At band practice today I turned on my SEM and got unmusical distortion coming out of it. As the sweep rose it caused the input clipping light on my Mesa M3 to flash in sync with the distortion. The only other pedal I had on at the time was my MXR Bass compressor with the output volume at around 3 o'clock. I tried decreasing the input and output volumes and the issue persisted. Anybody got any advice?