I have a Rocktron Piranha and Mesa Boogie Triaxis that I use a Rocktron Patchmate to switch between. The patchmate is simply selecting the output of either the Piranha or Triaxis, which then goes into the Pitchfactor, and then the pitchfactor output goes straight to the power amp. I’m having noise issues when using DSP or DSP+FX Bypass so I started doing some experimenting. When I use DSP or DSP+FX Bypass I get a volume jump when using the Triaxis vs. when using relay bypass. However when the preamp being used is the Piranha this doesn’t happen. There is nothing else being switched in or out of the signal chain. I can’t figure out why bypass type would effect output volume on one preamp and not the other if nothing else is changing. Ultimately I can just compensate with the volume on the Triaxis, but I’m also wondering if a ground loop would cause this since I’m getting excessive hiss at times when the bypass is set to DSP or DSP+FX.
