>I'm interested in filtering control voltages,
Afaik, only the 830, 820, 700, and half of the 110 can process DC. I don't
know about the 130 or 190, even though I've asked a few times. I guess a
320 can be considered a DC processor of some sort -- it has DC inputs and
can produce a DC output for considerable length of time.
>inspired partly by the '101
>vibrato circuit and partly by trying to make a PLL with two '300's and the
>ring modulator from the '110.
My, that sounds ambitious :) Let me see if I understand what you mean. You
are trying to have one 300 track another 300, taking the square outputs of
both 300's, using a 110 ring mod as a "phase comparator", smooth the output
with an 820, then send the output to the second 300 using the FM input??
Or am I completely lost here?? I think I understand how a "four quadrant
multiplier" would give the sum and difference frequencies using sines, but
I don't see how it would give you just the difference like an XOR using two
squares. Wouldn't it give you something much more complex??
Does it eventually lock?? Are the resulting outputs of the two 300's 90
degrees out of phase??
>I used the '820 lag as a cv filter for the
>PLL with interesting results; depending on how you adjust the frequency and
>tracking on the oscillator in the loop along with the lag time you get some
>interesting 'wobble' early in the note, and it changes the timbre of the
>note overall (like FM, I'd guess).
I think you would get FM if the 820 was set too fast, and afaik, some
ripple is typical for a "type I phase detector".
Regardless whether it works as a PLL or not, that sounds like quite an
interesting patch!!
>But as I understand it, the '820 would
>have a -6dB/oct response unlike the other filters.
Yes, the other MOTM filters are steeper, but they won't pass DC. The PLL
circuits I've seen only use one cap to smooth the VCO control voltage, so
afaik, that would make them 6dB/oct filters as well.