My friend is having some trouble with his system, and I have no idea what it is. What happens is when the HU volume is turned up to about half, the sound will cut out. BUT, only the door speaker amp cuts out. The power on the amp stays on, the amp fan keeps going, and the amp has old phono style dynamic level meters on the front which also keep going. The sub amp keeps on playing just fine. If he has the loudness on, it will cut out at a lower volume. Seems like when it gets to a certain power draw, it cuts in and out. Now, the system is the HU and two amps (1 for speakers and 1 for subs). Each amp has it's own fused power wire from the battery, but different grounding location, but each ground should be good. I happen to have the exact same amp he is having trouble with that I don't use, so we put that one in, same problem. We took out the fuse for the sub amp rendering it powerless, still same problem with the speaker amp. We even swapped out head units with mine, and same damn problem. And his HU worked fine in my car. I have no idea what to check next really. My only next idea was to stop using the factory power and ground locations for the HU, and to run some dedicated lines for it, but i'd rather avoid that unless there is a decent chance it will work. None of the stock fuses blew either, and he's been using the system with no problems for a good two or three years now.

Any theories? Thanks.
George.

 

Have you tried temporarily running a different set of RCA's to that amp? one of your RCA cables may be shorting or grounding out somewhere.

Hope this helps.