Hi,
I have made a video of the unstable tone my Mono/Poly has recently contracted, originating somewhere from the low pass filter.
What's curious is the velocity-sensitive aspect -- the harder I hit the keys, the more mangled and unstable that key's tone becomes. (Some part of me has always believed the M/P was sensitive to velocity, or responded to how hard it was played.)
This filter freak-out causes the sound to unexpectedly drop off, or pitch to randomly change when the LP is in self-oscillation.
Please have a look/listen, and maybe we can diagnose the problem.
http://www.youtube.com/watch?v=SttZhs7sKHEThanks everyone!
-Kaleb