oscillator. However, a single -ended oscillator has more
distortion than a push -pull one that
uses a tube such as the 12AU7. Minimum
waveform distortion of the bias frequency is important inasmuch as this
distortion produces noise in recording.
It should be added that even in tape
machines incorporating a push -pull audio output stage, such as two 6AQ5's, it
is general practice to use only one of
these tubes as the ocsillator when recording.
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Circle 69A
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a high power tube
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CCU New high power version of the
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KT66 and 6L6 tubes.
For full information, write Dept. XE -19, BRITISH INDUSTRIES CORP., PORT WASHINGTON, NEW YORK
Circle 69B
MAY, 1959
69
www.americanradiohistory.com
DISTORTION STORY
04Ci
lit
STEREO SYSTEM
achieves the full, true potential of stereophonic sound.
Roberts superbly designed transport mechanism. with its hysteresis
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accuracy of 0.2 %. This, with Roberts exclusive Multirase Head,
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Complete Stereo System
ROBERTS ELECTRONICS Inc.
$499
1028 N. LA BREA AVE., HOLLYWOOD 38, CALIF.
Do you know where you can find information about
the current articles in magazines about microwaves, loudspeakers, television
repairing, electronic musical instruments, traveling -wave tubes, transistor
amplifiers, oscilloscopes, or any other electronic subject?
THE OUESTION:
THE ANSWER:
EflODEX
fier.
FORMERLY
MDIOFILE
a new publication, but one which for over ten years has served engineers,
libraries, experimenters, researchers, hobbyists, radio amateurs, radio and TV
repairmen, and anyone else connected with radio or electronics. Covers radio,
television, electronics, and related subjects, and published bi- monthly as a
cumulative index throughout the year, with the last issue of the year an
Annual which may be kept as a permanent record of all electronic periodical
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Not
LECTRODEX -the electronic magazine index-has been expanded to include over twenty publications in the radio and electronics fields. Sold by
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then to find out where it happens and
how to stop it. This is following a development or design approach. But what
the industry also needs is a means for
demonstrating whether these things
happen and giving figures to them. For
which reason standardized tests, applicable externally to the amplifier, ,are
required.
It is suggested that distortion analysis
be based more on the transfer characteristics of the amplifier than on nominal
harmonic or intermodulation statements.
This is readily possible by a comparatively minor adaptation to the circuitry
of a harmonic test meter. A similar but
a little more elaborate modification to
IM test circuitry will enable exploration
of the non -linear effects producing phase
and amplitude modulation at extreme
high frequencies. This should take care
of the high -frequency transient effects
as well as various other peculiar forms
of distortion that give artificially low
readings under more standard measurement conditions.
Further it is suggested that some
standardized loading test be devised for
applying a load of specific phase angle
over a certain frequency range to see the
effect of reactive loading on the feedback of an amplifier. This will be more
informative than merely ascertaining
that the amplifier stays "on the ground"
with a variety of reactive loads.
Finally, to take care of the trigger
overload effects, it is suggested that some
standardized form of data be derived for
presenting information on the performance of an amplifier at conditions representing a specific overload. For example, 10 per cent, or maybe 100 per
cent beyond the nominal output. It would
have to be emphasized that this should
be a definite overload beyond the maximum power capabilities of the amplifier
and will not be satisfied by merely downgrading the nominal rating of the ampli-
!
RADIO MAGAZINES, INC.
Mineola, N. Y.
O. Box 629,
If an amplifier should give 30 watts
undistorted, it would not be a successful
method to rate it at 15 watts just so it
can have a 100 per cent overload without showing trigger distortion. If it will
give 30 watts with acceptable distortion,
then the test should apply an input, that
should give 60 watts, if the amplifier
did not limit at the 30-watt point, and
investigate what happens to the amplifier under this condition, giving figures
in power and distortion for this input
signal. This may seem rather rigorous
but it also seems the only way to specify
absence of undesirable trigger effects
in an amplifier.
Not a little thought is being given by
various groups to the problem of how
to rate, or specify, amplifier's performAUDIO "I
70
www.americanradiohistory.com
MAY, 1959
anee. Since no one distortion test ever
appears likely to be a catch -all for all
the things that can happen to distort
program material, it seems we must
settle for a fairly elaborate test procedure that is reasonably exhaustive of
the possibilities. Then it would seem to
be an opportune time to introduce a
standardized distortion- rating figure,
that will weight the various possible
forms according to their subjective annoyance value, and core up with a performance rating where a higher number
means better performance -less (audible) distortion.
REFERENCES
"Instability in amplifiers," Radio ¢ TV
News, Sept. 1955.
"Methods of measuring and specifying
distortion," Radio 4 TV News, Aug. 1956.
"How an output transformer causes distortion," AUDIO, Feb.Mar. 1957.
"Why do amplifiers sound different 4,"
Radio ¢ TV News, Mar. 1957.
"Electrical adjustment in fitting a new
output transformer," AUDIO, Apr. 1957.
"Output transformer specifications,"
AUDIO, June 1957.
"The fixed bias story," Radio- Electronics,
Feb. 1958.
"Audio measurements," Gernsback Library, 1958.
APPENDIX
transfer characteristic
The
can
be
written as a power series,
y =A(x +bxr +cx'+dx' +...)
(1)
where x is the input, A the amplification,
or its linear term, and b, e, cl, etc., the
coefficients of successive order terms introducing distortion.
If the input is a sine wave, it can be
written
x = V sin tut
(2)
Substituting this for the various order
terms of a in Eq. (1), the following substitutions can be made:
sin'wt =
cos Ant)
(2)
sin'tot = 1/e: (3 sin tut - sin 3wt)
(4)
(1
sin4wt = 1/4(3 4 cos 2cot +
cos 400)
(10 sin wt -5
sin $wt + sin Sc)t)
ainwt=
(5)
(6)
and so on.
Now assuming the transfer characteristic is, specifically,
y= A(x+cx' ex')
(7)
substituting, successively (2), (4), and
(6) leads to the expression:
y =AV
r/ 1+
17,70
.5074
eV'
5eV4
6
4
eV4
16
)
sin
z
=AA'
[x + (b
Low-Cost Hi -Fi with the
SOUND ECONOMY
of
Ab')x' +2Abb'x' +Ab'b'x4]
(12)
For low level amplification, where the x'
term contributes negligible second, the
distortion can be nulled by making
b =Ab'
(13)
Eut at levels where higher orders become
significant, the xi term also contributes n
component of second harmonic, and cancellation will only occur at one level, because
the coefficient of second harmonic will contain different powers of V.
Assuming the simple push -pull case where
two successive stages produce only cubic
terms of curvature has responses represented by
y=A(xcx')
(14)
and
z=A'(y+c'x')
(15)
this evaluates to
z
=AA'
3A'c'e'x'
(16)
about which similar remarks apply.
From the geometry of Fig. 11, which
represents half and quarter wave respectively, of the distorted wave, and the distortion residue, balanced on an average
basis the following relationships may be
derived, assuming each curve may be approximated by a quadrant of a sine wave,
of different periods:
1
b = cos'
Writing
(17)
1+u
1
c=sin' 1+a
(18)
;, the areas
can be derived.
b +c =
The up -going "pulse" has an area of
?ab
(19)
Ac
=-
The down -going quadrant of fundamental
component is f. Equating these areas, which
is the condition obtained by balancing out
fundamental in an average- reading distortion meter,
'ab
f
e
+f =a
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ßb(1-
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J
And the indication is `the
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Model HF 1016 -U (10")
Response, 30-15,000 cps.; bass resonance. 35 cps.; power rating, 15 watts;
16,000 gauss; ash Ib. Alcomax Magnet
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List $61.95
Model 812 -U (8 ")
Response, 50
12,000 cps.; bass
resonance, 65 cps.; power rating, 10
gauss;
2
$18.95
á36.5O
lb. Alcomax
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Model HF 816 -U
as above but with 16,000 gauss; 31
lb. Alcomax Magnet System list $49.95
e
approximation
(8)
-
commercial per-
Stentorians provide a beauty and realism that
has won the unqualified praise of nearly
every leading audio critic and user. both here
0
an expression ran be derived fcr
z
THE
-
As, from the geometry,
D
LOUDSPEAKERS
the
[a+(A'c' c)x'- 3A'ec'x'+
Hence approximate area under each part
(positive and negative -going) is, using this
At a value of V found by equating the Scot
term to zero, the third harmonic vanishes.
This is
=
(9)
5e
For smaller values of V the third harmonic
has a positive coefficient, for larger values
it is negative.
Taking the simple case where two successive stages produce only quadratic
curvature, if the first -stage transfer re-
AUDIO
(10)
and the second stage
z= A'(y b'yr)
(11)
the over -all characteristic is, by substitution,
e
3wt
sin5wtl
=A(x +be)
y
smolt+
8
e
sponse is
n
As a is the peak basis reading, the remaining factor is the correction, plotted in Fig.
11.
Æ
MAY, 1959
$14.95
$29.50
STENTORIAN TWEETERS
Pressure Tweeter Model T -10
Response, 2000- 16,000 cps.; power rating, 5 watts; 25/2 Ib. Alcomax Magnet
System
List $35.00
$20.95
31 /x" Cone
Tweeter Model T-359
Response, 3000 -17,000 cps.; power rating, 15 watts; 9,000 gauss; 8 or. AlcoList $25.00
max Magnet System
$14.95
complete literature on these and many
other famous Stentorian loudspeakers and
audio accessories, see your dealer or write:
For
Barker Sales Company
339 Brood Avenue, Ridgefield, N. J. U.S.A.
Exclusive Sales Agents for the U.S.A. and South America
Charier Member: Inst. of High Fidelity Mfrs.. Inc.
T /M
Whiteley Electrical Rodio Company
71
www.americanradiohistory.com
What's In It
For You ?*
*Better performance
.
.
.
with
a
TELADI CONDENSER MICROPHONE
A precision instrument built to rigid standards.
A professional "condenser mike" for wide
range reproduction under various acoustical
conditions and yet sanely priced to meet the
budget of any studio or serious amateur.
Variable Output
Selective Patterns
High Recognition Factor
Send
NEGATIVE - SUPPLY OUTBOARD CODAN
(front page .23)
volts, commonly lasts more than two
years of continuous commercial service,
an FP 217.9 (300 volts), or an FP 229.3
(400 volts) can be substituted if a
greater margin of safety is wanted. All
plug into the same socket.
Wiring, practically all of which is
under the chassis, can be done in any
workmanlike manner. In the prototype,
power leads were cabled, whereas high frequency leads were run substantially
"point to point ". Although the high frequency portion of this device shows
no tendency to oscillate, it is just plain
good sense to keep the grid and plate
circuits of the pentode separated as
much as possible.
As only one half of the i. f. transformer is used, the other L C circuit
should be opened, to prevent unwanted
resonances and adsorption. Construction
is simplified by liberal use of tie points,
which support minor components, and
firm up the wiring, as in Fig. 6.
After wiring is completed and checked,
and receiver connections provided for,
short the "squelch" connection to ground,
and measure the d. e. voltage from grid
of the a. f. tube to ground. This, which
is largely contact potential, usually
measures about minus one volt on a 11megohm -input vtvm.
Now, with the codan connected to the
power supply and receiver, and a signal
coming in, remove the "squelch" connector short and adjust the "bias" control until the grid -to- ground voltage of
the a. f. tube is the same as before. With
the signal tuned to exact resonance,
adjust the active coil of the i. f. transformer until the a. c. voltage from
pentode plate to ground is at a maxi mum.
Removal of the signal, easily brought
about for test purposes by rotating the
sensitivity control toward zero, immediately silences the audio system. Detuning
the receiver has the same general effect.
Due to the relatively higher selectivity
of the codan, and to the neon -lampproduced snap action, signals will tend
to snap in and out as the receiver is
tuned across the band.
By adjusting the sensitivity of the
codan, all signals below a specific level
can be eliminated, as well as the prevalent interstation "monkey chatter."
Sensitivity of this codan is such that any
signal producing more than 0.5 volts
rins of i. f. output will activate the audio
system at maximum sensitivity setting.
This sensitivity is more than adequate
for most areas, but it may be increased
to about 0.35 volts, rms, by substituting
a 6AW8A for the 6118 here used. This
requires a change in socket connections,
as the two tubes do not have the same
hase connections.
Although the constants and components here shown are for an i. f. of
nominally 455 kc., a simple change in
the pentode plate coil will permit operation at any i. f. up to about 2 mc.,
and down to or below 50 kc. Operation
at 10.7 megacycles is possible, but is not
recommended unless the codais can be
placed in very close proximity to the last
for full particulars and name of your
nearest dealer.
Sole importera
for the United States
D. RA
SOUND
IIII
COMPANY
New York, N. Y.
80 W. 55 St.
IF YOU ARE
MOVING
notify our Circulation Department
at least 5 weeks in advance. The Post Office
Please
does not forward magazines sent to wrong
destinations unless you pay additional postage, and we can NOT duplicate copies sent
to you once. To save yourself, us, and the
your old address and your new address.
Post Office a headache, won't you please
cooperate? When notifying us, please give
Circulation Department
RADIO MAGAZINES, INC.
629, Mineola, N. Y.
P. O. Box
Fig. 6 Under -chassis view of negative supply codon.
AUDIO
72
www.americanradiohistory.com
MAY, 1959
f. tube. At this frequency, the capacitance of the connecting cable becomes a
problem, and one of several alternative
codan circuits will work better than the
i.
PERFECT "HEAR " -PHONES
one shown.
By use of ample margins of safety, as
is recommended here, life of this codan
is substantially infinite, except for the
tube, which is nominally rated at 1000
hours, and which will probably last for
more than 7500 hours, barring accidents.
Tuning, with a codan of this type, is
both simpler and more precise than with
the usual method. Only stations above a
certain (adjustable) level are heard at
all, and these are not heard until they
are almost exactly in tune. Considerable
use of codan- equipped receivers in all
categories from aeronautical radio to
supposedly high fidelity broadcast indicates to the writer that a codan is a
2E
desirable for convenient listening.
AUDIO
ETC
(from page 1$)
the fire. It was at this sort of impasse that
I gave up and pulled everything out, to
start all over again!
Then more credit to Dyna, in a difficult
situation, for the excellent visual hook -up
diagram that comes with the system. It's
just a simple picture of the lay -out from
the rear, with the cables marked in big,
black lines; you follow your nose and plug
them all in. Don't have to have any idea as
to what they connect. (The labels on these
dozens of sockets are, as anybody could
guess, something less than communicative.
I never could have got to first base if I'd
tried to figure them out without any other
help. What can Dyna do, thought How can
you say everything in monosyllables')
Once assembled, your Dyna stereo system is ready for business-almost. All you
need to do, at this point, is to set a couple
of dozen controls in the right positions.
You merely flip the two monitor switches
on the tape preamps from INPUT to TAPE,
move a slide switch at the top of the
stereo control box from TAPE to INPUT
(this, even though there is no tape to be
seen within miles), turn four tone -control
position (I pasted paper over them to keep
them out of trouble), set both preamp
equalization controls at RIAA, switch the
two loudness controls on the preamps to
OFF and the third loudness control on the
control unit from LOUDNESS to VOLUME,
set the channel reverse switch to the position marked CHANNEL (that's what it
says), turn the two volume controls on
the preamps all the way up and the master
volume control on the stereo control unit
about halfway around, move the BLEND
control away from MONO 1 and MONO 2 to
STEREO, the BALANCE control to the halfway
point between RIGHT and LEFT
. .
let's see, have I forgotten anything? Nope;
that ought to do it. And now you'll get
that lovely, velvety semi -silence that is
Dyna's miracle -result and your pride and
joy, as you prepare to listen to your first
stereo disc. Amazing, I calls it.
Power Tangle
I seem to have skipped another aspect
of the hooking -up department, which accounts for a good part of the macaroni,
and that is the power -cable tangle. Unlike
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MAY, 1959
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www.americanradiohistory.com
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AUDIO
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Audio
Broadcasting equipment
Acoustics
fiers.
Looking at it another way, here are the
cables that run out from each of my eight
units, as I've just counted them:
Attached to Preamp A
6 cables.
Preamp B
9
Stereo Control Unit
6
Power supply
4
Phono
3
Tuner
3
Main amp. A
3
Main amp. B
3.
You can see what happens when one of
these units, or several, are moved by
themselves. Impossible! (But, of course,
once set up you shouldn't have to.)
Enough said. The moral is clear: if you
want the real advantages of this flexible,
separate -unit stereo conversion, you must
take the cable macaroni along with it, and
the multitude of switches too. You'll learn
to operate the system readily enough and
the only continuing problem is how to cope
with other people, young and old, who may
also want to play. As usual, I've taken to
large taped labels for this, and to taped over controls that shouldn't be moved. I
have a huge arrow pointing to the volume
control on preamp B, saying ON -OFF, and
another to the stereo master volume control saying maw VOLUME. Everything else
is pasted over and immovable.
It is quite possible, of course, that as
the jealous boss of your household you
may want to have your system set up so
that only you can make it go. Dyna will
oblige.
Home music systems
Recording
PA systems
Record Revues
(Please print)
Name
Address
El New
['Renewal
Name
Address
E
New
fl
Renewal
Name
Address
El New
Renewal
Name
Address
n New
['Renewal
Name
Address
E] New
Renewal
Name
Address
[]
New
Rather Warm for May
Renewal
U. S., Possessions, and Canada
only
RADIO MAGAZINES, INC.
P.
the neatly tailored signal cables, Dyna's
power cables are the usual length -fulllength -and the cord is high quality, stiff,
heavy -duty stuff, too. There seem to be
dozens of power cords. Power cords everywhere, and all plugged around and behind
and beneath each other. Under the circumstances, every single one is legitimate and
necessary. But what a pile of macaroni
these make!
In our older hi -fi systems, again, power
cords were a minor problem. Only one, at
first, and then maybe two, when the phono
came to be plugged into the system for an
over -all switched control. But separate
preamps, self-powered, and the other separate units began the march towards the
power cord tangle -and stereo has doubled
it practically overnight. Separate -unit
stereo has, at least.
There isn't a thing you can do in this
particular Dyna system (as in others) but
plug and plug and plug -in this case, into
Dyna's helpful preamp outlets, switched
and unswitched, four of them on each unit.
There is one long power cord for each of
the two big Mark III amplifiers, one for
each of the preamp units and one for the
power supply unit, plus, of course, a cord
for the radio and still another for the
phono -that makes already seven big,
snaky 117 -volt lines to run up to the common on -off control center at the two pre amps. Tangled in with them are still more
power cords -two power -supply cables, one
for each preamp-plus the main external
signal- carrying cables as well, two from
the phono, two from the tuner and two
from the preamps out to the main ampli-
O. Box 629, Mineola, N. Y.
I have a couple of reservations concerning this big Dynakit system, over and
against its complex but highly workable
and praiseworthy nature.
First, I was bothered by a purely external trouble, mechanical hum emanating
from the amplifier transformers. It's
modest, but you can hear it, persistently,
from any part of the room when the music
doesn't drown it out. My first Mark III
had this trouble but I thought it was just
one particular transformer, perhaps with
loose plates. Alas, both my present Mark
III's make a considerable humming noise
and removing the cage (as the company
suggested) doesn't do any good. (Not wise,
anyway, with those big, hot tubes.) I find
this hum musically annoying, even though
it remains at the same level regardless of
volume setting. I don't like hum-any hum.
Well, after many weeks, I finally got my
energy up and went about removing those
talking amplifiers from hearing range.
You can't enclose them -too much heat.
And if you want centralized control, the
cables involve length problems. I finally
moved the big amplifiers clean out of my
living room onto a foam-cushioned wood
box around the corner in the hall. A pair
of very long signal cables came next and I
prayed to myself, cathode follower, please.
No trouble experienced, so long signal
cables are feasible. Good!
The main amplifiers are now separately
plugged into a nearby wall socket and must
be turned on individually -have to do
something about that -but at last, I hear
not a trace of hum in my living room
when the system is turned on, and what an
improvement! The Dynakit system really
goes to town as it should, now, and I love
it dearly.
My second reservation has to do with
heat. Speaking generally, I am uneasy
about the very heavy current drain in this
equipment (and in many another high power stereo system as well). I don't like
the whopping amount of heat that is sent
out, mostly from the big power amplifiers.
It'll be uncomfortable in hot weather and
more than a match for an air conditioner;
but I don't find the idea exactly reassuring
in any weather, though Dynakit equipment
is as safe as it can be under the circumstances.
I can't help feeling that stereo's double
channel requirements are going to have to
lead to a lot more of the low -drain transistor type of circuitry, such as that in the
pair of Vico transistor amplifiers I used
last summer and fall for my stereo. These
two units, providing between them about
60 watts of rated output, burned up only
some 14 watts when at the idle. I left
them on most of the time. And the heat
production was correspondingly negligible.
If we must have high -output stereo,
then we'll have to begin thinking about
power cuts, here and there and maybe
everywhere, to bring stereo into reasonable
balance with mono hi -fi equipment. Lots of
people, I know, won't mind the big current
drain of the Dyne type of equipment nor
the generated heat; but for home stereo
use in general, less current and less heat
are definitely in order. After an hour or so,
the bottom plates on my two Mark III
amplifiers are almost too hot to touch and
the soft cushion underneath is likely to
begin objecting.
2. GLASER- STEERS STEREO
After using the Glaser-Steers mono
changer last year, I've exchanged it for
the new stereo version and herewith report
on same, with some enthusiasm.
The GS -77 is basically the same changer,
with the old values, much appreciated on
my first try, such as the turntable that
stops during the change cycle, allowing the
stylus to descend on a stationary disc, then
picks up to speed. The operation of the
current model is definitely smoother and
quieter than my earlier sample, out of the
first production. Hardly any overt mechanical noise to annoy, and the treatment of
AUDIO
74
www.americanradiohistory.com
MAY, 1959
the stylus is very considerate in the dropping.
How does a stereo -converted changer
stack up against separate -arm competition/ Are the basic stereo problems well
solved t
First, the stereo GS -77 has a redesigned
drive, for delicacy of movement and for
reduction of rumble. The motor is smaller,
the change-cycle slower -and I find this no
disadvantage at all. Remember that in the
Glaser- Steers changer the change cycle
remains the same for all turntable speeds,
a basic improvement of real value. Now,
in the new model, it is neither too fast, nor
too slow, at all record speeds, regardless. I
rather dislike a too -quick change cycle, especially since 78 rpm sides are so seldom
around to be joined up by the changer's
action. A pause is musically a good idea.
As for rumble, the GS -77 is quite good
very good for a changer, I'd say. You can
tell the difference clearly enough between
mono and stereo playing, but then you can
do the same for even the best tables, to
some extent. The expensive separate-unit
tables still do a better job on rumble than
is currently possible in a complete changer,
but this changer is easily acceptable for
most home stereo. Main likely trouble is
perhaps (a) in rumble- exaggerating stereo
records such as piano discs and (b) with
those speaker systems that have peaks in
the lower middle bass, intended or unintended. They are sure to exaggerate any
rumble that may be present. (It sounds
out less noticeably in a speaker system
with true, flat bass.)
The Glaser- Steers arm has been revamped to take stereo and is now, shall
we say, a 3% -wire system. Nominally 4wire, but the circuits include the arm itself
as a short segment of one channel; there
are only three contacts at the back end of
the cartridge, the fourth going through the
arm.
I rather wish it had been possible to use
four contacts in the mounting, with the
arm grounded at one end. Even that short
stretch of exposed arm, connected at both
ends as part of the circuit, could cause
trouble on occasion with bum pickup. Other
problems are possible, if I'm right, that
may not be so easy to pin down in a given
case. For instance, to take one I ran into,
there is a mono switch on the changer that
parallels the two sides of the cartridge, to
eliminate vertical response when playing
monophonic records. It does just that
but with my Mark III Dynakit stereo system it sets up a fine ground loop with a
hum level that is too high for comfort.
Trades rumble for hum. (Note that the
Dynakit blend control serves the same
function at the other end of the cartridge
circuit, without hum.)
I have tried a true 4 -wire system under
the same circumstances (the arm grounded
at the cartridge end and not a part of any
circuit) and there is no ground loop, no
added hum.
However, note well that most present
stereo-converted changers are of the
straight three -wire type with a common
ground throughout. This evidently works
out well enough in many situations. But
a 4 -wire system is a better idea, any way
you look at it. Probably worth the extra
cost it may entail.
The arm in the new Glaser- Steers accepts a new type of cartridge mount that
plugs upward from below and is fastened
by a knurled screw on top. A bit clumsy,
but it works, and allows for cartridge
change with the advantage of big, positive
contacts and easy wiring -up. I'm not overly
happy about the arm itself -or any present
changer arm that I know of, and in par-
-
-
AUDIO
he Spotlight o
eadership is on.
ticular the still -necessary practice of using
an ordinary spring to produce stylus -force
adjustment.
Glaser Steers, to be sure, has done nobly
with what it has. The changer arm rides
freely and as light as a feather when loose
from the changer mechanism. It will track
well most of the time and with most cartridges at even extremely low stylus forces
-two or three grams, as far as I can see.
Moreover, the spring, which looks like any
old changer -arm spring, actually is part of
a quite ingenious double -pivot arrangement at the arm's rear. I didn't even notice
it at first, but discovered to my surprise
that the arm "weight" did, unexpectedly,
remain constant over several inches of upand -down movement, one"g it was set.
Enough to allow for eival stylus force
over a span of eight or ten records on the
machine.
But this device loosens or tightens the
spring with the conventional small screw
wheel, to change the stylus force -and it
is here that I find the adjustment still not
accurate enough for the ultimate in stereo.
Like all such adjustments a. turn one way
isn't always equivalent to a turn back
again; the spring lets go suddenly, or
binds a bit, and the "response" to your
finger is not linear, so to speak.
Thus in my own use of the changer I
found that the GE stereo cartridge worked
perfectly, its only trouble being slight hum
pickup from the changer motor, near the
center. No weight problems. But the Else
(Stereotwin) rode either too light, skittering over grooves and turning fuzzy, or too
heavy, the stylus pressing back into and
against the protecting shell with a loud
chatter. I couldn't adjust the pressure in
between, to suit this model. The Shure
M7D, not designed for changer use (1
tried it anyway, just to see what would
happen), played generally very well in the
Glaser- Steers, partly because its surround.
ing protective shell is not close to the
stylus, which must be moved a long way
beforo hitting it. But an indication that
all was not well with this high -compliance
cartridge came in a kind of pulsing swish.
louder and softer as the record turned.
which I can only attribute to a hair toc
much side -pull on the very compliant
stylus. (Shure makes a stiffer cartridge
M3D, specificially for changers.)
Considering that these cartridges were
running in the Glaser-Steers with stylus
forces down to around 2 grams (I tried t
find the lightest possible setting) thr
machine really was doing a good, in its
own way. Probably impossible on earlier
changers of the pre- stereo era. But stereo
is enormously demanding. For top hi -fi,
with top cartridges, the changer of the
future
any-must do even better. This
one is good for almost, but not quite, anything you can ask of it.
No doubt about it, stereo has brought
with it the need for a radically new breed
of changer with a new type of arm, more
direct in its pressure (minus springs),
longer and with more perfect, friction -free
bearings. In my opinion, it will have to include as well a further change in the auto matie aspect of arm movement, taking ad.
vantage of really light arms for lighter
and simpler change mechanisms. But all
this takes time for development.
Minor beefs: Glaser -Steers might have
thought again before situating the stereo mono switch in an incredibly clumsy place,
just under the edge of the record, beneath
the arm! To get at it you must unload the
machine completely, or stop the record and
reach laboriously underneath with your
little finger. Can't be switched while the
record is turning -which is just the time
-if
MAY, 1959
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r
you'll want to do it; people always forget.
Also on this changer (as perhaps on others)
there is one position of the controls that
is potentially lethal; if you flip REJECT instead of OFF, the arm, when there's no reeord on the table, or only one, swings out
and drops at the 7 -inch position. When
this happens without a record in place
(i.e., when you bad meant to turn the table
off after using it manually), the delicate
stereo stylus hits a series of nasty rubber
bumps with tremendous force, relatively
speaking. My Shure stylus was ripped
right out of the cartridge, mount and all,
and deposited harmlessly off in a corner.
More power to Shure's foresight and I was
doing something wrong, of course. But
changers ought to be completely foolproof!
Well, this one is- almost. A darned good
changer, as changers go, and you won't do
better, I guess for a good while.
3. THOUSAND TIMES NO
Everybody who writes or speaks in public today is an authority, whether he wants
to be or not-whether he is or isn't in fact.
Either you're infallible, or you just ain't
nothing, brother. This drives me crazy, because obviously I'n not infallible, nor is
anybody else these days. I don't know
everything.
If I did know everything, there wouldn't
be anything left to learn.
Fellow telephoned he the other day, for
instance, long distance from a city a couple of dozen miles out of New York, wanted
me to come right over and set up his stereo
speakers for him. I said sorry, I couldn't
do it just then; he said, how much? and I
said, more than you can pay and he came
right back, well how much? He wanted an
expert, and he was darned well going to
get one, if it broke him.
He didn't get me because, as I quickly
tried to explain to him, it wasn't only a
matter of my time (a few other things to
de ...) but a matter of not really feeling
I could be of much use to him in his own
living room. After all, he has ears and his
ears are the ones that, supposedly, are
going to be pleased.
Now this sort of answer infuriates these
guys. They don't want to do it themselves
they want an "expert"' to set
it
up
right
and then everything-of course
guaranteed to work infallibly. After all, if the
expert says so, it must be right.
That sort of thinking has gone a lot
too far. OK if you want an expert, say,
to do a valve job on your old V-8 engine,
which needs it, beyond any doubt. OK if
you ask your M.D. to tell you whether
you've got pleurisy or only a smoker's
hack. Some things, in this doubtful world,
can really be determined exactly, preNavy definition, possibly, ED.
-is
'
eisely. Stereo listening, I maintain, isn't
one of them and I'm just as glad.
This particular guy didn't even give me
a chance to help him on the phone, for free.
I tried. What shape room did he have? and
was it live or dead, upholstered or full of
hard surfaces? He didn't even listen. I
said, it all depends-which it does, and no
doubt about it. He kept saying, you're an
expert, you just come out and I know you
can set it all up for me in a couple of minutes. I said listen, do you think I have the
magic formula for everybody's stereo? I'd
have to do exactly what you'll do, experimeut by trial and error, and perhaps I'd
get a good stereo sound, maybe I wouldn't.
(Or we might disagree as to what's good,
and then what?)
Why don't you try so-and-so, I continued, and -by the way -what speakers are
you using? I was certain that the one big
mistake the fellow could make would be to
anchor a pair of massive systems to the
frame of his house and then go ahead and
listen to see whether the placement was
OK. At least I might head off that development for hint.
Oh, a couple of AR-2 speakers, he said.
But I want you to tell me where to put
them, so .
Well! I almost busted at that. No use
trying to advise him that with two mobile
speakers be could try every conceivable
position in the living room at his leisure
and determine by himself which placement
suited him best -and it might even be enjoyable, as an experiment in listening.
Nope, he wanted me to do it and he was
obviously disappointed in me, an infallible
expert who'd let him down. He sort of hung
up as I was trying to tip him off on a
good way to start -look for symmetrical
locations, within the room, try both the
side wall and the end wall before you
make up your mind
.
I'll bet he called up High Fidelity mag
azine next. Editor John Conly lives a mere
125 miles from the guy and wouldn't he
drop down at his earliest convenience? Or
maybe High Fidelity had already said no,
politely
thousand times no-as our own
editor would (60 miles) though both of
them have much too kind hearts when it
conies to this sort of thing.
Somebody sends me copies of two of my
articles, one from this column and one from
another magazine with an entirely different readership, suggesting I'm not being
consistent. Of course not! The two pieces
weren't for the same audience but, more
important, I happen to have lived six
months longer at the time of the second
article-and I'm one of those experts who
tries to live and learn. Boy, I learned a lot
in those six months, mainly by being aware
that there was plenty tp learn. There still
is, there always will be.
...
TH E
ARM
THAT
CONTROLS
everything:
ESL Gyro
FOR LISTENING AT ITS BEST
Electro- Sonic
Laboratories, inc.
Dept A 35-54 36th St Long Island City 6, NY
PS:
(from page
of Guillaume Dufay. Dessoff
Choirs, Leslie Choboy, instrs., Boepple.
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RECORD REVUE
to coax and prod them into attending
Mass more often. The tone is fatherly, the
sentiments righteous and instructive, the atmosphere suitably subdued; the tenets of
Catholicism are, of course, entirely taken
for granted and are so preached, without
question, and authoritatively. There isn't any
question, needless to say, in n situation such
na this, where the approved commentary accompanies an actual recording of a Mass In
progress, by and for Catholics.
If you are genuinely interested in the
significance of the Catholic Mass for music
and /or are a Catholic, you'll find this record
useful and interesting. Don't listen if you
are inclined to argue about doctrine.
t
Vanguard BG 582;
BGS
5008 stereo
record of very old music done with a
modern touch but most musically, and an
interesting comparison between stereo and
mono versions. If I remember well, the
mono set -up for this recording was entirely
separate from the stereo. with separate
mikes, separate tape machine. (I was there,
but wns busy trying to sing the chorus tenor
A
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part.)
Dufay is almost the first of the world's
known and individual composers of enduring
fame. Before him. only a handful wrote music
of their own. under their own names -two
stand out still, Perotin and Machault, of the
Gothic period, plus an Englishman. John
Dunstable ; and Dufay adds a fourth, not
counting lesser names. Before these times,
MAY, 1959
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N.Y.
Don't
even
MENTION
that
word!
music that was other than troubadour or
popular stuff, so to speak, was the work of
many men, more nearly in the tradition of our
folk song. A man may have made up his own
new music -but his colleagues and successors
took it over as theirs and refashioned it to
their own needs.
There are three types of music here. Six
short pieces are three -part settings by Dufay
of Medieval hymns, out of Gregorian chant,
those ancient tunes with rhymed Latin texts
that persist and are familiar today in many
more recent arrangements. Dufay's 500-yearold versions are strange and lovely for the
ear ; they are performed with various combinations of instruments and voices here.
A second group is of solo songs, to instrumental accompaniment. The instruments
weren't specified Sn the old days, the playing
and singing being left to the performers'
judgment ; these are done with oboe, viola,
bassoon, and cello in some lovely arrange mente by the conductor. Chabay is an operatic
tenor who is theoretically quite out of style
for such music, but his innate musicianship
is fine enough so that these songs are beauti
fully, if anachronistically rendered. Better
thus than in dull, though scholarly versions!
There are profoundly moving moments in
this music.
The third group of works is for the chorus.
(The music was intended for solo voices; but
they undoubtedly sang in a style unattainable
today, perhaps with fiat, nasal, non-wobbly
tones ; the choral tone of our modern singers
comes closer to it than the sound of our own
trained soloists). Strange harmonies for many
ears here -but the music is a kind that easily
grows upon you. Witness the singers, most
of whom had never heard of Dufay when they
came to sing him.
Recording? I enjoyed Vanguard's mono disc
but the stereo was a revelation
more
persuasive, snore natural, a better conveyor
of the music, decidedly.
I tried both on a one -channel blend and
found that, as expected, the mono version
under that arrangement is technically brighter
and more clear, as well as at a slightly higher
level. Not a great deal of difference and the
sacrifice In level Is slight, with good surfaces. But given stereo reproduction -what a
difference! No doubt about It, stereo does
wonders for all kinds of music and especially
that which needs to be put over with
dramatic realism.
-far
Netherlands Chamber Choir-PalestrinaMonteverdi. Felix de Nobel, conductor.
Angel 35667
Motets for Christmas and Easter. Philippe
Caillard Vocal Ensemble.
Westminster XWN 18809
Here are two first rate European choruses,
the first Dutch and the second French. singing
the classical choral music of the sixteenth
century and the newly exciting, instrumentalinclined vocal music of the beginning of that
great century of quick changes, the seventeenth. In both of these choirs the musicianship of the singing is outstanding.
I mean by that a whole combination of
virtues. Sense of style-understanding of
the music and the way it can best be put
forth ; sense of pitch, extraordinarily good to
both groups
the consequent enjoyment
of any listener ; sense of rhythm, which leads
these choirs to sing the music with that freely
flowing sense of the word- rhythm that is essential, avoiding the "beating time" sort of
sound that kills the music so quickly ; sense
-to
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of diction, which brings us the words clearly
and dramatically -the words are the very
basis for the sense of the music itself.
The Dutch singers are buxom, both in
physique (see photo in album booklet !) and
in their pleasingly fat tones ; the French sing
sweetly and brilliantly through the nose, as
always, with the purity of an ensemble of
oboes and flutes. Lovely.
In performances like this, I think any
person with a musical ear can be pleased
,even though his knowledge
of the music may
nil. Music speaks its own language, when
is done well. My only complaint here is
technical: Westminster's groove cut is very
heavy and in the loud passages there is some
blasting. Groove-jumping, in some cases, isn't
too unlikely.
JE
be
it
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quotations.
N. Y. C.
HIGH FIDELITY SPEAKERS REPAIRED
Amprite Speaker Service
70 Vesey St., New York 7, N. Y. BA 7 -2580
ENJOY PLEASANT SURPRISES? Then
us before you purchase any hi -fi. You'll
glad you did. Unusual savings. Key Electronics, 120 Liberty St., New York 6, N. Y.
EVergreen 4 -6071.
write
be
WRITE for confidential money saving
prices on your Hi- Fidelity amplifiers, tuners,
speakers, tape recorders. Individual quoiations only ; no catalogs. Classified Hi -Fi
Exchange, AR, 2375 E. 65 St., Brooklyn 34,
N. Y.
INDUCTORS for crossover networks. 118
types in stock. Send for brochure. C &M Coils,
3016 Holmes Avenue, N.W., Huntsville, Ala.
LP RECORD CLEANING CLOTH in
handy case, only 250! Costs $1.00 in stores.
To introduce our "Record Collector's Catalog" included Free! Leslie Creations, Dept.
A-2, Lafayette Hill, Pa.
JOBBERS for the new, amazingly beautiful
MOODLITE. Ht-fi field preferable, but not
essential. For particulars and territories
open, write H. A. Hauslein, Sales Manager,
2145 Griffith Park Blvd., Los Angeles 39,
Calif.
FREE STEREO L. P. LISTS. 500 page
catalogue, 250. Inquire Select Records, P. O.
Box 2, Homecrest Sta., Brooklyn 29, N. Y.,
Dept. A -1.
SELL
Stancil- Hoffman Minitape M5A
Professional Tape Recorder, 7%" speed,
portable case, new batteries. $175 ; IBM
Electric Typewriter $85 ; Wagner- Nichols
Disc Recorder, $50. V. R. Hein, 418 Gregory
St., Rockford, Illinois.
:
RECORDS, masters, pressings, and tapes
(stereo and monophonic) duplicated from
or discs. Quantity discounts,
specialized service. Write -Merle Enterprises,
Box 145, Lombard, Illinois.
your tapes
REK -O -KUT M -12 -S, overhead lathe with
120 & 210 1p1, OI feedscrews, Audaz H -5
cutter bead (16 ohm), and TR -12H hysteresis
turntable. New condition. Cost $450. Sell
$325. Ship in original cartons f.o.b. Ed
Sumpf, 321 7th Ave., Santa Cruz, Calif.
MAY WE QUOTE you on our unbeatable
low prices on the hi -fl components of your
choice? L "n" J High Fidelity, 416 N. 15th
St., Kenilworth, N. J.
1
RECORDING TURNTABLE. Presto 8N, 3
speeds, complete with overhead carriage, including cutter. Never used. Now selling for
$1026:80. Available for $325. Phone LA 43724, New York, or write Box CE -1 AUDIO.
.
WANTED -Type BRK Concertone transport
mechanism only. Frank Viscardi, 216 Rock
Road, Glen Rock, N. J. OLiver 2-2323.
AUDIO
78
www.americanradiohistory.com
MAY, 1959
PROFESSIONAL
DIRECTORY
Fm/Q,
ANTENNAE
Get more FM stations with the world's most
powerful FM Yagi Antenna systems.
Send 25n for booklet "Theme And Veda.
lions" containing
FM
Station Directory.
APPARATUS DEVELOPMENT CO.
Wethersfield 9, Connecticut
Circle 7SC
LOOK
no further
. it you're
searching for hi -fi savings.
Write us your requiremnts now...
Key Electronics Cespeny
120 -K l Iesrty ft, e.Y. 6. N.Y.
ET
4.6071
Circle 79D
tltc fi)7cst
featuring
aC! raCt-.
HIGH FIDELITY COMPONENTS
r:
87o
w
SOUND
C O R P O R A T
Olympic 814
.
t.A. 15, Gafit.
I
O N
RI1-3171
Circle 79E
CANADA
High Fidelity Equipment
Complete Lines
Complete Service
Hi -Fi Records
Components
and Accessories
-
&LECTRO-UO10E
SOUND SYSTEMS
126 DUNDAS ST. WEST, TORONTO, CANADA
Circle 79F
9su/44e1/u,
Noted...
IBFM HEAD DISCUSSES PRICING.
The component high fidelity industry must
awaken to the peril of unsound retail
pricing practices if it is to maintain and
expand its current pattern of profitable
operation, Joseph N. Benjamin, president
of the Institute of High Fidelity Manufacturers, said in a recent address in New
York. Speaking before the Producers of
Associated Components for Electronics,
Mr. Benjamin, who is also president of
the Bogen- Presto Division of Siegler
Corporation, declared that recent discount
advertising should be of great concern to
manufacturers and dealers alike.
Speaking in behalf of a legitimate profit
for all concerned, Mr. Benjamin cited
seven important functions which the
dealer must perform for his customers.
Where discount pricing prevails, one or
more of these functions must suffer, and
both dealer and customer lose in the long
run, Mr. Benjamin stated.
LING, AZTEC MERGE. Over 90 per cent
of the stockholders of Altec Companies
have agreed to exchange their stock on a
share -for-share basis for Ling Electronics
AUDIO
stock, thus giving final approval to
merger of the two firms. The merger creates an organization with an expected
sales volume of 22 to 25 million dollars in
1959..1. J. Ling, board chairman of Ling
Electronics, stated that stockholders will
be asked to approve a name change to
Ling- Altec, and that Altec Companies will
be operated as a subsidiary.
NewTransMagnemite
Professional Transistorized
Battery -Operated Spring -Motor
PORTABLE FIELD RECORDER
PISHER OFFICIAL DECRIES CON FUSION. .Tames J. Parks, vice- president,
Fisher Radio Corporation, speaking in
Atlanta before the Southeastern Conterence of the National Association of Music
Merchants, contended that confusion in
the mind of the public Is having a serious
effect on the sales of hi -fi equipment
throughout the country. Mr. Parks' subject was "Understanding and Selling
Stereo Hi -Fi." Lack of technical knowledge at sales levels is the industry's
greatest problem, he stated. He asserted
that, while it isn't necessary for a hi -fi
salesman to be an engineer, it is important
that he have a good knowledge of the
equipment he is handling. Also, he bore
heavily on the importance of having a
wide assortment of phonograph records
available so that demonstrations may
cater to every taste.
nom.
.9frukabut
Cheek These Unusual Features:
Overall Gain 110 db.
v
No Microphonics or motor noises.
Low noise input stage (0.25 microvolts).
v
v
v
v
ee
Sherman M. Fairchild, president of Fairchild Recording Equipment Corporation,
appointed Donald J. Plunkett president in
his place effective April 1. Formerly New
York director of recording for Capitol
Records, Mr. Plunkett Is also president
of the Audio Engineering Society
.
Bernard Kardon will continue with Harman- Kardon, Inc., in a consulting capacity
after June when he relinquishes his title
of vice -president and general manager.
Sidney Harman, president, states that Mr.
Kardon will also remain as a director of
the company
Edward Waldman, with
Telectro Industries Corporation since
1948, has been appointed to the new position of general manager.
Richard Shahinian, audio consultant,
has opened shop as Festival Hi -Fi & Recording Company at 215 -32 Hillside Ave.,
Queens Village, N. Y.
.
William E.
Johnson has been named to the new post
of dealer sales manager for the Heath
Company
R. H. Rogers, pioneer in
electronics advertising, has been appointed advertising and sales promotion
manager of National Company
Siols, acoustics engineer formerlyGeorge
with
University Loudspeakers, Inc., has joined
CBS Laboratories, Inc., as group leader
for transducer research.
Recent additions to the sales and merchandising staff of Electro- Voice, Inc.,
include James 7L Price, who will act as
general manager of the RME division,
Henry ?Candler, who will specialize in
high -fidelity products, and O. H. Steinke,
who will assist with all activities involving distributor sales. Arthur S. Robinson,
Jr., has also joined Electro -Voice as traffic manager .
Joel M. Rowley, formerly
advertising manager for the Westclox
Division of General Time Corporation, has
joined V -M Corporation in a similar capacity
New ad and sales promotion
manager for Tung -Sol Electric, Inc., is
Well Uptegrove, formerly manager of technical advertising for Allen B. Dumont
Laboratories, Inc.
Appointment of
Robert McCarthy to the new post of product manager has been announced by Bell
Sound Systems. .
Stewart Edgerton,
formerly with the Ford Motor Company,
is the newly appointed vice -president and
controller of Shure Brothers, Inc.
v
v
Uses Dry Rechargeable batteries.
Batteries last 125 hours.
Modular plug -in construction.
Exceeds NARTB Broadcast standards.
v
11 x 10x7 inches -Weight: 15 lbs.
Full unconditional Two Year Guarantee.
Write for complete information and
direct factory prices to Dept. A:
Size:
v
.
AMPLIFIER CORP. of AMERICA
398
...
Broadway.
N.
Y.
13. N. Y.
Circle 79A
s ave on
Stereo hi-fi
see the best values in the
1959
ALLIED CATALOG
...
won
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largest choice
of systems and
comronents...
ever /thing in
STEREO!
.
iiHere's your cam Plate, marry. saving
guide to Hi -Fi! See how you save on
ALLIED-recommended complete systems,
including the latest in thriilmg Stereo.
Choose from the world's lar,test stocks
of components (amplifiers, tuners,
.
recordere, accessories). Want to build -yourown? -save up to 50';; with our exclusive Hi -Fi KNIGHT -KITS! Easy terms
available. For everything in Hi -Fi, for
changers, speakers, enclosures,
'
.
everything in Electronics, get the 452 -
page 1959 ALLIED
,
Catalog!
ALLIED RADIO
SUPPORT
YOUR
MENTAL
awon;.caá
HZ.-Ft
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32R,
ALLIED RADIO, Dept. 17-E9
100 N. Western Ave.. Chicago 80,111.
CI
Send FREE 1959 ALLIED Catalog
Name
HEALTH
Address
ASSOCIATION
City
Zone
State
Circle 79B
MAY, 1959
79
www.americanradiohistory.com
LAFAYETTE
STEREO TUNER KIT
THE MOST
FLEXIBLE TUNER
Molting, Ovtput
Ter New
ADVERTISING
EVER DESIGNED
Stern
FM
Tubas (including 4 dual purpose) +
Tuning Eye + Selenium rectifier Provide 17 TO.
11
INDEX
vlumana
MC
Whistle Filter
Tuned
(cared
FM
Pre.allgnd IF's
12 Tuned (froths
Dual Cathode Foible/et Output
Sep
ly Tuned FM and AM Sections
Armstrong Circuit with FM/AFC and
AFC
.
e 4t
M
sbasrd.
atrePAate
\
t}
PM-AM tamer
4g so a esOJ-
lbea
parmE PM-AM t.wer
ee
ae
4t
etrm4gt
/
I
esaar+.J PM or AM/
tamer
tuners.
FM specifications Include grounded-grid triode low notes front end with triode
fixer, double -tuned dual limiters with Foster -Seeley discriminator, Tess than lee
harmonic distortion, frequency response 20- 20,000 CPS ± ys db, full 200 kc
bandwidth and sensitivity of 2 microvolts for 30 db quieting with full limiting at
one microvolt. AM specifications Include 3 stages of AVC, 10 kc whistle filter,
built-In ferrite loop antenna, less than 1% harmonic dirortlon, sensitivity of S
microvolts, 8 kc bandwidth and frequency response 20 -5000 cps ± 3 db.
The 5 controls of the KT-500 are FM Volume, AM Volume, FM Tuning, AM Tuning
and 5-position Function Selector Switch. Tottefully styled with gold -brass escutcheon having dark maroon background plus matching maroon knobs with gold
Inserts. The Lafayette Stereo Tuner was designed with the builder in mind. Two
separate printed circuit boards make construction and wiring simple, even for
auch o Complex unit. Complete kit includes all parts and metal cover, a step-bystep instruction manual, schematic and pictorial diagrams. Sin Is 133/4" W K
.i.s
KT
-500
74.50
ONLY
7.45
Ddeel
Dual DoubleTuned Tracafermer
Coupled Limiters.
Mere than a year of research, planning and engineering went Into the making of
the Lafayette Stereo Tuner. Its unique flora Oily permits the reception of binaural
broadcasting (simultaneous transmission on both FM and AML the Independent
operation of both the FM and AM sections at the same time, and the ordinary
reception of either FM or AM. The AM and FM section ore separately tuned,
each with a separate 3 -gang tuning condenser, separate flywheel tuning and
separate volume control for proper balancing when used for binaural programs.
Simplified accurate knife-edge tuning Is provided by magic eye which operates
independently on FM and AM. Automatic frequency Control "locks In" FM signal
Permanently. Aside from its unique flexibility, this Is, above all else, a quality
high -fidelity tuner Incorporating features found exclusively In the highest priced
IN KIT
FORM
10%" D x
KT -500
DOWN
7.00 MONTH(
LT -SO Same as above, completely factory wired and tested
Net
Net
74.50
124.50
Solves Every Stereo /Monaural Control Problem!
LA -600
WIRED
134.50
±
RESPONSE 10- 25,000 CPS
0.S LIB
6 CONCENTRIC FRONT PANEL CONTROLS
4 CONCENTRIC REAR PANEL INPUT
LEVEL CONTROLS
ELECTRONIC PHASE REVERSAL
1E -WATTS
REVOLUTIONARY DEVELOPMENT IN STEREO HIGH FIDELITY. Provides such unusual features a a Bridge Control,
for variable c
signal
gnal feed for elimination of "pingPon'. (exaggerated separation) effects and for 3d channel
output volume control for 3- speaker stereo systems; 3d channel
output also serves for mixing stereo to produce excellent monaural recordings. Also has full input mixing of monaural program
sources, special "null" stereo balancing and calibrating system
(better than meten), 24 equalisation positions, all-concentric
controls, rumble end scratch filters, loudness switch. Clutch type
volume controls for balancing or as 1 Master Volume Control.
Has channel reverse, electronic phasing, Input level controls.
Sensitivity 1.78 millivolts for 1 volt out. Dual low- impedance
outputs (plate followers), 1300 ohms. Response 10- 25,000 cps
± 0.5 db. less thon .03% IM distortion. Uses 7 now 7025 lownoise dual triodes. Size 14" x 4'/r" x 10 % ". Shpg. wt., 16 lbs.
Complete with printed circuit board, cage, profusely illustrated
instructions, all necessary parts.
LAFAYETTE KT -600
Stern Preampllfisr BIt
Net 79.50
LA -600 Same as abers, wired
Net 134.50
-
STEREO AMPLIFIER.
EACH CHANNEL
PRINTED CIRCUIT BOARDS FOR
NEAT, SIMPLIFIED WIRING
2
MONAURAL AMPLIFIER
RESPONSE RETTER THAN 35. 30,000
CPS
yl DB AT IB WATTS
EMPLOYS 4 NEW PREMIUM -TYPE
7189 OUTPUT TUBES
LESS THAN 1% HARMONIC OR
-f
amplifier,
INTERMODULATION DISTORTION
In easy-to -build kit form to save
Into stereo now at mi mum expense) Dual
inputs ore provided, each with individual volume control, and the unit may be
sed with a stereo preamplifier, for 2 -1B wait stereo channels or, at the Rick of
u switch, as a fine 36 -won monaural amplifier
a
or, If desired, it may be used as
2 separate monaural 18 -watt amplifiers? CONTROLS Include 2 input volume can
trots, channel n Reverse switch (AB -BA), Monaural -Stereo switch. DUAL OUTPUT
IMPEDANCES ore: 4, 8, 16 and 32 ohms (permitting parallel (monaural) operalion of 2 speaker systems of up to 16 ohms. INPUT SENSITIVITY is 0.45 volts per
channel for full output. TUBES ore 2 -6AN8, 4.7189; GZ -34 rectifier. SIZE 9. 3/16 "d
(10 -9/16" with controls) x 51/4"h x 131/4"w. Supplied complete with perforated
metal coge, oll necessary parts and detailed instructions. Shpg. wt., 22 lbs.
1(T -310 Stereo Power Amplifier Kit
Net 47.50
-
jJáyette Radio.
Send FREE
LAFAYETTE Cntnlog
City
3. 69
of Columbia
Broadcasting Systems, Inc.
Classified
Cosmos Industries, Inc.
Connoisseur
67
78
39
Duotone Ccmpany, Inc.
Durant Sound Company
Dynaco, Inc.
46
72
59
65
EICO
13
Electro -Sonic Laboratories
Electro -Voice Inc.
Electro -Voice Sound Systems
77
Coy. IV
79
65, 77
25
28, 29. 41
27
Gotham Audio Sales Co., Inc.
Grado Laboratories
Gray High Fidelity Division
66, 73
2
11
Hartley Products Co.
Heath Company
51
7
Jensen Manufacturing Company
-9
31
Key
Electronics
79
79
KLH Research G Development Corporation 68
Kierulff Sound Corporation
Lafayette Radio
Lansing, James B. Sound, Inc.
Leonard Radio. Inc.
....
80
Coy
III
65
North American Philips Co., Inc.
63
ORRadio Industries, Inc.
10
Partridge Transformers
Pickering & Company
Pilot Radio Corporation
Precise Development Corp.
Professional Directory
78
Radio Corporation of America
Reslo
Rigo Enterprises, Inc.
Roberts Electronics Inc.
15
33
37
79
....
Coy. II
77
57
70
590
CUT OUT
AND
PASTE ON
POSTCARD
Address
I
1,
Sams, Howard W. b Co., Inc.
62
Schober Organ Corporation
69
I
Sherwood Electronics Laboratories
Sony Corporation
61
Stromberg -Carlson, A Divsion of General
Dynamics Corporation
52, 53
P. O. BOX 511
JAMAICA 31, N. Y.
Name
I
16
47
35
CBS -Hytron, A Divsion
Ferrodynamics Corporation
Fisher Radio Corporation
Fukuin Electric (Pioneer)
A superbly-performing basic stereo
you lots of money and Ist you get
V
4
49, 55
6
7(
Bozak
British Industries Corporation
facing p.
Ercona Corporation
FOR OPTIONAL USE AS 36 -WATT
-
75
66
76
Bell Telephone Laboratories
Bogen -Presto Company
AMAZING NEW BRIDGE CIRCUITRY FOR VARIABLE
3d CHANNEL OUTPUT 8 CROSS- CHANNEL FEED
PRECISE "NULL" BALANCING SYSTEM
STEREO /MONAURAL BASIC POWER AMPLIFIER KIT
36 -WATT
ONLY 4.75 DOWN
S.00 MONTHLY
5
79
79
.
Barker Sales Company
UNIQUE STEREO 8 MONAURAL CONTROL FEATURES
A
NEW!ALAFAIETTE
58
79
64
41/1" H. Shpg. wt..12¡2IIbs.
NEW! LAFAYETTE PROFESSIONAL STEREO
MASTER AUDIO CONTROL CENTER
180°
Acoustic Research, Inc.
Allied Radio Corp.
Altec Lansing Corporation
Arnperex Electronic Corp.
Amplifier Corp. of America
Apparatus Development Corporation
Arkay
Arnhold Ceramics, Inc.
Audio Bookshelf
Audio Devices, Inc.
Audio Fidelity, Inc.
Audiogersh Corp.
Tandberg
73
University Loudspeakers, Inc.
45
Zone.... State
AUDIO
80
www.americanradiohistory.com
MAY, 1959
basic contributions to our culture
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Johann Gutenberg of Mainz on the Rhine is credited with the invention of movable type, a contribution
of immeasurable worth to the arts and sciences. Unmeasured surely, but of great significance, are
the contributions to the art -science of high fidelity made by James B. Lansing Sound, Inc.: There is the
four -inch voice coil with its attendant high efficiency ... the acoustical lens ... the
ring radiator ... Now JBL brings you wide field stereo reproduction through
radial refraction. This is the principle on which the magnificent JBL Ranger -Paragon
and the more recent JBL Ranger -Metregon are based. Two highly efficient,
full range, precision loudspeaker systems are integrated by a curved, refracting panel.
"best" listening spot, but can perceive all the
realistic dimensions of stereophonic reproduction at its very best throughout the
listening area. The JBL Ranger -Metregon comes within the reach of all true
high fidelity enthusiasts. For, no less than seven different speaker systems may be
installed within this exquisitely styled, meticulously finished acoustical dual enclosure.
You may start with a basic system and progressively improve it. Perhaps some of the JBL loudspeakers
you already own may be used. Write for a complete description of the JBL Ranger -Metregon
You are not confined to one
and the name and address of the Authorized JBL Signature Audio Specialist in your community.
JAMES B. LANSING SOUND, INC., 3249 Casitas Ave., Los Angeles 39,
www.americanradiohistory.com
Calif.
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