stereo an book - American Radio History

stereo an book - American Radio History
MACO
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AN BOOK
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For complete technical details write Dept.
SH-P
The COLUMBIA
RECORD CLUB now offers
ANY6 STEREO RECORDS
GRANO CANYON
JOHNNY MATHIS
98
,$
Retail Value
only
up to 535.88
-
if
you join the Club now
and agree to purchase
as few as 5 selections from the more than 100 to
be made available during the coming 12 months
*to purchase
If you now own new stereo phonograph, or plan
one in the future - here's an opportunity
to receive SIX new stereo records - retail value up
to $35.88 - ALL SIX for $5.98
You enroll in either one of the Club's two stereo
*Divisions:
Classical or Popular - whichever one best
a
NUM.
1. Night and Day,
plus 11 more hits
15. Broadway's
newest smash hit
A OeCH..
ONases
2. A beloved
American classic
8. What'll
I
Do,
Warm, 10 more
MY FAIR LAOY
IN STEREO
MARCHE SLAY
CAPRICCIO ITALIEN
NIGHT ON
MITAOrOULOS
PHILHARMONIC
7. Three brilliant
hi-fi showpieces
-
5. 16 favorites
50. Where or When, 6. Complete score
Sweet Violets, etc. Manhattan, 10 more of this hit musical
ID MIFF aM adrai
'S MARVELOUS
I
LISTENING IN
AN IA7NOO(XTION
BEETHOVEN:
PASTORALE
SYNPMIN
BRUNO WALTER
ca_a
MOWN
MI
11. Berlioz' most
popular work
0. Be My Love,
24. 16 classical
Where or When, etc. and pop selections
NORMAN LOBOFF
I
ep ,
CHOIR
TIIE LAMP
STURM,
is LOW
MUSIC
MV IfaVa1IIE
9 mors,
37. Lovely "musical 9. No Other Love,
portrait of nature" Our Love, 10 more
WI
PATHETIOUE
SYMPHONY
NAltrapaulos,
New York
"must" for
any record library
MANALIA TARRSON
AT ENE 11151
NEWPORT
A
3. Didn't It Rain,
God Is Real, etc.
IOW N1I11113SELS
21. Four dashing,
fiery rhapsodies
22. Organist Cole
plays 11 hit tunes
ITALIAN SYMPHONY
LONCON SYMPHONY
(';
Ore..
MENDELSSOHN:
HAYDN:
Bernstein
AEI 'OM
l+nE'
I
TREMOR SUITE
TCE.10,
OSItY
ROMEO AND IULMT
r
NEW TOR(
PHILHARMONIC
gay symphonies
Ca,,o,
ENTREMONT,La.
La
Paloma, 11 more
IO
PUS
49. That's All Over,
One More Ride, etc.
records must be played
a stereo record player
COLUMBIA ® RECORD CLUB, Dept. 504-1
Stereo Section, Terre Haute, Ind.
I accept your offer and have circled at the right the
numbers of the six records I wish to receive for $5.08,
plus small mailing charge. Enroll me in the following
Division of the Club:
(check owe box only)
Stereo Classical
Stereo Popular
I agree to purchase five selections from the more than
100 to be offered during the coming 12 months, at
regular list price plus small mailing charge. Por
every two additional selections I accept, I am_ to receive a 12" Columbia or Epic stereo Bonus record of
(Please Print)
Address
ZONE.
,
.. State
9. Always, Please,
Speak Low, 9 more
1
21
2
22
3
24
25
27
29
30
5
6
7
8
9
11
membership plan
Dealer's
33. 11 beautiful,
immortal melodies
1
CIRCLE 6
NUMBERS:
10
CANADA: address 11-13 Soho Street, Toronto 213
you wish to have this membership credited to an
established Columbia or Epic record dealer, authorized to accept subscriptions, fill in below:
Iv" Orame,
Terre Haute
Indiana
NOTE:Stereo
only on
if
N
25. Two very pop-
Plat
27. Granada,
ALASKA and HAWAII: write for special
IN PINMCHI ,
OoNIn
uar piano works
40. "Hallelujah",
"Finlandia", etc.
Record
Club
EMI
B WTFL NE ONE
CHOIR
City
Romantic Yu,IC of
NAN
PHILIPPE
4,,-
NV TN MI MI6 II
TABERNACLE
PHILADELPHIA ARCH.
TCHAIKO V SKY
RACHMANINOFF:
Columbia
Name
16. Two colorful,
exciting scores
KOSTELANETZ
GRIEG
Theme a,
29. High-spirited,
The
-
.
12. Let's Dance,
Jubilee, 7 more
*
my choice FREE.
LEONARO BERNSTEIN
PNIHIRMOXiC
Faro
MORMON
PEDALS AND
»OOIT COLI.
*
EMI
PIPES,
FESTWAL
...
BELOVED
CHORUSES
Tchaikovsky
Philharmonie
30.
*
DEPTH *
TO COU MBIA
STEREOPHONIC SOUND
31. Solitude, Autumn Leaves, etc.
*
*
BALD MOUNTAIN
NEW TONI
suits your musical taste
Each month the Club's staff of music experts
selects outstanding recordings that deserve a place
in your new stereo record library. These selections
are described in the Club's entertaining Music
Magazine, which you receive free each month
You may accept the selection for your Division,
take any of the other records in both Divisions, or
take NO record in any particular month
Your only obligation as a member is to purchase
five selections from the more than 100 Columbia
and Epic records to be offered in the coming 12
months
and you may discontinue membership
any time thereafter
After purchasing only five records you receive
a Columbia or Epic stereo Bonus record of your
choice free for every two additional selections you
buy from the Club
The records you want are mailed and billed at
the regular list price of $4.98 (Classical Selections,
$5.98), plus a small mailing charge
Mail coupon below to receive your 6 records
NORM
Dealer's Address
aca...v. p...yr... 9 v.,...
12
15
16
31
33
37
40
49
50
19
... w,wr ..a..1*. ...r..
302
,era
F-B5i
HI-FI
STEREO
HANDBOOK
by
Edward A. Campbell
publishers: Jerry Mason, Fred R. Sammus
business manager: George H. Levy
editor in chief: Haskel Frankel
editor: Arthur Whitman
managing editor: Robert Angus
copy editor: Elizabeth Huling
associate editors: llene Dorn, Doris Mullane,
Pat Hagan Murray
editorial assistant: Edwina Glen
executive art director: Anthony LaRotonda
art director: Robert Thornton
production: for Allied Graphic Arts --Arthur Gubernick,
Lisabeth Joyce
sales promotion director: Arthur Levy
advertising representatives: The Benjamin Company
600 Fifth Avenue, New York, New York
MACO Magazine Corporation
Lexington Avenue, New York 22, N.Y.
Entire contents of this book
copyright © 1969 by Maco Magazine Corporation.
All rights reserved under
International and Pan-American
copyright conventions
675
STEREO
1
2
3
4
5
6
page 12
Where it came from, what it is, what it means to you
HIFI
page 18
IN FOCUS
Hi-fi precepts apply to both mono and stereo systems
AMPS AND PREAMPS
page 38
RECORD PLAYERS
Records and players are the basis of stereo listening
TAPE RECORDERS
page 52
Buy tapes? Make your own? It's up to you
TUNERS
page 64
Hi-fi makes your stereo pleasure unlimited
LOUDSPEAKERS
1
8
9
10
11
12
page 30
Inputs meet outputs-you have the heart of your system
page 14
This is the pay-off end of your stereo system
CONTROLS
page 88
Special units can make the owner's life easier
page 96
STEREO KITS
A
screwdriver and a soldering iron bring fun and profit
WHERE YOU START
page 102
This will be determined by your present equipment
INSTALLATIONS
page 110
Stereo components can work well with your decor
BUYING STEREO
A
page 120
bargain can cost you; a lot can buy a tot
GLOSSARY
page 4
A SHORT GLOSSARY OF HI-FI TERMS
AES-Audio Engineering Society. At one
time, the letters AES were used to designate the disc -reproduction equalization recommended as a standard by that society.
AMPLIFIER-An electronic device whose output is an enlarged reproduction of its input.
(See Audio Frequency, Preamplifier, Power
Amplifier, RF Amplifier.)
ATTENUATOR-A device, usually resistive,
that reduces the strength of the signal a
desired amount, preferably without distortion; it is sometimes called a "pad." L -pads,
H-pads and T-pads are attenuators with
different wiring arrangements.
AUDIO FREQUENCY (AF)-A frequency corresponding to an audible sound wave. Although the extremes vary widely, the range
of audible frequencies for people with normal hearing is generally taken to be 1515,000 cycles. An Audio (AF) amplifier is
designed to handle this frequency range.
The amplifier's capabilities may, of course,
extend beyond the audible range.
BAFFLE-A flat surface, box or horn used
with a loudspeaker to increase the effective
length of the air path from the front of the
speaker to the back, reducing the cancellation that could result from the interaction
between the out -of-phase sound waves emanating from those two areas. The baffle is
necessary to prevent cancellation at low
(bass) frequencies. An unbafiied speaker
has extremely poor bass response.
BASS (frequencies)-Low audio frequencies,
generally considered to be below 300 cycles.
It is interesting to note that Middle C on
the piano (262) is therefore considered a
"bass" note by audiophiles.
BINAURAL-Having two ears, or the effect
of hearing with two ears. Rather ineptly
used as a name for two -channel sound, it
now can be considered synonymous with
stereo, although it once implied listening
with earphones.
4
CROSSOVER
NETWORK-An electrical filter
to separate different bands of audio frequencies (as, for instance, bass and treble)
to feed a multispeaker system. Crossover
frequency or crossover point is the point
in the audio spectrum at which the network
divides the bands.
DAMPING-In the audio context, a shutting
off of vibrations. Both pickups and speakers
are damped to prevent extraneous electrical
signals and sounds. The output from an
amplifier should control the speaker, and
some amps provide variable damping, which
allows slightly more precise direction of
speaker vibrations.
DECIBEL (DB)-One-tenth of a bel, the unit
for logarithmic expression of ratios of
power, voltage or loudness, named after
Alexander Graham Bell. While DB expresses a ratio, it may imply an actual level
if the reference level is zero.
DISTORTION-Alteration in the form of a
signal (audio, for example) either by disproportionate amplitude changes or by the
addition of frequencies ( usually harmonics
of the desired frequency) which were not
present in the original signal. (See Flutter,
Harmonic Distortion, Hum, Hangover Effect, Intermodulation Distortion, Rumble
and Wow.)
ENCLOSURE --A loudspeaker mounting that
prevents the rear waves of the speaker from
interfering with the front waves. Most
good enclosures act to reinforce the bass
response of the speaker.
FEEDBACK-Essentially a graphic expression, exactly describing an existing phenomenon. Acoustical feedback occurs when
the vibrations from the speaker cone influence the action of record player or
amplifier. Electrical feedback is a circuit
in the amplifier that takes impulses from a
later stage and feeds them back into an
continued
'TRIMENSIONAL' TMS-2
-\_%j
-e
Components: C-12MC dual voice
coil woofer, two 8" mid -range speakers, two wide-angle
tweeters, two networks with "presence" and "brilliance" controls.
Dimensions: 30" wide, 25" high, 121/2" deep.
User net: mahogany $258. blond or walnut $263.00.
_",
"i=--_
,,,_-_
iiR `.__=-
Early American style, frnitwood-$279.00
`
-
e
CHANNEL
B
sgamed Store
were
New developments have proved
that a single cabinet integrated
speaker system can provide
stereo sound equalling or
surpassing the performance of
two separate units. Up to now,
however, to achieve sufficient
separation, such integrated
systems have had to be large
and often expensive.
Now, University, employing
a new principle of obtaining
stereo separation, presents the
TMS-2
containing two
complete multi -speaker systems
in one handsome enclosure
only 30" wide.
The "Trimensional" TMS-2
projects frequencies of both
channels to the rear and side
walls of your room. Thus, one
large wall area becomes channel
"A", another becomes channel
"B" ... exactly as if you had a
series of widely distributed
speakers for each channel. This
results in a new standard of
stereo performance
excellent
separation, real depth and
broad sound distribution.
-
in the room
IMPORTANT ADVANTAGES OF TMS-2 'TRIMENSIONAL' STEREO
3
_CI_
fl.
trols, and adjustable doors allow you to place the
compact TMS-2 virtually anywhere along a wall, or in a corner,
irrespective of existing furniture
or furnishings.
TMS-2 STEREO
4
Stereo spread
can be con-
.,
y
;,
trolled easily by the adjustable doors
according
to program material and personal
preference (e.g., wider spread for
full orchestral works, less spread
for small groups).
-
...
...
Full complement of con-
CONVENTIONAL STEREO
iSmooth, full-bodied, balanced
stereo sound throughout the
room (rather than the 'two point
source' effect with critical listening area of conventional systems) .
A 'Hole -in -the -middle' effect
A. eliminated by central position
of the dual voice coil woofer
together with the unique wall
reflection system.
Hear the TMS-2 at your dealer ..
now. But don't be fooled by its small
size. Close your eyes and let your
ears judge the quality of its musical
and stereo performance.
For the complete story, write to
Desk W-5, University Loudspeakers,
Inc., White Plains. N. Y.
GLOSSARY
FIGHT
CANCER
WITH A
CHECKUP
ANDA
AMERICAN CANCER SOCIETY
WRITE FOR
YOUR FREE COPY
OF THE NEW
H. H. SCOTT STEREO
111
.../
H. H. Scott Inc.
Powdermill Road
Maynard, Mass.
Dept. SH
Please rush me a free copy of your
new Hi Fi Guide featuring the full
line of new Stereo Components.
Name
Address
City
7one
sound system can reproduce.
measure of
an audio system's ability to reproduce all
frequencies within a given range with
equal efficiency. Rather than "equal efficiency," frequency response (or sometimes,
just "response") over the given range is
usually stated as falling within certain limits of deviation. Example : plus or minus
2 DB, 50-12,000 cycles.
GAIN-The degree of input -signal magnification achieved in each stage of amplifier.
HANGOVER EFFECT-The tendency of the
FREQUENCY RESPONSE-The
CHECK
HI FI GUIDE
earlier stage. Negative feedback decreases
power and corrects distortion. Positive
feedback increases power and distortion.
FLUTTER-Flutter is the very short, rapid
variations in the speed of movement of tape
or disc which show up as fluctuations in the
pitch of the reproduced sound.
FREQUENCY RANGE-The range between
the highest and lowest frequencies that a
State
loudspeaker to continue to vibrate at bass
frequencies after the exciting frequency
has been cut off. The effect is a "mushy"
sound in the bass register. Corrected by
proper damping, by either electronic or
acoustic means, or a combination of the
two. A speaker can be over -damped ; the
ideal situation is called "critical damping."
HARMONIC DISTORTION-The occurrence in
the output of an audio system of a harmonic (or harmonics) of an input frequency. A harmonic is an integral multiple
of the fundamental frequency, as 32, 64,
128, 256, and so forth.
HUM-Low-frequency noise or distortion in
an audio system, usually from the unwanted pickup of the power-line frequency (60
or 120 cycles) .
IMPEDANCE-The total opposition in a circuit to the flow of alternating current. It
varies with the frequency. This term, as
used in audio work, usually implies the
continued
6
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EVERYTHING FOR STEREO
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CITY
ZONE
STATE
GLOSSARY
"characteristic impedance" (the impedance
at a given frequency). Loudspeaker impedance is computed at 400 cycles. For
most efficient power transfer between circuits, impedances should be "matched."
INTERMODULATION
DISTORTION-The oc-
currence in the output of an audio system
of frequencies equal to the sums and differences of harmonics of the component frequencies in the input. Such frequencies
are also called "beat frequency products."
For example, the two frequencies 500 and
2,000 cycles could produce a sum of 2,500
cycles and a difference of 1,500 cycles.
LOADING-A way of increasing the sound
from a loudspeaker by coupling the sound producing source more efficiently to the air.
Front -loading couples by means of the
waves from the front of the speaker (in
practice, the Klipsch design) ; rear -loading
couples by means of the waves from the
rear of the speaker.
LOUDNESS CONTROL-A volume control
that automatically compensates for the response characteristics of the ear.
LOUDSPEAKER-A device
that transforms
electrical impulses into sound waves.
MAGNETIC PICKUP-A phonograph pickup
(cartridge) in which movement of the
needle moves a coil or coils in the field of a
magnet to vary the amount of flux in step
with an audio-frequency signal. Characterized by low impedance and low-level output.
NARTB-National Association of Radio and
Television Broadcasters. Like AES and
RIAA, the initials NARTB often imply a
standard recording and reproducing characteristic recommended by this association.
PEAK-(A) The maximum instantaneous
value of a varying voltage or current. (B)
An unusual or disproportionate deviation
in the frequency response of an audio device that is otherwise linear or uniform.
PHASE-In acoustics, a part of the sound
wave-increasing compression or rarefac8
tion. Two sound sources are in phase when
they are both compressing the air at the
same time; they are said to be out of phase
when one is compressing and one rarefying.
Since the sound wave of each frequency has
a different length, spatial considerations
strongly influence phase relations.
PICKUP-A device that translates into
electrical energy the physical motions of a
stylus tracking the waving grooves of a
turning phonograph record. Magnetic and
dynamic pickups have a constant -velocity
response, piezoelectric and capacitance
pickups a constant -amplitude response. (See
Magnetic Pickup, Piezoelectric Pickup.)
PIEZOELECTRIC PICKUP-An organic or
synthetic (usually ceramic) crystal used
in a phono cartridge. This type of crystal
has the property of producing a voltage
when twisted mechanically (as by a needle)
or of producing mechanical force when
actuated by a voltage. Characterized by a
higher impedance and output than that of a
magnetic cartridge.
POWER AMPLIFIER-An amplifier designed
to deliver power (see Preamplifier, below).
In audio, the power amplifier provides the
energy to activate the loudspeaker.
POWER OUTPUT-The output in watts delivered to the load ; in audio, the power
delivered to the speaker. This is electrical
power. The power output of a speaker is
acoustical power, and its relation to
power delivered to it is determined by the
efficiency of the speaker.
PREAMPLIFIER-In the strict technical
sense, merely a voltage -amplification stage
or device. In hi-fi, the term has come to
imply a unit that incorporates various
equalization and audio control circuits.
RF AMPLIFIER-An amplifier designed to
handle a specific band of frequencies in the
radio spectrum; generally considered to
extend from 10 KC to 30,000 MC.
continued
Stereo Preamplifier HF85
9,7
"The overall design of the HF -81 is conservative, -*nest and
functional. It is a good value considered Furely on its own merits,
and a better one when its price is considered as roll."
Hirsch -Houck Labs (HIGH FIDELITY Magazine)
70W Stereo Power
28W Stereo Power
Amplifier HF87
Amplifier HF86
-
Advanced engireering
Finest quality components
"Beginner -Tested." easy step-by-step instructions
LIFETIME service & calibration guarantee at nominal cost
IN STOCK
_cmpare, then take home any EICO equipment
-right "off ti -e shelf'-from 1500 neighborhood EICO dealers.
-
FM Tuner HFT90
AM Tuner HFT94
cocus
LEVEL
ASS
'~,
TREBLE
Stereo Amplifier -Preamplifier HF81
Amplifier -Preamplifier
"Excellent"
SATURDAY REVIEW; HI-FI MUSIC AT HOME.
"Outstanding quality
extremely versatile."
HF81 Stereo
-
-Kit ELECTRONICS
.
WORLD LAB -TESTED.
$69.95. Wired $109.95. Includes cover.
HF85 Stereo Preamplifier
"Extreme flexibility
.
.
.
a
Kit $39.95. Wired $64.95.
bargain."
-
HI -Fl REVIEW.
Includes cover.
New HF87 70 -Watt Stereo Power Amplifier
Kit $74.95. Wired $114.95.
HF86 28W Stereo Power Amplifier
Kit $43.95. Wired $74.95.
FM Tuner HFT90
"One of the best buvs in high fidelity kits."
CRAFT. Kit $39.95'. Wired $65.95°. Cover $3.95.
'Less cover, F.E.T. incl.
New AM Tuner HFT94
Kit $39.95. Wired $69.95. Incl. cover & F.E.T.
New AF -4 Stereo Integrated Amplifier
Kit $38.95. Wired $64.95.
HF12 Mono Integrated Amplifier
"Packs a wallop."
POPULAR ELECTRONICS
Kit $34.95. Wired $57.95. Includes cover.
New HFS3 3-Way Speaker System Semi-Kit
In unfinished birch $72.50; walnut, mahogany or teak $87.95.
New HFS5 2 -Way Speaker System Semi -Kit
In unfinished birch $47.50; walnut, mahogany or teak $59.50.
HFS1 Bookshelf Speaker System $39.95.
LGS-1 Brass Tip Matching 14" Legs easily convert HFS-1
into attractive consolette. All brackets & hardware provided. $3.95.
-
-
Stereo Integrated Amplifier AF4
_
12W Mono Integrated
Amplifier HF12
Other Mono Integrated Amplifiers:
50, 30, & 20W (use 2 for stereo)
2
-Way Bookshelf
Speaker System HFS1
Speaker
System HFS5
2 -Way
Speaker
System HFS3
3 -Way
Add 5% in the West.
BEYOND
COMPARE
GLOSSARY
RESONANCE-The natural period of vibration of a physical body. Some familiar physical bodies that have a natural resonance
console
maraniz
Consumer Net
Cabinet
$249
24
Slightly higher in West
In pre -amplifiers and power amplifiers,
Marantz has set today's highest standard
of quality.
Consider the Marantz Stereo Console. Here is
the essence of uncomplicated, beautiful styling.
So simple to use, even the most non -technical
person can easily achieve matchless
reproduction quality. Yet, this fine instrument
offers an order of versatility that pleases
the most discriminating professional users.
Carefully planned circuitry and wiring layout
result in unsurpassed freedom from distortion,
hum and noise.
Dedication to quality in every detall is the
reason why the Marantz 30 -watt power
amplifier, too, is in a class by itself. The
Marantz circuit permits this superb amplifier
to recover instantaneously from sharp, musical
transients-to effortlessly drive loudspeakers
of all types-to consistently outperform
amplifiers of considerably higher ratings.
For both stereophonic and monophonic
programs, Marantz is your assurance of
long, carefree operation and unprecedented
performance.
30 -WATT AMPLIFIER
Consumer Net $147
7.50
Cover Grill
Slightly higher In West
mmorbwanit
C
O
M
P
A
N
Y
25-14 BROADWAY, LONG ISLAND CITY 6, N. Y.
10
point are tone arms, loudspeakers, piano
strings. Often a resonance can cause an
undesired peak in the response of a device.
RESPONSE-The measurement of how a
phonograph (or any of its parts) reproduces sound. The response curve measures
the reproduction at all frequencies. A fiat
response indicates that it handles all frequencies alike, as it should.
REVERBERATION-Reflection or ricochet of
sound waves. A smooth (i.e., regular) surface reflects more than a rough (irregular)
surface. Regular surfaces are smooth plaster walls or ceilings ; irregular surfaces
include such things as heavy -pile carpets
and velvet drapes.
RIAA-Record Industry Association of
America, the association of phonograph
record manufacturers or producers. The
initials also refer to the standard recording and reproducing characteristic sponsored by that group. Since 1954, this has
been the accepted standard of the American industry. Since the move toward uniformity became widespread, it has been
possible to simplify record compensators
(as well as the playing of records). Although slightly different in some details
from previously accepted standards, the
RIAA characteristic includes the treble and
bass pre -emphasis which has become more
or less routine. When "de-emphasized" in
playback, it results in reduction of the apparent level of surface noise (treble) and
turntable rumble (bass).
RUMBLE-An undesirable low -frequency
noise component in sound reproduced from
records, caused by motor vibrations transmitted to the turntable. Rumble is primarily a vertical force or vibration, and could
be greatly reduced by pickups designed to
have no vertical compliance. Stereo discs,
TOP RATED
SHURE
however, are recorded with a vertical component and require pickups with vertical
compliance. Besides bass pre -emphasis
(see RIAA), better motor design and
mounting can keep rumble to a minimum.
STEREOPHONIC SOUND-This is a method
of sound reproduction (commonly called
"stereo") that uses two separate channels
from the broadcasting studio or recording
to the listener's ears. Ideally the original
sound pickup devices and the ultimate
sound reproducers (the loudspeakers) are
somewhat separated from each other in
space, so that the two sound channels are
not identical. (Also see Binaural.)
STYLUS TIP-That part of a phonograph
needle or stylus which actually engages the
grooves of the record. Since the groove is
approximately two to three thousandths of
an inch deep, the tip need not be any longer
than that. That part of the needle which
engages the cartridge (and to which the
tip is attached) is called the "shank."
SURFACE NOISE-Sounds created by imperfections or dust on the surface of a record.
TIP RADIUS-The radius of curvature of
the stylus tip, as seen in cross section
through the vertical plane.
TONE ARM-Properly, the pickup arm. This
holds the pickup over the record.
TRACKING ERROR-The difference between
the arc made by a pivoting arm over a record and the straight line of the bar that
held the cutting stylus.
TRACKING WEIGHT-The effective downward pressure of stylus on record groove.
TRANSIENT RESPONSE-The ability of a
phonograph to react instantly to the start
or the end of a recorded sound.
TWEETER-A loudspeaker designed to create high -frequency sounds only.
WOOFER-A loudspeaker designed to create
low -frequency sounds only.
WOW-Distorted sound due to speed variations of record turntable or tape reel.
M7D
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With your purchase of the above, you will
receive the Shure M7D magnetic stereo
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FO
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4
}1
TWO STREAMS OF SOUND, SLIGHTLY SEPARATED.
FLOW INTO YOUR LIVING ROOM
.
THE EAR AND
BRAIN FUSE THEM INTO A SINGLE WAVE OF RICH
MUSICAL EXCITEMENT
WITH ONE FLICK OF A
KNOB, A SYMPHONY ORCHESTRA
RIGHT INTO YOUR HOME
12
THIS IS
IS
BROUGHT
STEREO
CHAPTER 1
In Cole Porter's 1955 musical, Silk Stockings, Gretchen Wyler told the film
industry something they already knew: "Ya gotta have glorious Technicolor,
breath -taking Cinemascope and Stereophonic Sound !" A casual glance at
any hi-fi journal today will convince you she was right, and not just for the
movie industry. Today, you gotta have stereophonic sound!
So what is stereo and how do you get it? And does its arrival in your
home mean the end of your trusty Atwater Kent and your treasured original
recordings of Caruso and the Mound City Blue Blowers? These are fairly
big questions. To start getting at the answers, it may be wise to honor
custom and go back to the word the Greeks had for it.
To the Greeks, stereos meant solid. Our present concept of the word,
however, stems from its misuse in connection with photography. 'Way
13
STEREO
This is a stereopticon
of the type that could be
found in any parlor 50
years or so ago. "Stereo" was
a misnomer here, but
it makes very good sense when
applied to sound systems
back before we were born, people were getting a charge out of a hand-held
depth
3-D kind of viewer known as a stereoscope. This gave an illusion of
which
by means of what we now call a "stereo pair" of photos, each of
was viewed by only one eye. The photos were not identical; they were taken
from slightly different vantage points approximating the distance between
the eyes. The brain fused the two into one picture, with intriguing results.
How does this apply to what we're talking about? Well, we're talking
about binaural, or two -eared, sound. Two sound pick-ups, somewhat separated in space, produce two sound channels which are reproduced separately
and fed to our separated ears from left and right channels. The brain
fuses the two into one sound that has "depth." Some clever person-maybe
in the prerecorded tape business-realized that "stereophonic sound" was
apt to make a greater impression on the public than "binaural sound," and
began substituting the term. "Stereophonic" was shortened to "stereo,"
and here we are. Actually, the substitution was rather fortunate because
"stereophonic" is a much more flexible word than "binaural." We are not
limited to two channels in home sound reproduction, so "stereo" will be
descriptive even when we have more.
Stereo is new, in a way, because it exploded in the hi-fi field late in 1957
with the introduction of compatible stereo discs (we'll discuss what they're
compatible with later). It's also old, in a way, because engineers were
fooling around with it 30 years ago. Even the movie industry's bold sally
into stereo in the 1950's was an idea dredged up from its own past. Walt
Disney's pre -World War II Fantasia had utilized multi-channel recording
and reproduction successfully to provide a startling and enjoyable auditory
experience. So stereo, if you want to split hairs technically, is not new.
But from the standpoint of home-entertainment equipment, stereo was a
laboratory experiment yesterday; today it is a commercial reality.
What's the relationship between stereo and hi-fi? Well, hi-fi might be
defined as sound reproduced by means of certain high -quality equipment
14
with which the two -channel technique may be used. You will also find stereo
reproduction offered in very ordinary equipment, and there seems to be no
agreement on whether or not stereo and hi-fi need to go hand in hand.
Some experts believe that you must have hi-fi equipment for the reproduction of stereo; others feel that stereo adds something, even to mediocre
equipment. If there is no general agreement, even among experts, why do
we have stereo now? Well, ever since the art of audio began, sound engineers
have been concerned with the fact that sound -collection equipment (such
as microphones) and sound -reproduction equipment (such as loudspeakers)
are essentially "monaural" in nature. As you are very likely aware-or can
guess-monaural means one-eared.
The shortcoming, if any, stems from the fact that normal people are
surrounded with sound as they might be surrounded by water if they put
their heads into a full rain barrel, plus the fact of the distance between
their ears. Because the ears are oriented differently in space, the sound
entering each ear is slightly different. It is this neat arrangement that lets
us detect the direction from which a sound comes. It is also claimed-by
extension from the binocular -vision phenomenon, which is supposed to
enable us to perceive depth-that binaural hearing enables us to hear
depth. However, this cannot be the whole of the matter, for when we listen
to an ordinary sound system, the sound comes to us from a single point,
as it might if we were listening through a hole in the wall.
STEREO'S TWO -EARED SOUND
This "point source of sound" theory of monaural sound is somewhat exaggerated because it overlooks room reverberation, which tends to restore the
"surrounded by sound" situation. Also, the use of two or more loudspeakers
with a monaural sound system creates quite a pleasing illusion of depth
and realism-a situation most of those who used them were very proud
of three or four years ago. Whatever the physics of the matter, the conclusion
is inescapable that stereo adds something to even the finest hi-fi system.
It is probably clear by now that while written explanations of stereo may
contain some unprovable and even illogical assertions, the physical fact of
listening to two sound channels proves that it is worth -while. Perhaps the
contradiction only underscores the fact that there is a lot we don't know
yet about human hearing.
Another claim that may prove confusing is that stereo, especially in
hi-fi, captures the true nature of the original sound. As a matter of fact,
the true nature of the original sound-reality, if you will-is not sought
after, nor would it be appreciated if it were achieved. The acoustical volume
of a symphony orchestra, for example, or a full-sized dance band could
never be accommodated in an ordinary living room. This is one obvious
"reality" you could live without. Another facet of the problem is that your
home has different reverberational qualities from those of a concert hall.
15
STEREO
Is this departure from reality a bad thing? Of course not. The bass
emphasis which is characteristic of most jukebox sounds pleases most of
the people who listen to jukeboxes, yet it is most certainly not true to the
tonal balances of the original performance. Nor is the upper -frequency
brilliance so characteristic of many of today's symphonic recordings an
accurate reconstruction of the tonal balances involved, yet musically sophis-
ticated listeners enjoy them.
To put fidelity to original tonal qualities directly into the realm of stereo,
we find that the most striking demonstrations of stereo are those in which
exaggerated spatial effects and relationships are established. That is, you
are aware when listening that the kettle drums are here while the piccolos
are there. But in real life you rarely notice such things at all. As in a
well -prepared sauce, the ingredient sounds of an orchestral passage are
so blended that you don't detect them individually; yet they blend together
to produce a most pleasing whole.
Nevertheless, the exaggeration of spatial effects of stereo reproduction
is fascinating, and you probably will hear much more of it as time goes on.
This is especially true because such obvious devices are almost necessary
to create interesting effects with a very small musical group and to allow
the stereo feeling to get across even in single -unit stereo systems.
The ability to distinguish the physical location (or apparent location)
of different elements in the program material should not be the only virtue
of stereo, even though it provides the most dramatic demonstration of it.
Our two eyes do not tell us merely that the girl is on the left and the boy
on the right, or that a car is about 50 feet away from us. The eyes also
help us distinguish between a sphere and a flat disc; between velvet and
linen, between pink roses and yellow. Similarly, we should get from stereoand do-such information as presence, brilliance and dynamic range.
For stereo reproduction sound is picked up by two microphones, then goes into two channels
on stereo disc or tape. In home music systems, channels of sound are played through separate speakers
TAPE
LEFT
RIGHT
LEFT
MKROPHONE
MICROPHONE
SPEAKER
C-T01
dÓ0
2CHANNEI RECORDER-STEREOPHONK REPRODUCER
16
RIGHT
SPEAKER
Difficulties with stereo? Sure, lots of them, although none seems insurmountable. You probably have heard people fretting about speaker placement, balancing and phasing, about the matching of components, about
troubles with turntable rumble, about a "hole in the middle," about occasional ear-shattering distortion. Many of these difficulties, however, were
due to earlier inexperience in the preparation of equipment or, in some
cases, to the purchase of inferior equipment; to the lack of knowledge in the
use of it; to poor programs on tape or discs. Today you can get-well, that's
precisely why we have prepared this book: to tell you what you can get,
what to do with it, how to enjoy it.
As a sort of preview of what's coming, we have provided below a few
of the many questions being asked about stereo, with references showing
where the answers appear in this book. Though the questions do not cover
the whole subject, they should be a valuable guide as you read on.
FREQUENTLY ASKED QUESTIONS ABOUT STEREO
Can I convert to stereo or must I
and buy all new equipment?
start from scratch
See Chapter 10
Can I buy an all -in -one-piece stereo unit or must I
assemble separate pieces?
See Chapter 2
How far apart must the loudspeakers be?
See Chapter
Must all components, including speakers, be of exactly
the same quality and matched?
See Chapter 12
Will a record changer handle stereo discs or should
I have a transcription turntable?
See Chapter 4
What's the difference between "binaural" and "stereophonic" reproduction?
See Chapter 2
What is the meaning of the terms "wired for stereo"
and "ready for stereo"?
See Chapter 2
How much power do you need for stereo?
See Chapter 3
Must you sit in one spot to hear stereo?
See Chapter 7
What is three-channel stereo?
See Chapter 7
How many additional controls do I need for stereo and
where should I put them?
See Chapter 8
How much does stereo cost?
See Chapter 12
7
Can a single phono cartridge handle all my present
78, LP and 45 monophonic discs as well as the new
stereo discs?
See Chapter 4
17
THE BASIC PRECEPTS OF HI -Fl QUALITY APPLY
TO BOTH MONO AND STEREO SYSTEMS
YOUR
GOAL IS THE COMPLETE RANGE OF RICH SOUND.
BUT THERE IS NO FORMULA THAT ENSURES THE
FIDELITY YOU SEEK
LISTENING THAT PUTS
FINAL PROOF IS IN THE
HI FI IN FOCUS
CHAPTER
2
In the field of home entertainment, the terms hi-fi and stereo do not name
specific pieces of equipment as do words like TV and phonograph. Rather they
represent qualities of such equipment, in the sense that color is a quality of a
photograph. The specific generic term to cover what we are talking about is
sound, or more properly, reproduced sound. Audio (Latin for "I hear") is
often used instead of sound in referring to equipment.
The sources of the sound in home entertainment include radio, the sound
portion of TV, phonograph records, tape recordings and the sound from a
movie projector. These are called program sources. The program material
would be the original sound source : orchestra, solo musician or singer, and
so forth. Edison can be considered the granddaddy of reproduced sound,
having invented, besides the light bulb, the phonograph, movies and the
19
HI-FI IN FOCUS
electronic tube that ultimately made radio possible. So although you could
have fun tracing this science back into antiquity, audio as we know it is a
product of the twentieth century. While the phonograph predates the radio
and enjoyed a tremendous vogue before anybody had a crystal set, it didn't
come into its own from an audio standpoint until the 30's, when electronic
recording was developed and the stage was set for the enormous advances
that were to follow before very long.
THE ADVENT OF LP'S
Probably the most significant single advance was the development of LP
records by Columbia in 1948. This innovation accomplished much : it provided
more music time on discs, nipping an incipient trend toward tape recorders
and it called for lightweight pickups and low tracking pressures, as well as
much -higher-quality phonograph motors (to run steadily at the slower speed),
thereby triggering the production of many new and improved pieces of equipment. Finally, Columbia placed an emphasis, in its publicity on the LP, on
high fidelity: greater dynamic range, wider frequency range, higher quality
than previous 78 -rpm discs. And, of course, all the LP's were of vinyl plastic,
a material that had been used for very few 78's.
Not only did the LP's set off a great expansion of the recorded repertory but
they heightened the public's interest in recorded music. Hi-fi, too, got a push,
but in 1948 its main appeal was to hobbyists. There were two reasons other
than high-quality sound for this. One was that assembling your own system
from individually purchased components could be cheaper than purchasing a
ready-made unit. And very few ready-made units, mostly from makers such
as Capehart and Magnavox, were available. The second reason was that you
could "build -in" the hi-fi system to suit your taste and your space, which
would not only save the cost of a cabinet but avoid the necessity of staring at
a decal of Philippine mahogany superimposed on gum plywood.
So hi-fi began to mean something that you must assemble from components
and build into a storage wall. The term also conveyed overtones of hobbyists,
audio bugs and odd -balls. I suppose if this development had come a few years
later, it would have turned up as one of the activities Viceroy smokers were
engaged in during early 1959. But suddenly-perhaps because the radio-TV phonograph industry was temporarily in the doldrums-hi-fi became a commercial reality and moved out of the hobbyist category. While many people
may have misunderstood the significance of the term high fidelity when it was
exclusively associated with hobbyists, they are as nothing to the people who
misunderstand it today. This is because everything from a $19.95 portable
radio on up was labeled "hi-fi" in order to cash in on the craze. We use "was"
advisedly. This year everything is labeled "stereo." As one manufacturer
remarked, "Without stereo, you're dead," and it is very possible that monophonic (that is, non-stereo) equipment may not even be offered for sale in
another year. At least, that's how it looks to the experts.
;
20
Stacked high above
Dr. Peter Goldmark, chief
researcher at Columbia
Records, are discs cut at
78 rpm. In his hands
he holds the same music on
33 -rpm recordings. One
bonus was the smaller storage
space required; LP's
greater fidelity was the big
advantage to the listener
HI-FI AND STEREO
It is easier to define stereo, as the term applies to equipment, than it is
to define hi-fi. Stereo equipment must provide two channels of reproduced
sound (regardless of quality). High fidelity, on the other hand, is a goal
rather than a measurable fact. Some people will tell you that, to qualify for
the term, equipment should be capable of reproducing the audible range with
a minimal amount of distortion, noise and hum and at least 20 watts of power.
Others will say that the audible -frequency range isn't sufficient, and that
20 watts isn't enough to handle transient peaks without distortion. Still others
will concentrate on equipment, saying that you must have a rim -driven
turntable cushioned in sand, or a series of loudspeakers which break up the
audio spectrum into four or more segments. Purists generally concede that
you must have a tuner for radio (by which FM is meant; the term tuner was
hardly known 20 years ago) and that you're dead without a tape deck.
21
HI-FI IN FOCUS
Meanwhile, the $19.95 complete -in -a -unit "hi-fi" set continues to be available
-and to find purchasers by the tens of thousands.
Easy to define or not, let's discuss some of the qualities of high fidelity,
because there really is such a thing. Most people are able to distinguish audio
frequencies from as low as 60 cycles (a very low hum) to 15,000 cycles (a very
high whistle). People with normal hearing, that is. As we get older, our
high -frequency cut-off gets lower. It has been established by a number of
experimenters, notable among whom is Dr. Harry F. Olson of RCA, that
people prefer full -range musical repróduction if no marked distortion is
involved. So we might establish as one of the criteria of high fidelity that the
equipment be capable of reproducing the complete audible range, at least.
Some units go far beyond that today, especially at the high end.
THE PROBLEM OF DISTORTION
Surprisingly enough, it's possible, in theory at least, to reproduce this
entire range in a small table radio. But that's overlooking the matter of
distortion. The commonest type of distortion is amplitude distortion. To
explain this, let's suppose that we feed into our theoretical table radio five
frequencies, each of the same order of power 60 ; 600 ; 6,000 ; 10,000 and
15,000 cps. We might discover that the output varies tremendously from these
inputs. If we assigned to 6,000 cps the arbitrary output quantity equal to 100,
the five frequencies might reproduce like this : 10, 75, 100, 40, 10. Assuming
equal input, this would represent amplitude distortion. If we drew a graph of
the results, we would have a chart of the frequency response.
Harmonic, or intermodulation, distortion (IM) provides something in the
reproduced sound that didn't exist to start with, namely a "beat frequency" or
harmonic product. With reasonable care, distortion of these types can be
confined to low limits at moderate power. But at full power we have another
story. The full power of an amplifier might be 20 watts, but the power with
negligible distortion might be only 5 watts. On a table radio, which might
:
1111P ll III II Ill IIII
The frequencies of musical sounds for the notes on a piano
keyboard are illustrated above in cycles per second. The note to which
all Occidental orchestral instruments are tuned is A, at 440 cps
22
have a maximum audio power output of four watts, the temptation would be
to turn it up into the area of high distortion, where we would say it was
overloaded, simply to get a big enough sound.
Brilliance is a term that connotes bell -like clarity in the upper register.
Good or clean bass or depth implies concise reproduction of different bass register tones as opposed to the mushy thump that is apparent in some
equipment. Presence conveys a quality of three-dimensional realism and is
said to depend on clean reproduction in the mid -range (500 to 5,000).
Dynamic range is the range between loud and soft passages. The equipment
should be capable of reproducing the widest possible dynamic range, but this
range is often limited by the sound engineers who are monitoring a broadcast
or a recording, as well as by broadcast and recording techniques.
These qualities (brilliance, depth, presence, etc.) are listening terms. No
matter what the maker claims, or even builds into his equipment, you have
to hear them before they exist. The point is, though, that you can hear them,
and that hi-fi, despite problems of definition, has audible qualities, and is not
just a label. But when you venture into a discussion of what equipment is
needed to get these qualities, you will find more than two schools of thought.
There is the tuner vs. receiver controversy; the turntable vs. the changer;
the wide -range vs. several narrow -range speakers ; prerecorded tapes vs. discs,
etc. And now that we are in this area, perhaps we should first consider the
chain of equipment from program source to your ear(s).
THE CHAIN OF SOUND
All audio -reproduction equipment has units in common-namely, an audio frequency power amplifier and something to convert this power into sound,
either a loudspeaker or headphones. In the home, the audio -frequency voltage
to be amplified and reproduced comes from a tuner, a record player or a tape
playback; these three are the program sources. Tape heads and magnetic phono
cartridges require a preamplifier to bring the signal up to a level where it can
be handled by the power amplifier. Every table radio contains a tuner, an
audio amplifier and a loudspeaker. When a tuner and an amplifier and their
power supply are combined on one chassis, the unit is called a receiver. A
receiver is not necessarily provided with a loudspeaker, although it needs one,
of course, if its signals are to be converted into sounds.
A self-contained tape recorder includes the tape deck (tape -transport
mechanism, record and reproduction heads, plus various controls and indicators), preamplifier, power amplifier and speaker. A self-contained phonograph
includes a turntable or changer, tone arm, stylus, cartridge, power amplifier
and speaker (sometimes a preamp too). These components-tuner, tape deck,
record player, preamplifier, power amplifier and loudspeaker (s)-need not
be separate, though they often are, especially in hi-fi rigs. Separate components
give the user more latitude in selecting the items and the types, brands or price
ranges he wants. They also give him flexibility in adding or changing compo-
23
HI-FI IN FOCUS
This well -designed,
built-in stereo system
utilizes a Scott
tuner and preamp,
J. B.
Lansing speaker
system, McIntosh basic
amp and Rek-O-Kut
turntable with arm. Rig
looks, sounds good
nents. Finally, in the case of preamp, power and loudspeaker(s), there is an
economy because we are using the same components for all program sources,
instead of having separate items for each.
MEASURES OF QUALITY
Each item in the chain of equipment has its own measure of quality: tuners
must have good sensitivity and selectivity ; record players and tape decks must
boast an absence of wow, flutter and rumble, amplifiers will register claims for
high power with low distortion, etc. We shan't go into great detail about
equipment at this point except to add that all signal -carrying components
(tuners, amplifiers, preamplifiers, cartridges, speakers, etc.) should be capable
some control setting-of passing along the signal in the same form in
which it was received. Virtually nothing has a perfect, 100 per cent "flat
response," but many items of better quality approach it.
The final link in the chain is the mind of the listener as it interprets the
sounds his ear receives. His tastes enter in, and only he can learn to cater to
them. He may feel that Toscanini's recordings of Haydn, though brilliant, lack
depth ; or that Mengelberg's César Franck is at too fast a tempo. Not everyone
will agree on points like these, of course, any more than they will agree on the
setting of bass and treble controls. We mention them only to underscore the
fact that there is no absolute in this matter of hi-fi. We can make recommenda-
-at
24
tions and give you good reasons for them, but in the last analysis, the proof
of the pudding must be your-the listener's-proof.
BACK TO STEREO
So far we have been addressing ourselves not so much to stereo as to audio
equipment in general. As we mentioned earlier, stereo is a method of reproducing sound that provides two separate and different sound channels from
the source to your ear; two channels now, probably more later. Stereo equipment this year is available at prices ranging from $30 to $3,000. At any price,
it doesn't have to be good to be labeled stereo. The distinguishing feature about
stereo is that you have to have two of almost everything: two ears, two loudspeakers (or sets of speakers), two amplifiers (although these can be on one
chassis), two sound sources or channels, each producing a slightly different
variation of the original program material. To combine stereo and hi-fi, the
same sort of high -quality equipment is required as for conventional (monophonic) hi-fi, but doubled in most instances. Some of this equipment is peculiar
to stereo; that is, you can't just use two tape recorders or two phonographs.
You must have a stereo recorder or a stereo tone arm, cartridge and stylus for
60 cps
600 cps
6,000 cps
10,000 cps
15,000 cps
amplifier performance over a five -test
frequency range at constant voltage signals. With 50 as the arbitrary listening
level, the amplifier's range is actually only 600-6,000 cps
The bar graph shows possible
25
HI-FI IN FOCUS
disc reproduction. Some new controls are also needed to control the additional
sound channel as well as to balance the sound output from the speakers, provide
for the simultaneous reception of two different radio signals, and the like.
This, then, is stereo : a refinement of existing sound -reproduction techniques
so great that it amounts to a new technique. It requires some special equipment, but it can provide a listening experience which is head and shoulders
above that derived from the best available monophonic rig.
MANY SOUNDS, MANY METHODS
The reader may not only wonder what stereo sounds like ; after he has heard
it he will wonder what it should sound like. Stereo is not a single, absolute
entity. There are many different ways to record stereo and there has been a
great variety in the results obtained from different methods used in the last
few years (starting with Emory Cook's double -grooved binaural records in
the early 1950's and proceeding through stereo tapes to the present compatible
stereo discs). It is not even true that one recording principle governs all of
a company's products, for different types of program material call for different
treatments. When you listen to a stereo demonstration, don't try to judge it
by a single example. Unless you are familiar with the material, you won't be
able to tell whether the quality is above or below average.
Prevalent in hi-fi stereo stores is the gimmick record that features sounds
made by trains and jet airplanes. Such records don't tell you much about stereo
and should be considered for what they are: stunts. Musical records that keep
your attention jumping back and forth from one speaker to the other, no
matter how fine the program material may be, become tiresome because they
p
.**
'itl.ú Ei.,t
.
.--
.
11.1>0
Two fine stereo components are shown here: on the left, the
Roberts Stereo Recorder, Model 90-C, and, right, the Roberts Stereo Amplifier,
Model A-901. The two units may be purchased for $499.00
26
MONOPHONIC REPRODUCTION
LEF
SOUND
IGHT.
SOUND
MICROPHONE
MONOPHONIC
DISC
AMPLIFIER
SPEAKER
LEFT
AND
RIGHT SOUNDS
LEFT
'*
AND
RIGHT SOUNDS
Stereo reproduction brings listener closer approximation of concert -hall
sound than does a monophonic recording. Stereo's two microphones, amplifiers and
two sound tracks-give depth and fullness that are unattainable in a mono rig
speaker-
are unnatural. This technique is known as the "ping-pong effect." When overdone, it, too, can result in a stunt record.
With good stereo, you should not be aware that there are two separate
speakers, one on your left and the other on your right. What you should hear
is a well -integrated whole. We have heard demonstrations in which the sound
seemed to be coming from a speaker placed in the center, although none was
there. Shaw once remarked that witnessing a drama requires a "willful
suspension of disbelief." We know that the actual event is not taking place
on the stage, that these are just actors going through their lines. But we must
put this thought out of our minds if we are to enjoy the play. Then our enjoyment will depend on how successfully the dramatist, director, scene designer
and actors have created the illusion. By the same token, listening to music
electronically reproduced is-or should be-the creation of an illusion that
the musicians are really present. In the early days of radio, advertisements
used to say that "it sounds as if it was in the next room." Today we want it to
sound as if it were in this room.
27
.x_120
120
100
80
60
40
20
o
20
50
100
500
1,000
5,000
10,000
20,000
FREQUENCY IN CYCLES PER SECOND
In the diagram above, each curve on the graph shows
the sound intensity that is required at any frequency to produce a loudness
equal to that resulting from the 1,000 -cycle intensity indicated
THE SENSE OF IMMEDIACY
But in recorded or electronically reproduced music we do not attempt to
"hold the mirror up to nature." The illusion created is the one to which we
have become accustomed; for most of us are more used to getting our music
"canned" than to hearing it "live." We have developed certain tastes and
preferences. And besides, the results have to suit the situation, which is a
living room in the home. To understand how the listening situation affects
program material, consider for a moment television and the typical audience
reactions to it. In spite of the vast popularity of Westerns, vast panoramas of
western scenery seldom come across on the small TV screen, a fact that has
led to the development of the "Adult Western," where people in Stetsons talk
to each other in quite ordinary backgrounds and settings. Similarly, interview
and panel shows have been a great hit mainly because they involve a few people
sitting and talking as people might sit and talk in your own living room.
In the recorded music that we hear at home we like to get closer to the source
than we would be in a concert hall. For this reason, recording engineers have
emphasized things like the tinkle of a glockenspiel or the sonorous majesty
of the bass viol, so that these instruments seem close to us. The engineers
sometimes go so far as to pick up the scraping sound of violin bow on strings,
the sound of a singer drawing a breath, the humming of Toscanini as he
28
For stereo recording (at left), sound from many mikes is blended by an engineer
at the sound board. The resultant disc (at right) has two independent sound tracks; the
cartridge, with two signal -generating elements, uses only one stylus
conducted and the mechanical noises of the harpsichord as Landowska plays it.
These subtleties give a sense of immediacy to the recording and make the
listener feel that he was present when it was made, just as movie close-ups
interspersed with long shots can make an audience feel intimately involved
in the action taking place on even the widest of the new screens.
This is not to imply that such devices are faults or shortcomings, or that
they are the tricks of an unscrupulous recording engineer. We all enjoy
recorded music more because of the engineers-the good ones. The point is,
we should be aware that they exist, and that they are not slavishly attempting
to create, somehow, an exact duplicate of live music. They are trying to provide
an enjoyable performance. So stereo is not "supposed to be" one thing in
particular. It is a two -channel recording technique which, it has been found,
can create an even more pleasurable listening experience than monophonic
recording, an even greater illusion.
At least temporarily, we might sum it up this way : Stereo should-and when
it is good, it does-sound a great deal better than mono. There is an illusion
of presence, of more reverberation, greater reality. Stereo, further, should not
have faults like a "hole in the middle," obvious imbalances or grating distortion. The recording technique should not result in a performance that seems
unnatural. Viewed in this light, stereo can be evaluated by any layman, for
in the last analysis it is to be purchased and listened to by laymen.
29
THE HEART OF ANY STEREO SYSTEM IS THE PLACE
WHERE ALL THE INPUTS MEET ALL THE OUTPUTS
THIS STAGE IS PURELY ELECTRONIC -THE TINY
IMPULSES MUST BE MAGNIFIED A MIL_ION TIMES
THE UNITS ENGINEERS HAVE CESIGNED FOR
CHAPTER
3
More so than most other purveyors of consumer goods, manufacturers of
hi-fi equipment throw a lot of technical and pseudo-technical terms at their
prospective customers. This is especially true of amplifiers and preamps, and
many hi-fi enthusiasts have become glib with terms such as impedance,
negative feedback, odd -harmonic distortion and DC-operated filaments.
Much of the technical jargon is unnecessary to the reader who merely wishes
to make a good purchase, but a little bit of introductory explanation will
help to put things in their proper place later on.
Amplifiers are an essential part of all electronic equipment. As a matter
of fact, it was the development of the amplification principle-via an electron
or vacuum tube-that really started radio (and its various offspring) on its
way. To amplify is to enlarge or magnify. An amplifier draws energy from
31
AMPS AND PREAMPS
a source of electric power and causes this energy to assume the form and
proportions of the original signal, which is therefore apparently amplified.
This is an example of the old principle that "energy is neither created nor
destroyed, it is only transformed."
Amplifiers are used in countless applications and one way to classify them
is by the range of frequencies which they can handle efficiently. Thus an
audio amplifier handles audio frequencies. The electrical requirements of an
amplifier can include both AC and DC over a wide range of voltages, from
as low as 6 volts to as high as 600. That stage or part of the equipment
which supplies these various needs is called the "power supply." Power is
expressed in watts, and is the ability to do work of some sort. In the case
of the audio amplifier, the work to be done is driving a loudspeaker.
PR EAMPS
The job of the preamp is to take a very low signal and boost it till it is
high enough to be accepted by an amplifier. A preamp might take the .025 volt (25 millivolt) output of a phono cartridge and raise it to 2 volts, at
which level it would be suitable for delivery to a power amplifier. Preamps
first became known to audio fans when the GE variable-reluctance pickup
and other "magnetic" types appeared on the scene about eleven years ago.
AMPLIFIER
The amp merely enlarges audio
supplied to it by the preamp. Amplifier
should not change shape of curve
32
preamp takes signals from the sound source,
removes ragged edges, reconstitutes highs, lows,
adds emphasis to the bass and treble
A
POWER TRANSFORMER
ELECTROLYTIC
CONDENSER
OUTPUT TRANSFORMER
OUTPUT TUBES
AMPLIFIER
TUBE
RECTIFIER
SPEAKER
CONNECTIONS
INPUT SOCKET FROM PREAMP
Size and weight of transformers, plus number of amp output
tubes, are trustworthy indications of amplifier quality. Stereo power amps
consist of two monophonic amps (above) mounted on same chassis
Up to that time, most common or garden variety pickups were crystal with
an output of about one volt, which could be fed directly into an amplifier
stage. With but a fraction of that output, the new pickups required a
preamplifier in order to raise the voltage to the input requirements of the
average amplifier. Since these pickups also required special equalization
(compensation for portions of the signal which were not accurate reproductions), it was convenient to provide such equalization in the preamp.
The various present-day forms of magnetic pickups have a low-level
output requiring preamplification, and also a more markedly non-linear
response, requiring equalization. The subject of equalization is a bit too
involved for a full discussion here, but it is well to be aware of this fact:
virtually no piece of equipment in the audio field has a linear or "flat"
response before equalization. With proper equalization, almost any equipment can be provided with a flat response. This statement presumes (1)
sufficient power available so that some of it can be dissipated in equalization
circuits and still have enough left at the end and (2) that the output of
the equipment is consistent (as opposed to erratic) and is free of unusual
and extreme irregularities. By this latter phrase, we mean peaks or
resonance points. A rather appropriate analogy is this: that in spite of the
wide variation in vision capabilities of people, most people can be brought
up to 20/20 with correction (i.e., glasses) .
As recording techniques began to exhibit great variations, it became
desirable to provide some controls on the preamp, to select different degrees
or types of equalization. This is how the unit as we know it today evolved.
33
AMPS AND PREAMPS
i
Bogen ST 10 -AG stereo adapter
contains dual preamps and 10 -watt mono
power amplifier for add-on use
stereo adapter
Bogen STA
includes mono-stereo switch, reverse
stereo control and volume dial
Stereo conversion unit for
20-watt amplifiers is Harman-Kardon
AX20, which has dual preamp
To many users today, the preamp is a control unit, because that's how it
serves them. Basically, however, it is a voltage -amplification device, and as
such it was known for years by people who used a microphone, which is also
a low-level signal source. Preamplifier stages are a routine part of sound
equipment used with microphones. Tape recording and reproducing heads
also have a low-level output and require preamplification. Phono pickups,
microphones and tape heads all require different types of equalization.
HOW MUCH TOGETHERNESS?
For stereo it is possible, just as it was with mono, to purchase receivers
such as the Fisher 600 or the Harman-Kardon TA -230 which contain preamplifier and power amplifier, with integral power supply, on a single chassis tuner. It is also possible to get all these components separately, or
in various other combinations such as tuner and preamp (Fisher 90-T) or
preamp and power amp (Stromberg-Carlson ASR -444). Which way is best?
So far as quality goes, there is absolutely no difference. That is, quality
is not diminished by combining several services on one chassis. Other
factors besides quality should be considered, however. One is flexibility. A
collection of separate components is more flexible, of course, both from the
standpoint of initial choice and subsequent changes or additions. A second
factor is control. As a rule, the more separate pieces of equipment you have,
34
wouo
Stromberg-Carlson ASR 433
stereo unit has generous number of
controls for tone, volume
Scott Stereo Adapter lets
users operate system monophonically,
for stereo and stereo reverse
Stereo control unit from
Lafayette can be used with
variety of amplifier makes
a
wide
the more knobs there are to turn. Some people are fascinated by a multiplicity of knobs; some are genuinely capable of making very subtle adjustments with such a variety; some are bewildered and annoyed by it.
A third factor is physical space and convenience. From the standpoint of
physical space, it may or may not be more convenient to have separate
components, depending on your own situation. From the standpoint of
convenience, many people find it most practical to adjust sound from the
listening position rather than from the equipment location. This is especially
true of stereo. This factor suggests the practicality of the remotely located
preamp-control unit-"remote" in this sense implying at the listening
position. It is of course possible in some homes to have the entire equipment setup at the listening position with the exception of the loudspeakers.
In this case, there would be no particular advantage to a separate preamp.
HOW MUCH POWER?
The question of power requirements may be considered next-audio power
output, not electrical power consumption. The "watts" in both instances
represent the same sort of units of measure, but one is input watts, the
other output watts. Incidentally, no device is 100 per cent efficient (in
which case output would equal input). The heat which is dissipated from
electronic equipment is one of the losses that reduce efficiency. If we were
35
AMPS AND PREAMPS
Harman-Kardon stereo three-in -one
(above) combines dual stereo preamps plus
power amps (upper right) and stereo
AM -FM tuner (right). Three-in -one offers
space and cost economies, is ideal
for non -permanent set-up. Unit needs only a
speaker to become a full stereo system
to start out by saying, "What is the least amount of audio power one could
get by with," we would be asking an academic question. For although it is
theoretically possible, it is not practical at present to produce a high -quality
audio amplifier (that is, one with wide frequency range, good frequency
response and negligible distortion) without using a pair of output tubes
that yield a combined output of at least 10 watts. Since a stereo amplifier is
really two complete amplifiers, this means that the least we could expect to
find in a good stereo amplifier is 10 watts per channel, or a total of 20 watts.
The author has conducted tests in which the output power was measured
with a meter and has demonstrated that if 20 watts of power were actually
delivered, the sound level would be unbearable except outdoors or in a large
hall. The secret is that the amplifier is virtually never run "wide open" ;
20 watts implies plenty of "spare" power. In spite of this known fact, there
are 60 -watt amplifiers for home use, as well as people who advance apparently unassailable arguments for the necessity of that much power. One of
these arguments claims that transient peaks in music attain a level of 10
times the average level of loud passages. If an amp doesn't have the capability to handle this power, it is said, distortion will result. This point is
well taken, but it concerns only the perfectionist. For most people, once a
certain level of quality has been attained, increments of improvement will
not be in proportion to the money spent. So, in answer to the question,
"How many watts?" we reply that 20 watts (with negligible distortion)
from a stereo amplifier is plenty for high-fidelity results. Higher -powered
amplifiers of equal or better quality can provide some improvements (plus
considerable pride of ownership), but it is important to understand that
high wattage output is not per se high fidelity.
_So far, we've discussed preamps and amps in a general way, without
specific attention to stereo. Stereo, of course, is a two -channel system. It
follows that we must have a two -channel preamp and two amplifiers or a
dual amplifier (stereo amplifiers on a single chassis). We have already
36
Y
'f
established the fact that it is more convenient to have the control of loudspeaker output available at the listening position. This could be simply a
control unit, or a preamp control. It should be possible at the listening
position to (1) balance or equalize the output from both channels, (2)
control the over-all volume level without changing the balance and (3)
reverse the connections (phasing) of the two speakers or speaker systems.
Control units usually provide for a monophonic connection, for use with
the old-style recordings or radio programs, plus controls for equalizing the
phono preamp to match the recording characteristic of the program material. These functions need not be at a remote position, however, since it is
unlikely that the program source could be changed (for instance, from
stereo disc to monophonic disc) without walking over to the equipment. As
for a change in the recording characteristic, this could occur if you use a
record changer, in which case you would like to have record compensation
available at the remote-control position. But if a manual (single -play turntable is used, you can change the compensation when you change the record.
Examples of simple control units are the Scott Stereo-Daptor (about $25)
and the Bogen Stereo Adapter STA1 (about $16). Simple control units are
also available from Lafayette, Knight and other manufacturers.
WHAT TO SPEND FOR PREAMPS
In discussing the relative merits of separate components vs. components
combined on the same chassis, we mentioned (1) quality, (2) flexibility,
(3) control and (4) physical space and convenience. We did not mention
cost. A good preamp costs money and you may not consider it feasible to
purchase it separately. The Stromberg-Carlson ASR -444, a combination
preamp and stereo amplifier with two 30 -watt channels, sells for about
$169.95. The Stromberg -Carlson ASE -434 stereo preamp is $99.95; the
ASP-422 stereo amplifier with two 20 -watt channels is also $99.95. Therefore
the two separate units cost $30 more than the one-piece unit and provide
less power. The Scott stereo preamp 130 is $169.95; the combination preamp
and amplifier with two 20 -watt channels is $199.95. The Fisher stereo
preamp 400-C is $169.50; the combination preamp and 40 -watt amplifier
(two 20-watt channels) is $189.50.
These three examples should make it obvious that it is more economical
to get the preamp and power amplifier on one chassis. The choice is actually
complicated by whether you are buying all new equipment or adding to
what you already have. We shall consider this question in a later chapter;
right now we need only point out that in regard to the amplifier you have
two choices. You can start from scratch by buying a combination stereo
preamp-control unit and stereo power amplifier. Or you can convert an
existing mono rig by adding a second preamp, second power amp and stereo
adapter; a stereo preamp and a second power amp, available as a single unit
in some lines. Good stereo can be had with either choice.
37
PHONOGRAPH RECORDS ARE THE BASIS OF MOST
STEREO LISTENING " IN ORDER TO HEAR THEM
PROPERLY. YOU NEED A GOOD CARTRIDGE AND
NEEDLE PLUS CHANGER OR SEPARATE TONE ARM
AND TURNTABLE
A MAJOR JOB
KEEPING SPEED CONSTANT IS
°`RECORD PLAYERS
CHAPTER
4
The sudden emergence of the Westrex 45-45 compatible stereo disc in the
spring of 1958 marks the real beginning of stereo as a popular, commercial
product. (Westrex is not in the record business. It is a division of Western
Electric, the research and manufacturing subsidiary of Bell Telephone.)
Prior to that, it was a matter of mild curiosity, observable in some AM -FM
and AM -TV simulcasts and in the homes of the relatively few enthusiasts who
had the money to invest in stereo tape recorders and high-priced prerecorded
stereo tapes. With stereo discs to offer, the industry could tap the potential of
the 40 million phonograph owners, an audience worthy of their all-out efforts.
The terminology applied to the discs is worth examining; "45-45" refers to
the angular relationship between the vertical and horizontal forces involved
in the recording and playback processes. "Compatible" implies that the equip -
39
RECORD PLAYERS
Garrard RC121/11 changer,
made in Britain, is an attractive,
economical four -speed unit
American -made Glaser -Steers
GS -77 record changer boasts several
desirable operating innovations
British-built Collaro TC 99
record changer has detachable head,
manual -automatic switch
ment used in playback can also be used to play conventional monophonic
records. It is important to know that "compatible" does not mean that equipment for playing conventional records can also play stereo discs.
Stereo discs are 334k- or 45 -rpm microgroove records having the same
dimensional standards and recording characteristics as conventional, or monophonic, LP's and 45's. The difference is that the stereo groove contains two
sound channels instead of one; and that a special stereo cartridge with a
smaller needle, or stylus, is needed to play it. The word "compatibility" is
usually not extended to 78 -rpm discs, which call for a stylus of 3 -mil tip
radius. Nevertheless, some stereo cartridges are available with two styli,
and these are capable of playing stereo and monophonic 33- and 45 -rpm
microgroove records as well as monophonic 78's.
The term phonograph (Webcor spells it Fonograf) implies a complete unit
with amplifier and loudspeaker(s), usually portable. It may be equipped with
a record changer or a manual player. The term record changer is well understood: it is a device to play a "stack" of records automatically. Assuming that
a stereo cartridge is provided, the other elements of stereo disc reproducing
equipment are the same as for monophonic, except that in certain instances
higher standards of excellence must be maintained.
40
Thorens CD -43 operates at only
three speeds. It's one of the most
expensive changers on the market
Miracord XS -200, a West German
import, has 41/2 -pound turntable, four
speeds, repeat and pause
Dekamix changer, which can
play mixed sizes of LP's, 78-rpm
discs and 45's, is British import
TYPES OF RECORD PLAYBACK EQUIPMENT
An electric motor drives a turntable, usually indirectly, through an idler
wheel or belt drive. The motor runs at constant speed in most units, with
speed change (33-45-78) effected by a change in the idler wheel -drive linkage.
A few models change the speed of the motor electrically.
The term transcription turntable is meant to imply a unit of professional
quality, suitable for manual playing of one record at a time. A tone arm and
pickup cartridge are extra accessories. The terms player, record player and
manual player usually indicate that a tone arm is included (the cartridge may
or may not be). Players run the full gamut of quality. Both turntables and
players may provide one, two, three or four speeds. The fourth speed, 16%
rpm, is little used at present except for spoken -word recordings. A record
stays in position on the turntable because its center hole fits over a spindle.
The spindle may turn with the record or it may be stationary, with the record
turning around it. Two different spindles are needed to play all four speeds.
One plays 45's, the other 33's, 78's and the slow -playing 16's.
The cartridge is the transducing element which translates the mechanical
motion of the stylus into electrical signals. The stylus is usually provided with
41
RECORD PLAYERS
Rek-O-Kut
N -33H
Rondine
features modernistic styling
Presto Promenade works
equally well with any pickup arm
Another special -for -stereo
unit is Pickering's Gyropoise 800
Fairchild three -speed unit
is powered by belt under turntable
Collaro 4TR 200 turntable
plays all four record speeds
Swiss -made Thorens table
needs only a tone arm to make music
Weathers K730 player is
designed for use with Weathers arm
Gray turntable is shown
with Gray viscous -damped tone arm
42
the cartridge. Although still replaceable, styli today are considered semipermanent, as opposed to the steel needles of the old days, which were replaced
after two or three plays of a 78 (5 to 10 minutes). Stylus tips now are usually
either sapphire or diamond. It is generally conceded that the harder materials
(especially diamonds) are preferable because they last longer and wear more
evenly. A badly worn needle can cause irreparable damage to the modulated
grooves of the vinyl-plastic disc.
The tone arm is the vehicle that carries the cartridge -stylus assembly across
the record. It also contains the wiring that carries the signal from the
cartridge to the rest of the system.
TONE ARMS
If you decide in favor of a turntable, you'll need a separate tone arm. For
just as the turntable is sold as a separate mechanism to perform only the
function of rotating the record at a constant speed, the tone arm performs
only the function of supporting the cartridge and allowing it to work its way
across your records with a minimum of outside interference. Pickup arms
wired for stereo start at about $12 for some Japanese and European imports
and run up to $114 for the Weathers integrated arm and cartridge. The standard sizes are 12- and 16 -inch, although some popular models fall in between.
The proper matching of arm and cartridge was a tenet of hi-fi buffs in
monophonic days; today it is a fact of life for stereo owners. We have learned
during the first year of stereo discs that some cartridges wear records faster
than others; that putting heavy -wear cartridges in different arms affects the
rate of record wear. A rule of thumb is that tone-arm manufacturers who also
make cartridges probably have closely matched units. The Grado, Shure,
Electro -Sonic, Pickering and General Electric combinations are cases in point.
Your high-fidelity dealer can give you guidance with product combinations
from different manufacturers.
Tone arms, like other physical bodies, tend to resonate at certain pitches.
When they do, they pall their cartridges erratically out of the record groove.
Fortunately, most arms are designed to resonate at tones well below those
engraved on your records. Most arms, too, are equipped with screw adjustments for tracking weight and for the height of the arm. Stereo cartridges
generally track in the two-to -four gram range. On some arms, it's a matter
of shifting a counterweight. On others, there's a spring to be tightened. In
any case, be sure that the arm you select can have its tracking weight adjusted
easily. Then, after the system is in use, make it your business to check
tracking weight periodically to be certain it remains correct for the cartridge
you use. Tone arms generally are precision -mounted on their bases to allow
them to move freely. The degree to which stiffness at this point hinders
movement indicates a bad arm.
When you look at tone arms, you'll notice that they bend sharply at a point
just before the cartridge mounting. In the case of the General Electric, the
43
RECORD PLAYERS
AMPLIFIER P
AMPLM,IEAL
PREAMP B
PICKUP CARTRIDGE
o
¿IC
a
COId. A
DAMPING FACTOR
V
NEEDLE
6'-
i
MAGNETIC
COIL B
V
NEEDLE
RECORD GROOVE
RECORD GROOVE
Two popular cartridge designs are the piezoelectric, left, and the magnetic.
Former produces signals by applying force to crystal elements. In magnetics, stylus
vibrations cause changing magnetic fields in coils, feeding signals to preamps
arm is straight, but the cartridge mounting is held at an angle. These are
attempts to reduce tracking error across the face of the record as much as
possible. A straight arm, moving slowly from the outside to the inside across
a record would describe a small arc; only at one point in the arc would the
relationship of the needle and cartridge to the groove be correct. By bending
the arm and the cartridge, and by careful placement of the base, tone -arm
makers have eliminated part of the arc, thus reducing tracking error.
Some arms have plug-in heads; others do not. The chief advantage of the
former is that the plug-in head allows for fast, convenient change of cartridges. If, for example, you want to switch from stereo discs to 78 -rpm
records, it's a simple matter to unplug the shell containing your stereo
cartridge and plug in a three-speed monophonic cartridge. If your collection
includes primarily microgroove and stereo discs, this may not be necessary.
RECORD CHANGERS VS. PLAYERS
features (1) ability
to play either three or four speeds; (2) provision of two styli, for 78 and
microgroove records; (3) ability to handle 7-, 10- and 12 -inch discs; (4)
ability to play these record sizes intermixed; (5) ability to play both sides
of the disc without turning it over; (6) ability to play manually as well as
automatically; (7) muting during change cycle; (8) automatic shut-off after
the last record is played; and (9) interchangeable spindles for 45's and the
All record changers include some or all of the following
44
:
conventional center -hole discs. This is not by any means an exhaustive list.
It seems obvious that it would be difficult to engineer all these features into
a single piece of equipment and provide the same standards of quality in all
respects that could be incorporated into such a relatively uncomplicated piece
of equipment as a transcription turntable or a high -quality player. This is
even more obvious when one observes that all these features are available
in a record changer at a price equal to or lower than that of most turntable only units. It is for this reason that many hi-fi enthusiasts feel that single -play
equipment is the only choice for high-quality record reproduction, despite
the fact that a changer can provide more than three hours of uninterrupted
entertainment. Perhaps the ideal answer to the changer -or -turntable question
is to have a record changer for "background music" and parties and a high quality manual player for critical listening.
CRITERIA FOR PLAYBACK COMPONENTS
The motor of any record player must be a husky one, capable of maintaining
accurate and constant speed. Variations in speed will result in pitch variations
in the reproduced sound, called "wow" and "flutter." The motor should be
quiet and vibration -free. Vibrations transmitted from the motor to the
turntable will be reproduced electrically in a wide -range system as "rumble."
The arm should permit smooth and errorless tracking. The cartridge should
respond faithfully to the movements of the stylus. If a cartridge is too stiff
to respond, it lacks "compliance." The stylus should be of the proper size (tip
radius), in proper position on the disc, and not excessively worn. Adjustment
of the arm should provide recommended tracking pressure on the record.
Playing the record should involve minimum possible wear and damage to the
During recording, the stylus moves across the record in a straight line (left). In
playback, the tone arm moves stylus across the record in an arc. The difference creates
tracking error (center). The longer the arm, the smaller the tracking error
45
Garrard 4HF turntable can
be had with or without 12 -inch tone
arm on single -unit plate
Miraphon four -speed player
has plug-in head, design features
of Miracord record changers
Collaro TP 59 manual player
features similar arm, turntable
motor to that in changer
disc, including its center hole. Enlargement of the center hole is almost certain to cause eccentric rotation.
SPECIAL DEMANDS OF STEREO
The monophonic record has its groove modulated in a lateral (side to side)
direction only, tracing a path something like a snake. Both sides of the groove
are the same for this single -channel recording. Monophonic cartridges have
virtually no vertical compliance and so are relatively insensitive to rumble.
The stereo disc has a separate and different sound channel recorded on each
of the two sides of its grooves. The result is that the groove is narrower in
some places, wider in others. When the groove is narrow, the stylus is forced
to ride high in it ; when the groove is wide, it drops. Thus the stylus has vertical
as well as horizontal motion. These two motions are usually combined, so that
the stylus may move up and to the left, down and to the right, etc.
46
Rek-O-Kut's Audak tone arm
has adjustable counterweight at
rear of arm, plug-in heads
London -Scott stereo arm and
cartridge are sold as matched stereo
unit. The head is angled
1311.1.ir
Electro-Sonic's curved
arm is designed to reduce
record -tracking error
Shure Dynetic Reproducer
is integrated arm and cartridge
combination for stereo
Another integrated arm
and cartridge combination is
Pickering's Unipoise
Since the stereo cartridge has both vertical and horizontal compliance,
it
to be more sensitive to rumble than a mono cartridge. There are two
solutions to this-in addition to just putting up with the rumble: attenuate
the low -frequency response of the system, thus attenuating the rumble; or buy
a turntable in which rumble is at an absolute minimum. Because there is
more danger of overcutting the groove (so that it runs into the next groove)
in the 45-45 stereo system than in lateral monophonic recording, the recording
level on the discs has been lowered and the output of the stereo cartridges is
therefore lower. In some instances, the impedance of stereo cartridges differs
from monophonic counterparts and therefore requires special adjustment.
Another difference in stereo cartridges is the stylus. The Record Industry
Association of America (RIAA) standards for monophonic microgroove
reproduction call for a stylus of 1 -mil tip radius. Tolerance extends from .0011
to .00098 inch. The RIAA further recommends that "the desirable tip radius
for reproducing stereophonic phonograph records be .5 mils." We find, howseems
47
RECORD PLAYERS
Ceramic Electro -Voice stereo Power Point cartridge (left),
Ronette's Binofluid crystal are among the more popular non-magnetic
types of cartridges available for stereophonic systems
The Electro -Voice 21 MD (at left) and the Sonotone Model
8-T ceramic stereo cartridges are able to play 78 -rpm records as
well as mono long-playing records and stereo discs
The Tannoy Varì-Twin, a
British import, comes with four
terminals for U.S. market
Pickering stereo pickup
has four terminals, resembles
the monophonic Pickering
ever, that most of the so-called compatible equipment is provided with a .7 -mil
stylus, said to be suitable for both the stereo discs and regular LP discs. This
.7 -mil tip radius is apparently a compromise between the 1 mil recommended
for mono LP's and the .5 mil recommended for stereo discs. The compromise
needle is 30 per cent smaller than the standard for mono LP's and 40 per cent
larger than the desirable size for stereo discs. Actually, of 36 cartridges
surveyed, 25 provide a .7 -mil stylus for stereo, only four offer a .5 -mil stylus,
three are .6 -mil, three are .75 -mil and one is .8 -mil. This variety of offerings
is probably an example of the somewhat experimental nature of stereo cartridges and styli. It also represents compromises between desirable and
obtainable tracking pressures for the different sizes, since the smaller the tip,
the less the tracking force should be. It has been our experience that the .7 -mil
stylus in a stereo cartridge produces good results on both stereo and mono
discs. With 70 per cent of equipment currently offered being of that size, it
seems likely that it will become the standard, provided no objectionable side
effects are encountered in another year of observation.
CHOICE OF EQUIPMENT: CARTRIDGES
In the chapter on amplifiers, we alluded briefly to the different types of
cartridges : magnetic and piezoelectric. Between 1948 and 1958 it was generally true that most popular, moderately priced equipment employed ceramic
48
A
popular magnetic is Shure
Stereo Dynetic; it can track at
three grams, costs $45
Fairchild's Model 232 costs
$49.50, employs dual rotating coil,
tracks as low as two grams
Electro -Sonic Labs' Gyro
Jewel stereo cartridge is made for
use in ESL or other tone arms
GE's GC-5 and GC-7
Fairchild XP4, now retired,
was early stereo cartridge, cost
as much as $250 a year ago
Square Audiogersh Stereotwin
210D cartridge also employs magnetic
are stereo versions of familiar
variable -reluctance units
principle for stereo reproduction
pickups while most hi-fi owners chose magnetics. Today, the picture may be
changing. If you want a single cartridge for stereo, and for mono LP's, 45's
and 78's, the choice is narrow. Of the 36 cartridges surveyed, only 13 provided
this complete service, and of these, 12 are ceramic or crystal (piezoelectric).
At the present writing, only the Recoton-Goldring cartridge provided the
dual service with a magnetic cartridge, although GE is expected to come out
with a stereo version of its popular "triple play" cartridge. The choice between
ceramic or magnetic need no longer be influenced by decisions about whether
or not to buy a preamplifier. Preamps are now assumed to be part of the usual
complement of hi-fi and/or stereo equipment, and, with the lower output from
stereo discs, many ceramic cartridges also require preamplification.
CHOICE OF EQUIPMENT: RECORD CHANGERS
Generally speaking, any record changer sold by a hi-fi dealer will do all
the things it is supposed to do. Statistics on wow, flutter, rumble and tracking
distortion are subject to dispute, and are apt to vary from unit to unit within
the same brand. We believe a good turntable will give better results than the
best record changer in these respects, although the changers we have seen
turned in creditable results on the initial observation. What happens over a
period of time seems to be more important. The writer has lived through
several record changers and has had these experiences: one widely known
49
RECORD PLAYERS
:
Here are three common ways to use the power generated by the
a record player for rotating the turntable at a slow, steady
speed. Top, direct drive in which the motor is geared to the
turntable. Center, rim drive using an idler wheel. Bottom, belt drive
motor in
changer tended to be erratic, over a long period of time, in the matter of
going through the change cycle flawlessly on different sizes and types of discs.
It took servicing to correct the difficulty. On the other hand, a quality import
performed consistently and flawlessly in this respect but suffered occasional
speed troubles because of dried -out or broken idler belts. Happily, these are
easily replaced. Some of the annoyances that have cropped up in the past
have been corrected by new models. Early models of some players did not
provide for manual playing; others were not provided with the condenser
needed to absorb the audible "pop" that occurs when the record changer shuts
itself off automatically. Generally speaking, these defects have been corrected.
A final point before leaving the subject of changers: a person who does not
have a steady hand can do more damage to an expensive disc on one manual
play than a changer will ever do to it. If youngsters, extreme oldsters or
just plain careless people are going to be operating your music system, a
changer can be an important protection for your discs.
50
It does not follow that a piece of equipment designed to play only one record
at a time will be flawless and foolproof. Nevertheless, the use of a good turntable-Rek-O-Kut, Presto, Gray, among others-can provide superior performance with respect to the quality features of wow, flutter, rumble and the
like. In general, the turntable -only units will have more extensive motors,
heavier aluminum disc tables and superior engineering throughout. Although
there is room for disagreement, the writer feels that the mechanical selection
of a pre-set speed change on a constant -speed motor is more accurate and
reliable than an electric change of motor speed, and more apt to give trouble free service. Some manual players made by record -changer manufacturers are
the same basic equipment minus the changing mechanism. A clue is that the '
price is lower than the comparable changer. These arè not likely to provide
results superior to that of the equivalent changer.
THE END RESULT-PLAYING RECORDS
There are today at least 10 types of records in use. These include 7-, 10and 12-inch 78's (people still buy 7 -inch 78 children's records) ; 7 -inch 45's;
10- and 12-inch LP's and stereo discs. In addition, most early stereo discs
were 12 -inch 33's, although there were some 10 -inch 33's; stereo 45's are
appearing now; and some 7 -inch mono 33's have appeared in the past.
The choice of equipment should emphasize the most important service to the
purchaser. If you never play 78's, don't push compatibility to extremes. If
your only use for 78's is on kiddie discs, perhaps an inexpensive child's phonograph is the answer. Your preference in program material should also be
considered. Orchestral music is more demanding in most respects than popular music. The single, sustained tones found in instrumental and vocal solos,
on the other hand, will reveal wow much sooner than will any form of orchestral music. Whatever the choice, there will be ups and downs in recording
quality and standards. This is especially true of stereo, which must *still be
considered a new art within which we can expect much experimenting by both
recording artists and engineers.
Care of records is not a new or special subject in the field of stereo, but
bears repetition. Discs should be kept free of dust, should be handled carefully
and stored safely. It will pay in the long run to make a habit of putting discs
back in their jackets and back on the shelf as soon as they come off the turntable. Some record collectors find it worth while to use a record brush on the
end of the tone arm-not only to keep the disc clean but to keep the needle from
getting clogged up. The small stereo stylus can reach a point of distortion
and even groove -skipping within a half hour's playing, because of accumulated "fuzz" from dirty discs. The writer has found it advantageous to clean
records. There are patented record cleaners on the market for this. Or, you
may use lukewarm water with a small amount of detergent in it. Rather than
clean them all at once, at our house we clean them right after they've been
played, noting on the jacket the date this was done.
51
ar,
ewe
eon .r.
r7 LifiLl'
YOU CAN BUY STEREO ON PRERECORDED TAPES
OR YOU CAN RECORD YOUR OWN STEREO FROM
BROADCASTS AND RECORDS
NATURALLY. THE
BETTER YOUR EQUIPMENT, THE BETTER YOUR
RESULTS
THE STARTING POINT, OF COURSE.
COMES WITH
TH TAPE RECORDERS
CHAPTER
5
For all practical purposes, the magnetic tape recorder can be considered to
have begun after World War II. In the short space of 12 or 13 years, the term
"tape recorder" has become so widely known that it is necessary to stress here
that this unit in the home -entertainment system is both a tape recorder and
playback device. In fact, since the advent of prerecorded tapes, and especially
stereo tapes, the playback feature has come to assume major importance.
In the relatively short time since its introduction, the home tape recorder
has undergone many changes, some of which were outstanding improvements.
As originally introduced for home use, it was a single-track machine of doubtful fidelity and many mechanical difficulties. Home machines operated at
15 inches per second (hereafter abbreviated as ips) and it was generally
stated (though often difficult to prove) that frequency range could be evalu-
53
TAPE RECORDERS
Stereo on tape is easily portable, can be taken outdoors or to the beach.
Most stereo units consist of tape record and playback unit (center foreground),
two playback amps and speaker systems to reproduce taped signals
ated at 1 kilocycle (KC) per inch. That is, 15 ips should go out to 15,000 cycles
and any slower speed than that would give proportionately reduced frequency
range. Actually, in those early days, only professional equipment could attain
this goal. Today 2 KC per inch (15,000 cycles at 7% ips) is not uncommon.
Home recording proved to be a novelty whose fascination before long wore
off, and the home recorder might have died right then if it hadn't been for the
fact that, with improved fidelity, it came to be looked upon as a good instrument for the reproduction of music. Professionally, magnetic tape took over
the broadcast and recording fields and many hi-fi purists began to believe
that this was the only proper medium for high-fidelity music reproduction.
For a brief moment, tape enjoyed a tremendous superiority over records;
then LP's appeared, providing more playing time for less money and in a
considerably more familiar medium. Dual-track tape at 7% ips, but of a quality
at least equal to the 15-ips machines of a while back, came along for home use
in 1949, and this was a partial answer to the playing-time problem. The
availability of dual tracks suggested the feasibility of putting stereo on tape,
and thus the tape -recorder industry became the pioneer in making stereo
available for home use. This development took place in 1952 or thereabouts;
54
Crown stereo recorder is typical
of rugged professional models; it has
separate'preamps, speakers
Presto professional tape deck
has push-button controls that light when
in use, facilities for tape editing
American Concertone tape deck
comes with auxiliary units for recording
and playback, for professional use
and once again, tape enjoyed a clear superiority over discs-for a while. With
the large-scale advent of stereo discs in 1958, this superiority evaporated, and
the tape industry once again looked for a technological improvement. Four
tracks instead of two, 3% ips and a magazine -loading machine were some of
the answers. We'll examine these as we go along, but first let's look at the
nature, advantages and disadvantages of tape recording and playback.
HOW TAPE WORKS
Reduced to its barest essentials, tape is a narrow plastic ribbon, to one side
of which is applied a thin coating of iron oxide. Transported past a magnet
energized by an audio -frequency current, the iron on the tape is magnetized in
accord with the audio signal. Transported past a playback magnet, or tape
head, the tape sends its information back into an audio -reproduction system.
The information is not thereby removed from the tape, however, and can be
played back an infinite number of times.
Compared with a disc system, this is simplicity itself. As a matter of fact,
no practical home disc -recording equipment exists and so the tape machine in
55
TAPE RECORDERS
Ampex two -speed tape recorder -stereophonic reproducer (at left) can be used by itself or
as part of an integrated stereo system. Magnecordette, at right, is portable-it has a handlestereo tape-record and playback unit, plus dual VU meters for adjusting levels
the home was unique, at least as a recording device. It was ideal as a playback
machine, too. No problem here of tracking force, cartridge compliances, tracking error, stylus-tip radius, stylus wear or record wear. The tape is erasable,
re -usable and spliceable ; it is also long-lasting.
On the minus side are the facts that many of the tape machines are relatively
bulky and that it takes some skill to operate a tape deck properly. Threading
tape is more difficult than putting on a record and it isn't easy to spot a
particular point on two- or four -channel tapes. Less of the musical repertory
is available on tape than on discs and, as an added hazard, you can record
right over an existing recording if you are careless. Also good tape equipment
costs more than good disc equipment, and so do prerecorded tapes.
Evaluating all these plusses and minuses, we can describe the audio purist
who prefers tape as a person who is willing to pay more, and suffer a few
physical inconveniences, in order to get higher-quality sound through a
medium that will not deteriorate with use. This is a very' tenable position,
buttressed by the fact that owners of tape equipment not only enjoy the playback features of it but can also record broadcasts over radio and TV (including
stereo, with the right equipment), copy disc recordings while they are still
new and have suffered no deterioration, copy their 78 -rpm discs to preserve
the music and conserve space, and make live recordings when it suits them.
THESE ARE THE COMPONENTS
Let's take a look at the equipment itself, which can be broken down into
mechanical and electrical, or electronic, components. Mechanically, the tape transport mechanism is something like a movie projector. There are two reels :
supply and take-up. Tape winds from supply reel to take-up reel, and must
eventually be rewound if it is to be used again for supply; this operation
56
budget -priced stereo tape deg is the Telectro, at left, which utilizes piano -key
controls. Shown on the right is the Ferrograph, a professional portable stereo tape unit that
features single VU meter, separate controls for each stereo channel, editing facilities
A
may be powered by one, two or three electric motors. The requirements of
unvarying velocity are similar to those for disc equipment, and a minimum
of wow is, again, one measure of quality. Mechanical facilities for starting,
stopping, fast rewind and fast forward, revolution counting, automatic shutoff when the supply reel is empty, and speed-change mechanisms more or less
complete the equipment. Electronically, we have a recording head and recording preamp, playback head, playback preamp, power amplifier and loudspeaker.
.The same preamp may be used for both recording and playback, and the power
amplifier may be used to monitor while recording. Recording level indicators,
volume and tone controls, input circuit for an external signal source (such as
a tuner) and output circuits for external speakers and/or external power
amplifier and speakers round out the list of principal electronic elements.
THE ALL-INCLUSIVE TAPE DECK
Since it is rare to find a really high-quality sound -reproduction system in
a popular -priced, portable tape recorder, the hi-fi enthusiast usually feeds
the tape signal into an external hi-fi system. This gives rise to the "tape
deck." Essentially, this is the mechanical, or tape -transport, equipment only.
It may be provided on a mounting plate for rack or cabinet installation, or it
may come in its own free-standing case. To this must be added the preamp,
power amplifier and loudspeaker system. A microphone must be added for
live recording. A vast variety of facilities can be provided in a tape deck :
single-track, dual-track, four -track, monophonic, stereo (two types, as we'll
explain in a moment), and tape speeds of 15, 71,4, 33t and even 13i ips.
Considerably more equipment is available to play back stereo than to record
it. Thus we find (1) straight monophonic equipment for playback; (2) mono
for record and playback; (3) mono and stereo playback; (4) mono record and
57
TAPE RECORDERS
RECORDING
HEAD
COIL
i
Tape passes under electromagnet
in tape head. Sound signals are the end
POLES REVERSE AS
epc"\NO
CURRENT ALTERNATES
product of variations that tape
induces in the field of electromagnet
playback plus stereo playback; (5) record and playback of both mono and
stereo; (6) straight stereo playback; and (7) stereo record and playback.
Your choice of equipment will depend on the uses you plan to put it to. Choose
a type that provides some flexibility and ease of modification, to permit you
to change your mind about features you want and also to modernize as changes
or improvements are announced. It is also well to be aware of the fact that
many so-called stereo tape recorders will not actually record stereo, although
they do play it back. This confusion in nomenclature is due to the acceptance
of the term tape recorder, as mentioned in the opening paragraphs of this
chapter. In addition, the buyer should be aware of the fact that some so-called
stereo units do not have the complete dual audio system needed for stereo
and require supplementary amplifiers, preamps and/or speakers. Another
point to remember: buy the record or record -playback preamps that were
designed to go with your tape deck. These are more apt to provide optimum
equalization and voltage gain than another manufacturer's equipment.
When stereo tape first got started, monophonic equipment was converted
to stereo by adding another head a little distance from the first one (to record
on the second track of dual -track tape). These were called staggered heads.
Newer equipment features all -in-one stereo tape heads which are referred to
as "stacked" or "in -line." Prerecorded tapes must be designated for one or
the other arrangement; they won't work on both.
Before assessing the currently available stereo equipment, we should like
to digress for a moment and discuss the long-heralded but little seen RCA
machine featuring a tape magazine or cartridge. This machine was designed
to obviate the difficulty and inconvenience of threading and also té make
possible a lower cost per minute of recording time on stereo. A quarter -inch
tape is used and yet four tracks are provided. Operating at only 3% ips,
these tapes can provide two hours of mono or one hour of stereo program.
This indicates about 600 feet of tape in the magazine. By comparison, the
58
SPEED CHANGE KNOB
RECORDING HEAD AND
CAPSTAN HOUSING
FEED REEL
r_ \
(IM
,
1 a`\
TAKE-UP REEL
THREADING SLOT
RECORD -SAFETY LOCK
VOLUME LEVEL
INDICATOR
OUTPUT JACK
ON-OFF
TONE CONTROL
INPUT J MIKE
JACKS 1 PHONO
VOLUME CONTROL
Line diagram shows a typical
two-speed tape recorder with push -key
LOUDSPEAKER
CONTROLS:
RECORD
FAST FORWARD
STOP
controls. Inclusion of a speaker
means that the unit is self-contained
REWIND
PLAY
standard seven-inch reel contains 1,200 feet and would, if recording four track stereo at 3 e4 ips, provide slightly over two hours of entertainment. Using
the extra -long-playing or "super thin" tape (2,400 feet on a seven-inch reel)
would provide 414 hours under the same conditions.
Two models-SCP2 and SCP3-have been described but only one has been
shown, and even this is yet to be proved from the consumer point of view.
If successful, it might bring about great changes in the tape and tape -recorder
industry, but at this writing, it is really too early to know what it will do.
PORTABLE VS. NON -PORTABLE
Prior to stereo, there could be considerable discussion of the relative merits
of buying a complete unit (probably portable) vs. buying a tape deck and
associated components individually, for custom (and permanent) installation.
With stereo, however, virtually no direct comparison is possible. A complete
unit would consist of the tape deck plus two record -playback preamps, two
power amplifiers (or one dual amp) and two loudspeakers or loudspeaker
systems. To be comparable to the portable monophonic tape recorder, all this
has to be enclosed in a single carrying case. It is unlikely that such units will
ever be sales leaders. Much more likely to be popular are units that are somewhat smaller and anywhere from 25 per cent to 75 per cent complete.
If you want to carry the equipment around, or if you do not have room in
your rig for permanently installed tape-recording equipment, you will want
equipment in carrying cases. If, on the other hand, you are able to put the
tape recorder into your custom hi-fi installation and connect it to your existing
set of amps, preamps and speakers, or into one of the large equipment cabinets
now available for stereo use, then you can choose tape equipment that does not
duplicate these audio functions.
Besides the more obvious features incorporated into tape recorders, there
59
TAPE RECORDERS
Viking 75 is shown
in wood cabinet designed
especially for it.
Unit operates at 71/2 ips,
convertible to 3414 ips
are a number of accessories and refinements that you may consider necessary,
advisable or at least desirable. The machine is rare that does not include a
recording level indicator. This is a must, and if you buy a machine without
one, you should add it as an accessory. The recording -level indicator tells you
when the input level is high enough and warns you when it is too high. The
device can be either a neon flasher or a meter that actually measures the input.
Meters are more expensive; though desirable, they are not essential.
A revolution counter enables you to find a particular passage on the tape,
note where speed changes have been made, and so forth. To pinpoint a spot
on the tape, it is necessary to be able to listen (or monitor) while you are
looking. Elaborate editing facilities are desirable only if you plan to do
extensive and critical recording.
To minimize head wear, it is desirable to have means for lifting the tape
off (or away from) the heads during rewind and fast -forward operation.
Tape lifters are available on many recorders, either as original or accessory
equipment. For instance, the Viking 85 series tape decks include tape lifters,
while this feature may be added on the 75 series for an additional $5.50. The
popular Bell T-200 deck includes lifters, and virtually all of the more expensive
units such as Ampex include this feature as a matter of course.
Most tape recorders have combination record -playback heads. A refinement on more expensive machines is to have separate heads for each function.
This provides slightly better quality plus the ability to monitor while recording,
another feature we would classify as desirable but not necessary for average
home use. The number of heads provided is, of course, complicated by the
services offered (mono, stereo, half-track, quarter -track, etc.). The American
Concertone 30 series, for instance, is provided with five heads, to which a sixth
can be added for stereo playback. The Ampex 900 series has three heads-one
each for erase, record and playback, of either mono or stereo.
60
It is possible to provide for all transport needs with one motor plus appropriate belt linkage and switching facilities, or to have as many as three motors.
Additional motors tend to be used in the finest equipment, but a good machine
can be designed around a single motor-the Ampex 900 for one.
THE QUESTION OF PRICE
How much shall you spend on a tàpe recorder? This is an area where the
range is very wide and the sky's the limit. Good units for home use range from
a low of around $100 to a high in the neighborhood of $1,000. Units for professional use are even costlier. Bell provides a popular, versatile and high quality line in the T-200 series. The basic tape transport is available with
different -head combinations for approximately $110-$150, with the $150 unit
able to record as well as play back stereo. The RP-120 record -playback preamp
is about $60, of which two are needed for stereo recording. The complete unit
without sound system or mike, therefore, is about $270. An equivalent Viking
unit, the 85 series with two RP -61 record-playback preamps, comes to about
$298. The Pentron TM -4 tape deck with two record -playback preamps is
approximately the same price as the Bell unit with equivalent equipment : $270.
The Ampro 758 provides a complete sound system for mono only (with
loudspeaker) for about $285. To make stereo playback possible, an additional
power amplifier and speaker would be needed, while to record stereo, another
record -playback amplifier is called for. The Webster 290 at about $380 has two
left is the Pentron
Model X-8 stereo recorder.
Above is the RCA tape
magazine. Unit is roughly
the size of this book,
plays at speed of 33/4 ips
At
61
TAPE RECORDERS
left is Norelco's
Stereo Continental; unit costs
$299.50 with carrying case
At
1
.l.11`Z
y-,e,2%141,741`
--...40791.7111011
-w
Tandberg portable stereo unit,
left, is available with extension
speakers. Bell portable 406,
above, uses new four -track stereo
cartridges, costs $299.95
amplifiers, needs one additional loudspeaker to play back stereo and an amplifier to record stereo. The Ampex A122, priced at $495, has no sound system,
can play back stereo but needs an additional preamp. These examples illustrate
the fact that tape -recorder prices are frequently difficult to compare because
of the wide variety of possible features.
In this chapter, we have told you some things you should know if you are
planning to buy a tape recorder. Before leaving the subject of tape recorders,
we owe it to the reader to dwell at least lightly on the question : Should you
buy one? Remembering that this is a book about stereo, the answer must
depend on the relation between tape and stereo. The two areas of discussion
are playback and recording. Let's look first at playback.
In stereo playback, we are principally concerned with prerecorded tapes.
A large and varied repertory is available on tapes, having been building for
a period of six or seven years, as opposed to less than two for the stereo disc.
Music on stereo tapes ranges from the popular symphonies of Beethoven and
Brahms to the more esoteric works of the modern and the pre -Bach composers.
Stereo tapes also offer a wide range of material designed to show off your rig
to the best advantage-trains, planes, Trinidad steel bands and earthquakes.
Although at this time (June, 1959) new tapes are not being issued or distributed on the scale they were a year or two ago, it is likely that the better estab-
62
lished companies will continue to supply them when the stereo -disc market
has settled down into a discernible pattern. Prerecorded stereo tapes offer
owners economy in storage space, if not in price. They can be spliced if they
break; never become warped or scratched, as records do. And, unlike records,
they won't wear out with repeated playings.
VARIOUS PROS AND CONS
Prerecorded stereo tapes, however, are expensive. Up to now, at least, they
have been recorded at 7% ips on a two -track tape, using one track for each
channel. From the standpoint of time duration, they are equivalent to singletrack tapes and have a potential of one-half hour on a 1,200 -foot reel. Cost per
minute of these prerecorded stereo tapes is about twice that of stereo discs.
Stereo discs of 12 inches list for about $5.95, while a comparable quantity of
music on stereo tape will usually be in the neighborhood of $11.95. It can
be expected that the price of prerecorded tapes will come down, especially
now that RCA has brought out its magazine -loaded tapes. These are four -track
tapes that operate at 3% ips. Used for stereo, they can yield up to two hours
of playing time on a 1,200 -foot reel. This will cut down on the amount of raw
material that goes into a tape and will reduce the cost of the finished product
substantially. The magazine-loaded tapes will cost from $4.95 to $8.95.
Another matter worth considering is the resurgence of quarter-track, 7%ips reel-to-reel tapes. Fidelity at this speed seems to approximate the quality
that is possible with only two tracks, and from all indications a fine library of
program material should be available in a very short time. It seems likely
that in the near future cartridges will be something of a mass medium, while
quarter -track reel-to-reel will be a quality medium.
Should you consider any new unit designed to handle the tape magazines?
That question is still difficult to answer. Remember that in its present form
it will accept only the magazine it was designed for. This closes the door to
all previously recorded material, as well as to future recordings on larger reels
of tape. However, if it becomes available as a universal unit-one able to play
both reels and magazines-it may well be worth your serious attention. So
far, also, this unit is not available as to tape deck; it can be bought only as a
complete unit, including a so-so amplifier.
Turning now to recording, we find that there are at least three uses for
stereo recorders in the home. You can record stereo broadcasts, if you have
a stereo tuner; you can tape someone else's stereo discs, if you've a mind to;
and you can make live stereo recordings. We believe the last use is unlikely
for the average owner. The technique is complicated, and there would be little
occasion to do so in most homes. The other two uses will be somewhat less
infrequent, but are still apt to be quite limited because of the time and expertise necessary to do the job properly.
This, then, is the story on stereo tape: not necessarily part of a "starter"
assembly of a stereo system, but a good buy "for the man who has everything."
63
''3ED_BMI
WITH HIGH FIDELITY. YOU'RE NOT LIMITED TO
STEREO FROM TAPES OR RECORDS
YOU CAN. IN
FACT. RECEIVE FINE STEREO OFF THE AIR AT
ADDITIONAL COST- AND EVEN MAKE YOUR OWN
STEREO TAPES
YOU WILL FIND AVAILABLE AN
EXCELLENT CHOICE OF STEREO
TUNERS
CHAPTER
6
't is hard to imagine a home -entertainment system without a radio, although
some audio enthusiasts start building a hi-fi system around a phonograph and
an amplifier. This, from our point of view, is overlooking a tremendous quantity of excellent free entertainment. FM added a new note of quality to radio,
and stereocasting presents many new vistas.
For years, FM was the stepchild of American broadcasting. Developed just
prior to World War II, few commercial outlets were able to build before wartime controls put an end to building. At the conclusion of the war, the FM
band was pushed aside to make room for television. In so doing, every FM set
in the country (there were few, and they were expensive) was rendered
obsolete. Then, as new stations opened in the new band, AM owners began
duplicating their programs on both AM and FM, throwing the latter in free
65
TUNERS
i
1\
r
UNMODULATED RADIO FREQUENCY CARRIER WAVES
AUDIO FREQUENCY WAVES
V-AmmlúliÌ
III-111ff
4.
`tilil!I
RADIO FREQUENCY CARRIER WAVES, AMPLITUDE MODULATED BY AUDIO FREQUENCY
11111,1
II
111''!
FREQUENCY MODULATED WAVES
Unmodulated radio -frequency carrier waves, both AM and FM, have constant frequency
and amplitude (top). Audio-frequency programs are superimposed on the carrier waves to give
amplitude modulation (AM), line 3, and frequency modulation (FM), line 4
as an inducement to advertisers. Simultaneously, however, a few FM licensees
began broadcasting good music and other programs aimed at a minority
audience. They sprang up first in the larger cities. Today, however, there are
several hundred scattered throughout the United States. Educational broadcasters, in the form of school boards and universities, also took to the FM band
(Congress had wisely reserved a portion of it solely for educational use).
It was these outlets-both commercial and non-commercial-that showed
the way originally in high-fidelity FM transmission of serious music, plays and
public -affairs programs, and these are the stations that now account for much
of the nation's stereocasting. Since educational stations aren't bothered about
selling time, they can and do work with commercial stations in their areas to
produce FM -AM and FM -TV stereo. Lehigh University's FM station, for
example, frequently operates with commercial stations in the Allentown Bethlehem area to provide Pennsylvania listeners with stereo. In Chicago,
WFMT and the city's educational television outlet do a similar job. Live
concerts by the Boston Symphony are broadcast stereophonically by the city's
good music stations in conjunction with one or more educational broadcasters.
The bulk of AM -FM stereo is being done by such frankly commercial stations
66
as WFLN in Philadelphia. WQXR in New York and WCRB in Boston. Before
buying a tuner, you should check on listening conditions in your area.
THE NEED FOR SELECTIVITY
Before proceeding into the realm of stereo, though, we should pause a
moment to consider what functions radios and tuners perform. The AM
stations broadcast in the band between 540 and 1,600 kilocycles ; FM is between
88 and 108 megacycles. Each station has an assigned carrier frequency, which,
as its name implies, is merely a vehicle to transport sound (audio frequency)
programs to you. It is this carrier frequency that your tuner "tunes in." The
first thing that the tuner must do, therefore, is to select one station at a time,
rejecting all other stations and noises. Its ability to do so depends on its
selectivity, combined with external conditions such as the strength of the
particular station's signal in your locality, the size and quality of your tuner,
the aerial and the weather conditions during the broadcast. The ability to
tune in weak signals satisfactorily is a measure of the tuner's sensitivity.
"Sharp" tuning increases sensitivity but somewhat degrades fidelity. Therefore, tuners often have a broad -sharp sensitivity switch, permitting full
fidelity on normal -strength stations and full sensitivity on weak ones.
The carrier frequency that has been tuned in has superimposed upon it the
audio -frequency program information; another way to say this is that the
carrier has been modulated with an audio -frequency signal. At the tuning
stage, the radio isn't concerned with this modulation, which represents a
relatively small amount of plus -and-minus change in the basic carrier frequency. The first thing it wants to do is amplify this signal. To do so, it
converts all carrier frequencies to a single, lower frequency, known as the
RADIO FREQUENCY
CARRIER AMPLITUDE
MODULATED WITH
AUDIO FREQUENCY SIGNAL
TUNER
AUDIO FREQUENCY
SIGNAL DETECTED
(Removed from the
carrier)
tuner receives a carrier frequency modulated by an audio signal. The tuner
detects the audio signal, separates it from the carrier frequency and eliminates some of the
distortion, then passes the audio signal along to the stereo amplifier
A
67
TUNERS
Fisher AM -FM stereo tuner has
separate tuning, tuning indicators for
AM and FM broadcast bands
Priced in the deluxe class
($250), Ampex stereo tuner comes
in hardwood case or uncased
Scott 330-C stereo tuner
has separate AM and FM dials, common meter
for the proper stereo adjustments
-_.
moderately priced unit,
Sargent-Rayment stereo tuner offers
a minimum of stereo controls
A
Madison Fielding 330 tuner
comes with its own wood cabinet,
metal bracket and legs
68
intermediate frequency. (In AM, this is 456 KC; in FM it is 10.7 megacycles;
in TV receivers it is 40 megacycles.) At this stage, the signal is subjected to
substantial voltage amplification. Next, the process of detection strips off
the audio information from the intermediate frequency. We now have an
audio signal and we have finished with the tuner. The audio signal passes into
an audio amplifier where, after power amplification, it goes to the loudspeaker.
The term AM is short for amplitude modulation, which means that the
carrier frequency varies in volume. In FM, the variations are not in the
volume, but in the frequency itself. Because of this, and because of the much
wider broadcast band, a full -frequency response is possible in FM broadcasting. In addition, FM is relatively impervious to noise and static. In an
urban or suburban area-that is, an area close to where most broadcasting
stations are located-FM on a good tuner is usually more brilliant than AM
in tonal quality. In rural areas, where signal strength is apt to be low, FM's
ability to ignore static and other air -borne electrical noise, as well as signals
from other stations, provides a reception quality greatly superior to AM.
Radio in the hi-fi rig can assume several forms and several functions. In
form, there can be a tuner only, with separate preamp and amplifier; or there
can be a complete receiver that includes all three functions. We have observed
earlier that there is no good reason why an all -in -one unit cannot provide
nearly as good quality as separately assembled components. On the other
hand, the latter choice provides greater flexibility which, to some people, may
outweigh the simplicity of purchasing and installing a single unit. Suffice it
to say at this point that several possibilities present themselves for the distribution of control knobs and functions. They include the following: (a)
complete receiver; (b) tuner plus combination preamp-amp; (c) combined
tuner/preamp, plus power amp; (d) separate tuner, preamp and power amp.
A point worth remembering about the installation of any sort of tuner is
that for the really good reception most tuners are designed to give, you must
have a good antenna. You can get double duty from your TV antenna, although
if you want to listen to both TV and FM radio at the same time, you will need
a switching device. If you install a separate FM antenna, be sure that it is
oriented to pick up your favorite stations; experiment first.
STEREO BROADCASTING
One of the earliest forms of stereo experimentation was the AM -FM simulcast, in which two radio transmitters were used to broadcast the two sound
channels (one on AM, one on FM) and two receivers were used to receive it.
Simultaneous stereo broadcasting using TV instead of FM as one of the sound
channels has also been employed. No matter what is broadcast by these
methods, there is bound to be a real question about the quality of the stereo
that can be received and heard in the home. The question arises from the
obvious mismatch of most of the equipment used and the haphazard speaker
placement that results from the convenient positioning of the mono receivers.
69
RECORD PLAYERS
a
Madison Fielding MX 100 and Harman-Kardon MX 20 multiplex adapters
can be used with tuners of most manufacturers; are designed for use with Crosby system
of multiplexing, although they can readily be converted to other stereo systems
in
The Fisher MPX 10 adapter features maximum of controls and functions
to plug into
designed
is
specially
adapter
250
MA
Harman-Kardon
the
space;
of
minimum
the H -K stereo tuner, which has allowance of space on chassis for it
Multiplexing offers the possibility of true stereo broadcasting with a compatible system, using only one transmitter-an important consideration for
the broadcaster. If you're a regular FM listener, you may have noticed two
faint signals, one on either side of the main signal of your favorite FM
station. These signals, called side bands, generally carry the same program
material as the main band. It's possible, however, to split one of these bands
off and transmit a complementary stereo signal, or even an entirely different
program, over it. But if stereo utilizes one of these bands for the left channel
and the main broadcast band for right, FM listeners not equipped for stereo
hear only half the show. There are a number of systems designed to overcome
this problem and provide compatibility. The front runner at this time, and
the one most likely to become standard, is the Crosby system. Crosby's main
channel contains the sum of the two stereo channels (Channel A plus Channel
B), while the side band contains a phase -inverted A minus B signal. A multiplex adapter splits the side band off the main channel, subtracts it from the
main signal and provides a reconstituted pair of stereo signals. All FM tuners
receive both signals now; if yours doesn't have provision for a multiplex
adapter, you can have an outlet added by your serviceman for about $10.
70
Bogen TC 200 (left) and H. H. Scott Model 320 are two budget -priced
stereo tuners. The former is equipped for AM -FM stereocasts, the latter for FM multiplex.
Both cost roughly what medium-priced non -stereo tuners cost a year or so ago
First three -in -ones to make their appearance are Fisher 600 (left), which
features stereo 40 -watt amplifier; Harman-Kardon TA 230, AM -FM stereo tuner, dual preamps
and 20 -watt stereo amplifier. These units require only the addition of speakers
Multiplex adapters are available from several manufacturers, including Harman-Kardon, Sherwood, Madison Fielding, Karg and Fisher. Prices range
from $50 to $70. Basically, though, the stereo tuners now on the market are
designed to receive AM/FM stereo.
It sounds relatively simple to receive both AM and FM on an AM -FM tuner.
But equipment to receive them both at the same time is a horse of a different
color. Thus the stereo tuner for AM/FM stereocasts is really two complete,
separate tuners on one chassis, with two tuning pointers and two tuning knobs.
Such tuners are described as being capable of "simultaneous reception" of
both AM and FM, or as having "separate channels" for AM and FM.
Referring back to our list of the four forms in which we can buy tuners,
we find, therefore, that the tuner -only must be a stereo tuner; and a piece of
equipment that includes preamplifiers and power amplifiers must have dual
preamps and dual amplifiers for stereo. A stereo receiver, then, is really a
complete system for stereo, except for the loudspeakers. Tuners incorporating preamps, or preamps plus power amplifiers (that is, receivers), include
among their controls individual tonal adjustments and balancing for each
channel. All the better units provide either a "tuning eye" or tuning meter,
71
TUNERS
Pilot and Sargent-Rayment have stereo tuners equipped with stereo preamps. Pilot
FA 690, shown at left, has full tuner and preamp controls, separate AM and fM tuning
bars; the S-R tuner uses a combination of dials and buttons for controls
\\\
4affliaaNial.
The Harman-Kardon T 250 AM -FM stereo tuner has space on chassis
for plug-in FM multiplex adapter. The Bogen ST 662 features AM -FM stereo too, but
owners can convert to multiplex simply by attaching a multiplex converter
considered a sine qua non for FM. A tuning meter has the advantage of
being more accurate and easier to use than the "eye," other things being
equal; but many meters are so tiny that they are hard to read, so a tuning
eye (really a small cathode ray tube) might be preferable. As with other
hi-fi components, the more units you combine on one chassis the lower the
proportionate cost of each, because of the economy of the single chassis and
case. At the same time, some flexibility is sacrificed.
The biggest virtue of the stereo tuner is that simply by working properly
it receives AM/FM stereo simulcasts the way they should be receivedon equipment of identical quality. That is, two receivers of the same high
quality but located in one spot, easy to use and convenient to tune, and all
ready to go whenever such a broadcast comes along.
Multiplexing is extremely limited at this time, for a good reason. The
Federal Communications Commission must approve new techniques in broadcasting. Although the FCC has licensed a few broadcasters to conduct experimental stereocasts (mostly during the daylight hours or late at night), it has
not yet approved multiplexing in any form. In the event it approves some
system other than the Crosby (there are nearly twenty competitors), those
adapters which work only with the Crosby system will become obsolete. Most
units made for hi-fi use, however, are easily convertible to other systems.
72
Karg FM-only tuner must
be adjusted for each owner,
since this set has no
tuning dial. Karg also has a
stereo multiplex adapter
Heath AM-FM tuner kit is
one of several on market that
can be used as integral
part of stereo system. Kit is
easy to build, inexpensive
Before rushing out and buying a tuner, it will pay to find out what kind of
broadcasting is being done in your area. If, for example, there is no FM
station in your listening area, there's little point in buying an AM -FM stereo
rig. If, on the other hand, your local AM stations duplicate all their programming on FM-sans stereo-then you can save money by buying an FM -only
tuner and hoping for multiplex. Listeners in the larger metropolitan centers,
though, will want a good AM -FM stereo tuner with provision for multiplex
adapter, for there is sufficient program material available now in such areas
as Boston, New York, Philadelphia, Washington, Miami, Chicago and San
Francisco-to name just a few-to make such an investment worth while.
To get back to tuners, we believe in this line of reasoning: If you're starting
out from scratch, and have stereocasting in your area now, by all means get
a stereo tuner. If you already have a good tuner, you don't need to replace it
unless you really desire to listen to stereo broadcasts. Check the stations in
your locality first and see how much is available and what it is.
If you are going to buy a tuner, which of the four choices should you make
(tuner only, tuner plus preamp, etc.) ? This is again a matter of economics,
plus convenience. Single units give you everything in one place and represent
a better dollar value, but offer less in the way of flexibility in selection and
physical placement than do the other alternatives.
73
A GOOD LOUDSPEAKER CAN'T DO ANYTHING TO
IMPROVE THE PROGRAM MATERIAL THAT'S FED
INTO IT, BUT A POOR SPEAKER IS PRACTICALLY
CERTAIN TO RUIN
LISTENING PLEASURE
SO
KEEP IN MIND THE PAY-OFF END OF YOUR STEREO
PLAYBACK SYSTEM -
LOUDSPEAKERS
CHAPTER
7
The loudspeaker is the business end of the audio chain-it is what brings
the sound to your ears by converting audio -frequency electrical energy into
sound waves. The commonest and most basic type of loudspeaker is the
cone, which gets its name from the fact that it employs a heavy paper cone
to set up vibrations in the air. Audio -frequency electrical energy flows
through a coil of wire known as the voice coil. Situated in the air gap of a
permanent magnet, the coil moves in and out, imparting this movement to
the cone. The conversion efficiency of this device (from electrical watts to
acoustical watts of sound pressure) is generally low. The normal expectancy
is about 5 to 10 per cent efficiency; 25 per cent is considered very good. It
is important to know that this relatively low efficiency is the nature of the
beast in general, not a shortcoming of a particular product.
75
LOUDSPEAKERS
Elements of a two-way speaker system
by University include dual -voice coil woofer,
tweeter and crossover network
Set in modern surroundings, Jensen's
DS 100 Dual Stereo system allows listener
to direct sound to any room area
Electro -Voice's Stereo
speaker is one answer to stereo's
second-channel problem
Bozak's B-304 binaural cabinet has speaker
systems facing opposite ends. Doors open to any
angle, permitting deflection of sound
Uniform efficiency and performance over a wide range of frequencies
15 to 15,000 cps) is not a characteristic of the cone speaker. The
response to different frequencies is somewhat related to the maximum
diameter of the cone. A general rule is that the larger the cone, the lower
the frequency it can handle. Common sizes range from 4 to 15 inches, with
the latter considered necessary by purists for really good bass response, but
because the 15-inchers cost somewhat more, usually require tweeters and
take up extra space, the 12 -inch size is more popular. Size alone, of course,
does not guarantee a good speaker. And, paradoxically, a large speaker is
not apt to be good at high frequencies. This, again, is the nature of the
beast. A small cone responds most readily to the rapid and minute fluctuations of high frequencies, while the large cone is most suitable to the wave
lengths and large cone movements associated with bass frequencies.
(that is,
76
British import, the Goodmans Delta speaker system
covers full range in comparatively small, flexible enclosure.
It can be used as bookshelf speaker or mounted on legs
A
University Stereoflex is
add-on speaker, for use with
the existing system
The Stereodot system manufactured by Stephens Trusonic is a unique pair
of trim, compact add-ons designed to flank an existing full -range speaker to provide
additional channels for stereo. Add-ons and controls cost $169.50
It is because of this seeming paradox that two speakers are often used;
a large cone functions as a "woofer" for the bass range and a small
"tweeter" does the job for the treble range. Sometimes this total range is
broken into three, four or more sections, each handled by a specialized
speaker. Such systems make it possible to engineer each segment of the
system for maximum efficiency and fidelity within a relatively narrow range,
rather than for a compromise result over the entire range. Substitutes for
two- or three -speaker systems are the "coaxial" or "triaxial" speakers which
are actually such a combination of speakers connected to the same frame
on a common axis. In either case, separate or axially mounted, multi -speaker
systems are designed with "crossover" points-points at which the speakers
take over from each other in doing their separate jobs on portions of the
frequency spectrum. A two -speaker system might, for instance, have a
77
LOUDSPEAKERS
In mahogany or walnut, 1.B. Lansing's
Bel -Aire bookshelf model contains a ring
tweeter and an eight -inch speaker
Containing an eight -inch speaker,
the R/J Wharfedale, a British import, is
a popular bookshelf model
At left is the University
Ultra-Linear 12 -inch speaker system,
for shelf or floor placement
crossover at 1,500 cps. The woofer then would cover 30-1,500 cycles, the
tweeter 1,500-15,000. A three -speaker system might have an additional
crossover to a mid -range speaker at 800 cycles. This speaker would reproduce the frequencies from 800 cps to 1,500 cps.
As the frequencies get higher, they tend to propagate more like beams
of light, which is to say that they attenuate, or fall off, as you get away
from the axis of the speaker. To widen the horizontal angle of dispersion,
horns of one kind or another are often used with tweeters. Such horns also
tend to improve the efficiency of the speakers by improving their coupling
to the air, an effect similar to the one you get when you talk through a
megaphone, and still another reason why it is more practical to have
tweeters and woofers rather than a single wide -range speaker is that the
tweeter can be designed for maximum dispersion as well as efficiency.
The descriptive terminology for loudspeakers and speaker systems can be
confusing. There will usually be a statement such as "frequency response
30-12,000 cps." Strictly speaking, that is not a description of "response" but
of range. It tells us nothing about the speaker's relative response at different
parts of its range; nor whether it has a smooth or an erratic response over
78
its range. It is well to bear in mind that wide range is not in itself a
guarantee of a good speaker. Another stopper is magnet weight. Heavy
magnets are generally associated with power -handling capacity, but the
correlation is not a direct one; when judging a speaker, it is wise to note
the stated capacity rather than the magnet weight in pounds.
ELECTROSTATIC SPEAKERS
About four years ago, the electrostatic speaker made its appearance.
Structurally, this speaker bears no resemblance to the dynamic cone speaker
we have been discussing. The electrostatic has no cone, voice coil or magnet.
Its name derives from the fact that it works on an electrostatic rather than
an electromagnetic principle. Basically, the unit is a large capacitor (condenser) with three plates, using air as a dielectric (or medium permitting
the passage of the lines of force in the electrostatic field). You might think
of it as a cheese sandwich with the two outside plates (the bread) stationary
and the center (the cheese) movable between them (varying the capacitance). The important characteristic of capacitors for hi-fi is that they offer
less opposition to the flow of current as the frequency gets higher. For
this reason, we would expect electrostatic speakers to be suited for service
as tweeters, and they are. As such, they present a larger radiating surface
than the average tweeter and are felt to have a much better and smoother
high -frequency response than the average tweeter.
We have heard some excellent results from electrostatic speakers and
believe they have exciting possibilities for the future. At the present writing,
however, there are few makes and models on the market (compared with
the great profusion of magnetic speakers) and, with the exception of one
The Eico HFS-2'employs
floating tweeters for highs,
folded horn for bass
KLH's Model One
is acoustic -suspension design,
fine for stereo listening
79
LOUDSPEAKERS
Pickering Isophase, above, is an
electrostatic tweeter. It offers fine treble
response, should be used with a woofer
The Acoustic Research AR -3 speaker system
utilizes cabinets filled with fiber glass, offers
excellent bass response for its size
JansZen's Model 130 is a tweeter
electrostatic design. This unit comes in
various wood finishes to match decor
Model SP 12B, by Electro-Voice
is a 12 -inch speaker with one-pound
ceramic magnet; price is $34.30
or two Japanese imports, they are rather expensive. The two American firms
that have pioneered in electrostatics are JansZen and Pickering, and their
products range from $80 to $220. Other factors to be considered are appearance and physical flexibility. Unlike cone speakers, electrostatics are not
available for mounting or "building in" in any way that suits you. Because
of their special design and construction they come already enclosed, which
may add up to convenience and economy if you happen to like the looks of
them and can fit them into your available space.
CONE SPEAKERS
The basic cone speaker, like the "works" of a watch, has to be covered in
some way. Otherwise it would be unsightly, would work poorly and would
be in danger of damage. To reproduce low frequencies efficiently, the front
of the cone speaker has to be acoustically separated from the rear. If you
take a large board, cut a hole in it and mount the speaker in the hole, you
have performed the acoustical separation with what is called a "baffle."
Mount it in a wall, with the rear open, and you have an "infinite baffle."
Or mount it inconspicuously, cover it with a piece of porous cloth, and you
have also given it rigidity, safety and protection from dust.
80
SPIDER
MAGNET
CONE
SUSPENSION
Diagram of good cone loudspeaker shows how basic elements work: signals
from amplifier enter voice coil, causing it to vibrate within the field of the magnet.
These make cone vibrate, setting up shock waves in air that are heard as sound
When a baffle is attached to the front of a box, we have the basic enclosure
cabinet. Included are open-backs, closed-backs, vented (or ported) enclosures,
enclosures that provide "horn loading" and many others. Some enclosure
cabinets merely enclose, without engineering complications, but even the
simplest open-back cabinet provides a pretty good baffle. More elaborate
enclosures attempt by their construction to extend the low-frequency
response, raise the speaker's efficiency at the low -frequency end, smooth out
the low -frequency response and provide better coupling to the air. Other
enclosures of special design are intended to produce good low-frequency
response with relatively small speakers in a relatively small space. Remember
the rule of thumb is that for bass response you should have a big speaker.
Therefore these small space units are meant to provide good bass response
considering their size. They are not substitutes for larger jobs where space
and/or money are no object. The type we are describing might be lumped
together as the bookshelf type and include brands such as R -J, KLH and
AR. All three produce surprisingly good results, though some aficionados
advise supplementing them by a tweeter for the middle and high ranges.
When the front of the speaker cone moves out to produce a compression
of air, its rear is producing a rarification. We describe these two conditions
as being "out of phase." The ported or "bass reflex" cabinet attempts to
81
J.B. Lansing Ranger Paragon is
biggest stereo speaker. Fully eight
feet long, it houses two systems
a
Here is J.B. Lansing's Hartsfield,
monophonic corner horn. Unit should
be matched for best stereo
get these waves in phase at the front of the speaker (in a particular
narrow-frequency band) in order to reinforce and smooth out the bass
response. The bass reflex, pioneered by Jensen, is one of the earliest types
of enclosures for hi-fi and is still popular. It is a closed -back cabinet for
which a carefully contrived formula provides the over-all dimensions, the
size, shape and location of the port and, of course, the size and position of
the loudspeaker itself, to produce the desired results. Bass -reflex cabinets
tend to produce a sort of "boomy" bass that is not regarded with much
favor by audio enthusiasts these days.
We asked you to visualize a megaphone when we mentioned horns for
tweeters, and pointed out that a horn improves speaker efficiency. The size
of the horn bears a direct relation to the frequency (or frequency range)
involved. This is obvious if you compare a cornet and a tuba. Outside of a
movie theater (where size is no problem) horns for bass speakers were
considered impractical until Paul Klipsch started exploiting the Klipschorn.
His trick was to produce a "folded horn." While not exactly tiny, the folded
horn takes up no more than a quarter of the space needed by a full-length
horn for bass frequencies. This type of enclosure is designed to raise speaker
efficiency at low frequencies and-when driven by a capable speaker-it
almost invariably will do an excellent job.
82
Above are two examples of
cost -is-no -object mono speaker
design. Klipsch corner horn
is at left, Electro -Voice Patrician
at right. Both produce sound
that is of highest excellence. An
Electro -Voice Linden bookshelf
speaker shows the recent approach
to design of stereo speakers
Getting back to stereo, we find that we need two speakers or speaker
systems. The word "system" can refer to a two -speaker, high -low system
or a three-speaker, high-middle-low system, with appropriate networks. For
best results, these two systems should be identical, equivalent or equally
matched. Balance controls and separate tone controls for each channel can
help restore equality to unmatched systems. It follows that if you had
something like the biggest Klipschorn combined with, say a JanaZen 130
electrostatic tweeter, you would want two of each for stereo-if that is,
you had enough room and money. In other words, the necessity of duality
in stereo may preclude some choices that might have been made with mono.
Speaker systems for stereo are generally one of three types: two completely separate units; a one-piece unit containing two speakers or two sets
of speakers; and units with detachable speakers (usually portable) that can
be moved apart. A fourth variation might be a hi-fi unit or ensemble with
another speaker added to it. It has been generally conceded up to now that,
for optimum reproduction, stereo speakers should be six to ten feet apart.
This introduces a problem whose solution should be up to the manufacturers,
not the consumers. The problem is that having two speaker systems that far
apart-whether separate or in one cabinet-is relatively costly and preempts a good deal of space in the home. Manufacturers feel impelled to offer
83
LOUDSPEAKERS
Turn-ot-century decor was excellent for a love nest or other such purpose,
but would have left something to be desired as a listening room for hi-fi stereo. The
draperies, rugs and other impedimenta make this an acoustically dead room
something that will fit the small home and the small pocketbook, regardless
of whether it can provide optimum stereo. If very many of these small separation stereo units are sold, those who are responsible for stereo discs,
prerecorded stereo tapes and stereo broadcasts may have to take this into
consideration-that is, make program material available which sounds
different and interesting despite the limited separation of speakers.
CHOOSING
A
SYSTEM
What type of system is best? We would say without reservation that those
systems are best which permit relatively easy movement of the speakers (or
at least one of them) both as to distance (separation) and direction. Variations in the program material plus variations in room acoustics make it
virtually impossible to provide a permanently anchored set of speakers that
will produce optimum results on all material and in am* home. For this
reason, two compact speaker systems that are-or can be-mounted in two
separate cabinets, one for each stereo channel, is to be recommended. Very
elaborate arrangements have been suggested which take advantage of the
fact that bass frequencies are relatively non -directional while high frequencies are directional. But such arrangements suggest a lot of experimentation, plus complete freedom as to ultimate placement. Most married
84
Clean lines of modern room contrast in more ways than one with rococo
establishment on opposite page. The uncluttered decor of this room allows ample
unbroken areas to reflect sound, helps make it acoustically "live"
audiophiles, lacking such freedom, must find a compromise between perfection,
practicality and appearance.
We've been talking about two channels, but a third, phantom, channel is
making its appearance. The phantom channel is designed to fill up the
"hole in the middle' in much the same way that recording engineers plug it
up by using a phantom microphone channel that is divided between the two
basic channels when a disc is cut. The three-channel speaker puts a low frequency speaker between the two main units which derives its signal by
stealing a little from each of the two channels. Special circuits within the
amplifiers are necessary to provide the "third channel. Very little equipment
of this type is available at present, and we have not been able to evaluate
it in comparison with conventional two -channel stereo.
"Balancing," as the term applies to stereo controls, means equalizing the
sound output of the speaker systems or adjusting the balance until the result
is most pleasing. Properly, a balance control should cut one speaker down
while raising the other, so that the net combined volume is still the same.
Equalization of the tonal balance in the two speakers systems is also a very
desirable feature. It should also be possible to adjust the over-all volume of
the system without upsetting the balance by using a "master" volume control.
When two or more loudspeakers are near each other and facing so that
they "cover" the same area, they must be properly phased. When "in phase,"
85
LOUDSPEAKERS
Darkly shaded areas show parts of rectangular room that will have maximum stereo
effect when speakers are placed as shown. If the original speaker is corner type, choose an
along-the-wall type for the second unit. Third speaker improves sound even more
they produce maximum loudness; when "out of phase," their sounds tend to
cancel each other out, especially at bass frequencies. In speakers, being out
of phase usually means that one speaker cone is moving out while the other
is moving in. Flipping the phase control would reveal that one position
sounds better than the other. Phase differences can arise elsewhere than in
the loudspeaker, so the phasing control cannot be set permanently.
ROOM ACOUSTICS
Besides the various controls we have mentioned, it is possible (and usually
necessary) to fiddle with the speaker placement. This is due partly to the
nature of the stereo material and partly to room acoustics. "Room acoustics"
is a broad term that primarily describes the reverberation characteristics of
a room, and, in our present application, the effect of these characteristics
on the sound of music. Room acoustics can make or break a sound system;
identical hi-fi rigs will sound different in different rooms. In commercial
installations, acoustics are within the control of engineers and architects,
but in our homes we have little or no control over most of the factors on
which room acoustics depend. These are the dimensions of the room-length,
width and height-and their relation to each other; the nature of permanent
surfaces-walls, floors and ceiling-with respect to their ability to reflect
or absorb sound; and the nature and placement of furniture and furnishings.
In a room lined with sound -absorbent materials, there will be little if any
reverberation of sound, and we say it is a "dead room." A room with smooth
plaster walls, hard-surface floor covering and no drapes or upholstery would
86
If original speaker was along -wall type, second one for ste eo should be as
similar in design as possible. Three speakers are often the best solution to stereo coverage
an
in
oddly shaped room, but always experiment with placement before making decision
be a "live" room in which there would be much reverberation, or ricochet,
of sound. Reflected sound waves can reach you in phase, for reinforcement;
out of phase, for cancellation ; or in a wide variety of phases, producing din
or cacophony. How they reach you depends on room geometry, sound -source
placement, listener position and the wave length of the frequency reproduced.
While we cannot control many factors involved in room acoustics, we do
have some say about the nature and placement of furniture and furnishings, placement of the sound source and the listening position. The ideal
room is a compromise between the extremes of live and dead. The ideal
placement of equipment (sound source) is in a corner, facing along a diagonal
of the room. Second best is on the short wall, facing the long way of the
room. Either of these placements provides for maximum coverage of the
room with direct (rather than reflected) sound waves, using reverberationunder ideal conditions-only to reinforce and add brilliance. This arrangement also affords optimum distribution of high frequencies.
These same precepts would hold true for stereo, too, except that placing
the speaker systems six to ten feet apart precludes single -corner placement
and suggests that the best position is along one of the short walls of a rectangular room. The placement of chairs and sofas must be considered, because
people have to be able to listen. It is unfortunately rare to have a seating
arrangement that faces the short side of a room. More common is the
rectangular room that has a fireplace on one long wall with the seating
arrangement facing it. The writer resolved this problem by putting the main
equipment center and speaker system on one side of the fireplace and the
second speaker on the other side. The results are pleasant, though not ideal.
87
THERE ARE A GREAT MANY PRODLCTS ON THE
MARKET THAT MAKE LIFE EASIER FOR OWNERS
OF STEREO RIGS
- FROM
SPLICERS AND HEAD
DEMAGNETIZERS FOR TAPE RECORDERS TO DISC
COVERS. STYLUS PRESSURE GAUGES
MOST IMPORTANT ARE ADD-ON
88
PERHAPS
CONTROLS
CHAPTER
8
Except in the complete, "all -in -one" stereo set-up, a number of different pieces
of electronic equipment must be joined together properly and controlled or
"blended" satisfactorily. Often the equipment used will be made by different
manufacturers and have different capabilities. Certain items in this category
should be considered necessary, others "not mandatory but desirable" for
optimum convenience and satisfaction.
A new stereo preamp-amplifier such as is described in Chapter 3, or a stereo
receiver as described in Chapter 6, will as a rule have all the necessary arrangements: input jacks for different program sources, function selector, provision
for channel balancing and over-all volume control, plus parallel amplifier
connections for monophonic program sources. But if units are added to existing
equipment, or if a mixture of mono and stereo components are in use, some
89
CONTROLS
AM FM
STEREO TUNER
MONAURAL
TAPE
STEREO
RECORDER
PICKUP
AMPA
`
MONAURAL
PHONOPICKUP
AMP
s
lb
e
{
Stereo adapter offers
"ganged" volume controls,
has channel reversal
SPEAKER B
SPEAKER A
STEREO ADAPTER
sort of adapter will be needed to provide the necessary additional services.
If, for an example of the stereo unit addition, you had a separate tuner,
separate preamp-control unit and separate amplifier for mono, you might
substitute a stereo preamp-control unit for the existing preamp and then add
another monophonic power amplifier.
It must be borne in mind that stereo provides two separate channels that
are in essence separate audio systems. A mono amplifier, preamp, tuner (or
combination of these items) just cannot feed the second channel. Another
point to remember is that the average stereo rig is not a stereo rig only:
it's a combination of stereo and monophonic. If you use discs, for instance, you
will probably find that for some time to come you will be playing some mono
discs. If you use tape, you may very well decide to limit stereo to playback,
in which case you might have mono recording and playback plus stereo
playback. If you have a tuner, you must use it monophonically most of the
time, since stereo broadcasting is still fairly infrequent. So, counting both
mono and stereo, you must be able to handle up to six different playback
sources (stereo and mono, multiplied by disc, tape and tuner). An important
requirement is for your rig to accept and select all these types of material.
Adjustment of the two channels is necessary for several reasons. Among
them are differences in the nature of the various program sources, differences
90
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,
111111129rifilifillMfflr
....
c25.
eels
arfzi
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a8tn,-:
11111111111111111111111
ces
'.
Blonder -Tongue Audio Baton
permits owners to emphasize certain
parts of audio spectrum
iroif,oiiei
Iieellli.ra1e0t
Lafayette Stereo Control has
virtually all the controls of stereo
preamp on its front panel
between individual samples of each source, differences in the capabilities of
the specific pieces of equipment in the two channels (even if units are
identical in design, hand work makes it possible for them to vary from unit
to unit) and, finally, differences between the two loudspeaker channels because
of room geometry and because the user's set-up differs from that which the
recording engineer had in mind. That's not really the "final" reason, because
the tastes of the listener have to be taken into consideration, too.
ADJUSTING THE CONTROLS
Some facilities for "balancing" the two channels are therefore desirable.
The accepted use of the word "balance" is that it means to balance amplitude,
or loudness. We believe it is also desirable to balance tone, or frequency
response, to compensate for possible differences between speaker systems.
In either case (loudness or tonal balance), there are some shortcomings to
be aware of. It's hard to tell exactly how the stereo result is supposed to
sound-what was intended. An imbalance in loudness or tonal quality may
have been contrived to achieve an effect that the user may destroy without
knowing it. The user,may also, in attempting to fill "the hole in the middle,"
destroy some of the movement and spatial relationships that were intended
91
CONTROLS
Stereo adapter contains volume
control (left) for both stereo channels;
program selector is on right
Another answer to the control
problem is to replace mono preamp
with stereophonic model
to be there. This is just something we have to live with to get to understand
fully. The writer has found the same difficulty with color TV: trying to figure
out, while adjusting the controls, exactly how the picture really should look.
At least in TV, you have a standard to go by-skin tones, although there is
considerable latitude for interpretation even in that area. That is, perhaps,
the clue with stereo: use the manufacturers' instructions for preamps and
amps as a starting point, then adjust for some known quality in the sound;
when you have it, leave it, and let the chips fall where they may from then on.
Before proceeding to itemize some of the equipment available, we'd like to
pass along one recommendation concerning controls in general. That is, try
to avoid having too many knobs in too many different places, especially if
they overlap in function. One set of controls in one location is ideal. Perhaps
the acme in this respect would be to have a combined stereo tuner and dual
preamp. Then all the knobs could be in one place. One exception to this rule,
and the only one we need consider here, is that it is desirable to have sound channel control. at the listening position. If the speakers are in the same
place as the audio equipment, we would recommend a remote location for
channel control (phasing, balance, master volume).
There are many adapter units, either ready-made or kits, which provide
control for the two sound channels of a stereo system (loudness balance,
92
phasing, channel reversal, monophonic or stereo operation and master volume
controls). Among them are the Bogen STA -1 ($13.50) ; the Marantz Model 6
($45.00) ; the Scott 135 ($24.95) ; and in kits, the Dynakit DSC-1 ($12.95) ;
the Knight Y-778 ($9.95) ; and the Lafayette 315 ($27.50). Some have additional features, as noted below. In addition to these units, two items are
available for the bare essentials of remote control. These are the General
Electric RG -1000 ($14.75), providing balance, phasing and master volume;
and the Fisher RK-1 ($17.95), providing balance and master volume.
SPECIAL ADAPTER FEATURES
In addition to the ones previously mentioned, here are some of the special
features of particular adapter units. Loudness compensation for each channel
is provided in the Scott and Dynakit adapter units. This means that by
switching in the compensation circuit, tonal (bass -treble) balance will be
adjusted automatically as the volume level is changed, to compensate for the
deficiencies of our hearing apparatus at the extreme low and high ends of the
audio spectrum. The Marantz Model 6 provides input jacks for the various
program sources and a function selector switch to choose the desired source.
This could be an important feature since your monophonic equipment would
have neither input jacks nor selectors for the "A" and "B" (left and right)
stereo channels. Both the Scott and Marantz units have power on/off control
of associated equipment plugged into them (amplifiers). The Lafayette and
Dynakit units provide means of "cross -blending" of the two stereo channels,
to fill the hole in the middle or to feed a third, "phantom," channel. The Scott,
Stereo indicator
shows visually if the
balance is right.
Fisher's RK-1 remote
control (right)
and General Electric's
RG -1000 allow you
to make adjustments in
the listening area
93
L
CONTROLS
Dynakit and Marantz units provide jacks for tape monitoring. Several of the
units provide both phase reversal and channel inversion. The difference
between these features is this: for phasing, the connections to one channel
are reversed, which changes that channel's phase with respect to the other
channel, while channel inversion switches left to right and vice versa.
The multiplication of features on these adapters could go on and on, until
the units were virtual substitutes for the preamp. It should be borne in mind
that a remote unit needs only those adjustments which are most handily
made when the user is not at the main equipment location. You will find in
examining your needs and evaluating equipment for purchase that some units
provide more than is needed for remote control but not enough for complete
"adaptation." The information in this chapter is not designed to serve as a
specific buying guide, but just to acquaint you with what to look for.
ACCESSORI ES
You will find a great number of accessories at your hi-fi shop or in mailorder catalogues, items that will add convenience and versatility to your rig.
For the record player, there are various kinds of disc cleaners and protective
sleeves for records, slides for pull-out record -changer mountings, stylus pressure gauges and turntable levels. These last two are essential to any well ordered system. Just about any small dime-store pocket-level will serve for
the leveling job. Stylus pressure gauges are distributed by Weathers, for $2,
and, among others, by Gray and Garrard, for $2.50.
For the tape recorder, you'll need empty reels and boxes, a tape splicer
and splicing tape. Leader tape is a good thing to have. It comes in several
colors and can be used to identify tapes as well as to protect them. Connecting
cables of varying lengths and with various terminals at the end are always
handy when working with a tape recorder, and they can be used to make the
rest of your system more flexible, too. One gadget that is well worth having is
a device called a "Time-All"-an electric alarm clock that will turn your
Marantz stereo adapter (at left) and Dyna stereo control (right) provide
several functions in addition to ganged volume controls. Each is designed to be used
exclusively with manufacturer's preamps. The Dyna unit comes in kit form only
94
General Electric's Al -903 Rumble Filter
is electronic accessory that makes listening
more fun by eliminating bass rumble
Tape splicer from Robins Industries
is only one of several similar units on the
Audio Devices' Echoraser removes tape
print -through as tape passes it in course of
playing. Eraser sells for $12.50
Another accessory is Irish tape
strobe disc. With it you can check speed of
your tape recorder for complete accuracy
market. It repairs tape breaks
system on and off at a specified time. You can use it to tape radio programseven stereocasts-while you're away from home:
For the FM tuner, you'll want either a proper FM antenna or a set coupler,
which makes it possible for you to use your television antenna for the tuner.
A number of other electronic gadgets are useful not only for the tuner but
for the entire system. They include remote controls and wall -mounted volume
controls and speaker selectors; a device that shuts off your entire rig when
the changer finishes playing the last record; and connections for an outdoor
extension speaker with its separate volume control.
To improve the looks of the rig, there are attractive handles for pull-out
drawers, kits to retouch scratches in the woodwork, a variety of patterns in
grille cloth which can be used to make your speakers visually, as well as
aurally, appealing. While most of these items are not necessities, they can
make life with your stereo home music system much more pleasant.
95
IF YOU'RE HANDY WITH
A SCREWDRIVER
AND
SOLDERING IRON. IF YOU'RE WILLING TO DO IT
YOURSELF, YOU CAN SAVE MONEY AS WELL AS
HAVE FINE STEREO WITH SOME OF THE BEST
EQUIPMENT ON THE MARKET
TIME TO INVESTIGATE
NOW'S A GOOD
STEREO KITS
I
CHAPTER
01111
9
uild-it-yourself kits have carved out for themselves a very important and
significant spot in the electronics field and should definitely be considered by
anyone who would like to save some money in the assembly of a stereo system
or the conversion of an existing mono hi-fi system to stereo. They have proved
reliable and satisfactory over a period of time, and while over-all quality may
vary somewhat from manufacturer to manufacturer and-this should not be
overlooked-from builder to builder, the products themselves have no more
unusual ups and downs than regular factory-finished equipment.
Today's kits are designed for the layman-the man who may never have
taken the case off an amplifier before. Simple, clearly written, step-by-step
directions lead him by the hand through the construction process. Like any
other do-it-yourself project, the assembly of hi-fi and stereo kits requires a
97
KITS
Standard equipment for kit
builders is shown at the left. To
build a Rek-0-Kut turntable
(above), you will need screwdriver,
pliers and patience. This
kit retails for only $40 complete
certain handiness and adaptability. There are some people, we must admit,
who are "all thumbs," and who have never been able to hang a picture, tighten
a window shade or replace a fuse. This relatively small segment of the population will be no more proficient with a soldering iron than it is with a hammer.
But if you are at all handy around the house, though not a craftsman of any
sort, you can easily make it with kits. Kits are available for test equipment,
amateur radio rigs and all varieties of home -entertainment equipment. We
sball confine ourselves in this chapter, as far as possible, to stereo.
ONLY TUNERS ARE RISKY
With the possible exception of tuners, electronic kit equipment can be
evaluated against regular finished merchandise feature for feature, watt for
watt. That is, you can reasonably expect to come out in the end with a piece
of equipment that conforms to the printed specifications, and you can decide
what you want on the relative merits of the finished product. We say "with
the possible exception of tuners," because this is still a questionable area in
the kit field. The critical wiring and careful alignment usually needed in the
tuning stage of FM tuners seem to us a bit out of the range of a man who is
no more than fairly handy and has no special knowledge or previous experience. Kit manufacturers are trying to overcome this problem with the use
of prefabricated, or printed, circuits in critical areas as they have already
done in the amplifier field, and pre -aligned and sealed front-end assemblies
where the tuning occurs. Even so, the novice should be wary of tuner kits.
Perhaps one shortcoming of kits and the people who build them is that the
98
kits are so simple to put together. It is possible in many cases to construct
a piece of equipment successfully and acquire nothing beyond the knack of
following directions and using a soldering iron. The average kit is provided
with diagrams that are really representational drawings of the actual physical
appearance of the equipment. While this makes construction easier, it could
be profitably supplemented by an attempt on the builder's part to relate the
real circuit diagram to the literal picture. The understanding of circuitry
gained in this way would be very useful if repairs ever became necessary.
THE TOOLS FOR THE JOB
For the construction of most kits you need no more in the way of tools
than some screwdrivers, pliers, wire cutters and a soldering device. We recommend without qualification the purchase of a soldering gun, as opposed to the
soldering iron. The average kit builder will find a gun not only easier to use
but, since it must be triggered to heat, far safer than an iron. Solder is
intended, not to provide a strong mechanical connection but a good and
permanent electrical connection. In other words, don't expect it to hold wires
in place. Crimp your connections before you solder them so that they'll be
secure. Then add the solder to make the electrical connection permanent. Bear
in mind that the soldering iron is not used to melt the solder but to heat the
a virtually complete
hi-fi stereo rig from kits alone. Heathkit
record changer, shown at upper left,
costs $75. Or, if you prefer, you can build
an Audax tone arm (above) for $18.50.
It's designed for use with the turntable kit
offered by Rek-O-Kut. The Dyna preamp
(left), at $35, is one of the best buys available.
Two, plus adapter, make a stereo unit
You can assemble
99
KITS
Two different outlets for the kit builder's skill are Heath tape -deck recorder (left) and
River Edge cabinets for records, speakers, equipment. Kits offer economy over assembled units,
basic lessons in electronics and frequently very good equipment Indeed at budget prices
Among the more popular items available in kit form are amplifiers, preamplifiers and
tuners. Lafayette LA-90 stereo amp (left) has two 14-watt stereo channels, complete controls,
for $72.50. Eico HFT 94 AM -only tuner costs $39.95, is companion to HFT 90 FM -only tuner
parts involved so that the solder will flow into them when applied. This is an
important point. It is very simple to melt solder by touching it to the end
of the iron, but it won't stick to anything unless that part has been preheated by the iron. If the directions for the kit indicate that care should be
observed in the heating of certain critical parts, follow the instructions. Some
parts, made of plastic or impregnated with wax, can be melted by the indiscriminate application of heat. Other components, like transistors and crystal
diodes, can be permanently impaired by being heated.
All instructions, of course, should be carefully followed. This includes things
that novices tend to ignore, such as which way to route a wire around the
chassis. Very troublesome problems can result from the improper placement
of wire (known as "lead dress") , even though the connections are sound and
the parts are all in good shape. It is a good idea to check off-physically, with
a pencil-each operation or connection as you make it. A wire that was never
connected or never soldered can be very difficult to find later on, when it has
been covered up by other components.
100
A BRIEF LIST OF STEREO KIT MANUFACTURERS
COMPLETE AMPLIFIERS
Approved Electronic Instrument Corp., 51 Vesey St., New York 7, N. Y.
Arkay Radio Kits, 120 Cedar St., New York, N. Y.
Electronic Instrument Co., Inc., 33-00 Northern Blvd., Long Island City, N. Y.
Grommes Div., Precision Electronics, Inc., 9101 King Ave., Franklin Park, Ill.
Heath Co., 305 Territorial Rd., Benton Harbor 15, Mich.
Knight Kits (Allied Radio), 100 North Western Ave., Chicago 80, Ill.
Lafayette Radio, 165-08 Liberty Ave., Jamaica, N. Y.
Precise Development Corp., 2 Neil Court, Oceanside, N. Y.
Tech -Master Corp., 75 Front St., Brooklyn 1, N. Y.
PREAMPLIFIERS
Acro Products Co., 369 Shurs Lane, Philadelphia 28, Pa.
Approved Electronic Instrument Corp., 51 Vesey St., New York 7, N. Y.
Dyna Co., 5142 Master St., Philadelphia 31, Pa.
Electronic Instrument Co., Inc., 33-00 Northern Blvd., Long Island City, N. Y.
Grommes Div., Precision Electronics, Inc., 9101 King Ave., Franklin Park, Ill.
Heath Co., 305 Territorial Rd., Benton Harbor 15, Mich.
Knight Kits (Allied Radio), 100 North Western Ave., Chicago 80, III.
Lafayette Radio, 165-08 Liberty Ave., Jamaica, N. Y.
Precise Development Corp., 2 Neil Court, Oceanside, N. Y.
Printed Electronic Research, Inc., 4212 Lankershim Blvd., North Hollywood, Calif.
Regency Div. of I.D.E.A., Inc., Indianapolis 26, Ind.
Tech -Master Corp., 75 Front St., Brooklyn 1, N. Y.
POWER AMPLIFIERS
Acro Products Co., 369 Shurs Lane, Philadelphia 28, Pa.
Approved Electronic Instrument Corp., 51 Vesey St., New York 7, N. Y.
Dyna Co., 5142 Master St., Philadelphia 31, Pa.
Electronic Instrument Co., 11c., 33-00 Northern Blvd., Long Island City, N. Y.
Grommes Div., Precision Electronics, Inc., 9101 King Ave., Franklin Park, III.
Heath Co., 305 Territorial Rd., Benton Harbor 15, Mich.
Knight Kits (Allied Radio), 130 North Western Ave., Chicago 80,
Lafayette Radio, 165-08 Liberty Ave., Jamaica, N. Y.
Printed Electronic Research Inc., 4212 Lankershim Blvd., North Hollywood, Calif.
Regency Div. of I.D.E.A., Inc., Indianapolis 26, Ind.
Tech -Master Corp., 75 Front St., Brooklyn 1, N. Y.
AM -FM TUNERS
Approved Electronic Instrument Corp., 51 Vesey St., New York 7, N. Y.
Heath Co., 305 Territorial Rd., Benton Harbor 15, Mich.
Knight Kits (Allied Radio), 100 North Western Ave., Chicago 80, III.
Lafayette Radio, 165-08 Liberty Ave., Jamaica, N. Y.
Precise Development Corp., 2 Neil Court, Oceanside, N. Y.
FM -ONLY TUNERS
Approved Electronic Instrument Corp., 51 Vesey St., New York 7, N. Y.
Electronic Instrument Co., Inc., 33-00 Northern Blvd., Long Island City, N.
Grommes Div., Precision Electronics, Inc., 9101 King Ave., Franklin Park, Ill.
Heath Co., 305 Territorial Rd., Benton Harbor 15, Mich.
Knight Kits (Allied Radio), 100 North Western Ave., Chicago 80, Ill.
Lafayette Radio, 165-08 Liberty Ave., Jamaica, N. Y.
Y.
SPEAKER ENCLOSURES
Artizans of New England, Route 39 North, Sherman, Conn.
Bozak Sales Co., Box 1166, Darien, Conn.
Electro -Voice, Inc., Cecil & Carroll Sts. Buchanan, Mich.
Karlson Associates, Inc., 1610 Neck Rd., Brooklyn 29, N. Y.
River Edge Sales Corp., 80 Shore Rd., Port Washington, N. Y.
University Loudspeakers, Inc., 80 S. Kensico Ave., White Plains, N. Y.
R. T.
SPEAKER SYSTEMS
Electronic Instrument Co., Inc., 33-00 Northern Blvd., Long Island City,
Electro -Voice, Inc., Cecil & Carroll Sts., Buchanan, Mich.
Heath Co., 305 Territorial Rd., Benton Harbor 15, Mich.
Jensen Manufacturing Co., 6601 S. Laramie Ave., Chicago 38, III.
N. Y.
EQUIPMENT CABINETS
Artizans of New England, Route 39 North, Sherman, Conn.
Heath Co., 305 Territorial Rd., Benton Harbor 15, Mich.
River Edge Sales Corp., 80 Shore Rd., Port Washington, N. Y.
RECORD CHANGERS
Heath Co., 305 Territorial Rd., Benton Harbor
TURNTABLES, TONE ARMS
15, Mich.
Gray Manufacturing Co., Inc., 16 Arbor St., Hartford, Conn.
Pickering & Co., Inc., Plainview, N. Y.
Rek-O-Kut Co., 38-19 108th St., Corona 68, N. Y.
Weathers Industries, Barrington, N. J.
TAPE RECORDERS AND DECKS
Heath Co., 305 Territorial Rd., Benton Harbor 15, Mich.
101
PREPARING FOR STEREO MAY INVOLVE BUYING AN
ENTIRE NEW HIGH-FIDELITY STEREO RIG OR IT
MAY SIMPLY MEAN ADDING A STEREO CARTRIDGE,
SECOND AMPLIFIER AND SPEAKER TO THE RIG
YOU HAVE
YOUR PRESENT HI-FI EQUIPMENT
WHERE YOU START
STEREO WIRING FOR A RECORD CHANGER
REPLACE CLIPS WITH
THOSE SUPPLIED WITH
HEAD SHELL
CARTRIDGE
NEW WIRE FOR
CHANNEL B CARTRIDGE
TERMINAL
COMMON
TO CHANNEL A
-S
CARTRIDGE TERMINAL
DETAIL "A"
SEE DETAIL
"A"
SOCKET
CHANNEL
B
CHANNEL
A
CHANNEL
2
CHANNEL
B
A
HEADLESS SET SCREW
MACHINE SCREWS
NO JUMPER
BETWEEN SHIELDS
TONE ARM
CHANNEL
B
CHANNEL A
RECORD CHANGER
APPLY STRAIN
RELIEF HERE
Converting your changer or tone arm to stereo involves running second pair
of wires through arm to stereo cartridge, which replaces your present cartridge. Shielded
cables are attached at terminal plate under changer and connected to amplifiers
104
CHAPTER
10
The reader may plan to start from scratch in assembling a stereo system, or
he may wish to convert or adapt the elements of an existing monophonic rig
to two -channel. The desire to do the latter raises such questions as, "Should
I convert?," "Can I convert?," "How do I convert?" and so on.
In general we may say that conversion certainly can be effected; that it is
usually less expensive than starting from scratch; that sometimes the converted rig may be less convenient to operate or to house because of the
necessity for doubling up in some areas where new equipment would provide
two channels on one chassis; and that, quality -wise, the converted rig will
provide as good results on stereo as the original equipment did on mono.
For a complete answer to questions about conversion, we must consider
what your present rig consists of, what you want to get out of it-now and
103
less obtrusive than on units not so equipped. Most recent Viking, Bell, Concertone and Ampex (to name just a few) units fit into this category, and
these manufacturers offer a catalogue of accessory equipment.
Stereo playback is the most commonly desired feature and is relatively
easy to add to an existing mono machine. Where two -channel preamplification,
power amplification and loudspeaker systems are already provided in the rig,
the only requirement at the deck is the stereo (dual -channel) playback head
plus an electrical and/or mechanical means of switching from mono to stereo.
Strictly speaking, you can't "convert" a tuner, but you can convert to stereo
broadcast reception by the addition of certain components. The commonest
type of stereo broadcast.is that in which one channel is on AM, the other on
FM. Growing in importance is FM or multiplexed stereo. On the distant
horizon but as yet in the experimental stage is AM stereo.
On a monophonic AM -FM tuner, it is not possible to receive AM and FM
simultaneously, so it would be necessary to add a second tuner to accommodate
the rig to this type of stereo broadcast. An FM tuner is the likely choice,
because better -quality equipment is available, as a general rule, for this
service. The outputs of the two tuners feed into the stereo sound system in
the same manner as the two channels of any other program source. A more
107
....,a, ,waV Gillen I. 6U operate ana most likely incorporate
"provision for" reception of FM stereo. As explained in an earlier chapter,
a multiplex adapter is needed to complete the service for this kind of stereo.
If the owner wants to make provision for FM multiplex on a mono tuner
(either FM or FM -AM), he can add an outlet into which a multiplex adapter
is plugged, at a relatively modest price. Conversion of the mono AM -FM tuner
to stereo, therefore, may include the addition of a second tuner for AM -FM
stereo and/or the addition of facilities for receiving FM stereo.
If your tuner is a combination tuner plus preamp and audio control, its
audio features (preamp and control) must be supplemented for stereo by the
addition of a second preamp. A more expensive alternative is to abandon the
mono preamp-move it, sell it, trade it in-and get a stereo preamp on which
all switching and mixing facilities are in one place. If you are planning to
add a second tuner for the purposes outlined above, this might well be a
duplicate of the original (with preamp), thereby providing the second preamp
and control channel on a single chassis.
It's easy to add a second amplifier. Good results at greatest economy are
usually achieved by matching the original amplifier and adding an inexpensive
converter or adapter which essentially ties the two together. Most manufacturers offer second mono preamps that can be "stacked," or put in tandem,
a,..
108
l
L
with an existing mono unit. If cost is not a big factor, you can gain convenience
by replacing your single preamp with a dual unit. This is
a matter of the
handiness and versatility of controls, plus space conservation, rather than
of
quality. Here again, almost all manufacturers stand ready to fill your
needs.
A loudspeaker is one item you don't have to convert, because what
you need
is two separate loudspeaker channels. The best recommendation
is to match
your present (mono) speaker system if you're happy with it. By using
identical units, you ensure that the sound of the two channels will be as
closely
matched as possible, and therefore simple to balance. Unfortunately,
when
the mono rig contains speakers of very high quality, these are apt to
be
large in size as well as high in cost. This means that in "matching with
identical units," even if cost is not a problem, space may be.
The two factors -space and cost-are probably the reason for the
trend
toward smaller speakers for stereo. Full- and limited -range speakers can be
added to existing speakers with rather good results. Where possible, it would
make sense to buy an "add-on" from the maker of your original speaker.
THE SYSTEM AS
A
WHOLE
To sum up, you can convert any or all of your present equipment to stereo.
But you do not have to convert all, if you wish to get your feet wet without
tapping the mint too heavily. Consider the system as divided into two parts :
program sources, such as disc, tapé and tuner; sound system and controls,
including preamps, amplifiers and loudspeakers. If you are going to have
stereo reproduction from any program source, you must have a complete twochannel sound system. But you do not have to convert all program sources to
stereo. The logical place to start is with disc playing, and some people may
decide to convert only that service.
Your choice in the end-both as to which program sources to convert and
which of the alternative methods of conversion to use-should be determined
by your listening habits. Other matters that will enter into your decision are
the amount of money you have invested in the components of your present rig,
how recently you acquired them, how permanent the installation is and how
much money and space you feel you can invest in stereo. If you own a fairly
elaborate, good -quality hi-fi system, you will not for a moment question the
advisability of converting it to stereo, as opposed to starting all over again.
If the home -entertainment system, however, consists of something like a
portable phonograph, a TV -console unit or a radio -phonograph combination
of some years back, you may well think in terms of starting from scratch and
creating-either by degrees or all at once hi-fi as well as a stereo system.
The burden of this chapter has been the subject of conversion. The matter
of buying all new equipment will be discussed in Chapter 11 and will concern
the problem of providing a two-channel sound system fed by whatever program
sources are desired. As in conversion, the end result is a rig that will reproduce
both stereo and mono program material.
-a
109
:Lg.
^'
114'
THE BIG PROBLEM
IS TO
MAKE
u .t7
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®'
HI-FI STEREO
COMPONENTS PRESENTABLE ENOUGH TO FIT IN
WITH MILADY'S LIVING-ROOM DECOR
FOR THE
OWNER. THE SKY'S THE LIMIT OR THE EXPENSE
CAN PROVE TO BE SURPRISINGLY LOW FOR
GOOD STEREOPHONIC
110
INSTALLATIONS
CHAPTER
11
As we pointed out in the first chapter of this book, stereo is not necessarily
hi-fi. Two -channel sound can be provided in a diminutive piece of portable
.equipment that makes no pretense at high fidelity. But stereo can be hi-fi,
and we like to think that this is what most of our readers have in mind.
From this point of view, then, the stereo hi-fi installation is not apt to be
diminutive. It is likely to be a matter of considerable personal pride on the
part of its owner, however, so it may take the shape of a sizable one-piece
equipment cabinet arrangement, a combination of ene or two cabinets (an
equipment cabinet, for instance, plus two speaker enclosures) or a built-in
rig, possibly in the form of a storage wall. The choice, of course, depends on
the user's tastes and preferences, what equipment he already has, whether
he owns or rents and, finally, how much he can spend. Whatever his approach,
111
he wants his stereo set-up to sound good, look good, be convenient to operate
and easy to maintain-the four major considerations.
HOW
TO GET THE BEST RESULTS
"Sound good" depends on the components in the system and how they are
put together. "Look good" is a matter of taste and design. "Convenient to
operate" means that all the components and their controls are comfortably
accessible. "Easy to maintain" means that the equipment itself (rather than
just the front panels) and the interconnections between units can be easily
got at if trouble shooting or equipment changes are necessary, and also that
the rig has adequate ventilation and protection from accident.
The most convenient and practical disposition of components is to line them
up along a shelf. This provides good visibility and easy access for operating,
easy access for servicing and modification, plenty of room for heat dissipation
112
and for the separation of elements that might induce hum. (The loudspeakers,
for reasons we shall come to in a moment, would not be on the same shelf.)
This ideal is not always attained, however, because the shelf space may not
be available or, if it is, may not be as attractive as cabinet work. Trying to
"hide the body" in a decorative setting often results in features that are
neither convenient nor even sensible from the standpoint of heat dissipation,
electrical interference and good audio quality. A typical inconvenience is that
of locating a record changer near the floor, making it necessary to sit on the
floor to play it. While this practice may result in pretty "salon" photos of
alleged hi-fi rigs, it is considerably less convenient than having the disc equipment up where you can see it, reach it and operate it with ease while standing.
The pull-out drawer for the disc equipment is a handy invention because
it circumvents the other alternative for a built-in arrangement-having a
lift-up lid in the top. The writer prefers the fixed installation as opposed to
the movable one, however, because records and styli are less subject to damage
113
If the components are to be grouped in a cabinet or built -in -the-wall type
of installation, quality of operation as well as physical convenience must be
considered, which often leads to a compromise. Three problems that cannot
be compromised are heat, hum and acoustic feedback.
The primary sources of heat are the power -output tubes and, consequently,
the power amplifiers. A preamp generates virtually no heat ; the tuner may
develop a moderate amount. Sufficient room must be allowed for circulation
of air and dissipation of heat. Another point that the owner of a hi-fi system
should bear in mind is that heat rises; he should therefore try to avoid placing
the power amplifier directly under the other equipment.
The location of components with a power transformer near a low-level sound
source (phono cartridge or tape head, for example) can cause hum to be
induced into the low-level stage. The hum will then be amplified along with
the music. Ideally, a power transformer should be located as far away as
possible from such equipment. This will usually obviate the problem, but if it
does not, or if space does not permit optimum arrangement, try, by turning
the amp a little bit at a time (in the horizontal plane), to change the angular
114
relationship between the transformer and the turntable or deck. Leave the
amplifier in the position where it causes minimum interference.
We have described cartridges and tape heads as low-level sound sources,
which is to say that their output is of low amplitude. Wire lines or leads are
also classified as low-level or high-level, depending on the amplitude of the
signal they are carrying. The leads between cartridge and preamp, for instance, are low-level lines with which length and placement are more critical
matters than with high-level lines. Particular care should be exercised to
dress low-level lines away from sources of power-line hum, such as line cords
and power transformers. Get them as far away as space and practicality
permit. As for length, it is a good rule of thumb to consider the lead length
or cable length which the manufacturer provided as the maximum to be used.
This is usually not more than three feet. One reason is that some signal
degradation (that is, frequency response) will result from running low-level,
low -impedance, shielded lines a long distance. When manufacturers provide
equipment for long runs, the line is equalized to compensate for this degradation. It's easy enough to recognize low-level lines. They're shielded with
a woven metallic covering and grounded at each end.
The output of a preamp, for all practical purposes, can be considered a highlevel line. The lines from the power amplifiers to the loudspeakers are definitely
high-level. For the purposes of home installation, these lines can be of indefinite length and, incidentally, of any kind of wire. Lamp cord and television
Dream rig in a dream living room offers, besides swivel -mounted TV set, a stereo
changer at left, vertically mounted AM -FM stereo tuner and stereo amp, two speakers placed
unobtrusively on shelf above, with ample storage space for records, tapes, accessories
115
I
NSTALLATI ONS
Stereo system incorporating TV receiver utilizes Garrard stereo changer,
Fisher X101 amplifier and companion 101R AM -FM tuner, Bell tape deck. Speakers, concealed
in paneling above bookshelf and archway, are James B. Lansings and Wharfedales
twin -lead wire are frequently used for speaker lines. The latter has the
advantage of being flat so that it can be slipped conveniently under a carpet
for runs across a room. It is not advisable to locate a low-level phono cartridge
or tape head a long distance from its preamp. There are no particular limitations, however, on the separation between preamp and amplifier other than
what may be recommended by the manufacturer; and there is (in the home)
vitually no limitation on the distance between the amplifier and the speaker.
Acoustic feedback, to get to the last of the three factors that can't be compromised, is the return of sound waves or vibrations to the generating source,
either through air or a solid medium such as a wooden cabinet. Most people
have, at one time or another, heard the howl that is set up in a sound system
when the sound from the loudspeaker gets back to the microphone. That's one
example of feedback. Feedback is either positive (additive, or in phase) or
negative (canceling, or out of phase). Electronically, negative feedback is
often used in amplifiers to cancel out harmonic distortion. Acoustically, a
problem can result from feedback from the loudspeaker to the phono cartridge.
This can cause distortion, hum and added record wear. It can be avoided by
not putting the speaker near or in the same cabinet with the player. Another
problem that can result from having a high -power loudspeaker directly adja-
116
cent to the disc equipment is actual vibration from low -frequency components
of the sound. You can feel this vibration if you hold your hand against the
speaker baffle. In extreme cases, it can cause the needle to bounce or skip.
INSTALLING YOUR OWN SYSTEM
If you plan to install your own speaker system, a few construction and
installation hints might be helpful, in addition to the above -mentioned considerations concerning placement. The speaker enclosure should be as strong
and solid as possible, so that parts of it will not vibrate sympathetically at
whatever audio frequencies they happen to be resonant. The inside of the
enclosure is lined with acoustic deadening material to absorb sound waves
inside the cabinet (emanating from the rear of the cone) which might cause
vibration, set up unwanted resonances or result in undesired phase cancellations. If you are copying the design of a "tuned" enclosure such as a bass-reflex
cabinet, follow it to the letter, since the design is based on careful calculations
concerning the production and reinforcement of sound in various frequency
bands, as well as the smoothing of the over-all response curve and the damping
of transients. Baffles should be painted black so that loudspeaker cones don't
show through the grille cloth as black holes.
A large number of different grille -cloth designs is available but you may
still find that your taste (or that of your wife or your decorator) cannot be
Do-it-yourself stereo gets
a
boost from Knabe piano in center of stereo system
that includes every conceivable sound source-stereo records (turntable and record changer),
stereo broadcasts and stereo tapes. Unit also provides storage space
117
INSTALLATIONS
Handsomely paneled built-in unit at left has VU meters at preamps to allow visual
stereo balancing. Power amps are located in cabinet, center. Another answer, at right, involves
use of stereo adapter (upper right) with two mono amps, stereo tuner, changer and tape
satisfied by any of them. If this is the case, you need not feel limited to the use
of fabrics that are labeled "grille cloth." Ideally, the grille cloth is woven
loosely, to permit efficient transmission of the sound, and is constructed of
yarns (usually synthetic) that will not absorb sound. In choosing other fabrics
or materials you can be guided by these principles or-when in doubt-by an
actual A -B test. In order either to repeat or coordinate with fabrics serving
as drapes or slip covers, the writer has used without noticeable signal degradation materials like silk, linen, hopsacking and chair -seat caning.
BUILT-IN PROTECTION
Recalling for a moment the problem of small children, the writer has made
it a practice to give the speaker cone built-in protection by stapling a piece
of metallic window screening over the baffle before putting on the grille cloth.
This has not resulted in any noticeable degradation of sound and, when
attached securely, does not vibrate or resonate. The result is that when little
fingers poke at the source of sound, they hit a protective screen. This avoids
the tragic situation of a two- or three -hundred -dollar speaker with a hole
in the cone. Aluminum screening has proved more successful than copper,
because it is more rigid and thus has greater resistance.
It seems obvious that good visibility is necessary at the record player and
at the controls of tuner and/or preamp, yet often such components are deep
118
in the shadows. We have found it practical to install a small night light of the
type designed to plug into a wall outlet in the record-player compartment.
This is provided with its own light shield, and the light can be directed for
maximum usefulness. By means of an extension, the light can be plugged into
the amplifier (or whichever unit is being used for master power control) so
that it lights whenever the equipment is turned on. Thus it serves not only
as illumination but also as a quite visible pilot light and as a notification that
the rig is still running. In extending the cord from this light to the amplifier, care should be exercised to dress it away from low-level lines, to avoid hum.
Virtually all electronic equipment used in home-entertainment systems
(tuners, amplifiers, preamps, etc.) can be mounted vertically as well as
horizontally. This gives considerable latitude in the design of the built-in
installation. For example, in the author's two installations the tuner in one
case is mounted vertically so that the dial and the knobs are flush with the
counter top-you look down at the controls, making them easy to see and to
operate. In the other instance, where the tuner is mounted below a counter
arrangement, it is inclined at a 45° angle to improve visibility for a person
standing above it and eliminating the necessity to stoop down to look at it.
The record -playing equipment, of course, must be mounted horizontally and
be perfectly level. Tape decks are available for both types of mounting.
ELECTRIC -SHOCK PROBLEMS
Connecting the several different chassis of a hi-fi rig may produce hum
and/or mild electric -shock problems. It is sometimes difficult to solve one of
these problems without making the other worse. From the point of view of
electricity, associated components should be bonded together by a heavy
ground wire (#14 would do) and grounded at one point to the "system
ground," which can be a cold-water pipe, the external surface of a conduit or
an electrical -outlet box. This puts all the equipment at the same potential and
all the external metal surfaces at ground potential. As it happens, the various
components are grounded together by the metallic shields on the low-level
cables, which often increases hum, because with two sets of grounding wires
(the system ground plus the audio shielding) you have potential parallel paths
for the creation or reinforcement of hum "loops."
To summarize: If shocks are troublesome, the first thing to do is to reverse
the power cords, one at a time; sometimes this phase reversal is all that is
needed. If that doesn't help, try grounding the components together and to
a common system ground, as suggested above. If this results in hum and you
can't lick both the hum and the shocks at the same time, your best bet is to
call a reliable repair man.
Space limitations do not permit our making any valid generalizations about
taste and design in the appearance of the stereo hi-fi installation. The illustrations in this chapter are designed to provide some helpful ideas as well as
suggestions about the arrangement and location of equipment.
119
YOU CAN BUY STEREO IN A STORE OR THROUGH
THE MAIL
EITHER WAY, YOU CAN PICK UP A
BARGAIN YET NOT GET YOUR MONEY'S WORTH
OR YOU CAN SPEND A LOT AND GET THE BEST
BUY EVER
THERE'S A GREAT DEAL THAT YOU
MUST LEARN ABOUT
120
BUYING STEREO
CHAPTER
12
Whether you're converting existing equipment or starting from scratch,
your possible sources of supply are the same, and might include radio -TV music stores, hi-fi specialty shops, radio -TV parts jobbers and mail-order
catalogue houses. Generally speaking, the parts jobbers and catalogue houses
get the major share of the business because they have the most extensive
selection of equipment and because, as a rule, they offer competitive prices.
The price situation in hi-fi is a strange one. Unlike most finished consumer
goods, which carry a "suggested retail price" and are merchandised in a
three -step system (from manufacturer to distributor to retailer to consumer),
hi-fi components have a somewhat confused history in which the price was
"sort of wholesale" and a two-step distribution system was common from
manufacturer to jobber to consumer or from manufacturer to mail-order
121
BUYING STEREO
house to consumer, and sometimes even from manufacturer direct to consumer) . In recent years there has been an, attempt to regularize the distribution of this type of merchandise and to establish something more conventional
in the way of a pricing set-up. But because buyers were used to buying at
wholesale-or at what they were led to believe was wholesale-the term
"Audiophile Net" began to take the place of "Suggested Retail" or "Suggested
List." While the word net has an implication of rock bottom, this is not necessarily the case. In fact, by watching advertised sales, the hi-fi buyer can often
do better than the advertised net price.
WHERE AND HOW TO BUY
We can't in the space available here list specific hi-fi outlets in every locality,
but if you do not already know them, we suggest you ask friends, consult the
"Yellow Pages" and attentively read the magazines that cater to this field.
You will also usually find in the magazines the names of prominent mail-order
houses, the best known of which are Allied Radio (Chicago), Lafayette Radio
(New York), the Radio Shack (Boston), Leonard Radio (New York) and
Newark Electric (Chicago). These and other firms offer free catalogues on
receipt of coupons that appear in the magazines. The catalogues are useful,
whether you plan to buy by mail or locally, since they comprise an extensive
directory of equipment together with descriptions and prices.
Shopping in person, of course, has many advantages. For one thing, you
can see what the equipment really looks like. Although one expects photographs
in advertisements to flatter the equipment, the reverse often turns out to be
true. Many components that look dull and commonplace in the ads turn out to
be quite handsome. Shopping in person in the bigger hi-fi centers also gives
you an opportunity to listen to various components singly and in combination.
In addition, you may run into a "buy" or a close-out that you had no reason
to expect. It is wise to go shopping with a list of desired components in
hand, with model numbers and prices, since you may not find a salesman who
has time to help you plan a system unless you go in off-hours.
In buying for stereo, it is well to be wary of close-outs of monophonic
equipment which-while a bargain-can't be conveniently incorporated into
a stereo system. The only item in the chain that doesn't have to be specifically
designed for stereo is the loudspeaker. Second least specialized is the record
changer (or player or turntable) which is essentially the same for mono and
stereo except for the cartridge and the connections to it. Ideally, however,
the pickup arm should come wired for stereo, or you'll have a small conversion
job on your hands, adding leads (wires) for the second channel. Amplifiers,
preamps, tuners and tape recorders are essentially less adaptable, and should
be designed for a stereo system from the ground up.
Some of the catalogue houses and hi-fi shops feature special "package deals"
that offer a considerable saving in the aggregate if the user can be satisfied
with the particular assemblage of components included. Such deals, where
122
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BASIC TWO -CHANNEL SYSTEM
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A
B
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BUYING STEREO
typical assortment of stereo components is d splayed in the showroom of
used
Lafayette Radio, in New York City. The salesman is at a panel of the sort commonly
to switch equipment, so that customers may compare the sound of different items
A
available, should be carefully examined and checked out-especially in terms
of price. The reader may find that he can buy an entirely new system for a
sum he had been willing to lay out just to add a new tape recorder, say, or a
stereo tuner to the system he already has.
Most electronic equipment carries a 90 -day warranty on parts and tubes,
and our confidence in this warranty is usually based on the assumption that
the manufacturer has been in business for several years, is likely to be in
business for many more, and has a good reputation. Such factors are, we
believe, worth a few extra dollars and we recommend that the reader keep
this in mind when shopping for bargains.
In order to avoid repetition of the material on conversion which was outlined in Chapter 10, we will assume in the following discussion that the reader
is starting from scratch. He will obtain a stereo (two channel) sound system
plus however many program sources he desires or can afford. He has a choice
of getting every item in the chain as a separate unit or of buying items that
combine one or more functions, like tuners and dual preamps combined;
complete receivers; all -in -one amplifiers (dual preamps plus dual power
amps) ; and so forth. Separate components provide maximum freedom of
choice, flexibility of placement and flexibility for modification. Combination
units provide maximum convenience from the standpoint of grouping of
124
controls and-sometimes-a saving of money. The limited lists that follow
illustrate the relative costs involved.
WHAT TO PAY FOR STEREO
The simplest basic system incorporating stereo would include a record
changer with stereo cartridge, an all-in -one dual preamp-amp and two loudspeakers. In most of the examples shown, enclosures are provided for the
speakers. If you plan to build yours in, or construct your own enclosures,
appropriate savings can be deducted from the sums indicated.
Besides equipment that only masquerades as hi-fi, there's a wide selection
of components that are very good indeed. Here are some of them, from which
you can reasonably select a high-fidelity stereo system. The specific ones you
choose should depend on your pocketbook, your listening room and the feature
or features most important to you. They are listed to show price only; other
details have already been covered elsewhere in this book.
RECORD CHANGERS
There are nine major record changers: the Collaro TSC 740 ($42) and TSC
840 ($48.50) ; the Garrard RC 88 ($54), RC 98 ($68) and RC 121 ($42) ;
the Miracord ($66) ; the Glaser-Steers and Stromberg -Carlson units at
approximately $60 and, for that dream rig, the Thorens ($78.35). Manual
Visitors to a hi-fi show inspect a loudspeaker display. Shows are held
once or twice a year in the larger cities, give hi-fi shoppers a chance to spot trends in
new components, learn prices and specifications directly from the manufacturers
125
BUYING STEREO
well -stocked hi-fi dealer's showroom gives a graphic idea of the vast
number of components available today for stereo. Large dealers inventory thousands of
items, made by hundreds of suppliers-all for the hi-fi stereo buyer
A
players are available from the manufacturers of these changers at from $30
to $50. Quality turntables are available from Rek-O-Kut ($60 up), H. H. Scott
($140), Pickering ($60), Bogen -Presto ($75 up), Weathers ($50), Gray
(supplied with arm for $80), Fairchild ($100 up) and others. Turntables
require a separate tone arm. Most turntable manufacturers also sell tone arms
in the $15-$30 price range. In addition, such arms as the Grado ($29.95),
Garrard ($19.50), General Electric ($29.35), Shure ($89.50) and Electro Sonic ($35) are in wide use by audiophiles. The London -Scott arm comes
with a cartridge, for $90. Popular magnetic cartridges include the General
Electric ($23), B & O Stereodyne ($30), Stereotwin ($45), Shur M3D ($45),
Pickering 371 ($30), Grado ($30) and Fairchild ($49.50). Non-magnetic
cartridges include the Electro -Voice 26MDST at $22, the Ronette BF -40 for
$18.50, the Sonotone for $14.50 and the Weathers Ceramic for $17.50.
SPEAKERS
Speakers that are ideal for stereo use include the Eico HFS-2 ($140), the
Acoustic Research units and KLH speakers (from $99 to $199), University's
S-10 ($140) and S-11 ($240) units, the General Electric LH -12 ($140), the
Electro -Voice Regal ($103), Jensen's TR -10 ($114.50), the Bel Aire ($170)
from James B. Lansing, plus units from Wharfedale, Lafayette and Allied
126
Radio. Smaller systems, like the Telematic Minstrel and Hartsdale ($30 each)
and the Weathers Harmony ($130), are excellent buys in their price category.
Complete stereo speaker systems are also available from such manufacturers
as Bozak, James B. Lansing and University; prices run up to $2,000.
TUNERS
In the tuner category, the
H. H. Scott (Model 330 AM -FM tuner sells for
$225; the 320 FM multiplex tuner for $140). Harman-Kardon's T-224 sells
for $115; the TP -200 for $190. A complete receiver, Model TA -230, sells for
$260. Pilot's FA 680 sells for $200; a combined stereo tuner-preamp sells for
$270. The Model 600 complete receiver from Fisher costs $350; the 101R
AM -FM unit is $230. Bogen's TG200 is $129.50; the ST 662 sells for $190.
Other models are available from Stromberg -Carlson, Sherwood, Karg, General Electric and Sargent-Rayment. The kit manufacturers-Lafayette,
Knight and Eico-have stereo tuners already assembled for as low as $70.
AMPLIFIERS
Many of the tuner manufacturers are also in the amplifier business. Scott
has a $139 model to match its $139 tuner, as well as the Model 130 ($170) and
299 ($199). Harman-Kardon's units are the A-224 ($100) and the A-250
($180). Bogen's stereo amps start with the AG210 for $100, run through the
DB 212 at $115 to the DB230, for $170. In addition, there are the Bell 2221
($130), 3030 ($170) and 6060 ($220) the Fisher X 101 ($189.50), the Pilot
SM -245 ($189.50), the General Electric MS -2000 and MS -4000 ($140 and
$180 respectively) and the products of the kit manufacturers, which run as
low as $75 and are extremely effective.
So far, we've been talking about complete amplifiers. In separate power
amps and preamps, the kit makers are also prominent. Pilot's stereo preamps
include the SP -216, $189.50, and the SP -210, $89.50. The matching power amps
include the SA -232, $89.50, and the SA -260, $129.50. Fisher's 400-C stereo
preamp sells for $170, can be used with two Fisher basic amps. McIntosh follows the same plan, with a stereo preamp for $99, to be used with two basic
amps ($143.50 each for the 30-watters, $198.50 for 60 -watt amps). Similarly,
the Marantz Stereo Console ($249) can be used with two Marantz power amps
($147 or $198 each). The Leak stereo preamp goes for $110, its companion
power amp is priced at $189.
;
TAPE RECORDERS
In tape recorders, there are units such as the Viking ($113 and up) and
Bell tape decks ($120-150), the Norelco ($299) and Tandberg ($299 up) portables, the Roberts and Superscope (two Japanese imports in the $350-400
price range) the Magnecord, Ampex and American Concertone units, which
start from $450 and run well over $1,000, and such strictly professional units
as the Crown Presto and Ferrograph ($600 up). Cost here is related directly
to the features you feel are necessary and the quality you're willing to pay for.
,
127
BUYING STEREO
FOUR STEREO BUDGETS
A modest budget system, in which every item was kept to rock -bottom cost,
might look something like this:
45
Record changer
Stereo cartridge
Stereo amplifier
2 speaker system
15
100
60
220
The outlay for the various components in a medium-priced system might
be on this order:
Turntable
Stereo arm
Stereo cartridge
Stereo amplifier
2 speaker systems
60
20
45
140
200
465
still more ambitious system would probably include at least the following
mono and stereo components:
60
Record changer
A
Mono cartridge
Stereo cartridge
Turntable
Stereo arm
Stereo tuner
Stereo amplifier
2 speakers
20
45
70
35
115
200
280
825
If you're in a dreaming mood, here's a system in which all program sounds
are included. Price is no object in this system: Record changer
60
250
Turntable
20
Mono cartridge
45
Stereo cartridge35
Stereo arm
250
Stereo tuner
170
Stereo preamp
270
Stereo power amp
Stereo speaker system 1,900
600
Tape unit
3,600
These rigs don't begin to exhaust the possible combinations, nor do they
encompass mono equipment that might be purchased as add-ons for conversion. For complete details on the components, consult the manufacturers'
literature and their advertisements in such publications as MODERN HI-FI and,
finally, your local hi-fi dealer. A word of caution: Don't underestimate the
value of your own ears in the process of selecting equipment; in the end you
are the one who must be convinced that what you buy sounds good.
128
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