So, I bought an amp off someone, and when music is playing, its very scratchy, almost sounds like a blown sub. All volume levels. Of course, I can't get much bass from my subs cause they just distort too bad when I turn it up loud enough. And just so we're clear, it is in fact the amp, so I'm just wondering what circuit might cause this, or what in the amp might be having a problem. Any thoughts would be very appreciated.
I should add that replacement is 1500 plus dollars so I'm not going to do that.

 

And if it matters, its a custom configured Mmats DHV3000.2

 

And on that note, does anyone know a good amp repair guy in Canada? I have 2 apparently that need repair, and shipping back to Mmats in Florida is both expensive and time consuming