[sdiy] Moog ladder filter transistor pairs matched or not..??
Jean-Pierre Desrochers
jpdesroc at oricom.ca
Tue Feb 18 14:50:32 CET 2014
Hi list,
i'm about to build some VCF modules for my DOTCOM synth
in the next weeks. I'm gonna use the nice Moog ladder type VCF
like this one:
http://www.experimentalistsanonymous.com/diy/Schematics/Filters%20Wahs%20and%20VCFs/Minimoog%20ladder%20VCF%202.gif
Some DIYers used that Moog design and adapted it to their needs..
But when I check the info about the matching or not
of some of the ladder transistors, opinions differ from one
guy to another.
In fact, looking at the transistor ladder there are 5 pairs
of transistors stacked on each other. We'll call them
row 1 to row 5.
Most forums I browsed talk about transistor pairs rows 2,3,4
that need to be matched. Pairs on rows 1 and 5 need no matching.
But some DIYers say even rows 2,3,4 need not to be matched
for the VCF to work correctly..
What should I keep as a good info ??
JP
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