Western electric 1126 a schematic

Page 1

Western Elecnic Company
No.| |26-A AMPLIFIER

Page 2

Wmtlemiccompafly
No.| |26-A AMPLIFIER

Type
Audio frequency program operated level governing amplifier containing
means to reduce its gain when the input level reaches a pre-determined amount.
Consists of 126A Amplifier (three push-pull stages), 298A Control Panel and
20A Rectifier.
NOTES: Detailed operating imtmetiom [or the 20/1 Rectifier are ton/mined
in Inilmction Bltllelin N0. 978.

Typical Electrical Characteristics

Gain- 37 db as delivered when working from 600 ohms and into 600
ohms, both adjustable attenuators at zero attenuation. (53.5 db
maximum with all fixed input and output attenuators omitted.)

Operates from -600 ohms.

Operates into- 600 ohms.

Output Power- +17 db" (approximately) single frequency as delivered
with adjustable output attenuator at zero when gain reduction
starts. (+235 db, approxin 1y, with all fixed output attenuators
omitted.)

Output Noise - 45 db below ,001 watt unweighted. 69 db below output
level available when gain reduction starts.

Output Distortion - For Program: Less than 1 per cent for all operating
conditions up to 5 db compression. For single Frequency Tone:
(a) Below compression; less than 1 per cent. (b) for 5 db com-
pression; less than 1 per cent for frequencies above 200 cycles and
not more than 13/; per cent for frequencies as low as 50 cycles.

Frequency Characteristic- Flat within 1 db of the 1000 cycle value over
the range 30 to 15.000 cycles.

Power Supply- 105 to 125 volts. .7 ampere, 60 cycles a-c.

Compression Ratio - 10:1 (10 db input increase results in 1 db output
increase above single frequency input level of *20 db referred
to .001 watt as delivered).

Recovery Time -Variable in 5 steps of .2 second each from .2 second to
1 second.

" Referred ID .001 wall.

Instruction Bulletin No. 1000 P, Issue 2

-165-