car speakers cut out?

I had a pioneer deh490ih head unit and a kicker 12L7 being pushed my a fosgate amp. My problem is that when I turn the head unit up my car speakers all turn off but not the sub. They are the stock speakers. After about a week of this the stock speakers went out completely. I replaced the deck with another after testing the stock speakers and finding they were good. Now I'm getting the same problem with the new deck. I turn up the deck and the speakers turn off but the sub keeps hitting. If the sub is not hooked up the speakers work fine.

I checked the wiring to make sure no wires are crossed and they are good. I replaced the battery(optima yellow top) thinking maybe the battery had gone bad and also checked the altenator and all is good. Any advice would be helpful thanks in advance. Fred

I have had similar problems, one i found is maybe its a bad rca cable, or a bad rca input on your amp-also if you have the polarity backwards...but check the rca cable. I replaced mine, and it stopped all problems.

Thanks goodforcatfish; I'll try the RCAs later today. Any other ideas?

I really like the optima yellow top or the Orbital from napa. Both gel batteries work well. I always suggest an upgrade in battery when a person is upgrading their system. But lets not hijack my thread with battery talk, lets stay on task ;)

cglovesaly, I think your problem might be different from mine. When the sub cuts out its usually when the ohms are to low for the amp or when the amp is not getting enough power.

yes, nu age is right, the amp is trying to protect itself from blowing, i dont know what you are all running, but if you have it wired in parallel your amp probably isn't rated for the ohms, or the power.

also if you find that it is the rca's outputs on your head unit,nu age, you can try grounded the rca's to your power ant. ground, each wire, with a solder ground. i saw some pics somewhere on this forum, can't remember were. Its usually caused by a suface ground fuse blowing. let me now how it works!