dont forget most amps have a thermal switch built in to shut them off before they overheat, but I dont know how that could cause the distortion. I'd definatly switch out the rca's if they are old, and double check all of your grounds to make sure they are tight.

 

maybe you guys haven't figured it out yet, JENSONs suck. but besides taht open up your amp and check your RCA connetions to the board, maybe they are cracked. That happend to my amp and i got alternator whine in the lines that way, just resodder it up.