My Virus Rack does this, and I am pretty certain that the reason is simply the knob wearing out.
The second knob from the left (filter cutoff) does it badly, whereas the fifth knob (env amount) doesn't. The jumpy knob feels looser, presumably because it has been used more.
Today I found out that turning the knob while pressing it in stops it jumping.
Is it possible to tighten the knobs up, or replace them?
Daniel
|