I think thats going to be trial and error.
Is yours really "boomy" at the bottom end?
I have to cut the bass a lot to get rid of it.
Also - do you have a nasty AC hum even when the level is right off?
Yep - Ive got the same amp and the same nasty hum.
Its getting into the power amp stage from the AC supply - and is just really sloppy design. (Ive been an audio designer for 35 years).
Im trying to record with it and its hopeless.
Also - do you find it really really "boomy" at the bottom end...