Hi - my Mutant Bass Drum is emitting a continuous tone whose pitch is affected by the pitch control. The tone is present at both outputs. The module seems to be in permanent self-oscillation.

The Trigger input responds to triggers and produces a kick sound, but this is almost inaudible compared to the oscillation. The Decay control has no effect.

Any ideas on how to solve this problem, please?

Thanks, Mick

Start with all of your controls zeroed. In this case, this means that the two CV controls are at dead-center, and everything else is down. Then send it triggers as you slowly move the controls off of their zero points. My suspicion here is that you don't have the "Pitch Decay" and/or the "Amp Decay CV" set properly...the latter one, especially, since not everyone expects a control like that to be capable of polarization. However, since drum pitches do tend to change as the sound decays, those attenuverter-type controls are necessary here.

Hi Lugia,

Thanks for your advice. Unfortunately those adjustments have made no difference to the behaviour of the Bass Drum. Even at the lowest audible settings of the TONE and the BD LVL pots there is still a continuous tone at the output, whatever the settings of the CV controls.

I have the schematics but I can't work out how the tone circuit works.

When you exercise the pots with the module patched into an audio chain (in this case, preferably patched directly to the output) and listen to the output, do any of the pots exhibit "jumpy" behavior or, with audio path controls, cause any noise in the module's output? I'm sort of entertaining a theory here that there might be some sort of contaminant in one of those pots, could be something like a stray speck of metal in just the right wrong place...

The operation of the pots seems very smooth with no jumpiness and no crackles or noise at the output.

Thanks for the suggestion anyway.