[ARC5] Request for info - modulator cct using 6AG6 in class "B".

[Dennis DuVall]

 Also called a "Volume Compression” circuit.  Found references in several later Handbooks.

Dennis D.  W7QHO
Glendale, CA

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> On Sep 19, 2015, at 4:27 PM, mac via ARC5 <arc5 at mailman.qth.net> wrote:
> 
> Leslie,
> 
> Yes, you mentioned an "unmarked pentode" stage in the audio chain.  Sounds like, maybe, an "output limiter" circuit.  The scheme involved rectifying audio from later
> stages in the speech amplifier/modulator and feeding back a filtered, negative bias voltage to the suppressor grid of an amplifier tube near the head of the audio chain.
> The goal here was  an automatic gain control loop that followed the average, not instantaneous, variations in speech amplitude and thus overcome the operator's
> speaking volume variations.  Found some information in a 1946 RAHB on a  circuit to do this but don't remember widespread application in ham designs of the period.
> See anything that looks like a rectifier down near the output end of the audio circuits?
> 
> Also remember seeing something like this in a Navy TBK.
> 
> Dennis DuVall, W7QHO
> Glendale, CA
> 
> *****************
> 
> On Sep 19, 2015, at 3:36 PM, Leslie Smith wrote (in part):
> 
>> somewhere in this I find a circuit that I'm (pretty certain) seems to act as an overmodulation device.
> 
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