I just bought a house with a C4 system installed in it and I'm having the same problem. The amp that is cutting out is about 3 years old, so out of warranty. But shouldn't a $1,700 amp last more than three years? My rep, who installed this system for the prior owner, is saying either buy a new amp or send this in for repair at an estimated cost of around $800 - $1,000 (plus, presumably payment for any of his time spent on the matter). Seems like there has to be a better answer. Is there a way to contact C4 directly to explain the situation and ask for help?