I had problems with my zvex effects and my Skylark. No amount of turning down the trim pots fixed the problem with my fuzz factory or Octane III. I think it was due to the way the active filters shape the tone. They are more complex than a simple tone pot, and zvex effects seem to be particularly sensitive to a guitar's (and I would assume bass) settings, aside from the input volume and the pedal settings. Some people have suggested attenuating the signal with an external device, but I can't see how this would really be better than the trim pots. I will be curious to see if you have any luck.