[sdiy] CV mixer overload?

[Steve Ridley]

On the Moog 921A, the CV mixer had a gain of -0.5 and the
921B oscillators operated at -0.5v/octave.  That gave twice
the headroom of normal CV mixers, so you could mix two 
10v CVs without clipping.  

I'm not sure that many VCOs will respond usefully to a +20v
CV, but at the other extreme, extending the range beyond 
-10v is useful for VCLFO applications.  I modified one of
my VCOs for a wider CV range after I found CV clipping 
was limiting the LF range.  Just half the gain of the mixing
opamp and alter the resistors feeding the expo converter. 



Steve Ridley