[R-390] R392 Audio

[Charles Steinmetz]

Tom wrote:

>Charles was there not a solid state module developed by the military 
>for the 392?  How did it work?

Yes, indeed.  It is documented in Figure 20 of the 1961 R392 manual, 
TM-11-5820-334-35.  Meir posted some information about it, including 
the fact that the external feedback resistor (R629) must be removed 
when the Solid State Audio Module is installed (because it has too 
much phase shift to remain stable in a global feedback loop).  This 
means that the preceding audio stages (V606 and V607) are no longer 
inside a feedback loop.

IMO, it is a lot better than the original 26A7 circuit, although it 
is a bit noisy.

Best regards,

Charles