Is there a software option to decrease the input level on the H9? If not, can one put a control device to decrease the input in front of the H9 in the effects loop?
The H9 will accept a hot instrument level, but not a hot line level.
Some amps seem to have an excessively high loop level – the H9 is unsuitable for these.
Essentially it is a guitar pedal – if you want a line level effects unit, this may not be it.