I put my H9 in the effects loop of a Mesa-Boogie Caliber 50+, which resulted in grainy digital distortion and feedback. This is present when the pedal is bypassed. The feedback goes away when the pedal is on and the output level is trimmed to about -10db but it reduces the overall gain. Either way it’s useless because I cannot achieve unity gain in the effects loop and there is horrific noise when the pedal is bypassed.
I checked the input/output levels in the control app and noticed something strange. When I unplug the return of the effects loop, i.e. The effects out is going into the H9 but it is effectively because the return is disconnected, the input and output levels are fine, upper green range. If I plug the return in, both input and output jump up into the red, which explains the distortion and feedback. Obviously the effects loop is too hot, but only if the circuit is completed. The loop does not have adjustable output. There doesn’t seem to be an option to decrease the input level to the H9 from the app, either.
Anyone have a fix other than putting a buffer in front of the H9 in the loop? Any help would be appreciated!
