Universal Audio 1176LN Solid-State - Manual (Page 32)

The Technical Stuff
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Output Amplifier
The output amplifier is a Darlington pair followed by a class A stage based on a 2N3053 transistor.
The 1176LN output stage was essentially the same as the Universal Audio 1108 pre-amplifier. The
output transformer is a custom transformer designed by Bill Putnam Sr. Aside from offering output
impedance matching, the transformer forms an integral part of the feedback network used to stabilize
the output stage. Note that later revisions (‘F’ and beyond) used a push-pull (class AB) output stage.
(Revision E was essentially the same as revision D. Revision E added 220 Volt operation as well as a
10 M
Ω resistor across the ratio switch to avoid ‘pops’ while changing between compression ratios.)
Gain Reduction Control Circuit
Figure 5 - Gain Reduction Control Circuit