I was surfing the net a bit and stumbled over this link:
http://www.techman.synth.net/techman_website2_00002e.htmcopy:
"When it came to testing this module, I was a little perturbed that it
didn't work as I expected. in sub mode, turning up each of the four sub
octave pots produced glitches in the audio if I had signal on both the A
IN and B IN jacks. This couldn't be right. ... This time I happened to
put the scope probe on the non-inverting input of the input comparator,
and lo, the glitching stopped. Aha.. the capacitance of the scope probe
had stopped the clock jitter. Solution: I happened to have a couple of
18pF ceramic caps handy, so I put these across the non-inverting input
and ground (Pins 2 & 1) of both of the 311 comparators. Problem solved.
The module now appears to work as intended...."
Since I was experiencing the same problem, I tried it out. I needed to
take apart the whole module to be able to fit the caps, but the result
is very nice. Now I know what a MOTM-120 should sound like. Very cool!
Cheers,
Tom