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<DIV><SPAN class=183372522-12062023>So, I replaced a couple of the trimmers on
my Minimoog filter board -- the 1k and 500R trimmers were one-turn wonders, and
the 500R was actually a 470R cheapo flat trimmer that shorted out every time I
put a screwdriver in it. I replaced them with proper 18-turn trimmers, and
I think the circuit works better now.</SPAN></DIV>
<DIV><SPAN class=183372522-12062023></SPAN> </DIV>
<DIV><SPAN class=183372522-12062023>So, it seemed to work pretty well. I
was getting good filtering. It still didn't sound much like a Minimoog to
me. Also, I don't really like the way that it responds to high
resonance.</SPAN></DIV>
<DIV><SPAN class=183372522-12062023></SPAN> </DIV>
<DIV><SPAN class=183372522-12062023>Then I swapped the feedback resistors on the
input and output amplifiers (56k to 120k on the input, 120k to 56k on the
output) to make them both unity gain and drive the filter a bit more. This
certainly did not improve things. At the highest input attenuator setting,
the filter just sounds harsh and unpleasant. At a middle setting, it
sounds much better, but simply isn't loud enough. Hence, that was a bad
idea, and I will swap them back.</SPAN></DIV>
<DIV><SPAN class=183372522-12062023></SPAN> </DIV>
<DIV><SPAN class=183372522-12062023>Then, using the same VCO and ADSR settings,
I switched to my Dr. Octature Roland-style filter (but with gain cells to
eliminate signal droop with resonance) -- this filter simply sounds brilliant
(to me). It's loud, snappy, has much more pleasing resonance, and "she
responds like a limousine brought alive on the silver screen" to incoming CV
from the ADSR.</SPAN></DIV>
<DIV><SPAN class=183372522-12062023></SPAN> </DIV>
<DIV><SPAN class=183372522-12062023>Maybe I just don't need a Minimoog
filter. Or maybe there is still something wrong with it. I don't
know. I'm half done building the same board with 547/557 instead of
3904/3906. I'm going to finish that board and put it in the module to see
if it is any better. If not, then I will probably just abandon the whole
idea of building a Minimoog filter.</SPAN></DIV></BODY></HTML>