disc recording -chapter 4 of "sound"

disc recording -chapter 4 of "sound"
1C
Y'
kW
JANUARY, 1956
I1
500
ENGINEERING
MUSIC
SOUND REPRODUCTION
PRE -EM NASIS
TRANSITION FREO.
FREQUENCY, cps
MSS TURNOVER
FREQ.
RECORDING CURVE OF MSS ATTENUATION AND
e
TREBLE PRE -EMPHASIS
LAYBACK EQUALIZATION CURVE
For a down -to -earth explanation of the problems in disc recording, along with
a comprehensive treatment of the reasons for pre- and post -equalization - better known as recording characteristic -see Chap. 4 of SOUND on page 17.
One school of thought insists that a high- impedance dividing net work such as this ahead of the amplifiers gives better quality, but
little information is available. See page 13 for one good method.
HEGH- QUALITY DUAL CHANNEL AMPLIFIER
DISC RECORDING -CHAPTER 4 OF "SOUND"
-
Plus all the regular features
Edward Tatnall Canby's Reliable Record Revues
Harold Lawrence's "About Music"
Equipment Reports-Audio Patents-AUDIO ETC
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JANUARY,
VOL. 40, No.
1956
1
Successor to RADIO, Est. 1917.
AU D Io
1
.,.I\I.LI \f:
I
MUSIC SOUND REPRODUCTION
C. G.
Mcl'roud, Editor und Publisher
between an ordinary
performance and a
truly fine distortionfree recording.
Ilenry A. Schober, Business Manager
Ilarrie K. Richardson. A- oeiate Editor
Lewis C. Stone, Associate Editor
Emery Justus, Canadian Editor
Florence Rowland, Production Manager
Edgar E. Newman, Circulation Director
Your tape recording or PA
equipment can reproduce a
much wider range of voice
or music
you use these
microphones!
Sanford L. Cahn, Advertising Director
MrMO$A
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Special Representative- H. Thorpe Covington,
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MANG,
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Mid West RepresentativeSanford R. Cowan, 67 West 44th St.,
New York 36, N. Y.
-
West Coast Representatives
James C. Galloway and I. W. Harbison,
6535 Wilshire Boulevard, Los Angeles 48, Calif.
A dynamic semi- direc-
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CONTENTS
A
udio Patents-Richard
II. Dorf
U tters
A 'out Music- Harold Lawrence .._._.
._
N..w Literature
Editor's Report
11.0-Quality Dual Channel Amplifier-Cdr. Charles .11'. IIarri.wut
Disc Recording -SOUND, Chap. 3 -Edgar M. Villchur
The Schober Electronic Organ -Part
Richard H. Dorf
Audioclinic-Joseph Giovanelli
How Long is "Permanent" Employment?- Albert Woodruff Grant
Equipment Report-DeJar T6-820 Tape Recorder-Harm an - Ka
AM-FM Tuner-Garrard 301 Transcription Turntable
Book Review
Nc w Products
Record Review-Edward Taktall Canhrf
Coming Events
Audio ETC -Edward Tatnah Canby
Audio Clinic's AM Tuner Parts List
Industry Notes and People
Ac vertising Indes
4
6
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(title registered U. S. PM. Of.t is published monthly by Radio 5Iagarines, Inc., Henry A. Schnher, President;
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ropta 500. Printed in U. S. A. at Lancaster, Pa. All rights reserved. Entire contents copyright 1956 by Radio Magazine, Inc. Entered as Second Class Matter February 9, 1950 at the Post Office, Lancaster, l'a. under the Art of March 3,
AUDIO
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AUDIO
JANUARY, 1956
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SHURE BROTHERS, INC.
225 West Huron Street, Chicago 10, Illinois
TUBELESS
AUDIO
AUDIO PATENTS
RICHARD
H.
DORF'
COMPENSATION
INVENTIONS assigned to International Electronics Company have some
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Model 4201, Program Equalizer
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erts and is numbered 2,712,572. It is a
method of recording two signals ois the
same portion of tape without mutual interference and with the object of doubling
the available recording time on a given
length of tape.
In normal tape recording the head gap is
perpendicular to the direction in which the
tape travels. As the current through the
head varies and the tape moves, a series
IIt small magnetized domains are created,
,atlt with a field and polarity corresponding
to the intensity and phase of the head current at the instant of magnetization. These
domains may for simplicity be considered
as a series of individual magnets of the
requisite field strength and polarity, each,
of course, with a north and a south pole.
\Vitlh the usual recorder and head orientation, the individual magnets are oriented
in the direction of tape travel; since the
flux gap creating the magnetics is perpendicular to tape travel and the lines of forre
bridge the gap, we may pieture many small
Ina magnets at right angles to the gap.
As everyone concerned with tape recording knows, correct orientation of the playback head is essential in reproducing the
higher frequencies to nmxintuni advantage.
The reason is, of course, that if the playback head gap is not at exactly a right
angle to the small "magnets" a loss its
level occurs; and the loss occurs first with
those "magnets" which are shorter-representing higher frequencies -because with
a given gap width they will more easily fit
inside the gap entirely when wrongly oriented su that there is no field across the
gap.
It follows-and this can easily be verified -that if the playback head is oriented
so that it is at right angles to the recording head there will be no output at all at
any frequency-. Roberts takes advantage
of this fact.
Let us assume two recording heads arranged with their gaps at right angles,
each gap making an angle of 45 degrees
with respect to the tape, as illustrated in
Fig. 1. (A) of Fig. 2 represents a portion
of the tope with it number of radial lines
about a point representing possible positions of suutll "magnets." Since the number of possible orientations is infinite, 12
lines are shown at equal angles from 110
point. Now let its move the tape of Fin.
past the Channel 13 head of l'ig. 1. Of II
12 possible magnets in (A.), eight are e.,
oriented at right angles to the head wit i, h
just created them. They represent the recoding made by the Channel B head. The
remaining four possible magnets are unchanged.
Now let us record the saute portion of
tape with the Channel A head. (C) in Fig.
2 shows the result. The remaining four
magnets are now oriented at right angles
In the new head gap, while the original
Electronics Consultant,
St., New York 24, N. Y.
25.5
umgnets remain unaltered. Thus two separate signals have been recorded on the same
tape. Whirl) one will be placed back depends ou the orientation of the playback
head.
The illustration of Fig. 2 proves nothing,
of course; it is simply a representation
of the inventor's simplified analysis of
what happens. Ile has verified the actual
results experimentally, however. The two
signals remain tiistiuet, but the second recording plays back at lower level than the
first, though the difference is not great.
It seems obvious that all the heads could
be half -track ones, so that both recordings
could.he made on half the tape width and
two more on the other half, resulting in recording time multiplication of four Bales
over ordinary single -track recording. Multiple heads could be used simultaneously for
binaural or stereophonic recording, or single heads could be fitted with mechanical
means to change their orientnthot. Other
drawings in the patent specification show
ways of doing either.
Tape Amplifier
I)niiiel II. Dashicll is the designer of a
very much simplified vioctronisnt for a tape
recording, consisting of only three tubes
for all functions. The number of the patent
is 2,654,003. The scheme is diagrammed in
Fig.
3. The name of the company and the
of a con1bination speaker and microphone are clues that this invention is intended for dictating-machine or other non high- fidelity use.
In the RECORD position of the switch,
nmierophone signal goes to amplifier
through a potentiometer level control and
(Continued on page 5. '3)
use
f'
Fig. I (top)
lil/j3
10
9
,t
11\\,/34
4
8Ij\ 65
77,
9B/6/
lo/
(A)
(C)
(B)
90°
WA'
Inm^ItL
CHANNEL
a
Fig.
AUDIO
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AmericanRadioHistory.Com
98''_..65
7'
I
1t'cxt 84th
2
5
tttky3/4
10/
2
B
bottom)
JANUARY, 1956
k rl..
0
!
tnlll
'.
_-,
How Hi is Fi?
It's
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HIGH /FIDELITY
Because It Sounds Better
LETTERS
Biflex Cones
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The system of cone compliances described by Badmaieff ("Design of biflex loudspeakers," November, 1955) in such glowing
terms is my invention. It dates back to 1938, when I used a
method of ''applying a layer of viscous damping liquid to both
sides of the cone at the mid compliance." I sold about fifty
speakers with such a cone before the war, but then I had to
concentrate on sterner tasks. I resumed peacetime development
in 1946, by which time I had realized that doping a part of the
cone didn 't work very well, and I evolved the method of removing a narrow ring of the cone and replacing it with a plastic
cement. So was born what came to be called the Hartley 215
speaker.
Apart from the fact that starting in January, 1949, I posted
a total of some 10,000 technical data sheets to various hi -fi
enthusiasts in the U.S., which data sheets described exactly the
system of compliances and the effect they would have on frequency response, there remains the indisputable fact that some
thousands of these speakers are in use in the U.S., and they incorporate the mid -cone compliance which Badmaieff now describes in such terms as to lead the reader to believe that he is
the inventor. Cones with compliances such as he describes have
been in regular use in the U.S. since 1949-many in Los Angeles
-and they have been exhibited and demonstrated at Audio
Fairs in both New York and Los Angeles, as well as at the
Chicago hi -11 show.
However, for the technical guidance of your readers, I must
point out some basic errors in his article. His Fig. 3, alleged to
be an analogue of a speaker with a double -compliance cone, is
without foundation. The mathematical exposition is abstruse
and out of place in your pages, but a simple practical demonstration is quite easy. Let the values of inductances, capacitances,
and resistances in the equivalent circuit be specified, such values
being true equivalents of what the speaker is supposed to include; now measure the impedance of this network over the
whole audio range and compare it with an impedance curve of
the speaker it is supposed to represent. It will be found that the
two curves are not comparable.
Mr. Badmaieff states that the compliance represented by
R,,,,/C, in Fig. 4 gives an extended and smoother response in
the treble; this is correct and this is why it was incorporated in
my own speakers so long ago. His exposition of compliance
(same figure) is fallacious. The natural resonant bass
frequency of a cone is a function of the stiffness of the outer
surround. Experts like the famous Hawley Products Company
will confirm that within reason this figure can be made what the
designer wishes, and the more flexible the paper the lower the
resonance; the limit, of course, is the thinnest paper that will
stand up to the "bashing" a speaker gets in real life. Thickening or stiffening the paper raises the resonant frequency, and
the effect of Mr. Badmaieff 's dried viscous plastic layer can be
paralleled exactly, and with a great deal less trouble, by adjustment of the paper pulp at the outer edge of the cone and the
varnish used to protect it. This I knew when I was developing
the 215, but the notion of adding "goo" to the outer edge
seems to me to be quite absurd. Here we want freedom of movement, which is why I use a loose flannel surround.
Where a second compliance is truly needed is in the voice -coil
itself. With a conventional coil such as described by Mr. Badmaieff, the mass is too great to permit of good high -frequency
response, a fact which is demonstrated by his response curve in
Fig. 5 which shows a severe cutoff at about 13,000 cps. A voice coil assembly with an included compliance (described by me in
Radio Electronics, April, 1954) gives a much better output at
the top end, my 215 speaker with such a voice coil being only
4 (lb down at 20,000 cps.
If I may end on a more personal note have found in practice as a businessman that the average hi -fi enthusiast doesn't
take any notice of subtlety in design. The 215 was the result of
twenty five years' experience of speaker design in which every
single feature was the result of innumerable experiments and
measurements with one aim-to find out what was best. Sales
are not greater because many non- discriminating people refuse
to believe that a 9 -inch speaker can be as good as a 12 -inch
model; I believe it is better, as do those who own my speakers,
but since I have to live I must concentrate now on making more
imposing (and more expensive) speakers.
No one could be a more ardent disciple than I in the movement for putting our high fidelity house in order.
H. A. HARTLEY,
62, Lartymer Court,
London, W6, England
-I
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JANUARY, 1956
Only the
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-R
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There is no finer, smoother-running or easier -to- operate
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JANUARY, 1956
5
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Meet Hermon Hosmer Scott,
Audio Pioneer!
HAROLD LAWRENCE
Opera's Sound and Fury
applause welcomed kimonoclad Maria Callas in the Chicago Lyric
Theatre on November 17 as she emerged
from the wings to take a bow for her performance of Madame Butterfly. And what
a bow that was! Madam Callas dropped
to her knees and lowered her head until
it touched the floor, remaining in that posi
tion for an eloquent minute or two. Thee.
as if still overcome by the impact of Pup
eini's score, she rose and slowly departed
from the scene, her brow furrowed with
emotion.
A reception of another kind greeted her
off stage. Eight process servers armed with
summonses issued in a contractual dispute
bore down on her. The soprano let loose a
verbal barrage as impassioned as her thrilling performance of a few moments before:
"I will not be served! I have the voice of
an angel! No man can serve me! Get your
hands off me! " Quicker than you can say
" Gianni Schischi" members of the opera
company swooped down on the invaders
and hustled them out of the theatre to the
accompaniment of their heroine's trilled
outburst in several languages. Next morning, Maria Callas was on a plane bound
for Italy. At the Milan airport she told reporters, "Those Zulus maltreated me! "
This latest turbulent episode in the meteoric career of the Greek-American soprano
proved once again that the Artistic Temperament, like Chivalry, is not dead. Another diva and arch -rival of Maria Callas,
Renata Tebaldi, put on a show of her own
at San Francisco last October. A claque
was well in evidence during her performance in the title role of Tosca. Urged WI
by the professional applause, Madam Tebaldi repeated the famous aria, " Vissi
d'Arte." The critics were not impressed.
They brought the claque to task for milking the bows and reprimanded the prima
donna for her precedent -shattering and uncalled -for encore.
A claque in reverse was on hand this past
summer at the Aix-les-Bains Music Festival in France where a distinguished audience of 4,000, including ex -Bing Umberto
and ex -Queen Marie José, was enjoying a
special performance of Monteverdi's Orley.
The hero, baritone Giuseppe Valdengo,
strode out on the stage but didn't sing a
note. Instead he shouted in Italian -flavored
refuse to go on until the manFrench :
agement pays me 75,000 francs extra! "
To further emphasize his point, Valdenge
threw down his lyre. At first there was
a shucked silence. Then the audience exploded in catcalls, hisses and curses, the
king and queen rose from their seats, the
conductor hurried on stage to apologize
and ended by bursting into tears, and ValTHUNDEROUS
Mr. Scott is well known for his significant
contributions in measuring and reducing
noise. Scott noise level meters and analyzers are widely used in industrial laboratories and Scott's remarkable invention, the
Dynamic Noise Suppressor, uncannily eliminates noise from all records and poor broad.
cast reception without any loss of music. As
every audiophile knows, Scott manufactures
a most distinguished line of audio equipment.
Typical of the quality components that bear
the Scott name is the versatile 210 -D, a
combination preamp- equalizer, power amplifier. Dynamic Noise Suppressor, and featuring unusually complete tape recording
facilities. "In designing equipment for per-
fectionists," says Scott, "associated components must be of equivalent caliber. We
find the wide dynamic range and tonal
response of the Berlant Concertone most
useful in our laboratory test and design
work. Of equal importance, we find we can
depend on it in continuous daily operation."
Visit your Berlant- Concertone distributor
this week for a demonstration of the unusual
features that have made Berlant -Concertone
the first choice of audiophiles, according to
a recent independent survey The Concertone
recorder is priced from $445. The Berlant
Recorder with hysteresis synchronous motor,
specifically designed for broadcast and
recording use, from $595. Both recorders
are available as complete sound systems
with matching playback amplifiers and
speakers. For detailed literature tully
describing these recorders, write Dept. H.
H. H.
Scott
Berlant-Concertone
..
'...
wA.we
210 -D Amplifier
.personal choice
of leading
audio manufacturers
ail
lle,
Audio Division of American Electronics, Inc.
655 West Washington Blvd.
"I
Los Angeles 16, California
Consult Recordata Division
tor industrial requirements
West Ninth St., New York 11, N. Y.
ELISABETH SCHWARZKOPF
Soprano
deugo retreat. it to his dressing ruolo. Itut
the crowd was not quite through with the
singer. They located his expensive automobile and proceeded to take it apart, while
Valdengo ran through the streets shrieking: "Help! Police! They are taking the
wheels off my car!"
Americans, Too
\u yuall} volatile personality is Philadelphia -born David Poleri who recently
scored a notable success as Michele in The
Saint of Bleecker Street. Like Valdengo
and Tebabli. lie also played "Stop the
Music." About two years ago Poleri was
portraying the role of Don José in Carmen
at Chicago when he abruptly cut off in the
middle of a scene, marched toward the pit,
yelled a few angry words at the conductor
and stalked off the stage leaving Carmen
unstabbed, and alive and kicking.
The Carmen of that performance, incidentally, was Gloria Lane who later played
opposite Poleri in Menotti's opera. It appears to be Miss Lane's fate to be stabbed
(on stage) by Mr. Poleri, for as Desideria,
the spurned mistress, she is dispatched in
this manner by Michele.
Speaking of singer -conductor relationships, Enrico Caruso marked his debut at
La Scala in 1900 by demonstrating that be
could be just as temperamental as the next
i
singer. The trouble was, he chose to throw
his weight around with Arturo Toscanini,
(Continued on page 5m)
AUDIO
6
www.americanradiohistory.com
AmericanRadioHistory.Com
JANUARY, 1956
Scott
Sensational
FM Performance
at a
Best -buy Price
The 311 FM Tuner,
$99.95
There are NO weak stations with this new tuner
Terrific 3- microvolt sensitivity makes distant stations
sound as clear and strong as those nearby.
New wide -hand FM design gives super -selectivity, to
separate stations so close together you would ordinarily
pass right over them.
Wide -hand circuitry insures rock -steady. drift -free reception, so you never need readjust tuning.
Automatic gain control always keeps tuner perfectly
adjusted, no matter how the signal varies.
-
TECHNICAL SPECIFICATIONS
2- megacycle
-
-
wideband detector
2 stages of full limiting
80 db rejection
spurious response from cross -modulation by strong local signals
low impedance output
equipped for multiplex
beautiful accessory case $9.95
'Slightly higher west of Rockies.
of
-
-
310 FM BROADCAST MONITOR TUNER
For perfectionists and connoisseurs, H. H. Scott offers the
310 FM tuner. High Fidelity Magazine says: The 310
.. is a tuner that seems as close to perfection as is practical at this time." Price, including case $149.95 East
Coast; $157.45 West Coast.
by
'.'.-
Scott
The Greatest
Amplifier Buy
You Have
Ever Seen
Imagine! 22 watts
The famous "99 ".
the power
-- a
a
- complete
complete amplifier. now with twice
hrilliant 22 watts.
Complete equalizer- preamplifier with five -position record compensator. Equalizes virtually all records.
New adjustable rumble filter and record scratch filter
reduce record noise and rumble.
Two magnetic inputs, switched on panel. allow
loth changer and turntable.
use
of
-
FREE
valuable booklet
on high -fidelity amplifiers!
Send this coupon, with your name and address, or
write for FREE BOOKLET A -156 and complete
catalog on amplifiers, tuners, turntables, and noise
suppressors.
H. H. Scott, Inc., 385 Putnam Ave., Cambridge, Mass.
it-
99-B Transcription Amplifier 599.95'
controls - only $99.95
special provisions
through your 99-B.
for playback of pre- recorded tape
Continuously variable LOUDNESS compensation. with
volume -loudness switch. gives perfect tonal balance at all
listening levels.
TECHNICAL SPECIFICATIONS
-
Input selector switch for two magnetic pickups, crystal or constant amplitude
pickup, three high-level inputs, and NAR7B tape playback
frequency response
flat from 20 cps to 30 kc
hum better than 80 db below maximum output harmonic distortion less than 0.8%
first -order difference -tone intermodulation less than 0.3%
class A circuits throughout
easy panel mounting beautiful accessory case $9.95'
*Slightly higher west of Rockies.
-
-
-
-
Scott
385 PUTNAM AVE.
CAMBRIDGE 39, MASS.
Export dept.: TELESCO INTERNATIONAL CORP., 270 Park Ave., New York 17, N. Y.
n
UDIO
JANUARY, 1956
7
www.americanradiohistory.com
AmericanRadioHistory.Com
NEW LITERATURE
right from
the start
Electro-Voice, Inc., Buchanan, Mich., in
Bulletin No. 211, introduces the new E -V
line of do-it- yourself high -fidelity speaker
enclosure kits. The bulletin tells Just how
easily the music lover or high -fidelity
enthusiast can build his own speaker enclosure with simple household tools, and
save up to one -half the cost. Every piece
.
music
kit is precut, ready to askits are comparable to
Electro -Voice factory -assembled enclosures. Seven kit models are described and
In each E -V
that lives
semble. Finished
7fdi
SPEAKERS
COMPONENTS
TWEETERS
Your Sound System GROWS UP... Never Grows Old
RIGHT FROM THE START, Lorenz gives
you full listening enjoyment, plus the
satisfaction of knowing that Lorenz
LP312 -1
12" SPEAKER
With Coaxial
Tweeter
Assembly
years-ahead engineering and craftsman.
ship enables you to plan your present
and future sound systems! Lorenz
Speakers and Components are designed
for expansion, permitting your system
to Grow with your requirements
or,
you can expand and improve your present system at little cost. There's no limit
to your music enjoyment!
-
LISTEN TO LORENZ! You'll understand
why Lorenz is the choice of sound
engineers and high fidelity enthusiasts
acknowledged favorites for their crisp,
clean tonal qualities that add the
miracle of life to the magic of musk
-
reproduction. Three generations of
Lorenz research and technical mastery
guarantee Lorenz quality -performance.
6
LPSS KORN
TYPE TWEETER
atar
of
e,pandinr
Provides high
frequency
for any speaker
system.
ÇOUOSPEARER
Use tw,oe'ange
speaker,
part
system
T11.1
/
FILTER
For 2- and
3 -way
t\
TB -2
A
TWEETER
a.A
ASSEMBLIES
systems.
' Cro,sSner"
frequency 5,000 cps.
Coaxial arW Biaxial.
Fits across any
12" speaker.
.
rm
Lorenz Quality Speakers and Components are surprisingly low in cost.
Write for Catalog A -1
fidelity dealer
See and Hear them at your high
Exclusive U.S. Distributors
American Standards Association,
rn INGDoil PRODUCTS, Ltd.
23 Park Place, New York 7, N.
70 E.
available
45th St., New York 17, N. Y., has
booklet titled "The 400 AmeriField,"
Electrical
in
the
can Standards
each Ameriwhich indexes and describes of
electrical
can standard in the area
engineering. It is designed essentially to
purchaser to
help the user or prospective
in
find applicable standards on products
book also
The
interested.
which he is
the work
contains general information on Standards
of the ASA, the Electrical
Board and the International Electrotechnical Commission. Copies will beonmailed
hand
without charge until the supply
3-5
is exhausted.
a 60 -page
Electrical
Instrument
Co.,
120
Bluffton, Ohio, presents in Catalog
photodetailed information as well as Trilett
graphs
é
devices, and black -and -white television
equipment. A copy of the 2 -color 16 -page
booklet may be obtained from local Triplett representatives or by writing direct.
With Diaziel
Tweeter Assembly
N CN PASS
Alpha Wire Corp., 430 Broadway, New
York 13, N. Y., announces publication of
catalog S -55 which is devoted to audio
wire exclusively. It contains descriptions,
the
specifications and illustrations ofitems,
company's in -stock line of 145 audio
among the largest and most complete in
S -55,
the industry. A copy of Catalog mailed
together with price sheet, will be
free on request
Society of motion Picture and TeleNew
vision Engineers, 65 W. 42nd aSt.,12 -page
York 36, N. Y., is distributing
pocket -size booklet which describes the
-picture
several new methods of motion
which have
production and exhibition
conte Into use since 1952. It covers 35 -mm
sound pictures only, including Cinerama,
and
Cinemascope, VistaVision, Superscope
Todd -AO. Included are details of camera
aspect ratio,
aperture, projector aperture,
number
direction and rate of film travel,
and type of film tracks and loudspeakers,
to
and type of screen. Prepared primarily
explain to people in other countriesof what
prethese systems represent in terms
vious standards, the booklet will also be
supplied to domestic readers on requJ
Triplett
LP312-2
12rr SPEAKER
EXPAND AND IMPROVE ANY SOUND SYSTEM WITH LORENZ
lP2M
the Patrician IV,
Georgian, Centurion, Regency, Empire,
Aristocrat and Baronet. Simple step-bystep instructions are supplied with each
kit or may be obtained separately at
nominal cost. A copy of Bulletin No. 211
J -1
will be mailed on request.
Allied Radio Corporation, 100 N. Western Ave., Chicago 80, Ill., will mail free
a copy of "This Is High Fidelity," a new
100 -page book which combines an extensive, illustrated information section explaining high fidelity, with listings of hi -fl
music systems and separate components.
Among highlights of the book are matched
hi -fl systems in a wide range of prices.
Product listings include the latest individual components produced by virtually
all leading manufacturers. A separate
section covers tape recording equipment.
Irrespective of the nature of your interest
in high fidelity, you should have a copy
of this handsome catalog. It will be
3 -2
mailed free on request.
illustrated, covering
and grows
Y..
WOrth 4.9511S
650
Sun Radio & Electronics Co., Inc., has
Sixth Ave., New York 11, N. Y., tonow
indusavailable for free distribution
governtrial users, schools, laboratories,
and
ment
Catalog 56,
stersutheufifirst edition of
a directory of radio and electronic supplies. A triple -index system enables a
user to locate any part, by manufacturer,
specific product, or general category. To
avoid confusion, original manufacturers'
of Catalog
part numbers are used. A copy
56 may be obtained free by writing on
your company or professional letterhead.
3-7
c
AUDIO
8
www.americanradiohistory.com
AmericanRadioHistory.Com
JANUARY, 1956
The British Electronics Industry is making
giant strides with new developments in a
variety of fields. Mullard tubes are an
important contribution to this progress.
Britain's
foremost pentode
for 25W high
fidelity equipment
r
/.
The Mullard EL34 can be rightly acclaimed as the
most efficient high fidelity output pentode tube yet
produced in Britain. It is being fitted in many of
the British sound reproducing equipments which
are becoming increasingly popular in the United
States and Canada.
Used in push -pull ultra -linear operation (distributed load), two EL34 tubes will give 32 watts
output at a total distortion of less than %,. The
application of negative feedback reduces distortion
even further.
The EL34 is equally capable of supplying higher
power outputs where an increased distortion level
is acceptable. Under class B conditions, too watts
are obtainable from a pair of EL34 tubes in push pull for a total distortion of 5 %.
Another significant feature of this tube is its high
transconductance value of 11,00o µmhos, resulting
in high power sensitivity and low drive requirements.
Supplies of the EL34 are now available for
replacement purposes from the companies
mentioned below.
Principal
Ratings
Heater
6.3V, 1.5A
1
Available in the U.S.A.
from:
Max. plate voltage
800V
Max. plate dissipation
25W
Max. screen voltage
425V
Max. screen dissipation
8W
Max. cathode current
150mA
Base
Octal
Available in Canada
International Electronics Corporation,
Dept. Al, 81 Spring Street, N.Y.12,
New York, U.S.A.
8 -pin
from
Rogers Majestic Electronics Limited,
Dept. HE, 11 -19 Brentcliffe Road.
Toronto 17. Ontario. Canada.
Mullard'
DULLARD OVERSEAS LTD., CENTURY HOUSE, SHAFTESBURY AVE., LONDON, ENGLAND
ELECTRONIC TUBES
u04 e
wo14e
are#
Mullord
is the Trade Mark of Mullard Ltd., and is registered
in most of the principal countries of the world.
AUDIO
JANUARY, 1956
9
www.americanradiohistory.com
AmericanRadioHistory.Com
EDITOR'S REPORT
OUTLOOK FOR 1956
the custom for those in
spots where they might be expected to have some
inside information to engage in the gentle art of
prognostication at the beginning of the year, we shall
assay a step in that direction. And while we may be
expected to have the "inside information," we hasten
to disclaim any such favored distinction -we shall
only, guess just as you -and you and you -can do.
Predictions about the future run from the ridiculous to the ultra- optimistic, usually. In many instances
they result from the predictor having an ax to grind,
which is better than plain Pollannaism because one
can generally spot the ax if he looks carefully. Pure
optimism for the sake of saying something pleasant is
less excusable
there is a bitter pill in the offing,
let's know about it as soon as possible so we may prepare for it.
From our editorial "ivory tower" we are sometimes privileged to learn about new developments before they are generally announced -and about these
we are duty bound to maintain a rigid silence. Anything said herein may thus be considered to be speculative, and not indicative of anything known to be
scheduled for early unveiling. These comments are
merely the opinions developed by observation of trends
in design throughout the audio field as exhibited during the past year.
Phonograph equipment. Much as we regret the coming of another speed in the already-too -many- speeded
phonograph field, it appears that we will be exposed
to 161 rpm before long. It has already been announced
for Highway Hi- Fi "Muic in your Buick" it might
be if General Motors had introduced it instead of
Chrysler. (With less intelligent design it might have
been a "Scrambler in your Rambler. ") And while we
may possibly be subjected to sufficient sales talk to
convince us that the lower speed is "just as good" as
our present LP's, anyone who has ever heard a good
recording of 78 microgroove knows that the higher
speed has it all over the LP for response. We don't expect it, but we would welcome 78 microgroove releases
for super-hi -fi recordings over any further lessening
of turntable speed. If for no other reason, the difficulty of obtaining a wowless speed at 161 rpm should
be enough to unsell any music lover for his high -quality listening system, especially with changers or low priced turntables.
Amplifiers. The trend in amplifiers would seem to be
for higher power for those who want the best, with
50 or 60 watts becoming the standard in top -quality
systems. Simpler 10-watt amplifiers should take over
the smaller-system market, with a minimum of complexity in the control department. Since many newcomers to the hi-fi fold will be buying only LP 's, a
single phono position should suffice on the amplifier,
provided a well- designed tone control circuit is built
into the unit.
Loudspeakers. From what we have heard in the way
of performance of electrostatic high- frequency units
already shown, and from what we have heard in the
SINCE IT HAS ALWAYS SEEN
-if
-
wily of rumors of units to be introduced soon (not
secret), we are inclined to the belief that the electro-
static will emerge as the top -quality speaker with a
full range down to the lowest required. They will be
bulky, and undoubtedly they will be expensive, but
they will open up a new vista in realistic reproduction.
We'll give this one two years. For the middle -fi market, however, we expect the trend toward smaller and
more effective cabinets to grow. Some are doing excellent jobs now, and undoubtedly more will become
available.
Tape recorders. It is in this field that the greatest
gains in usage may be expected. As more and more
people become interested in high -quality music reproduction, the versatility and excellent reproduction of
the tape recorder will become a desirable addition to
the music system. We do not believe that recorded tape
will replace the phonograph record until some simple
and workable mechanism is developed that will handle
a 30- to 45- minute roll of tape in a magazine form.
\T'hen that comes, we can soon after expect a changer
for the tape magazines. But this observer cannot see
the lady of the household becoming familiar enough
Nvith present-day tape recorders to use one regularly
for music reproduction. Record changers are so much
easier to load and operate, and over three hours of
entertainment can be had with one loading of LP's.
We would like to see more tape recorders available as
units suitable for building into hi -fi systems easily
and effectively. The advantages of tape recorders are
not shown off best with even a multiplicity of 3- to
6 -inch speakers enclosed in whatever space remains
after the tape transport mechanism and amplifier gets
put into a 1.5 cu. ft. carrying case.
Radio tuners. We can't see how many of these could
be improved upon -some are pretty close to perfection
now. Perhaps they can be reduced in cost, since a good
tuner now costs more than many a complete radio console which includes a "power" amplifier, speaker, and
cabinet.
And that, dear readers, constitutes our outlook on
1956. Some is the result of observing trends, some
from projecting what we are told about equipment
now, and some pure wishful thinking. Perhaps we may
see fit to remind readers a year from now of what we
say here. Or perhaps we will recall all January, 1956,
amid rewrite the Editor's Report.
TRUTH IN ADVERTISING?
We have almost given up io o wing the new products
which are called "high fidelity since they now seem
to encompass everything manufactured -although we
don't remember seeing any high fidelity cornflakes
yet. However, we have been hearing radio commercials describing a phonograph in, substantially,
the following terms: any record sounds better on a
three speakers for
response to 50,000 cycles
...
...
...
true stereophonic reproduction.
Must have our secretary remind us to drop around
to the nearest discount house and hear one some time.
AUDIO
10
www.americanradiohistory.com
AmericanRadioHistory.Com
JANUARY, 1956
the first really new pickup in a decade
Made by perfectionists -for perfectionists.
The FLUXVALVE is literally the
cartridge of the future, its unique
design meets the demands of all
presently envisioned recording
developments, including those utilizing less than 1 mil styli.
There is absolutely nothing like
it! The
Turnover Pickup provides the first flat frequency response beyond 20kc! Flat response
assures undistorted high frequency
reproduction and new records
FLUXVALVE
-
For
a
The FLUXVALVE has easily replaceable styli.
The styli for standard and microgroove record
playing can be inserted or removed by hand.
impervious to humidity, shock and
wear...with no internal moving parts.
without the use of tools.
new listening experience, ask your dealer to demonstrate the new FLUXVALVE ...words cannot describe the difference... but you will hear it!
"FOR THOSE
HEAR
...
retain their top "sheen" indefinitely,
exhibiting no increase in noise ..
Even a perfect stylus can't prevent
a pickup with poor frequency characteristics from permanently damaging your "wide range" recordings.
With this revolutionary new pickup,
tracking distortion, record and stylus
wear are reduced to new low levels.
The FLUXVALVE will last a lifetime!
It is hermetically sealed, virtually
PICKERING
WHO CAN
THE
O C E A N S
DIFFERENCE"
P
I
O N
E E
I
D E
R S
L O
,
I
N
CO., INC.
&
N G
H
I
I
G H
S L A N D
F
I
D
E
N
,
L
I
Y
.
T
.
Y
Demonstrated and sold by Leading Radio Parts Distributors everywhere. For the one nearest you and for detailed literature: write Dep. A -9.
AUDIO
JANUARY, 1956
11
www.americanradiohistory.com
AmericanRadioHistory.Com
Where voices are
powered
by the sun
/
Lineman
neman mounting solar battery on pole
near Americus, Ga. The battery supplies
power directly to the line by day and
also charges a storage battery for night
time use. The solar battery contains tag
specially prepared silicon cells. Cush
coned in oil and covered by glass.
A new kind of telephone system developed by Bell Telephone
Laboratories for rural areas is
being operated experimentally by
electric current derived from sunlight. Electric current is generated
as sunlight falls on the Bell Solar
Battery, which a lineman is seen
adjusting in position.
The exciting achievement is
made possible by two Laboratories inventions -the solar battery and the transistor. The new
system uses transistors to the complete exclusion of electron tubes.
Transistors require little power
and this power can be easily supplied by the solar battery.
Compact and economical, the
transistorized system can carry
several voices simultaneously
without interference. It has
proved its ruggedness by standing up to heat, cold, rain and
lightning. It promises more and
improved telephone service for
rural areas and it typifies the
Laboratories' continuing efforts
to make American telephony still
better each year.
BELL TELEPHONE LABORATORIES
IMPROVING AMERICA'S TELEPHONE SERVICE PROVIDES CAREERS
FOR CREATIVE MEN IN SCIENTIFIC AND TECHNICAL FIELDS
www.americanradiohistory.com
AmericanRadioHistory.Com
lu sending and receiving terminals. transistors are used as oscillators. :upliliers and
regulators, and for signaling.
of the transistors (actual size) used in
the new system. New ideas. new tools, new
equipment and new methods had to he developed for this project.
One
High -Quality
Dual Channel Amplifier
Cdr. CHARLES W. HARRISON, Jr.'
A qualitative description of a preamplifier, high impedance R -C dividing network,
and power amplifier that are intrinsically simple -yet capable of great performance.
must be
capable of passing rigid laboratory
measurements, meet all listening
requirements, and be simple and straightforward in design in the interest of minimizing performance degradation and
eventual maintenance difficulties.
The circuits of the preamplifier, high impedance dividing network, and power
amplifier described in this paper are not
fundamentally new; they represent a
synthesis of well -known component circuits of recognized excellence.
In general, the playback system was
evolved a "block" at a time after extensive experimentation and listening tests.
Each unit had to "test" well, i.e., possess
appropriate frequency response, adequate voltage or power output, low distortion and hum level, and then "sound"
right when used as an integral part of
the sound system. Any unit not meeting
these criteria was rejected.
The preamplifier shown schematically
in Fig. 1, consists of a type 6J7 input
tube, followed by two type 6SN7 tubes.
Cdr., USN. Electronics Officer, Staff,
Commander Operational Development
Force, Norfolk 11, Va.
AI1101í -QUALITY AMPLIFIER
the method of "contact bias" are rejected
because of the excessive intermodulation
distortion developed in such circuits.
(This bias method permits the direct
grounding of the input tube cathode.)
The distortion in the 6J7 stage is low
even without feedback because the signal
voltages rarely exceed 100 my rms. If
desired, the low- distortion input amplifier stage described later may be used,
provided the entire bias resistor is heavily bypassed and the volume control is
replaced by a resistor matching the
pickup impedance.
Frequency correction of 6 db per octave below approximately 500 cps is accomplished by the passive R -C circuit
shown between the 6J7 and first triode of
the following 6SN7. The second triode
furnishes some amplification and permits
the application of negative feedback
around the two stages associated with
this tube. Following the volume control,
a 36 position R -C equalizer appears. The
maximum bass rise or cut is 12 to 15 db.
At high frequencies the available rise is
3 to 5 db, and the cut is approximately
12 db. No interaction exists between the
bass and treble sections of the equalizer.
"Local" feedback is effective in all stages
except the first; however, it is to be observed that the feedback loop never encompasses more than two stages. Unconditional stability, low output impedance
and the minimization of distortion is
thereby assured. The type 6J7 input tube
was selected because it is reliable and
quiet in operation. It does not generate
periodic "frying" noises and the hum
level output is acceptably low. In addition the tube fits a standard octal socket
having lugs of sufficient mechanical
strength to support one end of a resistor
or capacitor. The first stage serves exclusively as a voltage amplifier. No equalization is accomplished. It has been the
writer's experience that most preamplifiers featuring a frequency -selective feedback circuit for equalization which connects to the cathode end of the bias
resistor of the input tube generate an intolerable hum in any reproducing system
capable of good bass response. This
statement is sometimes true even when
complicated d.c. heater supplies are employed. It appears mandatory that one
employ a large bypass capacitor across
the bias resistor. Preamplifiers utilizing
6SN7
6SN7
TO BASIC
AMP. OR
DIVIDING
0.1
0.1
NETWORK
0.47 meg.
o
50 to
100 K
.005
BASS
60
2
TREBLE
6
0I
5
47000
203
0.1 m.
05
40
.0003
f
.00075
40
0.1 meg
0.22 meg.
0.47 meg.
.002.
.005
1.0 meg.
BASS and TREBLE INCREASE WITH INCREASING NUMBERS
Fig. 1. Schematic of the
AUDIO
290
2
preamplifier described by the author.
13
JANUARY, 1956
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The resistor marked 50,000-100,000
should be selected on the basis of bass
equalization required. Bass progressively
increases as its value is reduced. The
equalizer is followed by a two -stage amplifier, using a second 6SN7. Voltage controlled feedback is applied around
these two stages to minimize distortion
and yield low output impedance. A cathode bypass capacitor is used in the output stage to eliminate degeneration at
this point which would tend to raise the
output impedance. If desired a cathode follower output stage may be added to
this preamplifier provided the power amplifier to be used in not high gain; otherwise hum problems are sure to be encountered. If feedback is not required
around the first half of the 6SN7, the
second half may be wired as a cathode
follower. With slight circuit redesign,
type 12AY7 low -noise dual triodes could
be used in -lieu of the 6SN7 tubes. If an
FM tuner input is required, a two -position shorting -type switch should be installed adjacent to the volume control on
the left.
The hum level of this preamplifier is
extremely low. From experience the author can report that nothing is gained in
this respect by the employment of d.c.
on the tube heaters. It has been found
that less than one -third of the equalizer
positions available are needed in practice
to compensate for the various recording
characteristics in use.
This preamplifier does not feature
built-in AES, NAB, RIAA (new orthophonic) response characteristics. The
philosophy of precise preamplifier
equalization which fails to take into account the frequency response of the
pickup, power amplifier, and speaker to
be employed is a mystery to the writer.
System, rather than component engineering is required. As a practical example,
suppose that the AES playback characteristic is specified for a given recording
and that this response curve is built into
the preamplifier. Excellent results will
undoubtedly be obtained provided the
pickup, power amplifier, and speaker
are flat. Now let it be assumed that the
speaker (high -frequency driver in a dual
loudspeaker) is down 12.5 db at 12,000
cps, which is not at all unusual. The
program material in this frequency region is now attenuated by some 12.5 db
more than required by the AES playback curve. Percussion instruments will
appear to be in the background, a condition not acceptable to a person who enjoys "high- highs." To approximate the
AES play -back curve for a given sound
system may actually require a preamplifier having essentially flat response above
500 cps; the high -frequency pre -emphasis used in recording being more or
less offset by the high-frequency rolloff
of the loudspeaker and pickup being
employed. In addition to the factors mentioned above affecting preamplifier
equalization, the influence of listening
room acoustics must be given due weight.
290
o
1/2
12An
.02
x-Q
INPUT FROM
PRE AMP
6.3
0.47 M
v.
of
o.
^`-V
TO SASS
AMPLIFIER
TO TREBLE
AMPLIFIER
Fig.
2
Schematic of the high- impedance R -C dividing network between the
and the inputs to the two power amplifiers.
amplifier
14
A dual -channel amplifier has several
advantages over a single amplifier for
driving a dual loudspeaker. The use of
a distortion -producing dividing network
at high signal levels is avoided, as is the
power -consuming attenuator normally
required in the high -frequency channel
to obtain bass and treble balance. The
divided transmission system permits exact impedance matching between amplifiers and speakers and additionally permits one to obtain optimum generator
impedance in driving the bass and treble
speakers. This is generally impossible
when a dividing network is interposed
between an amplifier and dual loudspeaker. This scheme is a good way of
achieving linear transmission of low frequencies (such as emanate from drums,
gun shots, explosions, and thunder)
together with linear transmission of high
frequencies (such as emanate from triangles, castanets, cymbals, and tambourines), without severe modulation of high
frequencies by the low frequencies.
The circuit diagram of an R -C dividing
network employing cathode follower input and output stages is shown in Fig 2.
Two type 12AY7 tubes are used; one in
each channel. The values of capacitors
and resistors shown result in an 800 -cps
crossover. If, for example, a crossover
frequency of 500 cps is desired, the
values of the filter capacitors should be
multiplied by the ratio 800/500. The resistors do not change value. Similarly,
multiplying the capacitor values by
800/1500 yields a crossover frequency
of 1500 cps. Each R -C section of both
filters should be adjusted to be down 1
db at 800 cps (for 800 -cps crossover) by
padding the appropriate capacitor and
resistor so that the total attenuation for
all three sections in cascade is 3 db. The
low -frequency filter provides an attenuation approaching 18 db per octave above
the crossover frequency, and the high frequency filter provides an attenuation
approaching 18 db per octave below the
crossover frequency. By actual measurement on the R -C dividing network constructed by the author, the low- frequency
filter is down 11 db at 1600 cps and the
treble filter is down 11 db at 400 cps.
Thus the attenuation afforded by the
three-section R -C filters is 11 db in the
first octave, the crossover frequency
being taken as reference. The input impedance of the dividing network is extremely high. The output impedance of
each channel is low, permitting the use
of rather long cables to the bass and
treble power amplifiers without deleterious effect on the high frequencies. Ten
volts rms will not over-drive the dividing
network. If the network is used in conjunction with power amplifiers like the
one to be described in the following section the operating level need not exceed
one -half volt. Thus essentially distortion less operation is assured.
AUDIO
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JANUARY, 1956
amplifier. Values of R and
are discussed in the text.
Fig. 3. Schematic of the power
A schematic of the basic or power amplifier is shown in Fig. 3. The tubes employed are 1 -6J7, 1 -6J5 and 2 -5881.
'Using tubes selected at random the amplifier is capable of delivering 10 watts
at under 1 per cent intermodulation distortion; 12 watts at under 3 per cent. An
18 -watt power output is available over
the frequency range 20 cps to 140 kas
( by appropriate adjustment of the input
voltage) without visible wave form distortion (estimated at under 3 per cent
harmonic distortion). The amplifier is
absolutely flat at 12 watts output from
below 20 cps to 55 kcs for constant -voltage input, dropping to -2 db at 125 kcs;
-5 db at 175 kes and - 6.5 db at 200 kas.
One half volt rms will drive the unit to
full power output. It will deliver 12
watts for 0.38 volts rms drive. These performance data are based on the use of 10
db feedback.
The component values, i.e., resistors
and capacitors associated with the 6J7
voltage amplifier, were selected to minimize intermodulation distortion. It was
found desirable to use a voltage divider
te. obtain screen voltage and to bypass
the screen to the cathode of the tube. The
b:as resistor is almost entirely bypassed;
only a small portion of the total resistance being left unbypassed for the appliei Lion of negative feedback.
The phase splitter, employing a 6J5, is
an excellent method of coupling a single ended plate circuit to a push -pull grid
circuit. (A phase splitter, as well as a
cathode follower, is defined for later
wage as "one- half" stage.) This circuit is
self -balancing, and distortion is low. Any
unbalance effects at high frequencies are
generally negligible.
The output stage features the use of a
Peerless type 256Q 20-20 plus transformer. Note that the bias resistor for
the push -pull type 5881 tubes has a value
of 125 ohms. The 5881 tube is similar to
Western Electric type 350B and are interchangeable. Both have "power fila-
AUDIO
C in
stable with feedback values up to at least
30 db. Many of the popular circuits of
today feature the application of large
values of feedback around "3.5" to 4
stages. This is an invitation to serious
trouble. Marginal stability obtains and
at some signal levels violent subsonic and
supersonic oscillations may be generated.
Even though these frequencies may not
be heard, i.e., they fall outside the audio
spectrum, the power delivering capability of the amplifier is largely consumed.
Thus little "clean" power is available in
the frequency range of interest. This
principle is too frequently overlooked
in practice. The power amplifier will deliver a clean signal over its entire frequency range even without feedback.
This is not true of one well known circuit
which utilizes 20 db of feedback. A sine
wave input at 60 kc is likely to appear
at the load terminals as a series of triangles!
The writer is of the opinion that an
otherwise essentially distortionless amplifier does not require the application
of large values of feedback. The use of
20, 40 or 90 db feedback is nonsense.
Values of 10 to 15 db voltage- control
feedback are adequate for two important
reasons :
the feedback circuit
ments" in that 1.8 amperes at 6.3 volts
is required for cathode heating.
Feedback is applied around the "2.5"
stages; the required voltage being taken
from the secondary winding of the output transformer. The values of R and C
in the feedback circuit must be selected
by test. The value of R controls the
amount of feedback (usually expressed
in db), and C controls the high -frequency ringing, i.e., for the purpose
of damping out any small oscillations
that may appear on the leading edge of
a square wave. The equipment needed to
determine the proper value of R and
optimum value of C is : a vacuum tube
voltmeter and a sine and square wave
generator. It is customary to load the amplifier by a resistor equal to the nominal
load impedance of the amplifier when
choosing the correct values of R and C,
rather than use the loudspeaker as load.
Optimum generator impedance can be
obtained by varying the value of R in the
feedback path and conducting simultaneous listening tests. As R is increased the
value of feedback is decreased.
This power amplifier is basically
simple and utilizes the minimum number
of stages required to do the job effectively. Although feedback is applied
around "2.5" stages the amplifier is
2A
PEERLESS
(a) Instability tendencies are reduced.
(b) The experimentally observed bass
loss in the frequency region of
speaker resonance is minimized.
It is interesting to note that the designers of theater sound equipment restrict the use of feedback to the 10 or 15
db level.
There may be protests to the effect
that the equipment described in this article is not an "all triode" playback system. It would seem meaningless to insist
on the exclusive use of triodes in amplifiers until records are available bearing
the label "We guarantee all electronic
equipments used in making this recording were fitted throughout with triode
vacuum tubes." Note also that AM,
FM, and TV stations will never measure
up to the standards of the perfectionist
who insists on the utilization of triode
vacuum tubes in every tube application.
R
-560A
SWG
TRANSFORMER
FUSE
-e
ply
schematic.
Note that it
conventional
is
C-455A
CHOKE
O
6
117 v. A. C.
Fig. 4. Power sup-
PEERLESS
200
DPST
SWITCH
-
of
80
v.
200Opnro.
de-
sign.
X
6.3
v. or
6a
x
JANUARY, 1956
15
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AmericanRadioHistory.Com
e
Fig. 5. Above, the preamplifier; below,
the power amplifier. "Building block"
construction makes for flexibility,
Fig. 6. Above, the power supply is a
simple and neat construction; below, the
dividing network chassis.
The power supply illustrated schematically in Fig. 4 is entirely conventional.
It delivers 290 volts d.c. at 200 ma and
6.3 volts a.c. at 6 a. To minimize hum in
the playback system, the heater winding
is operated at a positive potential of
about 29 volts, the center tap of the
winding being heavily bypassed to
ground. Although often omitted from
commercial equipment, the bypass capacitor is a circuit element vital to the
successful operation of this hum reduction scheme. Because of the relatively
low d.c. voltages required for operation
of the preamplifier, R -C dividing network and power amplifier, one may expect that 450 -volt electrolytic filter capacitors, if used throughout the equipment, will have exceptionally long life.
The writer believes in building equipment with the best parts available. All
coupling capacitors should be rated at
600 volts, and if 0.1 ttf and less in capacitance should have a leakage resist ance of at least 1500 megohms. The bass
Fig. 7. Above, left, bottom view of the preamplifier with the base plate removed to
show layout of parts and wiring. Fig. 8. Above, right, bottom view of power am-
plifier with base plate removed.
Fig.
of
9.
Underside
dividing network chassis.
and treble controls in the preamplifier
should be of the shorting type and feature silver contacts and steatite insulation. Capacitors used in the equalization
circuits should be 5 -per cent tolerance
silver micas (except possibly in the largest sizes). Resistors in these circuits
should be within 5 per cent of specified
values, or better. Very precise values of
resistance and capacitance are required
in the filters of the dividing network. In
the push -pull portion of the power amplifier the capacitors and resistors used
should be selected for balance. The most
reliable volume controls that can be obtained should be used, in log -taper form.
In general, resistors rated at 1 watt dissipation are adequate, except in the following instances: The 33,000 -ohm resistors in the dividing network are 2 watt
types as is the 2400 -ohm resistor in the
power amplifier, and the 125 -ohm bias
(Continued on page 41)
AUDIO
16
www.americanradiohistory.com
AmericanRadioHistory.Com
JANUARY, 1956
Disc Recording
SOUND -Chapter 4
EDGAR M. VILLCHUR`
The whys and wherefores of the recording characteristic, together with a presentation of some of
the problems involved in making high -quality recordings with a minimum of noise and distortion.
HAVE OUTLINED BRIEFLY the
functions of each link in the chain
of sound reproducing components,
from pickup to speaker. It now remains
to treat each of these components in
some detail, and the reader may have
been led to expect a discussion of pickups to follow the last chapter. But
pickup design doesn't begin to make
sense until the fundamental methods of
disc recording are understood.
Most modern records are of the disc
type, are made to revolve at 331/3 RPM,
are recorded at an average of about 225
grooves per inch, and employ grooves
which are shaped to receive a spherical tip stylus in such a way that the contact
is exclusively with the sides and not the
bottom of the groove. The recording is
of the lateral type, and the recording
characteristic seems finally to have been
standardized on the RIAA curve.
Variables in Disc Recording
Lateral and Vertical Recording
In the earliest days of the commercial
phonograph, when recording and reproducing the human voice was for stenographic rather than entertainment purposes, and when the same machine
performed both the recording and the
reproduction, standardization of record
characteristics wasn't important. Records were matched to the playback
equipment automatically. The introduction of the prerecorded disc or cylinder,
however, which had to be playable on
home machines, changed the picture
completely.
Features that had to be standardized
were:
The recordings of Young, Scott de
Martinville, and Cros were all lateral:
the recording stylus moved from side to
side in a plane approximately parallel
to the record, and inscribed a visible
wavy line, a graph of time vs. instantaneous stylus position.
WE
1.
Woodstock, N. Y.
TOP VIEW OF RECORD, LATERAL RECORDING
SURFACE OF RECORD
REPRODUCING STYLUS
BOTTOM OF GROOVE
CROSS SECTION OF RECORD, VERTICAL RECORDING
Fig. 4 -1. Vertical and lateral recording.
AUDIO
TOP VIEW, LATERAL CUT RECORD
/
SIDE
/
SECTION OF REPRODUCING STYLUS
//
REPRODUCING STYLUS
BOTTOM OF
GROOVE
// / /////////// /////
/,/
;
VIEW, LATERAL CUT RECORD
Fig. 4 -3. Pinch effect.
The recording
stylus, of approximately triangular cross
width.
varying
section, cuts a groove of
This forces the spherical reproducing
stylus up and down twice per cycle.
Use of disc or cylinder
The electrical recording "characteristic "
CROSS SECTION OF CUTTING STYLUS
11144411M
per inch)
6.
Ilk
,ROS
2. RPM of turntable
3. Pitch of grooves (number of grooves
4. Shape of grooves
5. t'se of lateral or vertical recording
TOP VIEW, LATERAL CUT RECORD
Recording stylus. 1- shank;
face; 4- clearance face; 5back edge; 6- burnishing facets.
4 -2.
3- cutting
Fig.
The recordings of Edison, on the other
hand, were vertical, or hill- and -dale. The
vibrations of the recording stylus were
in a plane perpendicular to the record,
and the groove variations were in depth,
up and down rather than from side to
side.
These two methods of recording are
illustrated in Fig. 4-1. Edison was the
chief champion of hill -and -dale recording; he used the vertical method in his
cylinders and, later, in his heavy discs.
Vertical recording gave way entirely to
lateral in the commercial home record,
but remained fairly popular in broadcast studio use for a while. The death
blow to vertical recording was dealt by a
classic article on the subject by Pierce
and Hunt, which clearly showed that
the level of inherent distortion in the
record -reproduce process was much
lower with the lateral method. The
reader may note with satisfaction the
power of the just pen.
The main advantage of lateral recording is that second harmonic "tracing"
distortion (not to be confused with
tracking distortion), is drastically reduced or eliminated. Tracing distortion
is caused by the fact that the reproducing spherical stylus tip is guided in an
imperfect vibrational pattern, by groove
walls that were cut by a differently
shaped recording stylus. (See Fig.
4-2).
In the case of the laterally -cut groove
the inaccurate component of the playback needle's vibrations are almost exclusively up and down. This spurious
17
JANUARY, 1956
www.americanradiohistory.com
AmericanRadioHistory.Com
is for the purpose of preventing the
Fig. 4 -4. Illustration of the increase
of
needle excursion at lower frequencies to
maintain constant average velocity. At
250 cps the needle travels through only
one vibration during the same time that
two 500 cps vibrations are accomplished;
the distance of travel at 250 cps must
therefore be doubled.
bass -modulated grooves from cutting
over onto each other.
If the vibrations of the recording stylus are to represent equal energy over
the frequency spectrum the stylus must
have constant average velocity at all
frequencies. A little thought will indicate the fact that constant average velocity does not mean constant excursion
(distance of travel) at different signal
frequencies. As a matter of fact the excursion must exactly double with each
lower octave. If the stylus moves from
side to side .01 inches at 500 cps, then
to record a 250 cps signal at the same
average velocity it must move .02 inches.
This is illustrated in Fig. 4-4. It may
be seen that the average velocity of the
stylus is determined by the distance
through which it vibrates, divided by the
time consumed. Since the time for one
mechanical motion, however, is not necessarily translated into an electrical output signal from the pickup. If the
pickup has little or no electrical response to vertical stylus motion (a
characteristic possessed by modern high quality pickups, and called "low vertical response "), then the distortion in
motion is not allowed to influence the
signal.
The channelling of spurious needle
vibrations associated with tracing distortion into vertical motion is called
pinch effect, and is illustrated in Fig.
4-3.
Recording Characteristics
A recording "characteristic" is the
curve of frequency response, flat, warped
or otherwise, of the recording system;
that is, it describes the frequency va.
amplitude characteristics of the recorded
signal.
In the early days of recording the
artist shouted into a horn, and as much
of the recording diaphragm vibrations
as could be preserved were applied to
the wax. There was no problem of what
to do with the bass, since so little bass
was there in the first place.
There is a definite problem in recordings of wide frequency range, however,
with regard to signals at both ends of
the frequency spectrum. Both the bass
and treble must be doctored in a specific
pattern, and for reasons that will be
discussed.
Bass Equalization
Below a certain frequency called the
turnover frequency the bass portion of
the recorded signal is progressively attenuated, normally at the rate of 6
db /octave. (This means that the signal
voltage of the bass signal is halved, and
the bass signal power is reduced to one fourth, with each lower octave). This
Fig. 4 -5. (A) Groove pattern cut with
a
"constant amplitude" characteristic. (B)
Similar pattern cut with a "constant velocity" characteristic. Presently used
characteristic, (C) employs a constant
amplitude characteristic up to the "turnover" frequency, constant velocity above.
of the playback equipment-which is to
say its frequency discrimination characteristic-will then be the reciprocal of
the equalized pattern into which the
recorded signal has been forced. Without
any equalization, the amplitude of the
recorded grooves would be equal throughout the entire spectrum, as in (A) of
Fig. 4-5, resulting in what is called
"constant amplitude" recording. If
equalization is introduced so as to impart a "constant velocity" to the recording stylus, the pattern resulting from a
swept -frequency recording is that of
(B). Neither of these systems is used in
commercial record manufacture, but instead a combination of the two is employed which gives a constant amplitude
of the recorded grooves up to the "turnover" frequency, and a constant velocity
above that point, as shown in (C). Patterns of the sort shown in Fig. 4-5 are
made by feeding a constant level to the
input of the recording amplifier and
sweeping the frequency from the lowest
to the highest.
In the usual commercial recording,
the low frequencies are equalized to a
level which will produce a constant amplitude from the very lowest frequencies
up to the turnover point, and above that
point they are cut with a constant velocity. Consequently, when using a
pickup which has a response proportional to the velocity of the stylus, it is
necessary to boost the low frequencies,
which accounts for the "bass boost" of
the usual preamplifier for magnetic
pickups--since all magnetic pickups are
oa
UNTREATED SIGNAL
PcE NOSE
III IIIIIIIIIIIIIUIIIIIIIINIIIII
IIIIIIIIIIIIIIII
IIIIIIIIIIIIIIIIIIIIIFRtOIII
cycle of vibration at 250 cps is double
that of the time for one cycle at 500
cps, the distance through which the
needle vibrates must also be doubled in
a constant-velocity device.
The continual increase of stylus ex-
cursion at lower frequencies creates difficulties. It places excessive demands on
the recorder cutting head, and the recordist must space his grooves very
wide to prevent the large groove deviations of heavy bass passages from overcutting into adjoining grooves. He must
either sacrifice playing time by widely
spaced grooves, or risk the severe distortion caused by groove cut-overs.
Fortunately there is a solution to the
problem, made possible by the versatility
of our playback equipment. It is to attenuate the bass at a specified, uniform
rate, and to restore the lost bass in playback by equipment which progressively
accentuates the lower frequencies, at the
same rate and starting at the same turnover frequency. The "equalization" curve
18
10,000
NPE
St
RE-
SRF
PE
"°51
FREQUENCY, cq
IIIIIIIIIIIIIIIIIIIIIIIIIVIIIIII
TRANSITION FREQUENCY
10,000
(B)
SIGNAL AFTER PLAYBACK EQUALIZATION
SURFACE NOISE AFTER PLAYBACK
FREQUENCY, cp.
EQUALIZATION
10,000
(C)
Fig. 4 -6. Effect of treble pre -emphasis
and playback equalization on level of
surface noise relative to signal.
AUDIO
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IIII IIIIIIIillllllllllllllllllll
IIIIIIIIIIIiIII
JANUARY, 1956
velocity sensitive. Conversely, crystal
pickups-which are amplitude sensitive
-must be equalized in the high -frequency region in order to produce a
"flat" response. Some recent crystal pickups are designed to work into a low
resistive load, which reduces their low frequency response almost to the constant- velocity characteristic so that they
work satisfactorily into an amplifier designed for magnetic pickups.
emphasis, and the frequency at which
the boost takes hold is called the pre emphasis transition frequency. Figure
4-6 illustrates the change in surface
noise, relative to the recorded signal,
that the pre-emphasis technique brings
about. Treble attenuation in playback
simultaneously reduces surface noise
and corrects the high -frequency level
of the signal.
Over -all Recording Characteristic
Treble Pre -emphasis
Special difficulties are also involved
in recording the high-frequency portion
of the signal spectrum. The surface noise
that is produced in the course of the
needle- record contact is spread quite
evenly over the frequency spectrum in
terms of energy per cycle. This means
that each higher octave, containing twice
the number of cycles, will have twice as
much surface noise. Considering further
the increased hearing sensitivity in the
higher ranges, the common -sense conclusion must be that record surface noise
is primarily a treble phenomenon. This
means:
a) The "masking" effect of record
surface noise will occur primarily in
the treble range. Recorded sound at the
higher frequencies will tend to get lost
in the mud.
b) An attenuation of treble amplification in the playback equipment will
severely reduce the surface noise relative
to the total signal.
If the treble frequencies of the recorded program material are progressively emphasized or "boosted," a recorded signal will be created that will
sound unnaturally shrill in playback.
A reciprocal treble attenuation introduced in the playback chain will make
the sound natural again. This record reproduce procedure is just what is used
in modern records, in order to improve
the signal -to -noise ratio.
The initial progressive boosting of the
high frequencies is called treble pre-
The over -all pattern of modern record
equalization is illustrated in Fig. 4-7.
While the principles of bass and
treble record equalization have been
generally agreed upon for a long time,
the best way to introduce such equalization -the turnover and treble transition
frequencies, and the rates of attenuation
or boost to employ-has been the subject of much disagreement. Recording
equalization is a double -edged sword,
and can itself cause difficulties. For example, too much treble pre -emphasis increases high -frequency distortion at the
same time that it reduces noise, by unduly increasing the sharp, crowded
groove excursions required at high frequencies.
For many years there was a variety of
EXCESSIVE
ANG E OF
EXCU SION
(OVE 45 °)
(AI
(B)
Fig. 4 -8. (A) Over- recorded grooves,
showing cut -over. (B) Result of over
modulation, with excessive angle of ex-
cursion.
PRE -EM HASIS
TRANSITION FRED
s..
BASS TURNOVER
..
FREQ.
RECORDING CURVE OF BASS ATTENUATION AND TREBLE
..
PRE -EMPHASIS
LAYBACK EQUALIZATION CURVE
Fig. 4 -7. Pattern of recording and playback equalization.
AUDIO
Fig. 4 -9. Modern disc
recorder -the
Scully lathe.
recording characteristics in use, and
playback equipment had to provide
either a single compromise equalization,
or facilities for switching from the
equalization characteristics of one recording company to those of another.
Fortunately agreement seems to have
been finally reached by and large, and
most modern records use what is known
as the RIAA characteristic.
Dynamic Range in Recording
Dynamic range refers to the range of
power, from pianissimo to fortissimo,
that the reproducing equipment is capable of handling. For disc records it is
the ratio of the amplitude of the heaviest recorded signal to the softest.
In a sound reproducing system the
upper limit of the dynamic range would
be determined by the power capability
of the equipment, the lower limit by the
noise level. On a disc the upper limit of
the recorded dynamic range is determined by the allowable groove excursions, and the lower limit by the surface
noise.
In the bass, groove excursions are restricted by the danger of cut-over, as
discussed previously, even when there is
attenuation below the turnover frequency. In the treble range the groove
excursions do not become so great as to
involve cutting over into adjacent
grooves, but there is another danger,
just as serious. The high -frequency
groove "wiggles" are very close together,
and the greater the excursions of the
recording stylus the sharper the corners
of the wiggles become. (The condition
becomes increasingly aggravated as the
inner record diameters are approached).
This tends to create a groove shape
which cannot be followed faithfully by
the reproducing needle, and results in
increased distortion and record wear.
The technique of recording with treble
pre -emphasis reduces the relative surface noise in the signal, and it would
seem that treble pre -emphasis should increase the dynamic range of sound that
can be recorded onto a disc. Unfortu(Continued on page 53)
19
JANUARY, 1956
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AmericanRadioHistory.Com
.
Electronic Organ in Kit Form
For Home Construction
RICHARD H. DORF
In Three Parts -Part 2
How the tones generated
as
described last month are keyed,
in the Schober Organ.
filtered, preamplified, and "vibratoed"
The tone generators described in last
of the switching system for five G notes
of the great or lower manual. Each switch
consists of three horizontal fingers normally in the down position so that they do
not strike the bus wires which are at
right angles to them and run the length
of the organ (left -right). When the 03
key (G just above middle C) is pressed
the three fingers of the G3 switch rise,
each striking one of the lengthwise
busses. The center finger carries tone
from the generators at a frequency of
392 cps, which corresponds to the normal
pitch of G above middle C, and this tone
is thus introduced into the center or
8 -foot bus. Simultaneously the lower
finger, which carries tone from the generators an octave below puts this tone
on the 16 -foot bus, and the upper finger
puts tone an octave above 8 -foot on the
4 -foot bus.
The same generator tone is obviously
used for more than one key switch. The
same tone carried to the G3 center finger
month's article on the Schober Electronic Organ Kits furnish 84 saw tooth tones beginning with low C at
32.70 cps and going up to the high B at
3951 cps. Let us now look at the key switch assemblies which channel the right
tones to the right places when the organ
is played.
When any key is pressed, three different tones are switched, corresponding to
either 4 -, 8 -, and 16 -foot or 2 -, 4 -, and
8 -foot pitches. These pitch registers are
normal in pipe -organ work. The 8 -foot
or unison pitch corresponds to the normal pitch of the key pressed; the 4 -foot
or super register gives a tone one octave
above unison and 2 -foot two octaves
above; and 16 -foot pitch is one octave
lower than normal for the key.
Figure 9 shows the schematic diagram
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Fig. 9. Simplified schematic of keying circuit for the five G keys on the great manual.
This circuitry is duplicated for each of the twelve keys of the octave, except that there
is an additional set of contacts for the top C.
for 8 -foot register is also used by the G2
upper finger as 4 -foot tone and by the
G4 lower finger as 16 -foot tone. Between
the generator and each switch finger
there is an isolating resistor which prevents interaction and any "robbing" or
lowering of the volume of one tone when
another is also used, through additional
loading on the generator.
The actual circuitry is exactly as shown
in Fig. 9 except that there are twelve
times as many 3 -finger switches as shown,
one set of five for each of the 12 notes
of the chromatic scale. There is also an
extra switch at the top for the highest C,
since there are six C's on the standard
organ manual. Each of the three output
busses carries a complete rendition of the
selection being played, the only differences being that if an amplifier were
connected to the 4-foot bus the music
would be heard an octave higher than if
connected to the 8 -foot bus and two octaves higher than if connected to the 16foot bus. Precisely the same scheme is
carried through on the swell (upper)
manual, except that there is a 2 -foot bus
and no 16 -foot bus.
It is interesting to note that on the
Schober Organ no system for eliminating key clicks is necessary. Ordinarily,
when audio is keyed there is a click
when the switch is closed; this is very
destructive to musical values. Figure 10
shows how the click arises. Assuming
that, for instance, a sine wave is being
switched from its source to the grid of a
tube, the switch may be closed during
some part of the time when the wave is
not at its zero axis. (The statistical probability of this is extremely high, since
the wave passes through zero only at two
brief instants.) Grid voltage then changes
from its quiescent value instantaneously
to some other value, and of course plate
current does the same. The almost infinitely steep rise time of this sudden
change is in effect a portion of a wave
containing an infinity of high- frequency
components. These components are heard
as a click. In other organ designs it has
AUDIO
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JANUARY, 1956
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sembly is mounted beneath the keys at
the rear, and the keys press the actuators
down keeping the switch fingers clear of
the busses. When a key is played, its rear
comes up, the actuator is released, and
the fingers make contact.
Connections are brought to the switch
fingers by means of small etched- circuit
panels like the one shown in Fig. 14. As
the rear view of this panel (Fig. 15)
shows, the isolating resistors are mounted
on it. The whole card is then slipped over
the fingers of three adjacent switches
(note the nine holes at top) and the
fingers are soldered to the foil. Twenty
such panels are used for each manual,
plus one more with room only for the
three resistors and one switch for the
high C.
Figure 16 shows a portion of a completed great-manual switch assembly.
There are twelve 7- terminal blocks at
bottom from which wires go to the twelve
tone generators. The wiring harness between the resistor panels on the switches
and the terminals is `laced" by a new
method especially developed for Schober by C. G. McProud. A plastic book
binder is screwed to the metal channel
and all wiring is threaded through the
flexible plastic rings. This keeps each
wire in place as the work progresses and
is left in place at the end so that the
customary waxed -cord lacing technique
.
TIME
-0
Fig. 10. Effect of keying a sine wave tone,
resulting in key clicks in the output.
been found necessary or desirable to
place capacitive low -pass filters across
the switching systems, use gradual resistive keying, or to key plate voltage on
an oscillator rather than direct audio to
eliminate or reduce the clicks.
The secret of the Schober's clickless
keying is simply the generated waveform. The sawtooth has a very fast flyback-almost perfectly vertical, as can
be seen in the drawing of Fig. 11. The
filter system is designed to take care of
can take advantage of the high this
frequency components in imparting brilliance to stops that require it and can
roll off the highs for less brilliant stops.
When the sawtooth tone is keyed at some
point in its rise, the vertical rise added
by the keying is just like the vertical
part of the sawtooth itself, and the filters
treat it the same, To say it another way,
each wave of a good sawtooth has n
built -in key click. When you add another
by closing a switch, neither the circuitry
nor the ear can tell the difference.
From a puristic point of view there is
always, of course, a transient when a
switch is closed in that there is a change
in the output signal from zero cps to
some finite frequency. This frequency
transient or discontinuity is not subject
to remedy, but fortunately it is practically inaudible.
The switch components themselves are
shown in Fig. 12. At the right are five of
the plastic switch blocks, each with three
cured -in fingers of a "springy" silver
alloy. At left are the etched bus strips,
printed circuits carrying a thin gold
wire. These strips are piled up and the
switch fingers placed between them. One
end of the finished assembly (before wiring) appears in Fig. 13. The small phenolic actuators project up when the as-
-it
AUDIO
is unnecessary.
Wiring the key- switch assemblies is,
of course, one of the most time- consumaspects of the organ construction. However, the instructions have been worked
out so that a simple and unmistakable
procedure and a chart make the work
compound
number of small, simple,
similar operations-rather than complex.
The pedal key switches are of the more
rugged flat-blade type and have only
two output busses, 8- and 16 -foot, but
the scheme is electrically the same.
This is placed permanently in the console. The pedal clavier is a self- contained
mechanical unit and it is simply pushed
into place so that the ends of the pedals
overhang the switch blades. In this way
-a
(77
Fig. 11. Keying a sawtooth wave only
adds another vertical transient to the
many already existing.
necessity for extending wiring outside
the console is eliminated. Novel methods
of providing mounting lugs for the pedal
isolation resistors and the use of large
screw -eyes as a substitute for lacing
make pedal -switch wiring again a succession of simple operations.
The metallic material used for key
switches is a problem in organ design.
Low -level audio is always critical to key
since the slightest uncertainty of contact
results in either noise or complete failure. For this reason silver-against -silver
contacts are simply unusable, as is, in
fact, any normal coin -silver contact. In
the manual key switches the special silver
alloy of the fingers does not corrode;
neither does, of course, the gold used for
the bus wires. In the pedal switches
special palladium contact points are
employed.
Each of the keying output busses is
terminated in a maximum of 1800 ohms
to ground. The resistors for termination
are on the balance controls, and adjustment of these switches effectively varies
the terminating resistances. In the normal position of the Manual Balance Control, all great and swell busses terminate
in 1800 ohms. In the clockwise positions
the swell termination is reduced so that
the great produces relatively more output. In the counterclockwise position the
reverse is true. This arrangement takes
the place of separate swell shoes for the
two manuals, reducing cost and making
the organ easier to play. The pedal bal-
Fig. 12. Key switch
parts. (A) Etched
bus strips, with
gold contact wire;
(B)
spacers; (C) lo-
cation strip; (D)
switch actuators;
and (E) switch
blocks.
21
JANUARY, 1956
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Portion of switch plate with
several of the switch blocks already
mounted. Twelve terminal strips are provided for connections to generators.
Fig.
13.
ance control varies the terminations on
the pedal busses so that the pedal volume
can be balanced with any combination
on the manuals without having to depend on the present levels of the pedal
stops for the purpose. The idea in both
cases is to add flexibility to the playing.
Preliminary Amplifier
The Preliminary Amplifier is an assembly of fourteen 6SL7's which per-
forms three important functions. First,
it raises the levels of tones from the keying busses to keep the signal -to -noise
ratio high. Second, it isolates the filters
from each other positively so that the
stops are as independent as in a pipe
organ. Third, it is used in the coupler
system so that coupling is without effect
on other controls or sounds.
Of the 19 stop filters, 16 are fed by one
triode plate each, each triode carrying
2-. 4 -, 8 -, or 16 -foot tone from the proper
source according to the purpose of the
filter. Three filters, the diapasons, carry
both 8- and 4 -foot tone, the 4 -foot tone
present in small quantity to give the diapasons the necessary life and carrying
power.
Figure 17 shows the scheme behind
Fig. 14. Resistor card, with printed cir-
cuit wiring to provide all connections
between switch blocks and wiring.
the system ; the entire diagram is too
large to print here. The great 8 -foot bus
output goes to the grids of all the tubes
which feed 8 -foot great filters through a
single 47,000 -ohm resistor. The amplified
8 -foot great sawtooth tone at the plate
of each of these tubes goes to one great
8 -foot filter. There is a group of tubes
operated in the same way for all the
other registers.
Coupling on an organ lends great flexibility-if it is not a substitute for meager
resources. The Schober has the following
couplers:
Great to Great 4'
Swell to Pedal 8'
Swell to Swell 4'
Great to Swell 8'
Great to Pedal 8'
Swell to Great 8'
The meaning is simple. Ordinarily only
tones produced by playing on the great
manual will go through the great filters.
By using the Swell to Great 8' coupler,
the great keyed tones are made to go
through any swell filters in use as well so
that the tonal varieties of both great and
swell stops are available on the great.
The reverse is true for the Great to Swell
8' coupler. When the Great to Great 4'
coupler is used, all tones heard due to
great stops in use are also heard one octave higher as if the player were fingering everything in octaves. The same is
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Fig. 16. Rear view portion of completed key switch assembly, showing nine of
twelve cables leading to the tone generators.
the
22
Fig. 15. Rear view of resistor card, showing nine resistors mounted. Each manual
key requires three resistors for isolation.
true on the swell for the Swell to Swell
4' coupler. By pulling the Swell to Pedal
8' or Great to Pedal 8' couplers, pedal
tones will also pass through swell and/
or great couplers, adding those tonal resources to the ones normal to the pedals.
The flexibilty of registration this adds is
obvious.
The coupler system works electrically
in a simple way. Refer again to Fig. 17.
If the Swell to Great 8' coupler is used,
the corresponding switch is closed. Now
swell 8 -foot tone goes through a 27,000 ohm resistor to the cathode of the great
8 -foot coupler triode, operated as a
grounded -grid amplifier to keep output
phase unchanged. The plate output is fed
to the grids of the triodes feeding the
8 -foot great stops, right along with the
regular 8 -foot great tone. The level of
the coupled -in swell tone is kept to the
same level as the 8 -foot great tone by
the resistor network. R, is the series and
Rs the shunt leg of a voltage divider for
the coupler tube output. (The great
8 -foot bus terminating resistor at the balance switch is also a part of the shunt
leg but since it has a maximum value of
1800 ohms its effect is negligible.) For
the 8 -foot great tone R, is the series leg
and the resistance of R, plus the coupler tube plate -ground resistance is the shunt
leg of a similar divider. Both operate so
that the levels at the amplifier -tube grids
are the same.
As many busses can be coupled into
the cathode of the coupler tune as necessary, and each bus can be connected to
as many couplers as necessary. The
27,000 -ohm series resistors do not load
the keying busses and, in conjunction
with the low dynamic resistance of the
tube cathode they isolate the busses from
each other as well as keeping couplertube output identical to bus output. In
the actual circuit each coupler switch has
two sections so that, for the Swell to
Great 8' coupler, for instance, not only
is 8 -foot swell tone coupled to the 8 -foot
great filters but 4 -foot swell tone is also
coupled to the 4 -foot great filters.
Five small etched-circuit panels are
used on the preliminary amplifier chassis
(Continued on page 36)
AUDIO
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JANUARY, 1956
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AUDIO
JANUARY, 1956
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Selecting a Tuner
Q. How should I select a high fidelity
tuner? Mario Brener, N.Y.C.
A. There are three possible kinds of tuner
for you to choose from : AM only, FM only,
and a combination of the two. Since the
selection of a tuner is such a highly individual matter, several factors must be taken
into account. In locations having no FM
stations, obviously only AM is needed. In
some of these locations, the AM stations
will be weak and so it is important to use
a tuner sensitive enough to avoid annoying
hiss levels and, at night, complete fading
out of stations. Since the sensitivity of a
tuner is rated in microvolts, the number of
which is a measure of the minimum signal
with which clear reception without excessive noise can be obtained, the smaller the
microvolt rating, the more sensitive the
tuner. A rating of between five and ten
microvolts indicates a tuner of quite high
sensitivity. However, if price is an important factor in your selection and you are
located in a strong signal area, good reception can be expected with a tuner having as
poor a rating as 100 to 200 microvolts.
In localities where FM stations can be
received there is a decision to be made concerning the use of a tuner which will receive FM only or one which can be used for
either FM or AM. If you already have an
AM tuner, of course it will be necessary to
procure only FM. It may be possible to use
the radio frequency portion of an AM radio
set as an AM tuner, thus making it unnecessary to employ a combination unit. It is
sometimes not as easy to manufacture combination tuners which will have extreme
sensitivity as it is to produce such sensi-
If, however, instead of one speaker, an infinite number of speakers, each fed by a
microphone, were used, there would then
exist a wall transparent to sound and making it once again possible for the listener
to hear each instrument as coming from its
own true location. Such an arrangement, of
course, is not feasible but a fairly good
approximation of its effect is obtained
through the use of a two- channel system
(two microphones and two speakers). Since
the distance to be traversed by sound is
greater than that between audience and
orchestra in a concert hall, it is necessary
to transmit the sound via radio. Since radio
broadcasting studios are equipped with both
AM and FM facilities, both are used at the
same time to produce the desired two -channel (binaural) effect. Two microphones are
used. One feeds sound to the FM transmitter. These sounds are received by an
AM receiver and an FM receiver spaced
somewhat apart along the same wall, pointing slightly toward the listener. The AM
and FM tuners should be adjusted for equal
volume. The sounds so transmitted must
never merge during transmission or the
effect of a third dimension will be lost. The
use of two speakers, both producing all of
the sound, instead of each producing part
of it, will also remove the sense of depth
and, although there will be a greater quantity of sound present in the room, it will
not be binaural. Actually, the term binaural
implies that the two channels be continued
separately from the microphones in the
studio to the listener's ears. It is mistakenly applied to the use of two channels
terminating in speakers, which should properly be called "stereophonic." In the stereophonic system, both ears actually hear
AUDIOCLINIC
JOSEPH
? ?
GIOVANELLI
tivity in separate AM or FM tuners. The
sensitivity of an FM tuner, either alone or
in combination with AM, should be between
one and five microvolts for good reception.
Automatic frequency control (a.f.c.) should
be supplied in FM tuners to prevent the
tuner from drifting from the selected station. However, it is also important to have
the circuit so arranged as to make it possible to render a.f.c. inoperative when it
rejects a distant station because of the
nearness of a strong local signal.
The use of separate tuners makes possible binaural reception. However, there are
also a few combination tuners whose AM
and FM sections can be taken from separate outputs and used for binaural reception.
Binaural Broadcasting
Q. What is meant by binaural broadcasting? Barbara Antine, Alhambra, Cal.
A. In a concert ball, because of the fact
that he is equipped with two ears, the listener to live music is able to perceive depth
and the position of each instrument in the
orchestra. Were a wall to be placed between
the orchestra and the audience and a single
speaker placed in that wall giving as good
reproduction of the sound as possible, the
listener would hear all of the instruments
as coming from the same position; it would
no longer be possible for him to locate each
one as he could before the wall was present.
sounds from both speakers, and it is, therefore not strictly "binaural."
Why Two Needles?
Q. Why must I use separate needles for 78's
and LP's? Helen Hammond, Milwaukee,
Wis.
A. The purpose of long playing records is
to supply greater playing time using the
same size disc. In order to do this, the speed
was reduced and the number of grooves in
a given area was increased. The needle used
for playing any record must make intimate
contact with the walls of the grooves. Since
the grooves of a long playing record are
obviously smaller than those of a 78, the
needle also must be smaller. If a needle
designed to play 78's is used for a long
playing disc, it will be too large and will
tend to wear away the sides of the groove,
whereas, if a needle designed for long playing records is used for playing 78's, it will
be so small that it cannot make proper
contact with the groove walls and will tend
to bounce from wall to wall.
Roll off -Turnover
What are rolloff and turnover? Jeanette Trulo, N.Y.C.
A. When recordings are made, it is neceesary to accentuate the high- frequency response. When they are played back, the
highs are decreased. This is done in order
to minimize the high -frequency components
Q.
of the noise created by the needle passing
over the disc material. This decrease in
highs is known as rolloff. Rolloff occurs at
so many db down at a specified treble frequency, such as 10,000 cps. Bass response
is attenuated during recording and boosted
during playback. This attenuation must occur since unaltered base notes cause wide
sideward motion of the recording stylus
which would require too much space on the
disc. Turnover is the point at which the
attenuation or boost starts to take place,
usually about 500 cps.
Tape Recorder Maintenance
Q. Please outline some of the steps needed
for keeping a tape recorder in good operating condition. Ann Stell, Hewlitt, N.Y.
A. Some tape recorders may require special
maintenance procedures and for these, the
user should consult his service notes. However, the following steps may be used successfully with most machines: (a) Periodically clean the recording heads with alcohol.
Since tape leaves deposits of oxide on the
heads, after a period of time the tape no
longer makes intimate contact with the
heads, resulting in loss of high frequencies.
(b) Clean the capstan, pressure roller and
all tape guides with alcohol. This will prevent slipping of the tape which, in turn,
would cause deviations in the pitch of the
recording. On rara occasions, it may also
be necessary to open the machine and clean
the clutches, idler wheels and motor shaft
or shafts with alcohol. This, too, is done to
prevent deviations in pitch. (c) Lubrication is important and manufacturer 's notes
should be observed carefully in this connection. (d) Have tubes tested occasionally,
particularly the bias oscillator tube and
rectifier tube. (e) Check the tension on the
take -up reel and the drag on the supply
reel to prevent stretching the tape. Some
machines, however, do not employ a drag
on the supply reel. (f) On rare occasione,
it will be necessary to replace the head or
heads. Head wear may be indicated by decreased high -frequency response and /or
poor erasure of signal. (g) In order to
realize maximum performance from the
tape recorder, it is obvious that the tape
should have the best possible care. Tape
should be kept free of dirt and away from
magnetic fields. It should be loosely wound
before storage and stored, ideally, at 70°
F. in a moderately dry place. Reels of tape
should be placed in boxes and stored on
edge instead of flat. Tape that will not be
used for long periods of time should be
stored in sealed containers such as those
used for 16mm movie film.
Transistors
Q. Why are transistors not used in highfidelity equipment at the present time?
Robert Haynes, Peekskill, N.Y.
It is only recently that transistors which
can handle fairly large amounts of power
have become available. Because of their
high initial cost and their unusual power
supply requirements, they have not as yet
been used commercially for this purpose.
It is probable that within a few years their
price will decrease sufficiently to permit
their introduction into this market. In a
transistorized amplifier there would be
transistors analogous to the voltage-amplifier tubes used to drive the power stage.
Although the price of such units is quite
low, they are still not used because they
generate more noise than do vacuum tubes
with equivalent amplification factors. When
the signal -to -noise ratio of transistors has
been improved sufficiently, they will probably be used in high -fidelity equipment,
with attendant miniaturization of ampliA.
fier,.
AUDIO
24
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JANUARY, 1956
a
it's the `guts' in the ¡/o` chassis
that make the critical difference.
Over 35 years
leadership in Electronics
PILOTONE AMPLIFIERS
O/ major importance in the performance
of a high fidelity amplifier are its component
parts: the condensers, resistors, trans formers
especially the transformers and above all,
the output transformer.
All transformers look alike in the schematic
but that's where the similarity ends. This is one
case where `a boy can't be expected to do a
man's job'. No puny output transformer-how ever imposing the outer shell -can serve a good
high fidelity amplifier without introducing distortion. It takes plenty of 'iron'-not to mention
special winding methods -for an output transformer to handle the power output cleanly.
Inspect the Pilotone amplifiers-all 5 of them
-and compare them critically with the others
in the field-regardless of make, power rating
or price. Notice how much heavier the output
transformers in the Pilotone amplifiers actually
-
-
-
are. Even the power transformers how much
cooler they `run' in operation. Observe also that
the Pilotone amplifiers employ known brand name condensers and resistors generously rated
to provide wide margins of safety against
failure and breakdown.
After all, tubes are tubes and sockets are
sockets, but it's the `guts' in and on the chassis
that make the critical difference in performance. If you look for these things when you
choose your amplifier, we know that -like many
others -you too will select one of these Pilotone
amplifiers for your own home music system.
PROTONE AMPLIFIERS
AA -410.. $54.50
AA 420.. $99.50*
AA -903.. 69.50*
AA -904.. 99.50
AA -905 (illustrated) .. $129.50*
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each 4.95
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NOTE: Prices slightly higher West of Rockies
-
your dealer for a Pilot Hi -Fi Demonstration For complete literature on
Pilotons Amplifiers, Pilotuners and other high fidelity units, write to Dept. GA -1
See
the
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P1i
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RADIO CORPORATION
37 -06 36th STREET, LONG ISLAND CITY 1, N. Y.
JANUARY, 1956
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How Long is "Permanent"
Employment?
ALBERT WOODRUFF GRAY
Since nearly everyone works for a living, the conditions under which employment is agreed upon
may be later found to lack sufficient legal grounds to turn out the way we expected them to.
SMT was recently brought by a dis-
charged engineer of a radio parta
manufacturer to recover damages
for what he contended was a breach of
contract for permanent employment.
He had been engaged by this company
for the production of resistors and was
to receive as compensation one half of
one percent of the gross sales in addition to an annual salary of $10,000.
Shortly before the end of this first year
of his employment he was told that the
manufacture of these resistors was to be
discontinued and to his query of what
that meant to him, that, "You're
through."
In this lawsuit the employee contended that this contract was to continue
until the company had fully launched its
resistor campaign and for so long as it
continued in operation. The Federal
appellate court said in characterizing
contracts for permament employment
and holding that this employee had no
grounds on which to recover,
"Nor can it avail this employee that
his contract was, in his own words, permanent. In other words the Supreme
Court of Illinois has expressly held that
a contract for `Permanent employment'
is one at will. This is in accordance with
the decisions of other jurisdictions that
contracts not expressly made for fixed
periods may be terminated at the will
of either party. "1
However, only a few days after that
decision was made, the Supreme Court
of South Carolina denied another employee a recovery of damages for his discharge from employment under a similar
contract. In this instance the employee
had been injured by the inhalation of
poisonous fumes and in return for his
agreement not to claim damages for
this injury, he was promised by his employer continuous employment until he
died or reached the age of sixty five
years.
3712 Seventy Fifth St., Jackson
Heights 72, L. I., N. Y.
Meadows v. Radio Industries, Inc.,
222 Fed. 347. May 6, 1955.
Under a statute of that state an agreement to withhold a claim under the workmen's compensation act is void. Thus
deprived of consideration, his agreement
for permanent employment collapsed and
his suit for damages was dismissed by
the court with the comment,
"A contract for permanent employment which is not supported by any
consideration other than the obligation
of service to be performed on the one
hand and wages to be paid on the other is
terminable at the pleasure of either party
and not enforceable. However, when an
independent consideration passes from
the employee in addition to the performance of services the duration of the contract may be optional on his part without
impairing its mutuality. "2
What is the Distinction?
him in a distant state constituted such
an independent consideration as to take
this case out of the general rule and to
render the contract enforceable. "3
In contrast to the conclusion in this
instance is the decision of a recent lawsuit brought by a civil engineer against
a South Carolina steel company. Upon
receipt of a telephone call from the
manager of this company he went to
Columbia for an interview and two days
later was offered employment with an
annual bonus, a commission on sales in
addition to his salary and the condition
that he report for work the following
Monday, five days later.
When he hesitated, saying he should
give his present employer two weeks
notice he was told, "What do you care t
You have a lifetime job here. Come on
down."
Two weeks later he was told by the
same man, "I'm going to have to let
you go," with no reason for the discharge.
In reversing a judgment in favor of
Two earlier decisions by that same
court define this distinction in greater
detail. In one instance an employee at
the instigation of the employer had
abandoned a business which he had established in Michigan and moved with
his family to South Carolina under an
agreement for a fixed annual salary and
50 percent of the net profits in addition.
Discharged at the end of ten months he
sued for damages. There the court held
the contract enforceable and the employer liable for the damages suffered.
"The general rule undoubtedly is that
where an independent consideration
passes from the employee in addition
to the performance of services the duration of the contract may be optional on
his part without impairing its mutuality.
This rule finds its most frequent application in the case of contracts whereby, on
consideration of the release of a claim
for damages the employer promises the
employee employment but the employee
does not agree to serve.
"The abandonment by this employee of
his business in Michigan in order to accept the employment which was offered
Attempts are frequently made by employees in suits of this character to establish a contract for permanent employment on the ground that the contract
provides for an annual salary. Such an
instance was before the Supreme Court
of the state of Washington, in which the
(Continued on page 83)
! Gainey v. Coker's Pedigreed Seed
Co., 87 S.E. 2d 486 South Carolina, May
12, 1955.
8 Weber v. Perry, 21 S.E. 2d 193,
South Carolina, July 9, 1942.
4 Orsini v. Trojan Steel Co., 64 S.E.
2d 878. South Carolina, April 30. 1951.
this employee the court said,
"Here the employee shows a promise
of permanent employment and no more.
We find nothing to take the case out of
the general rule. His employment at
Atlanta was terminable at will. The
giving up of friends, church, social, and
school connections are such as face every
employee when moving from one town
to another or possibly from one part of
the city to another and it is not a sufficient independent consideration to take
the case out of the general rule."*
"Annual Salary" Not Sufficient Proof
AUDIO
26
www.americanradiohistory.com
AmericanRadioHistory.Com
JANUARY, 1956
MODEL A -310
The A-310 Theme has been termed the "definitive AM -FM tuner ". Reflecting the most sensitive styling
in the high fidelity field, it also delivers the measurable optimum in both AM and FM performance.
Model A -310
View of Model A -310 with
cage removed
FUNCTIONAL FEATURES
Functional Features: (a) Illuminated Tuning Meter; (b) Counterweighted Tuning
Control; (c) AFC defeat available on function switch or momentarily by depressing
tuning knob for center channel tuning; (d) Cathode follower output to drive tape
recorder.
RF SECTION
Circuits: FM: Armstrong Circuit with Dual Limiters (Double Tuned) and Foster Seeley Discriminator. Automatic Frequency Control. Low noise, all triode front end
with tuned cascode RF amplifier and triode mixer. AM: Superheterodyne with
tuned RF stage, and ferrite loop antenna. Two IF stages. 10 KC whistle filter.
AVC operative over three stages.
Sensitivity: FM: 1.8 microvolts for 30 db quieting; 1.2 microvolts for 23 ma quieting. AM: Terminal Sensitivity: 3 microvolts. Loop Sensitivity: 15 microvolts/meter.
Selectivity: FM: 200 KC bandwidth: 6 db down. AM: 10 KC bandwidth: 6 db
down. FM Discriminator peak to peak separation: 375 KC.
AM:530.1650 KC.
Frequency Range: FM: 88.108 MC
FM Drift: ±21 KC with AFC on; ± 20 KC with AFC off.
Image Rejection: FM: 50 db.
AM: 50 db.
AM: 50 db.
IF Rejection:
FM: 70 db.
Antenna Input:
FM: 300 ohms AM: Built -in low noise ferrite loopstick plus
high impedance terminal for external antenna.
Distortion: Less than 1% harmonic on FM. Less than 1% harmonic for up to 80%
to
AM and FM selectivity characteristics
mod. on AM.
Frequency Response: FM: ±1/2 db 20 to 20,000 c.p.s.
AM: 3 db 20 to 5,000 c.p.s.
Hum Level: 65 db below 100% modulation.
AUDIO SECTION
Circuits: Cathode Follower Output
Output Level: FM: 21/2 volts for 100% modulation;
AM: 1 volt (average).
Output Impedance: Low Impedance Cathode Follower
t
ä
1
ts
volt for 30% modulation.
OVERALL SPECIFICATIONS
Controls: (Total 2) Function (OFF -AM -FM with AFC-FM without AFC) and
Tuning/momentary AFC defeat.
Tube Complement: (Total: 12) 1- 6BK7A, 1- 12AT7, 1.6AB4, 1.6BE6, 3 -6BA6,
FM discriminator characteristics
1.6AL5, 2.6AU6, 1.12AÚ7, 1.6X4.
Dimensions: 123" wide x 4" high x 8%" deep (including ferrite loopstick -not
including knobs).
Power Consumption: 50 watts
Shipping Weight: 14 lbs.
Finish: Chassis, escutcheon and cage: brushed copper-Display panel for escutcheon and knobs: matte black -Edge lighted dial glass: yellow and white.
Hardware and Accessory Material Furnished: Mounting screws, template, FM
antenna wire, instruction booklet, shielded output cable.
Special Notes: (a) Can be stacked with C-300 amplifier in total height of 8 ", with
C -100 amplifier in total height of 7% "; (b) Face up mounting of Theme permissible
without special precaution.
OPTIONAL ACCESSORIES
(a) Brass finished escutcheon available on special order.
(b) Brass finished cage available on special order.
(c) Vertically calibrated dial glass available on special order.
Write Dept A8 for
PRICE: $125.00 NET
Free New Catalog
Slightly
harman kardon
INCORPORATED
hlrh,
e
the West
NOVI
te.04.41.M. Wan 400
FM detector output voltage characteristics
520 Main Street, Westbury,
www.americanradiohistory.com
AmericanRadioHistory.Com
c
L. I., N. Y.
Equipment Report
DeJur TK -820 and TM -819 Tape Recorders-Harman- Kardon
A -310 AM -FM Tuner-Garrard 301 Transcription Turntable
IN THE COURSE OF TESTING audio equipment, a unit is occasionally encountered
over which one enthuses because it offers
a number of advantages not common to
others on the market. The DeJur recorders
-TA -820 in a portable case and TM -819
as a unit to be built into a hi -fi system
-
fall into this category because of certain
features of particular interest.
To begin with, these two models, shown
in Figs. 2 and 3, offer a very satisfactory
performance, as shown by the curves of
Fig. 1. In the playback of an Ampex #5563
standard tape, it will be noted that there
is a gradual increase in output at the
higher frequencies; similarly there is a
slight droop in frequency response on
signals recorded and played back. At 71
ips there are no serious discontinuities in
the smoothness of the curves, and both
could be flattened out easily by slight
amounts of frequency correction applied to
associated circuits. Furthermore, while we
have not seen a schematic of these instruments, we have studied the chassis carefully and note that there are several tiny
potentiometers which are obviously intended for equalization purposes, and it is
probable that the playback circuits could
be adjusted to provide a perfectly flat
playback curve, and the recording circuits
1111111
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Performance curves for the DeJur
tape recorders.
adjusted to make a tape with the same
characteristics as the standard. Not all tape
recorders use the Ampex characteristic, but
this is the most nearly standard curve that
we have throughout the recorded tape industry, and with such an acceptance it
seems desirable to arrange machines to
reproduce this characteristic properly.
In any case, the curves show that the
performance is excellent at 7% ips, and
satisfactory at 3% ips. No one at all
familiar with tape recorders would expect
any better response at the low speed.
From the operating standpoint, these
recorders are quite unusual. In the first
place, the single motor employed is a two speed, reversible hysteresis- synchronous
unit incorporating a fly-ball "governor"
which senses the motor's operation. When
changing from one mode to another, for
example, nothing happens until the motor
slows down almost to a stop. The governor
then permits a contact to be made, and the
recorder then goes on with the newly
selected mode of operation.
For controls the recorder is equipped
with the conventional playback, record, and
stop push buttons; since it is a two-track
model, it has two more buttons for selection
of the track and the direction of tape movement. Then there are two more buttons for
fast wind -one for each direction. In addition, there is a record safety button and
a tape stop button, the latter simply releasing the idler roller from contact with
the capstan. The two speeds are controlled
by a switch at the back of the top panel,
which also changes equalization at the same
time. Reels do not have to be reversed to
play the second track.
To play back, one simply presses the
track button and the playback button, setting volume to the desired level. Pressing
the stop button brings the tape to an instant stop by the use of magnetic brakes
in the reel hubs. To record, one depresses
the safety button and the record button;
the circuits are set up for recording, but
the tape does not move until the safety button is released, thus permitting the user to
set level before starting the tape. Fast forward and rewind are controlled by pushbuttons, and the tape stops almost instantly
when the stop button is depressed, providing the track button for the same direction of tape motion is in the depressed
position.
All of the operations of the recorder are
controlled by relays-which gives the gen-
eral impression that the machine thinks
before it acts. For example, you depress the
playback button. Tape moves, but you hear
nothing until the tape gets up to speed,
then the sound is switched on. You are recording and want to rewind; you depress
the stop button, then the rewind button. A
few clicks are heard, the tape comes to a
stop, rests for some five seconds, then starts
to rewind.
Since the capstan idler is actuated by a
solenoid, this machine is one of the few
we have seen that could be clock- controlled
without the possibility of developing flats
on idlers-the takeups being by means of
belts. You simply choose the desired radio
station to record, set levels, and have a reel
of tape in place. Then without depressing
any buttons you disconnect the power by
means of the clock switch. At the desired
time, the clock turns on both tuner and
recorder. The relays operate, the solenoid
pulls the idler against the capstan, and by
the time the electronic circuits are warmed
up, the tape is "up to speed." When the
clock swtiches off, everything returns to
normal, and there is no deformation of the
idler pulley.
The portable model has a built-in power
amplifier and a speaker system
4x
"woofer", two 3 -in. midrange units, and
two electrostatic tweeters. It has two outputs: one to feed external speakers and one
to feed a power amplifier; a switch selects
the local speakers, local and external, or
external only, or switches all off. Another
serves as a tone control, and another the
input selector. Full modulation may be obtamed at 1000 cps with an input of 88 mv
from radio, phono, or TV, and from 2.5
mv on microphone and tuner positions.
-a
Fig. 2 (left). DeJur Model TK -820, featuring self -contained power
amplifier and five internal speakers. Fig. 3 (right). Model TM -819,
designed to be installed in a hi -fi cabinet as a component of a complete system.
AUDIO
28
www.americanradiohistory.com
AmericanRadioHistory.Com
JANUARY, 1956
"BUILD -IT- YOURSELF" AND ENJOY
IN KIT FORM
0
Heathkit FM TUNER KIT
Features brand new circuit and physical design. Matches
WA -1'2 Preamplifier. Modern tube line -up provides better than 10 uy. sensitivity for 20 db of quieting. Built -in
power supply.
Incorporates automatic gain control-highly stabilized
oscillator- illuminated tuning dial- pre- aligned IF and
ratio transformers and front end tuning unit. Uses MODEL FM -3
66Q7Á Cascode RF stage. 6U8 oscillator- mixer, two
Q!1 /I CO
(iC1((i IF' amplifiers, 6A13 ratio detector, 6C4 audio
`VLLFJ
amplifier, and 6X4 rectifier.
Shpg. Wt. 7 Lbs.
I© Heathkit
Heathkits
25 -Watt HIGH FIDELITY AMPLIFIER KIT
Features a new design Peerless output transformer and KT66 output tubes. Frequency
response within + 1 db from 5 cps to 160 Kc at 1 watt. Harmonic distortion only 1' at
watts, 20- 20,000 cps. IM distortion only 1 °0' at 20 watts. 4, 8, or 16 ohms output.
-turn and noise, 00 db below rated output. Uses 2- 12AU7's, 2- KT66's and 5R4GY.
\ttractive physical appearance harmonizes with WA -P2 Preamplifier. Kit combinations:
W -5M AMPLIFIER KIT:
W -5 COMBINATION AMPLIFIER
Consists of main amplifier and
KIT: Consists of W -5M empower supply, all on one chas plifier kit plus Heathkit Model
WA -P2 Preamplifier kit. Shpg. $7950
Shpg. Wt. 31 Lbs. Express $5975
lily.
wt. 38 Lbs. Express only.
-
e
*411414(*)
Ì
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115.--.111a-11151115:111F--1115111:.=.1U5-01.-S1
n
go
Heathkit HIGH FIDELITY PREAMPLIFIER KIT
)signed specifically for use with the Williamson Type Amplifiers, the WA -P2 features
i separate switch :selected input channels, each with its own input control-full record
equalization with turnover and rolloff controls- separate bass and
MODEL WA -P2
treble tone controls -and many other desirable features. Frequency
response is within ±1 db from 25 to 31).0(X) cps. Beautiful satin -gold
latish. Power requirements from the Heathkit Williamson Type
Amplifier.
Shpg. Wt. 7 Lbs.
..
$1975
O
t.)Y
l)
Heathkit Williamson Type HIGH FIDELITY AMPLIFIER KIT
l0
i,)J
©
['his amplifier employs the famous Acrosound TO-300 "Ultra Linear" output trans ormer, and has a frequency response within ±1 db from 6 cps to 150 Kc at 1 watt.
Harmonic distortion only 1% at 21 watts. IM distortion at 20 watts only L3°,,. Power
output 20 watts. 4, 8. or 16 ohms output. Hum and noise, 88 db below 20 watts. Uses
:'- ;SN7's, 2- 5881's and 5V4G. Kit combinations:
1V -3M AMPLIFIER KIT: Consists of
W -3 COMBINATION AMPLIFIER
main amplifier and power supKIT: Consists of W -3M amt ly for separate chassis conplifier kit plus Heathkit Model
s ruction. Shpg. Wt.
WA -P2 Preamplifier kit. Shpg. $6950
29 lbs. $4975
1 ,press only.
Wt. 37 lbs. Express only.
Heathkit Williamson Type HIGH FIDELITY AMPLIFIER KIT
I
his is the lowest price Williamson type amplifier ever offered in kit form, and yet it
retains all the usual Williamson features. Employs Chicago output transformer. Fre,.uency response, within +1 db from 10 cps to 100 Kc at I watt. Harmonic distortion
only L5% at 20 watts. IM distortion at rated output 2.7°,,. Power output 20 watts.
4, 8, or 16 ohms output. Hum and noise, 95 db below 20 watts, uses 2- 6SN7's, 2- 5881's,
and 5V4G. An exceptional dollar value by any standard. Kit combinations:
'W-4AM AMPLIFIER KIT: Consists of
W -4A COMBINATION AMPLIFIER
n,afn amplifier and power supKIT: Consists of W -4AM amply for single chassis construe plifier kit plus Heathkit Model
ton. Shpg. Wt. 28 lbs. Express $3975
WA -P2 Preamplifier kit. Shpg. $5950
o I.ly.
Wt. 35 lbs. Exprr.s only.
(j
Heathkit 20 -Watt HIGH FIDELITY AMPLIFIER KIT
The World's
Finest
Electronic
Equipment
in Kit Form
'i ris model represents the least expensive route to high fidelity performance. Frequency
.,ponce is +1 db from 20- 20,000 cps. Features full 20 watt output using push -pull
(. (Vs and has separate bass and treble tone controls. Preamplifier and
MODEL A -9B
n am amplifier on same chassis. Four switch:selected inputs, and
s, parate bass and treble tone controls provided. Employs miniature
b -,e types for low hum and noise. Excellent for home or PA
I
t,
licanons.
Shpg. Wt. 23 Lbs.
V UO CkAattiti.4
WW
Lakti
$3550
W¿
Neathhit construction manuals are full of big, clear pictorial diagrams that show the
p,adement 0/ each lead and part in the circuit. In addition, the step -by -step procedure
at scribes each phase of the construction very carefully, and supplies all the information
ye a need to assemble the hit properly. Includes in formation on resistor color-codes,
tirs on soldering, and information on the tools you need. Even a beginner can build
hr'h quality Heathkits and enjoy their wonderful performance.
ALIDIO
..
HEATH COMPANY
A
Subsidiary of Daystrom Inc.
BENTON HARBOR 25,
MICHIGAN
JANUARY, 1956
29
www.americanradiohistory.com
AmericanRadioHistory.Com
Playback output to an external power amplifier is 0.7 volts at normal operating level
of the Ampex tape.
As a final feature
strip of foil near
the end of the tape will shut the machine off
as the foil passes the guides. All of which
adds up to an excellent and handsome tape
recorder for the home user-the critical
type of user who want professional convenience and excellent quality.
-a
-
HARMAN -KARDON MODEL
A -310 AM -FM TUNER
"THE THEME"
The theme of our report on a tuner for
this month is The Theme -recently introduced by Harman -gardon as a companion
tuner for the Model C -300 "Trend" amplifier, which it matches in appearance.
This tuner, with its matte black panel,
brushed copper escutcheon, cage, and
chassis, and softly- lighted yellow and white
dial glass is attractive and compact, yet
aparently does not suffer in performance
from a reduction in size. The unit-shown
in Fig. 4 without the protecting cage, which
is supplied when the tuner is to be used as
-is
a table -top installation
4 in. high, 8%
in. deep, and 121 in. wide. When desired it
can be installed with the panel in a horizontal plane and for such cabinets as require a vertically calibrated dial glass, this
too can be obtained as an accessory.
Two limiters are used, together with a
Foster-Seeley discriminator.
In operation without AFC, there is a
slight drift -approximately 15 ke-from
cold start over the first hour. With AFC,
the set was tested by running for four
hours, turned off and left for 12 hours, and
then turned on again. The same station was
simple test that can
properly tuned in
be tried by anyone and without any instruments. The tuning meter is extremely sensitive, and for careful tuning the function
switch is turned to AFC OFF and the station
tuned in ; then the switch is turned to pMAFC again, and no drift is apparent.
Since this is a basic tuner, no tone or
volume controls are provided. One knob is
used for tuning and the other for the
function switch -its four positions being
OFF, AM, FM -AFC, and AFC OFF. The audio
output is from a cathode follower, and
two jacks are provided so that one can be
connected permanently to a tape recorder
while the other feeds, in the normal manner,
the control unit or a combined control and
power amplifier, such as the companion
Harman-Kardon unit, The Trend. FM output level for stations within thirty miles
is 2.5 volts on the average, which is under
conditions of complete limiting. As signal
strength is lowered, the output level reduces
accordingly. Actually, however, very few
if any -FM tuners will give satisfactory
performance below a signal intensity that
will give 20 db of limiting, and while stations as far as 125 miles have been listened
to for long periods, we could not consider
them good sources for high quality reception -and this applies to any receiver we
have ever tried.
The Theme, however, is a unit that has
given reliable performance for a period of
months, and is capable of providing high quality audio signals to any good home
music system to the complete satisfaction
of its user.
But apart from its appearance-which is
important to at least half of the people in
an average home-its performance is also
attractive. To the serious music lover who
enjoys what music is available from the
radio, a tuner must perform well, regardless of what it looks like. When he can obtain both in the same unit, he is more than
-a
satisfied.
The Theme has, first of all, excellent
audio quality, both from AM and FM stations. Frequency response on FM is flat
from 20 to 20,000 cps, and on AM from
20 to 5000 cps-which is about normal for
AM tuners and desirably reduced to preclude undue disturbance from atmospherics.
Sensitivity is claimed to be 1.2 µv for 20
db quieting, and this is borne out by comparison testing. High sensitivity on FM results from the use of a cascode input stage,
seen in the schematic of Fig. 5, and highefficiency design throughout the i.f. section.
-
4. Harmon Kardon "Theme"
AM -FM tuner with
protective cage removed to show
Fig.
chassis.
i fi
60.6
6B4
S
I
I-
6AD6
6
Áu6
V5
GALS
YT
I
E
E
IMIEMPE
Mr
POO
-i
IL$I Yfi
I2ATY
V9
I
roa
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66A6
VIO
L6
E
r
111001
S.
minor
036
T9
!_-
006
Ohl
3
MAIN1
suattit
rs9
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RN
C1
I
3
f'
CÓ 40TD
1.06(55
OT C55 03.1/015E 501161
RCL5T0R51.SWATT
AL
ALL
CAPACITOR VALUES WITH
DECIMAL
0007T TO 6[
0600C
wILDCS ITI.aT
PONT To x uMRL
á<ñráA<*aR
CCITYICS ToOYv00,
óu
Fig. 5. Complete schematic of the Model A -310 tuner.
AUDIO
30
www.americanradiohistory.com
AmericanRadioHistory.Com
JANUARY, 1956
THOUSANDS BUY AT LEONARDS
BOZAK LEADS IN SALES!
Yes, thousands of high fidelity enthusiasts know that at LEONARD RADIO INC.
they can buy the exact Hi -Fi equipment to suit their tastes. They have shown too,
that Bozak is their choice in speaker components and systems of quality. Hear
the Bozak Family Of Stars at Leonard Radio, New York Audio Mart.
rig. 6. Garrard 301 Transcription Turntable.
GARRARD MODEL 301
TRANSCRIPTION TURNTABLE
Within the past year or so we Lace witthe introduction of several new
turntables built on professional lines and
to high standards of quality, which is, in
itself, an indication of the interest the
serious music lover exhibits in the use of
the single -play turntable for optimum reproduction of LP records. While all models
can be used to reproduce all three speeds,
the trouble involved in changing 78's or
45's every few minutes by hand almost
rules out the use of anything but a changer.
The principal advantage of the transcription turntable is in its lower rumble content and as a system is improved in low fregilency reproduction, the rumble begins
-o show up. Additional advantages which
ire of some importance are the true-tinning surface of the platter and the inreased constancy of speed.
The Garrard 301 is the newest model to
i>e introduced, and it offers many attractive features. As seen in Fig. 6, the unit
Is mounted by means of a cast base plate
on which are mounted the controls as well
as the mechanism. The turntable is an
aluminum casting which is accurately mashined and dynamically balanced, and
bored out to accommodate a phosphor
bronze bushing which seats on the main
spindle. This spindle remains in its bearing at all times, eliminating the possibility
i.f contamination if it were removed for installation, inspection, or lubrication. The
bearing is lubricated by a pressure system
using grease and introduced by a conventional grease cup.
The motor is a 4 -pole model, well
shielded and dynamically balanced. It is
suspended within a cast frame by means
f six tension springs, each of which is
nessed
(
BOZAK
MID -RANGE SPEAKER.
MODEL
#209
This is the only loudspeaker designed specifically for operation
in the mid-frequency range. Designed to supplement the B -199A
Woofer in the mid-frequency
range, the B -209 employs these
exclusive features: a small diameter cone with a shallow opical
angle for broad coverage, and a
rubberized cloth -edge suspension. This unit operates over the
range of 400-2500 cycles with
6 db per octave crossover filters.
Net. .. 48.00
wired -in 4 -mfd filter. No transient distortion, with smooth,
peak -free response.
Net
. $83.85
B -199A . $49.50 ( Woofer only)
B -200X . $30.00 (Tweeter only)
MODEL #E -300
Sold only without speakers, this
5- cubic -foot infinite -baffle enclosure is the smallest recommended for a single woofer
Bozak system. It accommodates
the B -207A plus B -209 Mid Range
with an
network
(the
N -101 crossover
B -302A
system).
You can start with a two -way
system and then easily add the
mid -range unit and network at
Walnut,
veneer.
Mahogany
Net
or
..
Birch
$75.00
BOZAK THREE -WAY SPEAKER
SYSTEM. MODEL #B -305
This lowboy contemporary styled
speaker system contains 2 Bozak
13 -207
coaxial speakers and
B -209 mid -range with a crossover at 800 and 2500 cycles.
Available in blonde birch, mahogany, and honey walnut. Size:
36" w. x 19" d. x 321/2" h.;
Shipping wt. 86 lbs.
Net .. $390.00
1
BOZAK THREE -WAY SPEAKER
SYSTEM. MODEL #13-310
Here is the ultimate of sound
reproduction. 4 B-199A Woofers
and a B -200X Tweeter array plus
a B -209 mid -range speaker delivers the finest reproduction
with a minimum of listening
fatigue. Well balanced with no
exaggerated highs or doubled
bass, this unit will afford the ultimate in listening pleasure. A
built -in crossover network divides the frequencies at 400 and
2500 cycles, Available in Mahogany, birch or walnut.
Net .. $723.00
Mail and phone
orders accepted.
25% deposit,
balance C.O.D.
L
g. 7. Underside view of Garrard unit
shows interlocking controls and isolation
between motor and base plate. Note
grease cup on main shaft bearing.
F
ADDIO
SPEAKER SYSTEM.
MODEL #207A
The sound is clean and balanced
from 40 to beyond 16,000 cycles
on a robust foundation of the
most powerful bass from any
driver, regardless of size and
price. The B -199A Bass and
B -200X
Treble speakers are
mounted coaxially in a sturdy
cast -aluminum frame, with a
BOZAK SPEAKER CABINET.
a later date to form a three -way
B -302A
system. Available in
f.re
BOZAK TWO -WAY COAXIAL
EONARD
RADIO, INC.
69 Cortlandt St., New York
JANUARY, 1956
7,
N.Y.
COrtlondt 7-0315
31
www.americanradiohistory.com
AmericanRadioHistory.Com
J
on cvfmrolmt
The oldest American magazine specializing in
high fidelity equipment is AUDIO. From the
beginning, AUDIO's guiding hand has been that of
its present editor and publisher, C. G. McProud.
AUDIO recently devoted an Equipment Report
to a searching examination of the world -
famed PRECEDENT tuner. Its conclusion:
"Our observations indicate that the
PRECEDENT well justifies its reputation.
It is the logical answer to the demand
for a maximum of quieting, high sensitivity,
It would be
and excellent stability
appreciated for its engineering, for
its performance, and for its external
appearance -tops on every count."
...
May we send you, without cost, a copy of
AUDIO's complete report?
RADIO ENGINEERING LABORATORIES INC.
36-40 Thirty- seventh Street
Long Island City 1, N.Y.
damped by a soft rubber insert. With the
turntable removed and the idler held away
from the motor shaft, no vibration whatsoever could be felt on the base plate with
the motor running. Turntable drive is effected through an idler that bears on
stepped motor shaft and against the inside
of the turntable rim. The idler itself is
mounted on ball bearings, and is lifted
away from contact with both motor and
turntable when the power is switched off.
The speed selector lever, shown in Fig. 7
at the lower left, actuates a cam which
raises or lowers the idler so as to make contact with the proper motor -shaft diameter,
and is interlocked so it cannot be moved
from one speed to another while power is
turned on. In the off position of the power
switch, a friction brake is applied to the
turntable. Absolute speed of the turntable
can be varied over a range of about ± 5
per cent by means of an eddy -current
brake; since this brake is located on the
motor assembly and the control is on the
base plate, an ingenious vibration isolator
is provided between the control lever and
the brake mechanism to further ensure
freedom from vibration.
The effectiveness of this method of construction and the care in manufacture is
borne out by the measurement of noise and
rumble, which-by the same method used
previously and described in EQUIPMENT
REPORT for March, 1955, with additions in
the December issue-comes out to be 50 db
below a stylus velocity of 20 cm /sec (the
standard used in AUDIO 's measurements).
Since it is very hard to find records that exceed a signal -to -noise ratio of more than
45 db, this turntable would answer the
most critical requirement.
A unique method of mounting is used in
the Garrard for optimum results -short of
mounting the turntable on a half -inch steel
plate. The turntable base plate is solidly
mounted on a board, along with the pickup
arm; then the entire board is suspended on
conical springs. This effectively isolates the
record playing mechanism entirely from externally caused vibration.
Leak Moving -Coil Pickup
For these measurements, the now- available Leak pickup was used -also a British made product. This unit has an extremely
flat frequency response-extending from
20 cps to 20,000, with only a slight rise
beginning at 15,000 cps and reaching 3 db
at 20,000, (using Cook frequency test record for the source of signals). Apparently
this record must be well recorded up to the
highest frequency, for with the Leak
pickup a perfect sine wave is visible at
20,000 cps, just as it is all the way down
to around 15 cps-a value obtained by
playing the glide portion of the Cook record down to 35 cps at 333 rpm instead of
its normal 78. With the transformer used
with the Leak, the output for a 5.5 cm /sec
velocity is 18.5 mv, which is somewhat
above the average LP pickup. The low
impedance of the moving-coil type is
usually less susceptible to hum pickup also,
resulting in extremely high- quality reproduction. The Leak pickups operate only
with their own arm, and one simply
changes heads when changing from microgroove to standard. The most attractive
feature of the Leak pickup is, in this
observer's opinion, the wide frequency
range without any peaks. Of course, wide
frequency range in itself is not the whole
story, but rudimentary measurements show
that the Leak is satisfactorily low in IM
distortion as compared to any other pickups tested. Actually, we have noted relatively little difference between most of
the well known pickups in this respect.
AUDIO
32
www.americanradiohistory.com
AmericanRadioHistory.Com
JANUARY, 1956
PERMANENT EMPLOYMENT
(frnin page
O)
president of a corporation was in re:.eipt of an agreed annual salary of
$25,000 from January 1st. When he was
deprived of his position eight months
.ater he sued to collect the balance revaining unpaid of the $25,000 he claimed
to be owed for that year.
In its decision that here was a mere
hiring at will and the president of the
i!ompany entitled to this compensation
only so long as he continued as such an
officer, the court ruled,
"When a contract for hire provides
for payment at a yearly rate with no
provision that the hiring is for a specified period it is a contract terminable
at the will of either party. An exception
to this rule is provided for in those cases
where proof is given of a custom in the
industry which makes the hiring for a
definite period."5
In a contract for employment made
by a Florida hotel with its manager it
was agreed that the employment, though
c.n an annual basis, was subject to
termination by the employer in the event
cf dissatisfaction with the services of
the employee. In a suit for breach of
contract by this employee who had begun work on April 26th and discharged
three months later, the employee recovered a judgment against the hotel.
In affirming that judgment the Florida
appellate court said of such provisions
for discharge,
"While the contract for employment
ì; for a definite term, if it provides that
tae services are to be performed to the
satisfaction of the employer it may be
t rrminated by him at any time that he
good faith becomes dissatisfied with
t .e services of the employee, though no
r al or substantial grounds for dissatisfaction exist. The employer is in such
e se the sole judge as to whether the
s rvices are satisfactory and the courts
a ill not substitute their judgment for
his as to any reasonableness of the
grounds of dissatisfaction.
"But the general rule is that such
dissatisfaction must be real and in good
f.tith, not merely feigned or capricious
or mercenary. A reservation of the right
tl-Slo
WHY
SYSTEMATIC
GROWTH?
Because it is the only avenue to true high
fidelity. As your music system grows, you
must have as your goal more than just perfection of frequency response. No matter
how faithfully you re-create the audio spectrum, origin of the sound in a point -source
will dissipate the subtleties that preserve
realism and the listening ease of "live"
the two essential ingredients of
music
true high fidelity.
-
Only the Bozak B -310 adds. to precision
of frequency response. a broad source of
sound and wide -angle dispersion. The size.
range and placement of drivers on its 3 x 4
foot panel eliminate every suspicion of
"port -hole" origin. The cluster of four
B- I99A's provides a robust. enveloping bass
foundation: the B -209 above them is positioned to retain the spaciousness of symphonic sound without loss of the directional
quality essential to solos; and above them
all the B -200XA adds 180° coverage for a
velvet -smooth treble that is completely free
of harsh or eerie intonations. The realism of
the B -310 has won a reputation as the
B-30R A
supreme accomplishment to date in the reproduction of sound.
i.
Rohda v. Boen, 276 Pac. 2d 5S6,
Washington, November 18, 1954.
°
AUDIO
If you cannot start with a B-310. you can
grow into it easily and systematically with
the "building- block" Bozaks. Begin with a
B -207A. Then. as space and budget permit.
progress to the unrivalled realism of the
B -3I0
enjoying at every step of the way.
dollar for dollar,
-
B-207A
l'llr
VERY BEST IN SOUND
THE R. T. BOZAK SALES CO.
MAIL ADDRESS: P.O. BOX 966
Export Once; Electronics Manufacturers'
JANUARY, 1956
DARIEN, CONN.
Export Co., HR.,ville, N.Y.
33
www.americanradiohistory.com
AmericanRadioHistory.Com
/IßdHh1ß
Model 240
"Balanced Bar"
PREAMPLIFIER
Reg. Net $98.50
ft/Rd/LB
Model 260R
Fifty Watt
POWER AMPLIFIER
Reg. Net $149.50
harman kardon
Model A -200 "Guide"
FM -AM TUNER
Reg. Net $69.50
HP
udson
exxhiaive
GARRARD
IN
Model RC -80
3 -Speed
RECORD CHANGER
Reg. Net $49.50
SAR
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COMPARE IT
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SPEAKER ENCLOSURE
Ideal for use with Hudson
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Unusually smooth reproduction down to 35 cps. 294íI"
H. 19"
W, 17" D. Shpg.
wt. 37 lbs.
Model KD6, "Aristocrat" in
kit form, easy to assemble;
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UIPMENT
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to discharge for reasons of the sufficiency
of which the employer reserves the
right to be the sole judge, does not give
the employer the right to terminate the
contract without a reason or for a false
reason. He must act in good faith."
In contrast with this conclusion of the
Florida court is the decision of a case
in Massachusetts only a few months ago.
There the employee had been engaged
as production manager for a Boston
broadcasting station and the agreement
had been confirmed by the president and
general manager,
"This letter will serve to confirm our
agreement and understanding resulting
from our conference recently held in
Lawrence, Massachusetts and your acceptance of the position of program director at a salary payable weekly at the
rate of $9,000 per annum beginning
January 2nd."
On August 22nd of the fourth year
following, the contract was ended with
the payment of three weeks salary in
advance. In affirming a judgment for
the recovery of the salary from the time
of this discharge to the end of the year
the court said,
"In our opinion the evidence was sufficient to warrant a finding that the
parties intended the employment to continue for at least a year. The employee
continued to work for the broadcasting
company until August 22nd of the fourth
year following. If it were found that the
original contract was for a year we think
that from a continuance of the service
it could further be found that there was
an implied renewal of the contract from
year to year. "'
The test however that has been generally adopted by the courts in determining whether a contract for permanent
employment is merely a hiring at will or
a definite long -range commitment, is
whether some consideration is given by
the employee in addition to the mere
rendering of services. This appears
clearly in the decision of an action in
a New Jersey court in which a salesman
had been offered a sales territory on the
condition that he finance all the promotional and other expenses in the development of a market in this area and in return for this undertaking by the salesman he was to have the territory for
life.
In its recent summary of the law and
of this feature of consideration in the
decision of this case the New Jersey
court said,
6 Edwards v. Doherty, 74 So. 2d 686,
Florida, September 24, 1954.
' Mahoney v. Hildreth & Rogers Co.,
125 N.E. 2d 788, Massachusetts, April
7, 1955.
AUDIO
34
www.americanradiohistory.com
AmericanRadioHistory.Com
JANUARY, 1956
"In the absence of conditional, express, or implied stipulations as to the
consideration, a contract for permanent
employment or for other terms purport in. permanent employment, where the
employee furnishes no consideration additional to the services incident to the
employment, it amounts to an indefinite
general hiring at the will of either party
and therefore a discharge without cause
does not constitute a breach of such
contract justifying a recovery of money
damages therefor."
Then of the alternative in such circumstances the court added, "Where the employee has given consideration additional to the service incident to the
employment or, as it is sometimes stated,
where the employee purchases the employment, in the absence of a statute,
other terms in the contract or circumstances to the contrary, the contract for
permanent employment, for life employment, or for other terms purporting
permanent employment, is valid and
enforceable and not against public
po icy.
"Such a contract continues to operate
as long as the employer remains in the
business and has work for the employee
and the employee is able and willing to
do his work satisfactorily and does not
gi %e good cause for his discharge and
a discharge without cause, constituting
a breach of such contract, entitles the
employee to recover damages therefor.
Deeming them to be at variance with
geieral usage and sound policy, the
courts have shown a marked reluctance
to enforce contracts for life employment.
In large part this stems from the realization that such contracts frequently are,
in practical effect, unilateral undertakings by the employer to provide a job
for so long as the employee wishes to
continue in it but imposes no corresponding obligation on the latter. In this respe<:t the burden of performance is unequal, as the employer is bound to the
terms of the contract whereas the emplo.vee is free to terminate it at will.
"Agreements of this nature have not
bee upheld except where it most con vine:ingly appears it was the intent of
the parties to enter into such long -range
commitments and they must be clearly,
spe.dfically and definitely expressed.
Only then is it grudgingly conceded that
not all such contracts are so vague and
indefinite as to time as to be void and
unenforceable because of uncertainty and
'
indi flniteness.1/8
Shiddell v. Electro Rust -Proofing
Cora., 112 Atl. 2d 290, New Jersey, November 5, 1954.
AUDIO
A
TURNTABLE FOR THE HOME, BUILT TO
FAIRCHILDS STUDIO EQUIPMENT STANDARDS!
IRCHILD
T
TURNTABLE
t
aircltild, now in its third decade of
supplying equipment to meet the
most exacting standards of recording and broadcasting studios throughout the world, presents for the first
time a home turntable of compatible
excellence.
Automatic Idler Pressure
Release.. no flats on Idlers evert
Unless your remember to "turn the switch
to the off position ", most turntables (probably yours) will develop "flat" spots on
the idler. This naturally results in greatly
deteriorated performance. With the Fairchild Automatic Pressure Release such
damage is impossible. Since pressure is
applied to idlers only when motor current
is on, you can safely shut off the "411"
from any remote point for example, at
the innin control or by clock switch for
lazy listening.
You would naturally expect superlative
performance in a table from Fairchild,
and the new "411" gives it. Vibrationless
operation makes possible utilization of the
full dynamic range of modern LP recordTurret Control
ings; its rumble content is actually lower
The "411" takes full advantage of all the
than that of most records. The Turrosmooth performance inherent in silent,
matic's absence of reproduced noise is
flexible, endless -belt drive. But also, step matched only by its complete acoustical
silence you will only know by the soft
pulley type idlers in an ingenious turret
mounting provide:
illumination that it is running! Flutter and
wow are no longer a consideration, being
I. Instantaneous, silent, fool -proof
speed shift
completely imperceptible (typical meas2. Greatly increased driving surface for
urements: less than 0.07% RMS at 78 and
positive non -slip drive.
less than 0.1% at 33).
OTHER FEATURES:
-
-
All bearings poured babbitt precision rifle- drilled
for highest polish. (Babbitt running on polished.
hardened steel is still the smoothest, most quiet,
and most durable bearing devised.)
Thrust bearing is ROTATING polished steel
ball turning on nylon seat
. self -adjusting,
self- aligning, practically wear -free.
Main bearing sealed to shaft -no one (including
you!) can mar its mirror-like surface after assembly and final teat.
For the full story
... see
TWO STAGES of motor isolation from frame
and turntable.
Polished aluminum turntable, non - magnetic.
Heavy cast -iron flywheel for greatest stability
and smoothness of motion.
Built -in "45" center raises or lowers quickly and
easily.
Clearance provided for playing 16" transcrip-
tions with appropriate arm.
your nearest Hi -Fi dealer or write:
FAIRCHILD Recording Equipment Co.,
JANUARY, 1956
Whitestone, N.
Y.
35
www.americanradiohistory.com
AmericanRadioHistory.Com
ELECTRONIC ORGAN
(from page 22)
R
R:, and associated capacitor components of Fig. 17. Other
components are mounted directly on tube
pins and tic points, so that this assembly
is merely another ease of making a number of simple connections rather than the
complex assembly it appears to be at first
to carry the
TO ONE
GT 8' FILTER
0.1
s'
GT 8' COUPLE
TO OTHER
i
8' GT GRIDS
glance.
Woodwind Circuit
Two of the stops on the organ -the
Clarinet and Stopped Flute- imitate
pipe -organ and orchestral tones which
have almost no even -harmonic content. A
symmetrical wave for this purpose is
produced by the woodwind circuit shown
in Fig. 18. To obtain a symmetrical wave
it is necessary to invert a 4 -foot signal
and reduce its level by 6 db, then mix it
linearly with 8 -foot tone.' Eight-foot
tone is taken from the swell 8 -foot keying
bus and applied to the grid of V,a. It
appears in phase on the cathodes of both
tubes and thus effectively on the grid of
VIA in reversed phase, then on the plate
of V,4 in the original phase. Swell 4 -foot
Acknowledgement is due to Baldwin
for this basic idea, though not for the
circuitry.
L
u-
GT to GT 4'
l,ryyl/y
0.1
27,000
SW to GT
0.1
27,000
l
GT
le'
BUS
8'
SW 8' BUS
Hg. 17. Simplified schematic of coupler circuit which permits interconnecting manuals
or buses.
the two preliminary -amplifier triodes
feeding the Clarinet and Stopped Flute
filters. The woodwind circuit is built on
a small chassis with all the components
but the tube on an etched-circuit panel.
Next month we shall describe the re-
tone is applied through a voltage divider
directly to the VIA grid, and appears on
the plate reversed. The mixing takes
place in this manner and the result, again
reduced in amplitude, is the woodwind
output, which is applied to the grids of
symphony
Sound by Stephens
i.
;II%%
in.
sound
ay, noteworthy when selecting
finest. in superlative speaker systems.
Designed. constructed. and tested by
thepioneer sound engineers in high
fidelity equipment, the name Stephens
Ow
stands for true fidelity with music listeners
the wrírld over. Each pictured note represents
h
quality speakers and components
that will insun the listener
a
1
true symphony
in sound. Consult your Stephens dealer
as
Iii
a
reRmnmended TruSonic speaker system
for your particular needs.
STEPHENS
MANUFACTURING
CORPORATION
6530 WARNER DRIVE: CULVER CITY. CALIF.
CABLE ADDRESS "MORHANEX" EXPORT ADDRESS
458 BROADWAY. NEW YORK
AUDIO
36
www.americanradiohistory.com
AmericanRadioHistory.Com
13.
N Y
JANUARY, 1956
mining sections of the Schober Electronic Organ Kits.
wood -.nu' sw
8
Cl
tt
U IO0.00e
te.aa0
47
. a,d
470,000
12
.047
Via
Vit
s.
L.
fite,
-IQ,QffwLibuildisq
th, a TECH - MASTER Kiz(
C)
es
e
you'll enjoy building a Tech -Master Kit almost as
f much as you'll enjoy using the finished product.
Simple, step -by -step pictorial diagrams guide your every
move right down to the last detail. Your feeling of pride
and accomplishment will be well justified when you plug
in the last tube and put your unit to its initial test. Then
you will definitely agree, as do thousands of others, that
when you build with Tech -Master, you build the best.
t,
tió
B.
Fic 18. Schematic of woodwind circuit,
wh ch converts sawtooth wave output
frc n generators to square wave for cer-
tain tone effects.
BOOK REVIEW
/10
Ito
HI-FI
WILLIAMSON
FM TUNER
TYPE
Tuning range 87-109
Grounded -grid RF
Self contained power supply
200Kc IF bandwidth
Micro AFC with front -control cutoff
stags
4 uv
No -drift ratio detector
vernier tuning
Standard de
sensitivity for 20 db quieting
.8 volt RMS cathode- follower
emphasis network
output
3.2 volt RMS high -impedance output
Switchcontrolled
300 ohm input impedance
AC receptacle for auxiliary equipment.
Model FM -18, complete with punched chassis, tubes,
_. _529.50
and hardware (less wire and solder)
Mc
'l'll
(
1
.
PHONOGRAPH, by Roland
320 pp., 8 vo., illustrated. New
FABULOUS
,latt.
ork: J. B. Lippincott, 1955. $4.95.
Musical instruments have been man's
pot :.essions since time immemorial. They
have been simple and complex, from a
pipit to a pipe organ. When Thomas A.
Edison invented the cylinder phonograph
78 :ears ago, man was for the first time
relei.sed from the duties of performer.
This is the start of, and unfortunately,
almost the end of the book.
That Mr. Gelatt has spent a great deal
of time in researching to prepare himself to write this book, no one can deny.
It is a story crying to be told, but this
author fails dismally in writing the history
of the phonograph, per se, as it has grown
front Mr. Edison's original instrument.
Far too many pages are consumed in
bringing the reader to the first decade of
the present century, and all that has happemsd since is glossed over or completely
neglected.
What he fails to tell us, or even show
us in pictures, is the fascinating development of the machine once it became springdriti en, of the early attempts of the electrical drive, etc. The renaissance of the
phonograph was due in no small manner
to t,e development of a mechanism to handle the playing of records automatically,
yet this point is almost completely slighted
by the author in his essay at an historical
preoentation. And finally, one mere chapter
is allotted to the completely revolutionary
development of microgroove records and
the high -quality sound reproducing equipment which is today a $250 million industry in the U. S. alone! Archives full of
pictures of the varying sizes of records,
historically interesting machines, and the
like are overlooked in favor of far too
many "shots" of early recording sessions
of the great and near great.
C ironological data is interestingly pre sentd in an appendix, and in many respects the book has reader interest. But
as a history of the phonograph it fails
disn ally and serves only too vividly to
point up the need for such a story. May
soma enterprising author now undertake
what could become the real reference work
in tats field. \Vllat we have here is a good
oxal.ple of piny not to write such a hook.
B. Keim
-L.
AUDIO
20 -WATT
AMPLIFIER
Frequency response Rat and smooth thru entire audi
ble range
Less than .0025 distortion al normal
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Excellent transient charameristics.
Model TM-15A, complete with tubes sockets,
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-
Zebexe
Self- Powered
PREAMPLIFIER
EQUALIZER
PREAMPLIFIER
Cathode follower output
loudness -compensating
Input selector
4 input channels
control
Independent bass and treble boost and attenuation
5- position equolization control
AC
receptacle for ouxiliary equipment
Self -contained
power supply.
Model TM -165P, complete with matching gold
escutcheon._.___
$24.50
_
with Cathode
Follower Output
input channels
Separate bass and treble
AC outlet for
3- position equalizer
controls
Powered by main amplifier.
auxiliary equipment
Model TM -17P, complete.... _.....___........_......_519.95
4
T-V
CRAFT KIT
630 -TYPE
OtK)
TV KIT
MC horizontal sync.
Advanced Cascade turret
3 -stage sync. amplifier, clipper and separator
4 -stage stagger -tuned video IF
AdjacentDirect
channel trap
2 -stage video amplifier
coupled keyed AGC circuit
5 microvolt sensitivity
For 21" to 27" (90) picture tube.
MdI 630 -9, complete
with all components,
brackets, speaker, and tubes (less kine, wire and
...._ ..5159.50
solder) . -
'The quality and performance of Tech Master kits reflect the combination of long
experience, skilled engineering, and painstaking craftsmanship, which has made Tech Master the foremost name in Custom Television. This is your assurance of the uniform
excellence of every Tech- Master product.
IF secSuper -selective 12- channel turret tuner
9 microvolt
tion completely wired and aligned
AGC
sensitivity
3-stags stagger -tuned IF
CerSyncro -guide MC with horizontal hold
amic core horizontal output xmfr with beam power
amplifier. For L.V. electrostatic Lines 17 " -21 ".
Model 5516W, complete with tubes, hardware, and
._...$94.50
brackets (less kine, wire, and solder)
Zelwa
SUPERMET
-
AC -DC RADIO
550-1720 KC
Super- sensitive
AVC
circuit with built -in loop antenna
5 tubes.
Model 365K, complete with tubes and handsome
$19.95
bakelite cabinet (less wire and solder)
Broadcast Band
Write for latest catalog of complete Tech -Master line
Television
Radio
Audio
TECH -MASTER
CORPORATION
75 Front Street, Brooklyn 1, N. Y.
JANUARY, 1956
37
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AmericanRadioHistory.Com
NEW PRODUCTS
G -E High Fidelity Amplifier. Flexibility
of installation was given full consideration in design of the new General Electric
20 -watt amplifier, which is engineered
around a dual chassis to permit its use as
a single cabinet- enclosed unit or as two
separately installed units. One chassis
serves the power amplifier, push -pull
drivers, phase inverter and power supply.
The second chassis, which can be detached
from its companion if desired, constitutes
the preamp -control unit. Five separate inputs, three outputs and nine independent
panel-mounted controls provide an amplifier adaptable to virtually any combination of tuner, record player, tape reproducer, and the like. Frequency response is
within 1 db from 20 to 20,000 cps at
moderate listening level. Total harmonic
distortion is one per cent at full rated output. The selector control has eight posi-
Fisher PM-AM Tuners. Separate tuning
meters for FM and AM are among the
many unique features incorporated in the
new Fisher Models 80 -R and 80-T high fidelity tuners, identical except that the
80 -R is for use with external control
chassis while the 80 -T includes complete
audio control facilities. FM sensitivity
affords full limiting on signals as low as
1
microvolt, while AM sensitivity provides full output from a signal of the
same intensity. Frequency response on
FM is 20 to 20,000 cps ± 0.5 db. In broad
tuning position AM frequency response is
within ±2 db to 6000 cps. A 10 -kc whistle
TE30 are base -mounted while the TR35
and TE35 are rear- mounted. The units
have high output, excellent response, are
easily adjusted, and are shielded against
hum pick-up. The rear-mounted heads
measure 45/64" from face to mounting
shoulder, while the base -mounted heads
measure 9/16" from top to mounting
shoulder. Both models are 31/64" from top
to bottom and 21/32" from side to side.
Shure Brothers, 225 W. Huron St., Chicago
J-10
10, Ill.
Improved Miraphon Record Player.
Among many features inherent in the new
Model XM -110A Miraphon record player is
a special method of motor mounting by
means of isomodes for the elimination of
chassis vibration, and the turntable bearLions, five of which compensate
The preamp -equalizer incorporated in the
80 -T consists of two cascaded triode
stages, and has sufficient gain for even
the lowest level magnetic cartridge. It affords a choice of six equalization settings.
Direct current is supplied to all heaters.
Separate bass and treble controls afford
up to 15 db boost and cut at 50 and 10,000
cps, respectively. Specification sheet available on request from Fisher Radio Corporation, 21-21 94th Drive, Long Island
J-13
City 1, N. Y.
for vari-
ations in record characteristics, one is for
tuner, and two are auxiliary positions.
Other controls include level, loudness,
bass, treble, rumble filter and power. General Electric Company, Electronics Park,
Syracuse, N. Y.
J -8
Radial-Motion Tone Arm. The path of
the cutting stylus is traced by the playback stylus when records are played with
the new Ortho -sonic Tone Arm. Designed
to eliminate tracking error, the arm is so
constructed that the cartridge and stylus
are moved across the record in a straight
line from the edge of the record toward its
center. In operation the cartridge is never
touched by hand, the stylus being positioned on the record by slightly tilting the
tone arm. Friction of the horizontal movement is reduced to a minimum since the
carriage assembly rides on four precision
ball bearings suspended on a ground -andpolished stainless -steel rod. The cartridge
filter eliminates interstation interference. Both tuners are self -powered, are
equipped with flywheel tuning mechanism
with anti -backlash gear, and feature completely shielded construction including
bottom plate and tuning- capacitor cover.
Alton Lansing Speaker Systems. Two
ing "floats" in a spring mount. Both the
turntable and tone arm are mounted in
double rows of ball bearings. A plug-in
head will accommodate the user's choice
of cartridge, and an easily reached thumb
screw under the tone arm permits instant
cartridge pressure adjustment. The turntable is white- rubber matted. The XM -110A
is started by moving the tone arm to the
right and at the end of each record it automatically shuts off. Audiogersh Corporation, 23 Park Place, New York 7, N. Y. 3 -11
new Iconic speaker systems are recent additions to the broad line of high -quality
audio equipment manufactured by Altec
Lansing Corporation, 161 Sixth Ave., New
York 13, N. Y. The larger of the new
systems, Type 826A, contains one 15 -in.
low- frequency driver, an 800 -cps dividing
network, and a high- frequency driver
mounted on a large sectoral horn. These
units are housed in an 8%- cu. -ft. bass reflex enclosure designed as a low chair side cabinet. The system is guaranteed by
Audio Transistor. Sold only in matched
pairs for optimum output and minimum
distortion, the new Raytheon Type 2N138
is a PNP fused junction germanium transistor for push -pull class B audio output
applications. In a typical class B applica-
carriage is independent from the mass of
the arm and is hinged on its own needlepoint pivot. Reduction of both vertical
and horizontal friction assures extended
record life. Proper stylus force can be
effected through the twist of a thumb
screw. The Ortho -sonic arm is easily installed on any turntable mounting board,
and will accept practically all popular
cartridges. Bard Record Company, Inc.,
66B Mechanic St.,
New Rochelle, N. Y.
J-8
Shure Magnetic Recording Heads. Built
to meet the demands of professional
usage, the new Shure Micro -Gap recording heads are especially well -suited for
applications where miniaturization is a required factor. The Micro -Gap Series is
comprised of Models TR30 and TR35 recordng heads, and their companion erase
heads TE30 and TE35. The TR30 and
tion using a 4.25 -volt supply the average
power output is approximately 50 mw with
a power gain of 30 db. Physical dimensions
are identical to those of the 2N130 series
of miniature transistors. Complete information on the 2N138 may be obtained from
Technical Information Service, Raytheon
Manufacturing Company, 55 Chapel St.,
J-12
Newton 68, Mass.
Altec Lansing to have a frequency range
of 36 to 22,000 cps. The smaller of the
Iconic systems, Type 824A, uses a 12 -in.
woofer in conjunction with Altec's well known 3000-cps high- frequency speaker
and matching network. Its small bass-reflex cabinet is only 28 ins. high and 16 ins.
wide, yet the system is guaranteed to have
a frequency range of 60 to 22,000 cps.
Both systems require no assembly on the
part of the purchaser as they are delivered completely assembled and wired.
J -14
AUDIO
38
www.americanradiohistory.com
AmericanRadioHistory.Com
JANUARY, 1956
I
STREET
4
Visit
HARVEY's
brand -new
AUDIOtorium
REET
STaea
42nd s
AMPEX
612 -SS
STEREOPHONIC SOUND SYSTEM
First tce dual cno ^ ^el .'o eophonic tope system des,ned soeCf,.o.iy for
the home, the 611 -SS combines the new Ampex 611 stereophonic tape
phonograph (playback only) with two complete and independent Ampex 620
amplifier-speaker systems for unrivaled
valed reproduction of stereophonic topes.
The space effects made possible by Ampex stereophonic sound cannot be
duplicated on single channel systems in any price range. The 612 will also
play the conventional half track and full -track tapes with customary Ampex
playback quality. Tape speed is 7l/ in. per sec.; frequency response extends
from 40 to 15,000 cycles. Standard 7.in. RMA reels. Complete with custom designed cabinets,
as
Model 612-SSE
Also available in
S69900
._ ........ .......__..._........_____..._.
completely portable system, with Samsonite cases,
a
os
569.00
Model 612 -SSP
THE
New
DYNAKIT Mark II
50 -WATT Amplifier Kit
something altogether new _
mptomise "dream" amplifier in easy to build
o Popular price) The DYNAKIT
Mark II employs a special new circuit i
conjunction with es newly developed transformer of unique construction
Its beautiful simplicity- if has only three tubes plus rectifier and includes
printed circuitry- makes it easy for the home constructor to reproduce the
impressive performance characteristics of its laboratory prototype with
only three tools: soldering iron, pliers and screw driver.
Here
ea®t
is
kit form at
Rated power output is 50 watts (continuous); intermodulation distortion is
than 1% at rated power; harmonic distortion is less thon 1% at any
frequency from 20 to 20,000 cycles within I db of rated power. Frequency
response is within ±.5 db from 6 to 60,000 cycles; ±.1 db from 20 to
20,000 cycles. Square wave response is essentially undistorted from 20 to
20,000 cycles. Output stage hos the new OCA7's in pushpull; output
impedance is 8 or 16 ohms.
less
Complete, with tubes,
ouzo ul transformer and iosL us bons
x6975
Stan White
MODEL 4330
-
Everything worthwhile in high -fidelity equipment is IN
STOCK at Harvey's
our demonstration facilities are
second to none! Orders shipped same day received,
-
I
PLAN AVAILABLE
B.
N.Y.C.
THE
.
,
,
NEW
PAMPHONIC
Sr.
SPEAKER SYSTEM
Embodying several new and unconventional design
features, the Pamphonic Sr. Reproducer is a de luxe
two -way speaker system with 1500 -cycle crossover in
an exceptionally rigid enclosure. The treble unit is a
special elliptical cone speaker with aluminum voice
coil; the woofer is o 15 -in. unit with a flux density
of 16,000 gauss. The cabinet, constructed of one inch wood and infernally braced, employs a tuned
vertical bossreflex chamber for exceptionally smooth
low- frequency response and has the treble speaker
oriented for rear -wall reflection to assure unusually
wide and even high -frequency dispersion. The speaker units, dividing network and enclosure were conceived from the ground up to function as an
integrated system, rather than just a woofer and a tweeter in an all- purpose
cabinet. Together they cover the entire audible range of frequencies and
ore capable of handling power levels in excess of 15 watts.
$295"
Available in mahogany or walnut finish
PRINTED -CIRCUIT
- MINIATURIZED
`Preamp with Presence
-as described
by C. G. McProud in Ma, Audio Engineering. 3 equalization choices, presence control, volume and loudness controls, and
8axendoll -type bass and treble controls.
FAIRCHILD
Complex multi -flare horn system with
four separate driver units. Bass horn
(30 -150 cps) has equivalent axial
length of 14 feet. Mouth area is 7
square feet, and is substantially increased with proper room placement.
Lower mid frequencies ore handled by two 8" speakers (150-600 cps)
located on each side of the cabinet, with a phase shift network between
speakers for three- dimensional effect. Higher mid -frequencies
(600 -3000
cps) are handled by a multi flare horn with on equivalent
axial length of
6 feet. High frequencies (3000- 18,000 cps) ore handled
by a multi -flare
horn with an equivalent length of 4 feet. Frequency response is
substantially
flat from 30 to 18,000 cps- Power handling capacity is
60 watts. Available
in four finishes
mahogany, blonde, walnut, and ebony,
with three coats of lacquer, hand rubbed... _..__.. _...
$33950
Other units in stock priced horn $49.50 to $1,500.
TIME PAYMENT
.
.
s
1111-fil
Prices are net, F.0
at 1123 Avenue of the
Amer'cas
(6th Ave,)
Nothing has been spared
to make this new
extension of HARVEY'S,
which adjoins the
old store, a hi -fi shopper's
paradise- Devoted
exclusively to high fidelity,
it has more display
area .
demonstration facilities
more
more conveniences
of every sort for
hr -f, lovers.
Bask kit containing the 1.0 henry encapsulated choke, the printed circuit
panel completely drilled, and the
$So
4 metal chassis ports..
..
..
.._.._.
...
The complete kit of parts, including the basic kit and oil other parts
and tubes os specified by author.
(3550
With complote, mpl if,ed instructions.
THE
THE
MEET
TRADE -INS ACCEPTED
subject to change without notice.
New
220XP PHONO CARTRIDGE
with elliptical
microgroove stylus
A stylus with an el oli cal cross ection can
follow the violent zigzags of the s modern LP
l
i
record groove with considerably greater accuracy than one with a circular
cross section. The new Fairchild 220XP cartridge features for the first time
an elliptical diamond stylus in the I -mil microgroove size for matchless
tracking on LP's. Combined with the additional new Fairchild features of
reduced dynamic moss, increased compliance and toroidal damping. the
new stylus design enables the 220XP cartridge to deliver a completely
distortionless replica of the signal recorded in the groove, so that for the
first time the music can be heard
as it was actually recorded ......................_._.._.........._.
$60o0
HARVEY
ESTABLISHED 1927
RADIO COMPANY, INC.
103 W. 43rd Street, New York 36
JU 2 -1500
_
AUDIO
JANUARY, 1956
39
www.americanradiohistory.com
AmericanRadioHistory.Com
High-Speed Tape Duplicator. Rapid copy
of both single- and dual-track tapes which
have previously been recorded at 3.75, 7.5
or 15 ips is facilitated by the new Model
DA -11 Tape Duplicator recently developed
by Presto Recording Corporation, P. O.
Box 500, Paramus, N. J. Now in commercial use, the DA -11 operates at a tape
speed of 60 ips. The basic duplicator con-
Simplify design and
calculation
corder will not be visible even if the flap
is opened and papers added or removed.
The unit may be carried or put down anywhere while operating without exciting
suspicion since the quiet motor and ball bearing construction assure unobtrusive
practical
ELECTROACOUSTICS
RETTINGER
M.
The keynote of the book is UTILITY in a practical coverage of the
rapidly developing field of electroacoustics.
Electroacoustics is presented in
the light of the most recent developments. The modern methods and devices discussed in the book are those
used at present in radio, sound -film
recording, and allied arts.
Special emphasis is placed on the
relatively new and promising field
of magnetic recording.
Many tables and curves show at
a glance the required quantities, reducing calculations to a minimum.
The diagrams in the book are useful
not only for lessening figure work
but also for checking calculations
and illustrating relationships.
lists of a tape reproducer to play back the
master tape and a recorder which copies
the play -back output on new tape. A number of slave recorders may be fed from a
single reproducer. The unit produces duplicate tapes which are completely uniform
in response with no increase in distortion
over the originals. Because it operates at
60 ips, the DA -11 provides a good frequency response up to 120 kc and may be
adapted for telemetering or other applications where high -frequency recording is
J -15
required.
Speaker
'University "Decor- Constte"
is
latest addi-
the
System. The "Senior"
tion to the new University line of "Decor Coustic" speaker systems. Powered by
three separate drivers which afford exceptionally wide frequency range, the Senior
incorporates the University Model C12W
as a woofer, the Model 4408 'reciprocating- flares" horn speaker for mid -range,
and the Model HF-206 super- tweeter
which extends the upper frequency response well beyond the limit of audibility.
Program and Sound Effects Filter.
Twenty -two cut -off frequencies ranging
from 50 to 12,000 cps make the new
PULTEC Type HLF-3 high- and low-pass
filter ideal for the reduction of rumble,
hum, noise and distortion in music as well
CONTENTS
MICROPHONES:
Anecdotal
History of Microphones-General Aspects
Microphone
Types of Microphone
Technique. LOUDSPEAKERS: Direct -Radiator Loudspeaker- Loudspeaker Enclosures- Loudspeaker Cabinets-Corner
Cabinet for Loudspeakers-Horn Loudspeakers-Directional Radiation-Damping Loudspeaker- Cabinet Panels-Speaker
Measurements-Speaker Distortion. CIRCUITS:
Constant -Resistance Crossover
Impedance-Measuring NetNetworks
works- Mixen. MAGNETIC STRUCTURES:
Permanent Magnets.
General Aspects
Poem- Mammas Svanita: General AsOutdoor Loudspeaker Outputpects
Specifications
Power Requirements
Testing Public-Address System InsWlations -The Hollywood Bowl Sound-Reinforcement System -Loudspeaker Matching. VIBRATIONS: Transients -Vibration
Isolation. ARCHITECTURAL Acousncs:
Convex Wood
Dynamic Symmetry
Splays for Broadcast and Motion - Picture
Studios- Recording Studios-Television
Studios
Home Acoustics Sound -Absorptivity Measurements -Acoustic Measurement Facilities. MAGNETIC RECORDING:
Ring-Type Magnetic- Recording and Reproducing Heads -Front Gap -Back Gap
-Alternating- Current Magnetic Erase
Frequency Response ExperiHeads
mental Results. APPENDIX: Octaves
Decibels Volume Units, Dbm versus
bm versus Voltage- BibliograWatts-Dbm
phy- Index.
FOREWORD.
continuous
performance.
hours at a tape speed of
time is
15/16 ips on a 5 -in. reel. Tape speeds of
15/16 and 1% ips are incorporated in the
Model 210 -AB, while Model 210 -BC affords
1% and 3% fps. Tapes may be played back
on studio equipment or home recorders.
Earphone playback is afforded by a built -in
amplifier which is powered by a set of dry
cells with 100 -hour operating life. The low drain motor is powered by five mercury
cells which last from 2 to 24 hours. Electrical rewind transfers a full reel of tape
in less than two minutes. The recorder
weighs only 11% lbs. and measures
16 x 12% x 4% ins. Manufactured by Amplifier Corp. of America, 398 Broadway,
New York 13, N. Y. Complete technical
specifications and descriptive literature are
J -17
available on request.
-
-
-
-
-
-
-
-
-
- -
-
271 pages
1955
$10.00
Order your copy today from
AUDIO
P. O. Box
629
Mineola, N. Y.
as in other types of program material.
Better sound effects are possible because
of more mid -range frequencies. Low cutoffs are OFF, 50, 80, 100, 160, 250, 500, 750,
1000, 1500 and 2000 cps. High cut -offs are
1, 1.6 2, 3, 4, 5, 6, 8, 10, 12 kcs and orr.
Circuit is constant "K." 18 db per octave,
600 ohms. Shielded toroids minimize hum
pickup.
% n rack panel. Manufactured by Pulse
Techniques, Inc., 1411 Palisade Ave., West
J -18
Englewood, N. J.
Wireless Microphone. Little larger than
a package of king -size cigarettes, the new
Budelman wireless microphone has an
output of 75 mw and, when used with a
companion receiver, permits high quality
transmission over a range of several hundred feet. Audio response is 60 to 12,000
to be
of cps +2 db. Small and light enough
Acoustic balance is achieved by means
easily concealed on the person, the microwhich
the brilliance and presence controls
phone- transmitter overcomes the limitaare incorporated in the Type N -3 -L /C 3imposed by conventional microway crossover network. The enclosure is tions
phones,
University's newest "Decor- Coustic"ofhorn
x 2% "x,exclusive of
the
loaded phase inverter. The design
pack of similar size. Operating
enclosure permits optimum performance battery
FM band of 26.110 to
is
in
the
frequency
fiat
is
placed
no matter whether the unit
in the 26.470 me with a 15 -kc nominal deviation.
against a wall, in a corner, or even handle
Five hours continuous operation is procenter of a room. The Senior will
vided with a single set of batteries. Bandup to 30 watts of program signal. ManuInc.. width and deviation of the equipment have
factured by University Loudspeakers, J-16
been selected to permit operation of three
White Plains, N. Y.
units simultaneously without mutual interference. Standard batteries and tubes
are used throughout. Specially designed
EnRecorder.
Tape
"Secret"
Bight-Hoar
use, the unit is now being
compart- for professional
tirely concealed within a false Model
210 used by a number of motion picture
ment of a briefcase, the new
networks. Further inforand
TV
studios
pridesigned
was
recorder
two -speed tape
is available from Budelman Radio
marily for all types of investigative work mation
where secrecy must be preserved. So in- Corporation, 375 Fairfield Ave., Stamford,
J -1
genious is the construction that the re- Conn.
almeasuresbu44
AUDIO
40
www.americanradiohistory.com
AmericanRadioHistory.Com
JANUARY, 1956
Dual - Channel Amplifier
(from page 16)
resistor in the power amplifier is a 10
watt type. It is a good idea to use wirewound plate -load resistors in the low signal -level stages. Although a Peerless
transformer and choke are not essential
circuit elements in the power supply, the
writer built and tested the amplifier with
a Peerless 256Q output transformer, and
has no data on how another transformer
type may operate in this circuit! Small
broadcast -type connectors may be used
conveniently for inter -chassis connections where audio voltages are involved.
Four- conductor cables terminating in
male plugs are useful for power connections and the chassis connectors being
standard four -hole sockets.
The writer's present dual -channel playback system consists of a turntable,
pickup and arm, a preamplifier (Fig. 1),
an R -C dividing network (Fig. 2), two
identical power amplifiers (Fig. 3), two
power supplies (Fig. 4), and the dual
loudspeaker described in an earlier
paper.' The equipment corresponding to
each schematic presented here was constructed on separate chassis as shown
photographically in Fig. 5 and 6. This
building-block technique was employed
so that new innovations may be checked
with minimum constructional labor. The
preamplifier was built on an aluminum
chassis having dimensions of 7 x 12 x 3
inches. The arangement of parts may be
seen in Fig. 7. If Vector socket -turrets
are used the circuit can be built in a
5 x 10 x 3 inch base. The employment of
aluminum material that is not painted
permits one to make the numerous low resistance ground connections required
by the circuit configuration. It is very
important to keep ground leads short in
high gain circuits. The dividing network
and power supply fit nicely on a chassis
measuring 51/2 x 91/2 x 11/2 inches. The
orientation of parts in the dividing network is shown in Fig. 8. The power amplifier can be built on a 7 x 12 x 3 inch
black- crackle finish steel chassis with
room to spare. A bottom view of this
mit appears in Fig. 9. Since high signal
evels obtain in this circuit a ground bus
may be used (grounded to the chassis at
each end) without development of hum
difficulties. The writer finds the use of
a ground bus a constructional advantage.
At present four parallel -connected
lass drivers are in use in the bass section
of the speaker described in reference 1.
The driving -point impedance of the array is 2 ohms. Accordingly, the secondary of the output transformer in the
bass amplifier is connected for this load,
1 Charles W. Harrison, Jr., "Coupled
Loudspeakers," AUDIO ENGINEERING,
Vol. 37, No. 5, pp. 21, May, 1953.
4UDIO
A schematic for the 24 volt d.c. field
supply required for the operation of the
WE 594A driver is not included in this
article because this driver is not generally available. Several other makes of
high- frequency reproducers are available
with permanent magnet fields, however.
and R and C selected for 10 db feedback
and minimization of ringing, respectively. The value required for R is 330
ohms, and for C. 0.005 pt. The high -frequency driver in use is a Western Electric type 594A having an impedance of
24 ohms. A resistor of 48 ohms is connected across the voice coil so that the
impedance of the parallel combination
is 16 ohms. The output transformer of
the treble power amplifier is connected
for this load. In this case R is 1500 ohms
for 10 db feedback, and the optimum
value of C = 1360 pf2.
2
and
Acknowledgment
Technical contributions to this article
were made by CDR. S. E. Ramey, CDR.
R. R. Potter, CHRELE. J. C. Bradbury
all of the U. S. Navy; and Captain Jack
Kadey of Capital Air Lines. Photography is by Mr. Lyle Trenchard.
For a load of 4 ohms, R is 1000 ohms
C is 1500 ma.
lltrintosh
of
p/oT1/
superior performance!
amplification, low distortion and abundant power
compares with the McIntosh -tong the
standard of high fidelity excellence. The fundamentally different McIntosh circuit delivers amplification with n 0.4
of theoretical perfection! The result: outstanding realism,
clarity and listening quality. Make the McIntosh listening
test at your dealer's.
For clean
no other amplifier
Distortion: /3ye Harmonic and 1/2% IM, even at full
rated output, from 20 to 20,000 c.p.s. Power: 30 watts
continuous, 60 watts peak (for Model MC -30); 60 watts
continuous, 120 watts peak (for Model MC -60). Frequency Response: 20 to 20,000 c.p.s. ±0.1 db at full
rated output. Highest efficiency means longer life.
1
Outstanding
DISTORTION vs. POWER OUTPUT
Performance
I.0
of the
OS
o
/
--
x
a
*-SC
100-
...
I
oSa
0%
20
10
a
K
CC
MFA*1MiNlNT
so
1
AS
POLYPS OUTPUT
lAx
I
'
y
as
-------?---1---20
McIntosh
Patented
Circuit
114
60
>:
SAS WATTS
SINGLE FREQUENCY HARMONIC DISTORTION
(
I
r
I
I
GOASANTrrD A.M. VALUE AT 60
wall*
r r ,60
mPIG1,AfT
1
50
100
200
500
1
PSCOOCNCT IN
KC
2 KC
S
CC
10
KC
20 CC
WATTS
SO
KC
100 CC
CTCIES
Write for
complete details on
McIntosh amplifiers and free booklet.
LABORATORY, Inc.
324 WATER ST., BINGHAMTON, N. Y.
Export
D ;T.
25 Warren St.. N. Y. 17
Coble: Sirnontrlce
JANUARY, 1956
MC-60
$19850
41
www.americanradiohistory.com
AmericanRadioHistory.Com
EDWARD TATNALL CANBY*
I. WEEKEND POTPOURRI
(These are the records I played during
one active weekend in the country, as foreground to everything from eating dinner to
waxing floors. In a reviewer's life, music
is the foreground; all other activities form
a pleasantly engrossing background.)
Haydn: The Creation. Teresa Stich-Randall, Anny Felbermayer, sopranos, Anton
Dermota, ten., Paul Schoeffler, bar., Fred.
Guthrie, Bass; Chorus, Orch. Vienna
State Opera, Mogens Woldike.
Vanguard VRS 471/2 (2)
This "Creation," sung in German lacks for
us the absurdly lovely charm of the well known English text with its preposterous
menagerie of animals right out of Noah's Ark
-the tawny lion, the "flexible tiger" and that
astonishing bit of creation which "in long
dimension creeps, with sinuous trace"-the
worm But those English words are at least
available in printed form here, along with the
original German (which came In turn from
English), for a running visual translation as
one listens to the records.
This is a lively, spirited "Creation" with a
splendid orchestra, the Vienna Philharmonic
in its opera alter ego, and a knowing group
of soloists. The chorus to me Is somewhat
disappointing though Its singing is precise
enough ; part of the trouble is an unfortunate
balance which places it too far to the background for proper impact. (I've 'lung in the
chorus of this piece in four performances.)
The solos tend to drown out the chorus in
their many joint numbers.
The all- important archangel Gabriel, soprano in sex, is done beautifully by Stich Randall with just the right Haydnish combination of angelic purity and peasant earthiness ; the Eve, Felbermayer, isn't as good ;
she's not only earthy but also somewhat inaccurate here as to pitch and voice control.
The next -most -important archangel, Raphael,
(the tenor) is excellent and the third of the
trio, the bass angel (Oriel) is good too along
with his cohort Adam, Mr. Schoeffier.
There's none of the oratorio -style stodginess
in this performance that we often find in the
work, even when done by supposedly notable
performing groupa, and for this we can be
thankful. Yet somehow I don't think the full,
breathless freshness and wonder of the "Creation" is brought out here, nor the boundless
humor of it either. Could It be that this is
too much to ask of a professional opera group,
even a Viennese one?
!
Mozart: Piano Concerti K. 488 in A, K.
466 in D mi. Clara Haskil; Vienna Symphony, Sacher, Paumgartner.
Epic LC 3163
Two more items in Epic's Mozart Jubilee
edition, now growing to monumental proportions. The famous and familiar D minor con-
certo gets what. to my ear. is just about the
definitive performance -which is saying a lot,
I know. There are ideas and ideas, of course,
as to what makes a good playing of this famous piece for nee, this is lt. Rich, big orchestral sound but beautifully balanced, the winds
shining through the strings as they should.
the solo piano unpercussive, big, very natural
in sound. Clara Haskil is an impeccable Mozart player and yet a large- minded one too.
She is beyond criticism ! I can scarcely imagine the music more sweetly phrased, more
unaffectedly musical -and more convincing.
Two conductors share the record. Of the
two, Paumgartner (director of the Epic series)
does his usual top-rank job with Mozart.
Sacker's A major (whether his doing or not)
seems less focussed, less musically alive by a
few notches.
What matter that a string or two here plays
a trace falsely, that not every sound is perfect
in ensemble? Better this, and a really musical
interpretation, than all the sheen of the beet
orchestra without musical understanding.
;
Chromatic Fantasy and Fugue;
Italian Concerto. George Malcolm, harpLondon LD 9187 (10 ")
sichord.
A pair of Intelligent and dynamic performances, these, by a harpsichordist who has the
big feel for the works. whose registrations are
imaginative and dramatic, his music both
authentic in detail and romantic in expression.
Two of the best performances I've heard in a
long while -piano or harpsichord.
The recording is technically interesting
it is an Absolute Recording, that is, a close-up
portrayal of the instrument's sound without
audible room reverberation. Therefore, if
played at the absolute loudness of an actual
harpsichord, the recording will freely take on
will
the color of any room you play it in
seem to be inside the room, without the usual
complication of the audible recording-hall
sound that surrounds most recorded music. If
you keep the volume down low, you'll be astonished at the absolute, literal realism of this
type of recording.
Bach:
-
-it
An Evening of Elizabethan Verse and Its
Music. W. H. Auden; the New York Pro
Musica Antiqua, Greenberg.
Columbia ML 5051
A good idea, this, to have the Elizabethan
poetry read out loud before it is sung in the
musical settings of its own day. Auden's excellent written essay, on the jacket, makes
some good- points, too, about the relationship
between written poetry and the music to which
it may be set, especially in that fabulous time
of the end of the 16th century when, under
Elizabeth I, English poetry and music were so
extraordinarily close. (They're dismally far
apart, nowadays.)
The Pro Musica group (not to be confused
with other Pro Musica,, notably the Belgian
under Safford Cape) sings expertly and on the
whole very musically though for my ear the
star countertenor (male alto), Russell Ober-
lin, sings his solos in a somewhat hard and
brassy way with his superb high voice. The
vocal ensemble is of the rich, unblended sort
with plenty of vibrato, American style, that
is what most people take for granted hereabouts, though, as the British know, it is only
one way to sing. (British madrigal singing
often features close blending with virtually
no vocal vibrato.)
There are madrigals and also solos and
duets here, the latter two types with harpsichord, playing the original lute accompaniments in a very lutish style. It is astonishing
how much the featured prior reading of the
texts, by Auden (helps to make the music's intentions clear to the listening ear ! And this
even though Auden reads with a seeming
Bath") which sounds to me like a sounding fault
rather than a speech defect. Here's for more
and better texts
go with all recorded vocal
music.
-to
The Mitchell Boys Choir Sings.
HlFlrecord R -301
Christmas Music from Trinity -New Haven.
G. Huntington Byles, choirmaster.
Overtone 11
How astonishingly differently do we train
up that basically uniform organ, the human
voice Here are two groups including kids of
tender age -they couldn't have had more than
a few years' experience in the training process-and you will be amazed at the divergencies not only in style of singing but in the
very sound of the boyish musical instruments
themselves, so quickly adapted physically to
these utterly different traditions.
In reverse order, the Trinity -New Ifaveo
choir from the East Coast (Connecticut) city
represents the very best of the Anglican tradition of singing, as re- developed in this country
-not so much the music, which includes a
good variety of material, as the very sound
of the choir. Here are those heavenly, white gowned little angels (devils, too, behind the
scenes) with big black scarf -ties around their
angelic necks, who traditionally form the alto
and soprano parts of high -church Protestant
choir singing ; here is the usual excellent pitch,
always a bit on the high side, never fiat, the
high, piping quality, the "boy -singer" tone,
that you expect in this all -male church choir
tradition, and it is only remarkable that none
of these little singers can have been in the
business for more than a few brief seasons.
It is the tradition itself that goes back and
back, into the hallowed past, and it is the tradition that is so familiar to us; these kids fit
themselves unerringly into it in no time at all,
picking up the whole feeling and style by quick
imitation, as kids can always do.
And from the West Coast comes the Mitchell
group. More boys, no older, no longer in training, just as recently emerged from babyhood
yet whose small vocal organs, one and all, reflect with utter faithfulness the carefully polished sound of the Hollywood crooner and the
lady songbird! As the notes tell us, Bob Mitchell's careful training of his boys emphasizes
the all -important full vibrato (missing at New
!
-
AUDIO
42
www.americanradiohistory.com
AmericanRadioHistory.Com
JANUARY, 1956
listening quality
is everything!
impartial
new
Lab
Audax
reports on the
Ili -Q7 magnetic
cartridge:
leading recording studio: "Because readings
A
showed an amazing total
lack of distortion, checktests were repeated 3
times."
Consumer
sheet: "Good frequency and tran-
sient response.
;
Practically no high
frequency distortion. Low intermodulation distortion."
Ideal as these reports are, they belong in
the I ab. Listening quality is everything -and the new Audaz Hi-Q7 has
it to a degree not equalled by any other
pickup. But -HEAR it yourself
...
there is no other way!
Haven) and every boy has it to perfection, as
though born to croon.
This is the essence of a style! Ilow can they
learn it so qickly? Each and every long note
begins just so, with that kind of hoarse, very
slightly below -pitch attack, followed by a bit
of non- vibrato, then, exactly calculated, a
"tall" of heavy vibrato to end it off. Complex
to describe (and if we lived in another age
you'd call me a musicologist) but the sound
itself is instantly familiar to every one of us
from a thousand films and Juke boxee and DJ
programs. Every songbird, every groaner In
the business has it down cold -even Marlon
Brando had to learn it. This is the Absolute
Necessity in style for our day in pops singing
-the style of our time, though it cannot
be
written down or indicated In any way on
paper for posterity to reproduce. The Mitchell
boys merely apply It with precision to an unexpected area In music, and so point it up as
a phenomenon of vocality.
Botts records have boy soloists as well as
ensemble singing : both have organ accompaniment. But, typically, the Trinity organ is one
of G. Donald Harrison's classic -style instrumente, based upon the principles of 17th century organ building, whereas the Mitchell boys
sing with n harp and a Mighty Wurlitzer
theatre job. (See below.) The music from New
Haven includes "classical" stuff ranging from
Victoria and Praetorius through numerous
Anglo-American anthems and carol settings,
while the Mitchell boys from Hollywood sing
"0 1Vhnt a Bentiful Morning," "Irish Lullaby,"
"Ave Maria" and "When You 1Vieh Upon a
Star." But whichever type you favor, I strongly
suggest a try nt the other record as well, Just
to point up the wonderful contrast between
these two traditions, imposed on boys who a
couple of years ago were all of them Just so
many small American brats In the great
American melting pot.
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Horowitz Plays Clementi Sonatas.
RCA Victor LM 1902
Every piano student knows Clementi -or
thinks he does. The familiar little Clementi
"practice" sonatas are fine for the fingers and
very uninspiring to the ear. But Clementi actually was n big musician and a much bigger
man than those arbitrarily selected items from
his large output might suggest. IIe was one of
those composers who quickly fall out of style
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finally, looks up the facts.
Horowitz has championed the bigger sonatas
of Clementi. virtually unknown to pianists today, as tine music and as pioneering writing
for the piano that tremendously influenced
such greats as Beethoven. Here he plays us
some of the evidence and it's convincing.
These works, composed in the late Mozart
period, are Indeed far more Monistic, technically more modern, than Mozart himself as far
as piano style Is concerned. At every turn they
suggest Beethoven -quite remarkably considering their pre -1800 date. Not "great" music
but certainly very good music, and Beethoven lovers, Mozart- lovers, pianists, all should find
this record most interesting in spite of an oc-
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Schumann: Quintet in E Flat, Hummel:
Quartet in G. Hollywood String Quartet,
Victor Aller, pf.
Capitol P 8316
Here's an interesting companion -piece to
the above -Hummel is another forgotten composer of the Mozart- Beethoven period who also
was among the near -great of the time and
wrote really excellent music. if something less
than of super-genius grade. The Hummel Quartet here played is an expertly lyric piece, skillfully written, sounding midway between Mozart and Mendelssohn with a good touch of
the inevitable Weber in it. (Weber's influence
was fantastic at this time.) Very enjoyable.
The ultra- familiar Schumann Quintet with
piano gets a vigorous reading and musical,
too, but it seems seomehow to be a bit out of
touch with the great tradition of Romantic
playing that centers upon this work. There
are too -pronounced rubatos (slowings-up) in
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Schubert: Song Cycle, "Der Winterreise."
Laurens Bogtman, bass; Felix de Nobel,
pf,
Epic LC 3154
NEW YORK 4, N. Y.
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Reprints of articles which appeared in AUDIO
from July 1952 to June 1955. 124 pages of articles of greatest interest to the serious hobbyist.
The AUDIO ANTHOLOGY and 2nd AUDIO ANTHOLOGY
are no longer in print.
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Beethoven: Violin Concerto. Nathan Milstein; Pittsburgh Symphony, Steinberg.
Capitol P -8313.
Speaking of Beethoven (my weekend listening wasn't chronological but I've arranged the
records in part that way for convenience),
here is the finest Violin Concerto I've heard
well, if not ever, then for a long time. 'ith
Milstein and Steinberg, it is In the modern
manner : that is, without fancy flamboyance,
a bit on the cool side, stressing the music's big
architecture, the soloist remarkably self-effacing in favor of Beethoven -who gives him
plenty to do in musical terms as It Is.
The Violin Concerto is one of the most
leisurely, long- breather works in all Beethoven
and therefore is one of the toughest to play,
because as always with the composer it has
huge architectural lines that must be brought
out, leisure or no. Too much lush detail and
the piece falls apart into endless bits of lyricism ; too much architecture and the wonderful singing quality is sacrified, as of each
moment. These two men, it seems to tue, have
managed to hit in this performance the ideal,
hair -trigger balance between these dreadful
alternatives. The music sings to perfection
without a trace of hurry or nervousness, yet
the big lines, the huge over -all building -up of
shape, the mammoth conception, the musical
girders, are all there. Not a note is overplayed
-or underplayed ; every note counts in the
whole.
In two words-highly recommended.
II
Illllllllf
Talk about tradition -these fluid, dramatic
songs are subject to all the drastic physical
variation in performance that can come from
differing voice training and production -far
more variation than would be conceivable In
any instrumental piece. But there is a tradition, even for the piano part.
This basso sings expressively and with an
excellent sense of pitch and diction and a good
deal of variety, to suit the dramatic changes.
But his pianist gives me the creeps. lie plays
every song like a Sousa march ; the. delicately
alive Schubert plano figures, so poetically descriptive, become so many boogie-woogie obligatos ! It's not unmusical in any pounding
sense, just hopelessly out of the accepted tradition, which seems and surely is right, even
for today.
Beethoven: Gellert Lieder, Op. 48. Schubert: Schwanengesang. Inez Matthews,
Period SPL 717
sopr., Lowell Farr, pf.
These Schubert songs, sung by a colored
soprano, are beautifully done, combining the
essence of the Schubert tradition with the
warm, special color and the superbly musical
pitch -sense of Miss Matthews' voice. Iler
pianist, no powerhouse, makes an effective accompanist, rather too subdued in the recorded
balance. No Sousa here.
In the Beethoven songs, grander, more
solemn and aria -like, Matthews sings with a
bigger, fuller tone as is exactly proper. In the
Schubert she uses an accurate but small -scale
voice production. True, an Austrian or German singer of the same calibre could deliver
a more authentic and perhaps more effective
rendition of these two cycles of songs, but a
singer as musical as Matthews is bound to do
interesting things with the music. A good
record, if not very stunningly recorded.
Debussy: The Blessed Damozel (La Damoiselle Elue). Berlioz: Summer Nights
(Nuits d'Ete). Victoria de los Angeles;
Radcliffe Choral Soc., Boston Symphony,
RCA Victor LM 1907
Munch.
If you've tried the gorgeous late- Debussy
"Martyre de St. Sébastien" in the complete
version with chorus and solos, or Epic's recent
AUDIO
44
www.americanradiohistory.com
AmericanRadioHistory.Com
JANUARY, 1956
excellent "Pellene," or If you've enjoyed any
of the big Berlioz vocal works of late, then
I ere's a 'Ilse to snap up quickly.
The "Ibunozel" Is an early Debussy work,
f yen
before the familiar "Afternoon of a
"'nun" if I remember rightly and much like
in its sweet, lushly youthful impressionism.
It plays atmospheric orchestral colors against
c women's ,horns and soprano solo. The Berlioz fits remarkably well Into the same
1,
though earlier; it will remind you of his
well-loved "Enhance du Christ." now popular
t the Christmas season every year.
This is a nicely impressionistic edition
though of slightly mixed nationality in the
{ erformhng,
Ile los Angeles has a perfect command of French style and diction and one of
the most wonderfully true voices in the tunatt'as as to pitch ; Munch complements her
style with his Boston players. The Radcliffe
saris, no French maidens. sing ardently and
with enthusiasm, dieting their French almost
tun energetically : the youthful effect of their
',ices Is well suited to the fresh harmonic
(olora of the music, If a trace thin and lacki-.g in tonal richness for such a tapestried
-core.
is rubbed in at the beginning and keeps coming
back in new guises, not very subtly ; the
Gershwin: An American in Paris; Gershwin- Bennett: Symphonic Picture, "Porgy
rind Bess." Philharmonic, Orch. of Horni,urg, Jurgen -Walther.
M -G-M E3253
Tide and others In a series of Gershwin per
formances by the same group present it ruttier
interesting contrast between known history
In Europe--a lid present Impact -in the U.S.A.
Early lost year this orchestra presented an
ell- Gershwin concert in Ilantburg, as en offshoot of the M -11-M recording project, which
rested n sensation. The Germans raved. over towed the concert hall, demanded a repeat
performance then and another later in the
ear ; finally. a tour of German cities was set
cp to meet the extraordinary demand for more
fund inure of the same, spreading Gershwin as
bayed by this Hamburg orchestra far and
Boccherini Quartets. New Music Quartet.
Columbia ML 5047
Any new release from the Quartet that
played such wonderful Mendelssohn (Mt.
4921) and Schumann (Mt. 4982) on recent
Columbia releases Is worth looking into, I'd
say.
This review really belongs hack at the head
of this month's installment along with Clement) aìul Ilumntel. Itnecherini Is another of
those second -rank composers of the end of
the 18th and early 19th century whose stock
went 'way down for a bundredodd years, is
now coming back up with our more wide ranging interest and appreciation of music.
Ile lived mostly in Spain (like Scarlatti),
wrote vast numbers of quintets and many
quartets. Like Clementi, be was actually n
major force in the development of the modern
musical forms- Clementi for the piano sonata.
Itoccherinl for the "chamber music" ensemble.
Ile was slurringly dubbed the s'wife of
Haydn," meaning a sort of feminine, weaker
Iaydn, but for our more discriminating ears
he has a lot more individuality than that.
Of these four quartets, three are latter
works. They sparkle with Italian vehemence.
good humored violence and sweet lyricism
they'll remind you a lilt of the explosive music
of Rossini, though that came later. The remaining quartet is Ids very first, obviously of
an earlier period. It evidently stems from the
aid -late 1700's, perhaps the time of Mozart's
early manhood; it is near to the galant In
style with rather simple harmonies in the
main and fanciful, ornamental melodies. The
slow movement ill lovely, the last very catchy.
(It's odd that at least four notable Italians
in this period lived expatriate lives outside of
Italy and achieved international fame that
still keeps their music alive: Searbtti and
Boccherini in Spain, Clementi in Englund.
Cherubad in Frtuaci.I
The record? Beentifully recorded and even
more beautifully played.
i
:
-
-
I
1
I
wide over the Teutonic lands.
Yet, to my all- American ear, this is not
really good Gershwin, in a subtly continental
way, and I think you will be interested to find
the same thing when you hear it Lt's not
merely that the traditional out -of -tune Paris
taxi horns, del.ghl of a'million listeners, are
impeccably In tune and not at all Parisian,
tor even American There is a pervasive Germanic seriousness, thoroughness, a lack of
!
tounce, a skillful -very skillful -but metholgal imitation of the real American letting I>ose that was so happily Gershwin's own. It's
strange. to an .\uænctun ear. Interesting. too.
Of course. the Germans are quite right. The
essence of Gersltwlm'a score la here, the notes,
the tempi. the main substance. And they
rightly recognize him for what he was. n brilliant and original musical mind that bucked
only the training and background for extendeddength aymphuuic composition that he
tried to nt. uut Inet Lire by himself, from scratch.
See also M -G -M E3237, with the Rhapsody
in Blur mud the Concerto in F, same players
and Sondra Blanca, Europe -domiciled American pianist,
i
music Is contrived, yet not very complicated,
and only the few short traces of easy Wilder style jazz in it seem to time to be unaffected
and worthwhile. I'd much rather hear his
Octet stuff and I think It's better music, too.
\'III\ -Lobos is the extreme opposite, a man
of enormous. unbelievable technical prowess
who writes and writes and writes the most
prodigious quantities of music. nominally classical. fusing the clnuusicol and Brazilian popular- folklore elements with perfect ease. None
of his music (such as I've heard) seems to me
very profound. but every bit of it is so expertly, skillfully written that you can't help
admiring )t.
The three works here are typical of theta minute's listening will show you how enormously more skillful, more secure, more confident is Villa -Lobos than Alec Wilder. The two
works for flute. with clarinet in one, bassoon
In the other, fairly titillate the flutist 'till be
shines and glitters with pure executant joy!
You can almost see his face flushed with pleasure at the end, like a skier's after a good
downhill run and some fancy turns, well skied.
-
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45
3
end of
off
Villa- Lobos:
Quintette en Forme de
Chores, Bachianas Brasilieras #6, Chores
4-2. Alec Wilder: Quintet for Woodwinds.
N.Y. Woodwind Quintet.
Philharmonia PH 110
(No-here's one small label thu t hasn't
saaished lifter all. It's still alive, and has
senne past items of chamber music very much
to Its
credit,
with the Stuyvesant
String
Quartet.)
Au pally Interesting wind recording. tint
contrasts two (cry opposite ci ui pose rs. Alec
Wilder, a brilliant but tender offshoot of the
Arent jazzpops developtent long known for
L s ell -ahl tenet rucordinga with Kew York erish names ("'the Neurotic Goldfish"
.1,
j izz harpsichord and jazz oboe (Mitch Miller),
before such things were commonplace. has had
a NW rut tbris town ris the olnssienl spawns hait as
did Geralwhi, out to mention Morton I ;. uld
and Benny t' Iman. This Quintet seems to
me to be forerai and hothouse, product of too
much classical lamp-lighting. A basic "motive"
AUDIO
George Wright Plays the MIGHTY WURHlFlrecord R 701
LITZER PIPE ORGAN.
\\'ell, ever since Inst September when I ran
a review of an earlier MIGHTY \VURLI'i'ZElt
record on a somewhat obscure label, we have
been besieged with requests for the same.
which seems to he nu,st ly nnolita inable. (Sometimes I wonder whether my learned dlaqulaitluns on Itoc,berini and Haydn and Clementi
ever get read! ,lust mention MIGHTY WURLITZER and the At'uto roof practically falls
in !I For your benefit. the address of the obscure Libel is Starlite Records, 818 Vine
Street, Hollywood 38, Calif. (See Fall 1955
issue, Vol. 1, No I. of .\ l'uto's new sister pub blieation The Tibia for further listings. Eli.)
Or, don't bather: here's something just as
good. If not better. I wonder how many
MIGHTY WI'RLITZERS there are left in the
wo. ld? This one. "silent for so tunny years"
as the totes have it, seems to have been revived elsewhere than in the Paramount. New
York, where this really remarkable organist,
George Wright, cut his \\'urlitzer eye teeth
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45
JANUARY, 1956
www.americanradiohistory.com
AmericanRadioHistory.Com
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N.Y.
is evidently
of California vintage. Wherever it is, Its perfectly enormous and it Has Everything, beyond
your wildest dreams. Such sounds! Such fi!
(It's in Los Angeles. Ed. ED.)
But the best of it, really, is the superb musicianship of Mr. Wright and his incredible
playing skill. The notes say his style is "creative, imaginative and, above all, musical:"
I agree completely. His subject- matter varies
from "Jalousie" and "Roller Coaster" through
"Love for Sale" and "Stars and Stripes Forever" but in all honesty I was delighted to
listen to this Ike all the way through, both
alwaya
sides, and thoroughly enjoyed the II.
enjoy hi -fl when it Is done musically.
Does this seem a bit odd, coming from
Canby? Well, it isuI. Music Is nntslc, oddly
enough, anywhere and any time. I make no
claim to be able to like it all and there are
some of the classics I've never learned to take
1
with pleasure, even to my shame. (Let's name
no names.) But there's plenty of music that
hits me pleasurably just its it tines ninny
another musical- minded listener. whether it's
"Nyorleans," Calypso or Boogie it's the genuine musical feeling that counts, wherever and
:
whenever. George Wright has it.
This isn't the only MIGHTY W. record.
either. You can fairly swim in MIGHTY
WURLITZER sound if you want to. I won't
list 'em all-theré ll he more coming, surely.
Just ask for George by name -that is, NUR LITZER. And the company's full name is high
Fidelity Recordings. Inc., 6087 Sunset Blvd.,
Hollywood 28. No roofs falling in this time,
please.
SCOUTING AMONG
THE OPERAS
Professional Series arm and cartridge 5106.50
Puccini: Manon Lescaut. Albanese, Bjoerling, Merrill; Rome Opero House Orch.
and Chorus, Perlea.
RCA Victor LM 6166 (3)
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IF you're not so young you never heard one
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My Scout #-2 has been having an opera
binge, at my instigation. He is quite enthusiastic about this and the "Alda" following
(same performing group, more or less) and
highly recommends both. This opera, he feels,
is well up to the more familiar Puccini operas
-perhaps a bit ahead of them-and this I
can understand. The most popular operas on
any stage are apt to get their fame from a
combination of good stageworthiness, quick.
easy, dramatic appeal and nice tunes for the
soloists. This doesn't always add up to a given
composer's best work in a larger sense. by any
means, and LP records are the Ideal medium
to make this clear to us listeners.
The performance is "sharp and real. scusi.
tive and understanding," be says and he particularly likes Albanese's work in the title role.
For those who may quail at too much new
Puccini, Scout #- suggests that he can be
wonderful for listening if "all the chicken fat
is wrung out of him." This performance, I
gather from him. has no chicken fat at all.
Good
!
Verdi: Aida. Milanov, Bioerling, Barbieri,
Warren, Christoff, Rome Opera House
Orch. and Chorus, Perlea.
RCA Victor LM 6122 (3)
J
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Here's a companion performance to the
above and. as already mentioned. Scout #2
is enthusiastic about it. "Terrific," he says.
"Everybody in the performance seems caught
up in the spirit of it." That's a lot more than
can be said of some other ":ides." which
sometimes seem to be mainly stage pageantry
with a lot of musical noise attached. That
may be OK in the opera house for a good
show, but a recorded "Aida" must stand up
on its own musical feet-so take Scout #2's
words to heart.
Ile feels that in particular this recording
brings nut a maximum of the good material
that points to the late Verdi operas. "Othello"
and "Falstaff." (This was n transitional
opera, between those late works and the long
string of early Verdis) -which gives It a
maximum of performance solidity. Maybe if
you've thought "Aida" was pretty noisy stuff
before, you'd better try this one.
RADIO MAGAZINES, INC.,
P. 0. Box 629, Mineola, N. Y.
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
JANUARY, 1956
a:s
Moussorgsky: Khovantchina. Soloists Nat.
Opera, Belgrade, Baranovich.
London XLLA 29 (4)
Here's the only complete operatic recording
Moussorgsky s "other" opera -the famous
toe of course being "Boris Godounov." If you
know that work at all. or any other Moussorg>ky music with voice, you'll spot here intartly the dark, macabre excitement that is
;o typically Moussorgsky, the fiery draina, the
_rand and powerful voice of the people and.
,seedless to say, those great Russian vocalize:ions that are so thrilling to hear.
I listened to part of this and found the
erformance excellent, but the Jugoslav voices
vere somehow n bit on the light side, less
weighty titan their Russian criulvalents
hough excellent in style. The orchestra is
tceasionally uneven in detail work but not in
.my unmusical way.
Scout #2 observes that this opera doesn't
spend its vast resources building up one Cenral character of tragedy, as does "Boris."
nstead it is a broader work, with more gotralized shape, nearer to conventional opera
tandards than "Boris." It has more fiat, weak
.:retches, too; but the best scenes are as
::and as anything in Moussorgsky.
I'd say that for anybody who owns n n
trding of "Boris," this is most important.
tlsu for plenty of others who .inst like this
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Borodin: Prince Igor. Soloists, Chorus,
Notional Opera, Belgrade, Danon.
London XLLA 30 (5)
Scout #2 was bored by this one. finds that
.t n large work of music it doesn't stand up,
though there are, of course gorgeous moents including the familiar "1'olovetsky
Maidens" and so on. That is just as I've alc.ays felt about longer excerpts of this opera,
r the whole of It. Borodin did not have the
urge-scale dramatic ability that welds n big
.ere together, lovely as his melodies are in
uany spots.
The performance, too, says the Scout,
i, oesn't seem to get off the ground
though
l'd suggest it's likely that this is Borodin's
alt at base, rather than the Jugoslays', The
Nuussorsky recording above, sane performers,
Ins "all the fat suspense and tautness that
this one lacks." It sounds "all blubbery," as
'Pout #2 puts it, in comparison to "Khovant china."
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CIRCLE 47B
JANUARY, 1956
47
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AmericanRadioHistory.Com
the famous
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AUDI
Edward Ztnall Canby
THE HOME -GROWN TAPE PROGRAM II
Scrambled Time
Ia Part One of this intermittent series I
traced the varied history of my present
radio program from its 78- r.p.m. "live
record" days until I shifted gradually to
tape and then, after a long time doing my
work with an assistant, to solo tape, relying entirely on editing for the effects that
previously had depended on the adroitness
of my assistant in platter- spinning.
How does one "edit" tapet The fundamental principle is simple enough and by
this time most people know that you can
patch up recorded sound on tape to suit
yourself -though, to be sure, very few people actually are aware of the extensive editing that they hear every day, via thousands of records and radio programs. Peo-
still, I think, assume that the recorded
tine- sequence they hear is that of the
original time -that is, the beginning happle
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last. How wrong they are!
(I heard a recorded symphony a day or
so ago in which the first ten minutes
sounded dreadfully tired, but then the performance picked up life and animation.
"Thant" As an old tape hand, I immediately suspected that the opening moments
might have been recorded last, not first
or perhaps at the end of a day's work while
what followed came from the fresh beginning of a recorded session, a day before
or even a week later. Time has precious
little meaning any more in recorded con-
-
tinuity.)
To edit, you slice up hunks of recorded
time like so much spaghetti, (or should I
say noodles), then patch them together
again with white sticky tape in any fashion
you may please. But you'll have to
"please" rather carefully. If your tape
joints are clever, you'll have no audible
,joining -just a smooth, new time continuity all of a piece and unbroken. And very
few people will ever stop to think that
they're actually hearing time scrambled.
But if your joints are badly chosen, the
results can be not only noticeable (which
is taboo) but very unsettling; for there's
nothing we dislike more instinctively than
to have that smoothly eternal mechanism
of steadily passing time tampered with!
Like the force of gravity, time is with us
always and to disrupt its flow in any
audible way, to confuse the ear as to what,
happened when, is as devastatingly disturbing as might be a sudden change in the
force of gravity.
Just ask the man who's been seasick. He
knows all about gravity gone haywire. Bad
tape editing -noticeable tape editing where
you are aware of the time-tampering-is
just as unnerving. It gives our time- sense
a stomachache.
How does one get this seemingly unbroken new time continuitvf The details
are fascinating and very psychological, for
this is a matter of fooling the ear or,
should I say, satisfying it by tricks, satisfying the imagination. You think you are
hearing such -and -such a situation, via a
recording, and you want desperately to
imagine the continuing sequence of events
in an unbroken time -sequence, normally.
We cling almost frantically to that normal
time -flow and we accept "substitutes"
very readily, if only they allow us to go on
wilnotit time- interruption.
I've long since learned, for instance, not
to patch my voice, as recorded on a bright,
cheery morning, onto the same voice as of
the wee, small hours of the night before. I
myself am not aware of any special difference as I speak; but the transition, instantaneously, from my night- before voice to
my morning -after one can be startling; my
whole personality has changed overnight
(with a good night's sleep) -and now it
changes in a quick flash right in the middle
of a word or at a fleeting pause for breath!
Listening, you will insist on running the
two into the same sequence of time (you
reject the idea of a night's time intervening in the middle of an unbroken sentence)
and so the change just sounds crazy, disturbing, unnerving.
Similarly, I've learned to look out for
strangely disturbing effects produced by
overlooking the normal breathing intake
of speech. Nobody consciously notices the
breaths you take, and they are just barely
audible, even hi -fi. But sometimes, by acciI patch two breathing sounds together. Easy to do when you're hooking up
pieces of sentences made at different times.
As played back, I finish a sentence, take a
quick breath -then take another on top of
it. Very disconcerting; it sounds as if I
were blowing myself up like a balloon.
Oppositely, if I fail to allow for that
little breath -pause in joining together two
pieces of sentences, you will hear a ghastly
effect as though I were s-1ueezed completely
out of breath and gasping like a fish. (I
don 't gasp, but you the listener, want nie
to, when you don't hear me take
new
breath. You're waiting for that breath,
even though you're not consciously aware
of it, and you become quite distressed if
I go right on talking and fail to take
All of which, you see, points up the fact
that the basic purpose of tape editing is
to fake a perfect illusion of continuing,
unbroken time, and by implication, an unbroken continuity of place, or space. Sudden disappearances of background sound
between bands of an LP record are very
bad for example, because they arbitrarily
wrench you out of the concert hall into
dead, timeless space, then pop you back
it)
AUDIO
48
www.americanradiohistory.com
AmericanRadioHistory.Com
JANUARY, 1956
again, in imagination. You very much prefer, as I see it, to remain figuratively in
the same spot and in the same stream of
time; so you insist on imagining that the
intervals between movements on an LP
record are actual passages of time -that
the orchestra is still there, pausing, getting
ready to start again. Continuity of background noise -even when it is faked -will
do that for you nicely.
The Set -Up
But away from generalities and let's get
to business. Before I get to editing I must
speak of the set -up. Not that very many
readers are likely to plunge into home solo
radio program producing day after tomorrow, but as a basis for new ideas I suspect
my set -up may he of interest to a good
many amateurs and professionals.
First, I am midway between amateur
and professional. Professional output
yes. But with amateur gadgetizing, make
shifts, simplicity. That's my own particutar choice and need not be yours.
For solo work, here in my study at home,
have -starting at the outside
four ,anel folding screen of economical card ward. On the inside there is a quilt, tacked
n with a stapling gun. (In New York I
ave the same screen with a layer of Ozite
tug lining glued on.) This screen is placed
-.ehind me, quilt -side in, and my equipment
s in front of me on a pipe -leg table in
I. corner of the room.
The corner is lined
with Ozite, glued to the wall for about five
feet out each way, and up and down from
'slow the table as high as my hand might
-each, sitting down. The table has a pad
f Ozite under the tape recorder. That is
ny sound proofing and it is excellent. Noth.ng more is needed. The rest of the room
remains just as is, plain plaster, woodwork
-
-a
I
Ind wooden floor.
On the table is
(at the moment) my con
erted Magnecorder PT -6, with electronics
y Howard Sterling. Optimum sound qualty at 71 ips and-most important
red
safety button that must be pushed in besore the machine will record, in record
osition. This was lacking on the original
!Lachine. Separate equalization for Magne+order -type tapes and Ampex -type (now
standard) tapes, which is what I use for
he program.
My McProud control box, a foot square,
was made for an earlier phase of the pro
gram (as already described) in which I
tad two phono inputs and mike, plus cue
hannels for headphones, all used by my
assistant while I sat back and orated. Now
use, mostly, one phono channel and the
mike channel, on adjoining pots. The sec ml phono channel is convertible to a high evel input and this is used for tapes played
'rom another machine. Very important
!-hen I make tapes in the field and want to
dub in excerpts while I talk. (Also for
Spying my older programs that are equal zed wrongly and won't play on today's
:andard broadcast machines.)
The control box 'sits immediately to the
tight of the recorder and a goose -neck
lamp teeters with a wobble on top of it.
':;very so often it topples off and falls on
is face on my tiny typewriter, a Hermes,
which sits in front of the recorder, between
it and my lap. I got a Hermes for travelng, but now I use it exclusively for these
Ilroadcasts -do my typing right at the
console," and read it straight into the
-
-a
-
Irdke.
The mike is an Altec, fastened by a
goose -neck to the back of the table. Its
thin bottle -shaped nose stretches out over
the top of the control box, pointing straight
:.t my face, about six inches or so away.
That's a story in itself. It took me many
AUDIO
months to discover that at close range the
Altee is quite directional and produced an
unpleasantly dull off-mike effect if I talked
at the side of the "bottle" instead of endwise. Nobody told me. Now that I speak
directly at its nose, all is well.)
The mike has a variable bass cutoff,
which is indispensable for me. I keep it
permanently set at 40 -cps cutoff, which
takes the boom out of my voice as amplified in playback and makes for a much
more natural effect. (In a studio the
deader, quieter surroundings allow speakers to work further from the mike; moreover, most professional radio voices have
vastly more "projection" than mine and
so their owners can speak at a foot's distance with more umph than I have at six
inches.) As is well known, the more your
voice is amplified in playback over its
original absolute level, the more boom will
it have.
My show uses records. To the right of
my recorder table I have another on which
(at the moment) sits a D & R turntable,
with (at the moment) an Audak HI -Q 7
pickup and professional arm. A good table
is absolutely essential for any sort of work
on this line and I still do not trust a
changer, or equivalent, to produce broad cast -quality low rumble and, more important, steadiness of pitch.
Finally, off to my left, on the edge of
a bureau, is a cheap old amplifier, in excellent condition, into which feeds the output
of the recorder. It feeds, in turn, a "bookshelf " type speaker system wheh stands
(at the moment) by my chair and aims
the recorded sound under the table, where
it sort of oozes up at me from around the
edges. Purely arbitrary and a better system is to aim the speaker away from you
out into room behind your back, outside
the screen. Much more natural playback.
(But my speaker cord is too short and I
won 't bother to change it for awhile, most
likely.)
The less said the better about the rest
of my work room, which is usually piled
up with heaps of old tapes, records, screwdrivers, cameras and what -not. My only
point in this respect is that you don't need
a whole room, much less a specifically
soundproofed room, to turn out rather professional home tapes. Just a corner will
do, plus the screen to put around it, and
the strategically placed cheap padding on
both wall and screen.
Clip vs. Fade
My first move, for any show, is to align
the tape recorder heads, a job which I detest and often wish to bypass, but usually
don't. One lives aid learns. Then comes
the theme. Cue up the middle of the scherzo
from Schubert's Fifth Symphony (the record is marked), leave the table running
but the record slipping, held by one finger.
Start the tape rolling with the other hand,
open the phono pot and let go of the record
simultaneously, and you're off. That is, if
the record hasn't jumped a groove while
you were getting ready and so starts in
the middle of the theme. The levels have
long since been pre- marked in red china marking pencil right on the pot, so I know
how far to turn it
Earphones on my head, one phone off,
the other half on, so I can just hear the
music. (Forgot to mention this vital bit of
equipment. They are the Permofiux hi -fi
phones, and their wide tonal range I find
essential for accurate listening.) I know
that with the phone clamped over my ears
I talk less naturally and so I leave 'em
half uncovered.
When the theme gets to a certain point I
slowly open the microphone pot (volume
JANUARY, 1956
Especially
where
space
Is
limited
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Two important steps
toward achieving
better sound
control to you amateurs) to its predetermined level, also marked in red. Why
slowly, Well, most studios clip a mike into
the circuit via a switch. If there is the
slightest trace of studio noise in the background this makes it instantly noticeable.
Now
have much more than a trace of
noise; indeed, you can hear both the turntable and the recorder itself, as background
to my voice.
But if I fade up the mike slowly, while
the theme plays, then the background steals
in quietly and is absolutely not noticeable.
At the proper point, as
listen on the
phones, I fado the music down to predetermined point B, the level for a music background to my voice (worked out long ago
by extensive recording experiment) and I
talk. "Hello! This is Edward Tatnaf
Canby.
Meanwhile I am following
the theme in the phones, while I talk, and
I must quickly turn off the music as it ends.
before the next part begins-and at the
same time grab the record with one finger
to stop it. (Some music leaks through even
in the "off position.) This takes a nice
bit of coordination. It was a long time
before I learned to stop the music at the
right place while continuing to talk unconcernedly into the mike! Either the music
stopped wrongly, or I muffed my speech.
Usually the first try sounds like, well.
pretty bad. I need some vocal warming -up.
The second try is better, maybe, but the
music starts wrong. The third try is fine,
but I didn't fade down the music quite far
enough (in spite of the red mark) ; the
fourth is OK except that my "Hello!"
sounds sort of silly. Not casual enough.
(As if I could really be casual, with all
those controls and things to be thinking
about.) Try, try again. Sometimes it takes
an exasperating six or seven attempts before I get nay theme down. I just rewind
the tape and start once more.
Then
work. I always end the theme
recording with the mike open, for background sound. When the next section is
spliced on, it also will have background,
open -mike sound on it, even when it is
music, without speech. Whys Backgroundnoise continuity, which you can see is a
cardinal point in my opinion.
the background sound suddenly stopped as the
music began, you woukl instantly be aware
of it. But instead, it continues, and then
I slowly fade it out, well after the music
is under way. Never a so-called "clip,"
turning off the mike via a switch. In this
fashion I am sure that you will never consciously be aware of the background sound
at all though, as I say, it is actually quite
loud. Pure aural illusion, and it's one of
the most valuable tricks in this business of
making a semi-amateur job sound professional.
use the same technique for all subsequent joints. At the end of every section
of music I fade open my microphone before
the music ends, so that when I stop the
machine there will already be background
sound established, though you will not have
been aware of its gradual entrance. Then
when I patch on the next piece of spoken
comment, the two backgrounds merge
neatly and you will not notice a thing-no
sudden appearance of background hiss or
hum or rumble as my voice starts speaking.
It is all camouflaged for your ear, men
tally, by the fact that it was already there
before you expected it, before the music
came to an end. Sneak entrance.
Many a radio station I've listened to
could profit by n bit more of this sort of
technique. Too often they reach the end
of their music (or an ad or plug) -and
only then, with a very audible clank, does
the studio mike open up by switch, instantly
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calling attention to every trace of background. It's worth remembering that back-
ground sound -even hiss and hum ---can he
an asset if treated carefully, because it
tends to give a sense of space and area,
to make you feel that you are
some
room, not merely off in a disembodied electronic vacuum. Think again of the LP records. Better by far to stay put inside a
rustling, noisy concert hall between pieces
of music, than to be switched suddenly into
that soundless ionosphere for ten seconds
of interval, then, instantaneously just as
the nnasic begins, back into the concert
hall with a thump.
"in"
The Vanishing Script
So much for a major, if simple, point
of technique. Before I stop this installaient
I'd better untangle a few doubts I must
have stirred up as to the actual "writing"
of this home -grown radio program. What
about the script When is that worked up?
Directions to myself
Lt my more conventional days of assistant- produced shows, first in the studio and
later on at home, I wrote out complete
scripts ahead of time, as anybody in his
senses would do. All the words for me to
speak, plus complete music cues for my
assistant or assistants. Carbon copies for
all concerned.
When we used records (mostly 78's,
then), I marked the exact grooves with n
marking pencil, and on the groove I indicated the precise point where the music
started. The script itself gave the record
number and side -"Columbia MM 369, 2,
Band 2 from ,end line, at
And in
addition I nually put in musical identifications-"First note of trumpet blast."
(Even so, I never could avoid a long rehearsal where the actual musical sound was
pointed out to the assistant, then more or
less memorized by him.)
But when I went solo, these directions
became notes to myself. Inevitably I began
to simplify them. Somehow, I couldn't get
excited over the idea of complete directions
for "posterity" or something. I remembered the cues perfectly well -why bother
to write 'ens out.
soon got down to the
minimum, the record number and a couple
of words of rough identification. "Bach,
"X."
I
Pr 4- Fy D mi."
But already I had crossed a fatal bridge.
I had accepted the fact that my script was
no longer intelligible to anyone but myself.
It was no longer a script. And with that,
I began to ease up all along. I ad liblied,
departing from the script, adding words,
rewriting (so to speak) as I spoke.
I began to ad lib and then take down the
ad lib parts from the tape onto the typewriter, just to have them "on the record."
Or I wrote them in, in pencil. Or just
wrote "(Ad Lib here) ", not bothering to
put the details. So, you see, it soon began
to be a question as to which was "the"
show -the script or the actual recorded
version, ois tape.
There wasn't much doubt, as I continued
to work solo. No assistant, no necessity for
detailed directions and so no need for a
detailed script. My typing began to turn
into a set of rough notes, more or less complete, for the actual show which existed
only in one form -the taped one. I kept the
written work mainly in order to know the
gist of what was on the tape without having to play it over, and also in case I
wanted to edit or correct or change it later
on, for repeat use. (This happens all the
time.) The script was merely a convenience,
strictly personal.
Now this was getting pretty unconvenif not downright revolutionary. PerI shouldn't say it in print, but
tional,
I'll
haps
AUDIO
50
www.americanradiohistory.com
AmericanRadioHistory.Com
JANUARY, 1956
depend ou the Profession's good will to let
nie continue to get away with it! People
write in to me and say they liked so-and -so
program -could they have a copy of the
vripti-assuming, like normal people, that
I had one. Well, I did, and do, mostly. But
nobody could make head or tail of it but
nee. Illegible scrawl. And if I were to copy
it out neatly, I still would have to go to
the tape itself to "correct" it, to get the
final, official version of the program itself,
It's on the record -literally.
Needless to say, I keep all my tapes,
though there was a time when I blithely
erased them after they had been used. I'd
as soon burn up my entire script pile
sooner-as things now stand.
One final and even more drastic step completes this de- scripting process. I started
this one a long while back. out of pure
Laziness, but now I do it regularly.
I write the show as I record it, section
by section. Instead of timing each piece,
I look at the tape reels and estimate how
fir I've gone, how much more time I have
loft. I write a paragraph, practice -read it.
then record it. I play it back for effect.
then write another, or add the music that
should follow. This goes on, piece by piece,
section by section, each one put together
on the typewriter, then read directly into
the mike before the next one is clone. No editing-yet. I leave the patching -up process
until later, unless I happen to want to try
editing a stretch, to see whether it's going
be work out right or not. If I know it will
work, I just leave it, and go on to the next
-
slice.
At about twenty three minutes into my
24:30 allotment, judging roughly by reel
.,ze, I stop and take stock. Better be rounding out an ending. I usually go back and
tone with a stopwatch up to that point,
skipping the numerous hunks of tape that
are going to be taken out, just to see where
I am. Then I do a tentative ending -try a
short piece of music for size. or take a long
one and edit out pieces of it, patching them
together to fit the remaining time. Too
long? Take out a sentence, or a repeat in
the music, or try reading the last Para
graph again with a few less words.
And so I get pretty close to that fatal
28:30 -the one rigid requirement that must
be met, within not very many seconds each
way. (That's where I bump into my neighbors on the air, after all.) And at this
point I go back and begin the hook -up
process. Editing.
Cough, Cough
11y- tape at this point is really an odd
eation. No more odd than an unedited
studio tape, of course, especially a musical
recording -and indeed it is strangely like
that ultra- modern interim- product. An unedited symphony tape is made up of many
fragmentary "takes," uu,joined, with much
extraneous clutter and clatter and noise
b'tween takes. There is no "script" for a
symphony on tapes, only a set of detailed
directions, telling the editor where to splice,
what to keep, what to discard. Those directions are not the recorded symphonic performance itself, nor are they its script.
.1 ist notes, directions.
e
So it is with my unfinished home tape.
Play it and you have most of the finished
job before vou, but the sections bump and
bang against each other and there are slices
of false beginnings, muttered comments
by myself (sometimes unprintable -"And
so, you xce, old Bach was really not so
mathematical cough cough DAMN ! Stupid!
Clank Clank, Ah -IIUM, (where was If . .
Oh yeah,) And so, old Bach, you see, was
REAT.ÁX not so mathematical.
" Same
with the musical portions. Unedited, they
overlap, stop, repeat nonsensically, and
there are always fragments of erased commentary here and there that interrupt grotesquely for a second or so, like voices on
the radio when somebody's hunting stations. All in all, a very strange sound for
those who haven't heard it. For me it just
.
means -more work to come.
And so, when the joints are joined, the
extraneous material cut out and heaped all
over the floor and the table, when the time.
continuity is duly faked up and complete.
I re -time. How I hate that final step
because it usually isn't final. Somehow,
unaccountably, my program is a minute
and three seconds too long. What hours
can be crammed into a minute!
Sometimes it takes tue two or three of
them to get rid of that extra bit. I go back
and play through the whole show, editing
out a word here, a couple of them there.
removing a whole paragraph (after being
sure that I'll still seem to make sense) ;
I check the music and, perhaps, take out
a slice from some piece, editing the jagged
ends together so they fit. (But it may take
a half hour to find a good place to do the
job.) Each little excision subtracts a few
more seconds and, eventually, the total
timing is down to the required 28:30, or
-
thereabouts.
Much as I hate to believe it, I must admit
that these agonizing pruuings -to fit do more
good than harm. They are equivalent to the
final revisions and blue- pencilings, on paper, that go into any writer 's preparation
of a work, or into a musician 's composition. But instead of blue -penciling nptyped material, I blue -pencil my recorded
voice. That's tape editing for you.
*
So much for the general approach to the
home -grown tape program. Do it in bits
and pieces, feeling your way as you go
just as many a semi- professional, free-
lance, documentary film maker operates.
Edit, edit, edit. Shape and mould the material while the show is a- building, while
you're recording. Polish it up after recording, as well as on paper, beforehand.
Which leaves me where I had expected
to be at the end of this second installment,
out of space in which to go on to describe
a whole raft of little editing tricks that
have sort of worked themselves out as I've
gone along. Some of then are nothing new
to any professional editor, some are merely
variants of standard professional technique. (But who ever gets around to letting
amateurs in on professional techniques ?)
A few may be, as they say, original with
me. I'll get to these in Part III, in a forth coming issue.
un alaunnnun0.uuuuuunuunnnuuuunuuualununnnueuwmumimimmnnnuuuunununuuunuuuunununuunuuuuuumnuuuuuuuuuunuuuuunnuune
CANADIAN SHOWS
The International Montreal Audio Show
Windsor Hotel, Montreal January
18- 19 -20, 1956
Toronto Audio Show
Prince George Hotel, Toronto
AUDIO
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February
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(John M. Conly)
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AUDIO
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... As to the
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High 3idelitg
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woofer that works exceptionally
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I have heard clean extended bass
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THE AUDIO LEAGUE REPORT
(Oct., '55) Pleasantville, N. Y.
"Speaker systems that will develop much
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ACOUSTIC RESEARCH,
1
-2 -3, 1956
JANUARY, 1956
23 Mt. Auburn
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INC.
38, Mass.
51
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ABOUT MUSIC
(from page 6)
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AUDIO
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Record Revues
1
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the fiery young conductor who three years
before directed the première of La Bohème.
At the first rehearsal, Caruso substituted
a falsetto for the high C at the climax of
"Cite gelida manina." " Toscanini,''
writes T. R. Ybarra in his excellent biography of Caruso, "asked him for a stronger
high C. Caruso nodded pleasantly. However, at the end of 'Che gelida manina,'
there came no strong C from Caruso. 'How
about that stronger high note I asked you
fort' inquired the conductor ominously.
And the tenor, in his current enslavement
to temperament, answered with a touch of
petulance: 'I don't feel like singing it
just now.' Toscanini bristled."
In four out of the five rehearsals ordered
by Toscanini, Caruso sang half- voice. Finally, Toscanini threatened to walk out.
This brought on several La Scala dignitaries who managed to soothe the protagonists. But the battle ended in a draw. Caruso came down with a fever the next day
and barely made it through the performance.
There are a number of conductors who
know how to cope with singers. One of these
is the redoubtable Sir Thomas Beecham.
A friend once heard an opera conducted
by Beecham at Covent Garden. When the
curtain fell on the last act, be went backstage to visit the conductor in his dressing
room and told him how much he enjoyed
the performance, how magnificently the orchestra sounded, etc. "As a matter of
fact," he said, "you brought out details
in the instrumentation which I don't believe I was ever aware of before tonight.
But I have one reservation, Sir Thomas.
Your men played so loud that I couldn't
]tear the singers on the stage." Sir Thomas
stroked his goatee, his eyes twinkled, and
lie said, "That was my intention, old chap.
I drowned them out deliberately in the
interests of the public."
In Latin countries, the public seems
capable of taking care of itself. Over -ripe
tomatoes are sold outside provincial Italian
opera houses for just such a purpose. Temperament, it appears, can be on both sides
of the footlights.
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JANUARY, 1956
PATENTS
Of
(from page 2)
nnplifiers V, and V to the recording head.
", is connected as an oscillator to furnish
ins through the output amplifier V,.
In the PLAYBACK position, the head is
.witched to the input of the amplifier and
he recording level control is eliminated.
nrr extra amplification is required on
back, V, is now utilized as an ampliI:
fier, and V, feeds the speaker. The tuned
circuit still appears to be across the grid
of V,, but the variable capacitor has such
a low value that the tank has no effect
this
you can be
at audio frequencies.
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3
DISC RECORDING
(from page 19)
irately, however, while pre -emphasis does
extend the lower limit of the dynamic
range by reducing surface noise and allowing softer signals to become audible,
it increases treble groove excursions at
the same time, thus restricting the upper
limit of dynamic range that can be used
without distortion. It can be seen that
the decision as to the optimum characteristics to use for recording is not a
simple one.
Figure 4-8 shows over-recorded
grooves which have eut over onto each
other along side of normally eut grooves.
Modern Techniques for Increasing
C ynamic Range
Older records had a severely limited
dynamic range. Not too many years ago
recorded orchestral crescendos were con s derably watered -down versions of the
original, and any really soft passages
would have been wasted, as they would
AUDIO
have been drowned out by surface noise.
Modern records have increased this
dynamic range, approaching that of the
original sound, by the use of several
techniques. First, the surface noise has
been greatly reduced through the use of
improved materials. This makes it possible for the recordist to cut soft musical passages at a very low level. It takes
a touch smaller groove wiggle to override the inherent irregularities of the
material of the groove wall itself.
Second, there are methods for extending the upper limit of the dynamic
range. One such method is to employ
variable -pitch recording, that is, to increase the spacing between grooves automatically when a heavily recorded passage appears. Another method, called
quality- control, is to attenuate instantaneously the dangerous portions of the
signal which might create cutover or
high -frequency distortion. The use of
JANUARY, 1956
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COMPARE ON
A
improved pick -ups and needles, nlakiit'
it possible to trace heavily recorded
grooves more faithfully, also works to
increase the allowable dynamic range.
SQUARE
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response of
Jim Lansing Signature
extended range speakers
combination of tight electrical and rigid
mechanical coupling account for the exceptional transient response of Jim Lansing
Signature units.
A
Tight electrical coupling results from high
flux density and close voice coil tolerances.
Rigid mechanical coupling is achieved by
use of a 4" voice coil with a 4" dural
dust dome attached directly to it, Thus,
cone area between coil and suspension is
kept relatively small; compliance between
coil and dome is eliminated.
Structurally, when a 4" voice coil and
dome are used with a curvilinear cone,
a shallow piston assembly Is made possible. This shallow form factor permits a
better distribution of highs than would a
deep cone.
Recording Equipment
The turnlables, cutting heads, amplifying equipment and tape machines (the
latter *III ..t always make the initial recording) used in recording must be of
the highest quality, so that a minimum
(if limitation is put on the capabilities of
the reproducing equipment. While a detnjled discussion of recording equipment
is not ;Ipltopriate here, a typical pro -
tesionnl recording turntable and cutter
ill11- crated in F'i,p. 4
-9.
AUDIOCLINIC'S AM TUNER
iw d nrteIlk 11111
ram the question
I
:rttswcr 1111. tn,ent,
udiocliuic," in
issue, the parts list for the
Iii-ii AM tuner described by \tr. f:ioc :uællt
lias Ien the subject of numerous inquiries
'l ul ll readers who wished to duplicate the
performance attributed to the circuit.
For the benefit of readers su inclined,
1110 schematic is here
repeated together
mill the heretofore missing parts list:
th, December
t
Remember, only Jim Lansing Signature
Speakers are made with 4" voice coils.
! !
('
(
Extra low total mass-smaller stylus
load- tracks with less than one
gram vertical stylus force -exclusive
micrometer style counterbalance
nylon bearing surfaces to reduce friction and resonances -easy stylus inspection by simply lifting arm off base
work
-all
-
height-standard cartridge mountings
satin aluminum
finish -available in sizes listed below,
less cartridge.
14 Inch
2nd
Harmonic
mum
Tracking Distortion
Error*
Index **
2.7°
.S° per inch
17
21
"
1.8°
.3° "
Any Length $14.95
Direct from Manufacturer
Based on 12 Inch record
"
The percentage of 2nd harmonic distortion, which is a function of arm design, is
directly proportional to the distortion index.
''°0
Write today
VOLPAR
4404 West 22nd Street
Panama City, Florida
CIRCLE
54B
.
25 50'7 DISCOUNT Factory-fresh guaran1.1'r'e0nls, d9(t and up; .end 100 for
cntulogu,. SuI"l'll\wl:s'l' REC0I:D SALES,
Dept. A.. 110. \\'iuL,ru. Houstou,'l'rxas.
teed
a- F.Iruuut Broad-Band F \I antennas. All
seamless aluminum. $111.95 ppd. Wholesale
Supply Co., La neu litt rg 10, ]lass.
1111:11
FIDELITY SPEAKERS REPAIRED
.\mprite Speaker Service
Vesey St.. New York 7, N. Y.
711
Mk 7-255o
W.\RI'l'YI'IN1:
Composition. 1)5.1, 111M.
paste -tip. ruled forms. advertising layout and
technical matter in English and foreign languages. Ca lherine It,in, 574 Broadway at 18th
st.. New York. Gliautercy 7417211.
1'1111
hack T.,
'l'wo Ampex 3511 recorders; 0110
15 ips, two -ease portable wish
Ampex 591.$ \baiter Amplifier, $1051); nitr
7 .
:, ills, reek mount, $5511..1. NI. Edelman,
\Liss,
I.aitrel St., Baton Rouge, Ltt. Phone
'l'.\l'1: Itla'u1tDl:ICS, Professional quality.
Transport, $175: heads, $75; amplifier, $150.
Write for specifictstious; E. .1. Lesher, 17311
Ileluherwny, :11111 :\rbor, \llrh.
,
10 Inch
12
14 "
'l'IIIS .\11)111 EXCHANGE bris the largest
sleet ion of mew and !idly guaranteed used
equipment. Cat+doc of used equipment ou.ree, Dept.:\T:, lia -19 11i11quest.Audio l: change,
si,b \c,.. .lamnien 12, N. Y. W. 5- 0415.
.\I-DIU EXCHANGE EXCHANGES AI'Dlu
Fuit s.\I,l ;: III; \\I.I :i'I' l'.\CKARD AUDI()
('..
Overall
Length
the
nsl'11.1,. '1'u1L Model 211h s. Like new In origiual ersrloit, $luu. .I. \I. Edeünnn. M.11., :133
I.aure'. 'talon Ronge. 1.n.
VOLPAR PROFESSIONAL ARM
Pivot to
Needle
by
:\\I-F:1I 'tuner.
Brawl New l'ilot
t'nir'4sild Cartridges and arms. Also Wllliaun.,,a "I'lu:rl.iue;u" amplifier and 'lapesonic
;n.\ ist professional lape recorder. Write for
derails. e:1rr aotllieb, Carnegie Inst. of'Technology. 1'i1lsb11rab 13, l'n.
CIRCLE 54A
Maxi-
and must reach the New York omee
first of the month preceding the date of Issue.
1
2439 Fletcher Drive,
Los Angeles 39, California
-adjustable
fall.
!- 11501.
lames 8. Lansing Sound, Inc.
manufacturera of precision transducers
NEW!
CLASSIFIED
10e per word par Insertion tar noncommercial
advertisements: 25e per word for commercial advertisements.
Rates are net. and no discounts will be
allowed. Copy must be accompanied by remittance In
Rates:
l'. Two-gang w :iriahle ,:Iparitur.
utuu capacitance 3110 µµf
(' 3-30 µµf trimmers, usually a integral part of
511
µµf, mica or ceramic
.02 of, paper, 200 -100 v.
"Gimmick" capacitor glade by
twisting two pieces of insulated
wire together. (See below.)
I N34 germanium diode
L, 'Broadcast band slug -tuned antenna
coils,
4.7 nleg.
11,
;
It. \Itl:.\IN Two famous 'relefnuken í'47M
condenser microphones, complete, gtutrnnleed.
$275 each. 9 l:dgeltill Roud, Winchester. )lass.
:
V \I 931;1i, used, less cartridge. $15: ltI 'A
:t- speed, new, less cartridge. $15. \ \':liter Robmercy l'lace, Los Angeles.
inson. 1541 S. Gramercy
California.
'l'It:\DI.1 portable tape l'Iti:s'rai 1l' 91111 raid
: (2 -nick Magnerur,l 1"l'r, -. \III or
"1'0-1'1 to
(reek \Ltgneco nl 1'T6 -AII and
standardize equipment. Frank Oppilz, Central
Recording Studios, 934 Kansas Ave., Topek n,
1
capacitor made by twisting t wo
insulated wire together. The
gauge of the wire and the thickness of the
insulation are not critical, and there is no
is a
pieces of
connection between the two wires. The pair
should be from 0 to 8 in. long as a start. 1f
C, is too large -the wires too lung -tuning
will be broad. Reduce the length a little at
:1
tinte, realigning C;C, and L, -L, after
e::cli change in C;. Compromise between seloctivity and output signal.
Alt,.
520A speaker system
-,. I:rcelbut Bondit ion. Delivery- N.E. urea.
C. II. I :od,la il, It.l'.D. #1, Torrington, Cann.
S.\ I.1::
.
amplifier for
(';
El l;
WANTED: Frequency respuuse reeo nler.
Apparatus Co. 421.1t with associated
oscillator power supply for Alive 2111 microphone: distortion analyzers and other acoustic measuring equipment. Describe fully null
slate bonoul prier. !tux C.1 -1, AUDIO.
Sound
FAIRCHILD 240 control unit and 260 50.
watt amplifier. $125.
S.
Leen, Hyannis, Mass.
British
ICEI'ult Di:lt.
PROFESSIONAL
transportable model, in tsw o 1,1 rry lag' rases,
with 3 heads, 3 motors, lo -watt playback and
dual monitor system. Beautifully built, de
strated only once at Audio T'ait. $57:, or near
offer. John Ould Ltd., 510 South Fifth Avenue,
Mount Vernon, N. Y. MO 4 -1375.
K tl11ss1 s,
WANTED: REL Precedent Inner and g
tape recorder. Dr. George Wentz, 417 Comanche, Sun Marcos, Texans.
\leissner FM -:\M tuner -amplifier with Peer s-23012 0.T., $65 ; also Partridge CFB
primary for Williamson, $25.
Barney La npher, Janiesville Road, ,lamesville,
less
11.'1.. in.011(I -alun
N. Y.
\\':\N'l'l:D: USED FM BROADCAST
'l'R:\NS\Il'l'l'EIL Box CJ-2, AI7I1I0.
NEW 1'11.0T AF -80o Tuner, $139.50 ;
Stephens 206.\X A, $1115; Garrard 1{C -80,
$39.50 ; Pedersen PRT-11.0 prenntp, $89.50.
Inox C.1-3.
AUDIO.
1melitier KIT, unI I IL\'l'IIKIT Williamson
assembled, Model W4-AM, $31.7x. C. A. Turner,
midland, California.
PARLOR PLAYER PIA Ni The heel Item
5 -in. Dual-Track, 7'. ips. $5.25 ppd.
Weir, 111 Catalpa St., Middletown, l'a.
.
McCoy.
AUDIO
54
www.americanradiohistory.com
AmericanRadioHistory.Com
JANUARY, 1956
PROFESSIONAL
DIRECTORY
CINEMA'S
TAPE AND FILM
Oc'llJssr
OF
MAGNETIC TAPE 8 FILM
The Ampex Corporation is establishing
nationwide network of authorized servrepresentatives for Ampex :nnli
equipment under the direction of ilan -I.I
ice
II
Van Childs, manager- of the compa 's
Customer Service Engineering depart m. II
Service organizations will adjust and
repair Ampex sound equipment at m,
..IILLE a during the warranty period and
:It competitive rates after the warranty
has expired. Service representatives will
maintain a complete stock of replacement
parts, and will be trailed at the Ampex
l Iitl,ry in Redwood City, Calif.
Eallicrafters Company will imam be put .haSod by Penn-Texas Corporation, ac...wiling to William J. Halligan, h alli..rafters president. The boards of directors
of both companies have approved th.
agreement transferring assets, and till
proposals will be submitted for appn,s :Il
to stockholders at special meetings to bI
called shortly. L. 11. Silberstein, chairmaul
of the board and president of Penn-Texas.
says it is the intention to continue with
the present II :IIIicrl f leis management.
I
CO.
OIVISION AFROVO. co
BURBANK. CALIF
1100 CHESTNUT STREET
CIRCLE 55C
/944
HOLLYWOOD ELECTRONICS
DISTRIBUTORS OF HI -fl COMPONENTS
Jintnty Carroll, Jr., is following in III'
footsteps of lis (lad. Jimmy Carroll, Sr.,
sales engineer in t he sound department of
New York's J t:t r vey I; ;IIItu Company-he's
installing a complete music system in 111'
id Connect icul's most latish mansii ,P."
Ed Altshuier, formerly nrEl iami
manager for Herlant- Conoertone, is L.
new consumer III"od u lIs pales Manager
for the nMarketing division of American
l' :lee troni os, Inc., Los Angeles, of which
Dell;, Ut- Cuncertone is a subsidiary.
Lynn Eaton. viIe- president of National
Company, Inc., has been appointed asPersonne
sistant tu the president
reassignments at \Iagnccord, Inc., 111111
George Gynn named product manager for
the tape recorder division, Michael G.
Seidl anpIinted product manager fol- all
\lague\lusie items, and .Manes E. Steel,
named \\-extern regional Hall's manager
of the Maguelttusie division
Dr. S. J.
Begun, illterlllllinlallly- kune'u :n1111ait>
magnetic recording, has livra al'I"int
director of marketing for f.IA-Vite I'I,rIII,r :Ition where lie will sup,' vise the firm's
luttent and research dill., r ment s.
.
.
.
.
I
.
Everythingin HI -FI Sound Equipment
CIRCLE 55D
AMVEXWORLD'S
FEATURING
RAe.mc
HIGH -FIDELITY HOUSE
Most complete stock of Audio
components in the West
Phone: RYon
1
SANTA MONICA SOUND
GRanite 8 -2834
12.136 Santa Monica Blvd.. West Los Angeles 25, Calif.
CIRCLE 55H
GIBSON GIRL TAPE SPLICERS
splices in
CIRCLE 55E
a
wink!
NO SCISSORS,
NO RAZOR BLADES,
11,666.1.616 66. ends
-Pi
the finest in
///ii
feat1 i'iny gke t07
w
end 6616s ,1616 edges
ice
01,-+
eTrs
820
W.
Olympic Blvd.
A T
L.A. 15, Calif.
Al
7.0211
n OS sal el.d
e.n,d.6l H T
CANADA
CIRCLE 551
-
Complete Linee
Complete Berries
Hl -FI Records
Components
and Accessorise
&LECTRO-UO10E
SOUND
SYSTEMS
WEST. TORONTO,
CANADA.
CIRCLE 55C
FIDELIVOX
RECORDED TAPES
THE
1- O- N- G -E -S -T
HOUR OF
.
.
.
.
so,
made
-3000-20,0000
Horn loading
-
cps
1000 cps cutoff
Dimensions -81/2"
"x41/2"
51/
x
-
Force mass ratio
4 x 107 dynes /gm.
Audiophile
net
$8995
complete with
crossover network
Write for complete information
KELLyff
UHF
reproducer.
AT LEADING HI -FI MUSIC CENTERS
ERCONA CORPORATION
Division)
(Electronic
551 Fifth Ave., Dept.
A -1
New York, N. Y.
CIRCLE 55A
IF YOU ARE
MOVING
Please notify our Circulation Department
at least 5 weeks in advance. The Post
Office 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 Post Office a headache, won't you please cooperate? When
notifying us, please give your old address
and your new address.
Circulation Department
RADIO MAGAZINES, INC.
P. O. Box 629. Mineola, N. Y.
MTI -M PRESTO SPLICER
I
$67
available for magnetic
if acetate Tapes
A heat weld
No Cement
No adhesives
. . . in seconds!
Diagonal cut capable
of
withstanding 3
pound pull
Inaudible with playa
bark amplifier gain at
maximum
.1l pirar
.1lao splices leader to
any base magnetic
tape without edhe-
sires.
Literature and sample
pticc
On
request
SOOTHING
CATHEDRAL ORGAN BACKGROUND MUSIC
Free Details
Moderate Cost
Mail Order
ELECTROSONIC,
.
SPECIFICATIONS
Frequency response
new line of pre -recorded tape
devoted entirely to
two channel stereo -binaural
write for free catalog
STEREOTAPE
High Fidelity Equipment
AUDIO
.
in England!
node
5607 melrose ave., hollywood, cal.
DUNDAS ST.
that's on the record
for music's sake, add a KELLY
EVERYTHING
`
demonstration test tape $2.00 p.p.
CIRCLE 55F
141
Yet, you can play a recording from
end to end and you can't hear ALL the
music unless your hi -fi equipment
includes a KELLY Ribbon "tweeter ".
Then, you can be sure that you've heard
STEREOTAPE
a
O N
I
disappointing.
}I/
CIRCLE 551
SOUND
C O R P O R
R
r+.
ROBINS INDUSTRIES CORP.
HIGH FIDELITY COMPONENTS
r':
FINEST
TAPE RECORDER
ncoaus
-8171
Fair Oaks, Pasadena 1, Calif.
S.
-it
I
I
7460 Melrose Ave- Los Angeles 46,Calif WEbster 3-8208
536
It is one thing to hear a few
bars of a sonata
whets the
appetite of the connoisseur and
gives him a foretaste of future
enjoyment. But to hear half of a
complete symphony is more than
nom...
.
ugly se
part...what?
.
CINEMA ENGINEERING
[
,,,JJ,,,
a
.9,1.4441/11
Noise & program erasure. Use the best.
Cinema's Bulk -Tank Type Degausser 9205.
Economically priced. Buy yours today.
part
Nalei
.90icia
7230 Clinton. Upper Darby 3. Pa
CIRCLE 55K
JANUARY, 1956
PRESTOSEAL
3727 33rd st.. Long Island City
MFG
CORP.
1,
N.Y.
CIRCLE 55B
55
www.americanradiohistory.com
AmericanRadioHistory.Com
NOW ULTIMATE
PERFECTION
IN TONE ARM PERFORMANCE
Ortho-sonic v/4
TRACKS
COURSE OF ORIGINAL
RECORDING STYLUS
0/1//1956
ADVERTISING
INDEX
the biggest
I
...
EDITION
-
most authoritative
ELECTRONIC
BUYING GUIDE
VITAL ENGINEERING
PRINCIPLE SOLVED!
REPRODUCTION
FLAWLESS
attained.
Stylus moves in straight line from edge to
center as in original recording.
record life
fits smallest cabinet .
.
plays all
size records . . . no scratching possible
INSPIRED
...
DESIGN:
Increases
all popular cartridges fit.
history of Hi -Fi development
introduction of o
single component created such wide interest, laboratory and editorial endorsement.
Get ORTHO -SONIC V, 4 with its 10 incomparable features which eclipse conventional
tone arms.
ONLY $44.50
Never before
in the
has the
At Better Hi -Fi Dealers Everywhere
WRITE FOR ILLUSTRATED LITERATURE
ORTHO-SONIC INSTRUMENTS, Inc.
66
B
Mechanic Street, New Rochelle, N. Y.
CIRCLE
free!
56A
ALLIED'S
SPECIAL 100 -PAGE
HI -FI CATALOG
Acoustic Research, Inc.
Allied Radio Corporation
American Elite, Inc.
A M I Incorporated
Audak Co.
Audiogersh Corporation
51
56
52
Cover 2
43
45
Bard Record Company. Inc.
Bell Telephone Laboratories
56
Berlant Concertone
Bogen, David Company, Inc.
Bozak, R. T. Sales Co.
British Industries Corporation
6
12
3
his leading 100 -page book shows you how
Hi -Fi music system at lowest
post. 'Fells you what to look for in each
nit; shows many handsome, practical inItallation ideas. Offers you the world's
argent selection of complete systems and
nrlividual units from which to make your
noney -saving choice. To understand HiPi, to own the best for less, you'll want
his invaluable catalog. It's FREE -write
o select. a
or your copy tod:1v.
ALLIED RADIO
etzi,
ioa44401144
ALLIED RADIO CORP., Dept. LL -16
100 N. We
Ave., Chicago 00, III.
Send
FREE High Fidelity Catalog
Name
Address
City
I
Lees
Zone
SSI
saasA
State
wide MASTER catalog. Compare
specs and prices first
then
buy and save. t
55
54
53
52
Inc.
Electrosonic
Electro Voice, Inc.
Electro -Voice Sound Systems
Ercona Corporation
0V1ae
0r
55
48, 55
35
Goodman Industries, Ltd.
49
44
Harman-Kardon, Inc.
Harvey Radio Co., Inc.
Heath Co.
High -Fidelity House
Hollywood Electronics
Hudson Radio and Television Corp.
Hycor Co., Inc.
27
39
29
1456 pa ges
es
100,000 items
Complete descriptions
11,000 illus.
8 c 11 ", 6 lbs.
Specifications -Prices
tratIOns
350 mfrs.
Ls! rT
50
l:n
as
At
$295
o, pets
eme.emo+
L/ytt
UNITED CATALOG PUBLISHERS, INC.
110
St., Now York 13
CIRCLE
56C
55
55
34
2
MARCH OF DIMES
55
Kingdom Products, Ltd.
8
Lansing, James B., Sound, Inc.
Leonard Radio, Inc.
56
Marantz Company
McIntosh Laboratory, Inc.
Mullard Overseas Ltd
50
Pickering & Company, Inc.
Pilot Radio Corp.
Presto Recording Corporation
Prestoseal Mfg. Corp.
Professional Directory
II
31
41
9
25
5
55
55
Racon Electric Co., Inc.
Radio Engineering Laboratories, Inc.
Rauland -Borg Corporation
47
32
43
Cover
FIGHT
INFANTILE
PARALYSIS
3
Robins Industries Corp.
55
Santa Monica Sound
Scott, H. H., Inc.
55
Shure Brothers, Inc.
Stephens Manufacturing Corp.
Stereotape
'
Or
00-11
S,aE
Cover 4
Fairchild Recording Equipment Co.
Fenton Company
Rek -O -Kut Company
,C
46
55
Kierulff Sound Corporation
Your guide
to an easy
understanding
of Hi -Fi -plus the
world's largest
selection of
Hi -Fi systems
and components
-
23
Duotone Co., Inc.
Laboratories,
tions and prices.
DOLLAR -WISE PURCHASING
Over 100,000 items
350
manufacturers in this industry-
33
facing p. 1, 47
Cabinart
Cinema Engineering Co.
Classified Ads
Collaro Record Changers
Electro -Sonic
OFFICIAL REFERENCE SOURCE
Electronic supplies for research and industry. Not just
listings -but complete descrip- t.
tions, specifications, illustra-
7
I
36
55
Tech -Master Corporation
Tung Sol Electric, Inc.
37
United Catalog Publishers, Inc.
56
Volpar
56
4
...
CIRCLE 56B
JANUARY 3-31
AUDIO
56
www.americanradiohistory.com
AmericanRadioHistory.Com
JANUARY, 1956
... the
long awaited compá
to the famous
e TURNTABLES
0/ea/life`
the
Neu'
REK -O -KUT TURNTABLE ARM
Among users of fine audio equipment, the name Rek -O -Kut
is synonymous with the finest ...and the simple
announcement of a new Rek -O -Kitt development
carries the assurance of a superior product.
A reputation such as this is not easily come by. It remains a constant challenge and must be closely guarded.
No Rek -O-Kut product is therefore committed to market
unless and until it has first been exhaustively tested and
re- tested in the lab and in the field.
-
The new Rek -O-Kuc Turntable Arm is presented with
just that confidence that by its inherent design and
demonstrated performance, it will contribute immeasureably to the quality of record reproduction.
-
The Model 120 is designed for all records up to 12
inches in diameter, and the 160 for records up to 16
model
120 - $2695
inches. Interchangeable plug -in heads accommodate stand-
ard cartridges and both arms provide means for precise
adjustment of stylus pressure.
Regardless of the turntable you own, the addition of
arm will bring a welcome improvement in
performance this because of better tracking, superior
damping and resultant lower distortion and record wear.
For those who seek the very ultimate, we earnestly recommend that they consider both
Rondine Turntable and
a companion Rek -O -Kut Arm. We will gladly provide
a Rek -O -Kut
-
-a
descriptive literature to aid in the making of a selection.
model
160 -
52995
See your hi-ft dealer or write to Dept. QA -1
R
EK
-O
-KUT COMPANY
38-01 Queens Blvd., L.I. C. 1, N.Y.
Makers of Fine Recording and Playback Equipment
Engineered for the Studio Designed for the Ilome
IN CANADA: Atlas Radio Corp. 50 Wingoid Avenue. Toronto 10. Ontario
EXPORT: Morftan Exporting Corp.. 458 Broadway. New York 13.
N. V.
www.americanradiohistory.com
AmericanRadioHistory.Com
Partial view of COP installation at modern
Lincoln Fields Race Track, located
just south of Chicago at Crete, Illinois
OFF AXIS and ON AXIS
Coverage is Clear, Penetrating, Uniform
Electro -Voice CDP Public Address Loudspeaker System was chosen for the 8,248 seat
North Side Gym, Elkhart, Indiana, one cf the
nation's largest high school gyms. Cluster of
stacked CDP's can be seen in photo taken
during construction.
Model 848 CDP. 25 watts. 16 ohns. Conservatively rated ±5 db from 175 to 10,000 cps. Crossover at 1000 cps. Variable polar patterns. Size:
10''/ in. wide, 20''% in. high, 20 in. deep over -all.
List Price: $69.50 Net Price: $41.70
D
COMPOUND
DIFFRACTION
PROJECTOR*
Outdoors or indoors, everyone can comfortably hear everything when
you use the CDP. Listeners off the axis, where the majority of audiences
are, do not have to strain to hear, while those on the axis are not
assaulted by blasts of sound. The CDP provides smooth peak -free widerange response, with 120° sound distribution at all frequencies up to
10,000 cps. Unit energy is far more efficient- there's no wasted power.
You can do a better job with fewer units at less coat. CDP utilizes two
coaxially mounted diffraction horns, working from both sides of a single
diaphragm, plus optical slit diffraction for smooth sound dispersion.
CDP delivers 2Y octaves more musical range than comparative units.
Molded of glass fibers, CDP is weather -proof, blast- proof, splash- proof.
Compare the CDP with any other unit in the environment in which it
actually will be used -in the field or in an auditorium. Prove to yourself
why it is so superior, why it is the best value ever!
Vat.
0109.001 and Pat. Pend.
NO FINER CHOICE THAN
Send for CDP Public
Address Handbook
Bulletin No. 195.
Gives complete and
helpful information.
ELECTRO- VOICE, INC.
Export:
www.americanradiohistory.com
AmericanRadioHistory.Com
13
BUCHANAN, MICHIGAN
East 40th St., New York 16, U.S.A. Cables: Arlab
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