Damn, I spent a fortune on that amp, and the consensus seems to be that it was bad. That sucks.
I'll look for another one and see if it's any better.
Did you buy it used?
If you still have it, talk to @timowens - you could compare notes and determine if there is a difference, I'm sure he will help (if he still has his). Maybe if it really is defective, it can be repaired at a reasonable cost.