Moog VCF Transistor Matching Question

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In a message dated 10/24/00 9:01:59 PM, metamatic at webtv.net writes:

<<  Is it necessary to match all the transistors in the ladder, or
just the pairs?
 >>

Hello Richard,

For the filter to respond reasonably well, it's most important to match the 
top pair and the bottom pair (just match between the pairs, not necessarily 
match all four parts with each other).  I have actually tried replacing 
individual transistors in a Minimoog's filter with randomly selected, 
unmatched and untested transistors, just to see what would happen (the middle 
ones, not the top or bottom pair).   I couldn't hear any difference in the 
sound of the filter, and my ears are pretty good.  However, some people 
insist that the filter works best when all of the devices in the filter are 
matched to each other.  You'll probably have to go through around 100 
transistors to find ten that match, though.

Have fun,
Michael Bacich