Hi, maybe you guys can help me. I am playing a sax into an SM57 which then goes into a Blue Tube pre-amp, then into a Qtron...which then goes into the board. When I turn the Qtron on it's much louder and there's some feedback. Turning it off makes the sax sound much quieter. Any ideas on how I can get the raw and processed signals to be equal as well as getting rid of the feedback.