[sdiy] Improving Moog 921

[WeAreAs1 at aol.com]

In a message dated 3/12/01 2:28:31 AM, boldman at interplanet.it writes:

<< I do not have the Minimoog schematics right here, but if  I remember well,
its summing section derives from the 921A.
So, as the Mini also drifts in tune, what about resistors and 741 op amps
on Minimoog's summing section?
 >>

Besides Terry Michaels' excellent sugeestions for improving stability of the 
"old" Minimoog VCO's, another useful modification is to remove the old 
wirewound trimpots and replace them with modern multi-turn trimmers.  It 
doesn't really improve the stability of the VCO's, but it makes them a hell 
of a lot easier to tune!  I use the top-adjust square ones, not the 
side-adjust long ones.  Those old trimmers are nearly impossible to 
fine-tune, even when they are in new condition, much moreso when they are 20 
or 30 years old.

Michael Bacich