Aug - AmericanRadioHistory.Com

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(pending changes in his product) or not published at all. He is not permitted, however, to amend or alter the report.
Webster 97 -0 Preamp and
96 -10 Amplifier
SPECIFICATIONS (furnished by manufacturer):
separate preamplifier -equalizer- control unit and
power amplifier. 97-0 PREAMP - Inputs: four
high -level inputs, marked Tuner, TV, Tape, and
Xtal; low -level inputs marked Mag and Mic.
Controls:
selector switch for six inputs; turnover
(O, AES. 500, LP, 800); rolloff (0, 4, 8, 12, 16 db
at 10,000 cycles); treble (t 15 db, 10,000 cycles);
bass (t 15 db, 50 cycles); concentric individual
volume and loudness controls; AC power on -off
toggle switch; high -frequency range filter (5,000
cycles, 7,000 cycles, flat). Input level -set controls
furnished for all six inputs. Outputs: two, both at
low impedance; one to amplifier, the other, not
affected by volume, loudness, filter, or tone controls,
to tape recorder. Switched AC power outlet.
Response: t I db, 20 to 20,000 cycles. Output:
2 volts. Dimensions: 143( in. wide by 10 deep by
4 3/8 high, overall. Tubas: 12AY7, 2- 12AÚ7,
12AX7, 6X4. Price: $129.50. 96 -10 AMPLIFIER -
Inputs: one, at high impedance (0.5 megohm).
Controls: input level control. Speaker terminals:
4, 8, 16 ohms. Rated power: 10 watts. Response:
at one watt, within 0.3 db, 20 to 40,000 cycles,
down 2 db at 100,000 cycles; at 10 watts, within
0.5 db, 20 to 22,000 cycles. Narnienk distortion:
3 watts, 50 cycles, 0.3 %; 10 watts, 50 cycles, 0.75%;
10 watts, 30 cycles, 1.5%. Noise: 80 db below 10
watts. Dimensions: 12 in. long by 7 1/8 wide by
6 1/8 high, overall. Tubes: 2 -655, 6S37, 2.6V6GT,
5Y3GT. Price: ,$89.50. Manufacturer: Webster
Electric Company, Racine, Wis.
This amplifying system from Webster
Electric was obviously designed and built
to the highest commercial standards; all
control facilities of real value have been
included, and provision made for a multiplicity
of input sources. There is even
that rarity, two distinct input channels
suitable for magnetic cartridges. Electrical
performance and mechanical construction
are exceptionally good. Curiously, though,
the preamplifier in particular has much
more ear- than eye- appeal, and the input
and output screw -terminal connections are
anything but easy to work with. These
deficiencies are only so annoying because of
the equipment's superiority in other respects.
The preamplifier has three standard
high -level input channels, labeled Tuner,
Tape, and TV. Another high -level channel,
for crystal, ceramic, and other constant -
amplitude cartridges, is affected by the vari-
it should
be. There are two low -level input channels
labeled Mag and Mic. They are identical
except for input loading resistors; the termination
for the Mag channel is loo,000
ohms and that for the Mic channel is s
able equalization controls - as
megohm. Both channels are affected by the
equalizer controls; consequently, each con-
AuUsT,.1955__
trol has a flat position. By changing a
terminating resistor you can have two
microphone channels or two magnetic
phono channels, as you prefer. Easier yet,
use external load resistors of the recommended
values to get two phono channels.
Preamplifier noise level was very low and
gain extremely high.
On the front panel are six small holes,
and behind them are screwdriver -adjusted
input level -set controls, one for each channel.
Incidentally, the instructions contain
some good advice concerning these adjustments.
Keep them turned down as far as
possible, and the main preamplifier volume
control as far up as possible, in order to
achieve minimum distortion. This applies
equally to any similar equipment.
The selector switch is the first main control
on the front panel. Next are individual
turnover and rolloff equalization
trots.
Response in their center positions
was almost perfectly flat, and the maximum
boost and droop of each met specifications
well within the error tolerance of our test
equipment. Further -and most important
- they caused absolutely no discernible
ringing on transients. Then, to the right,
are concentric volume and loudness controls.
We have commented before that this
seems, to us, most sensible of the many possible
arrangements for loudness compensa-
tion. Acording to our checks, maximum
compensation at 5o cycles was 12.5 db; at
10,000 cycles, 3 db. Less compensation
than most loudness controls furnish but, in
our opinion, entirely adequate.
In the upper right -hand corner is the AC
power switch and, in the lower right -hand
corner, a pilot light. Between them is the
filter switch, with a flat position and two
others labeled 5 kc and 7 kc, corresponding
The Webster 97 -o preamp- control gets blue ribbons for flexibility and overall quality.
controls. Turnovers available are flat, old
AES, Soo (RIAA), old LP, and Soo (old
RCA). Rolloff control positions are
marked according to decibels attenuation
at to,000 cycles: o, 4, 8, 12, and 16.
Curves for both controls are well- chosen
and our workbench checks showed them to
be right on the nose.
Next along are treble and bass tone con-
to the points at which sharp high- frequency
cutoffs begin. We found that the actual
frequencies at which cutoff began in our
test unit were 3,900 and 6,8oc cycles. Although
cutoff was very sharp - 18 db per
octave - ringing caused by the control teas
insignificant.
There are two outputs and both are at
low impedance. One is for connection to
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