So let me start by saying i ran my friends Alpine hu in my car last week with the exact same setup and everything worked perfectly. I just installed my Pioneer 880 today and everything started up fine but my sub amp. The speaker amp would turn on fine, but my sub amp, a Massive Audio P1000.1 will turn on then quickly go into protect, then turn on, then go into protect in intervals. Turned off my car, disconnected the sub, turned down the gain a bit and the amp lit up fine. Hooked the sub back up and tried to start it out again. It worked for a bit with the gain turned all of the way down. Once i went to turn up the gain again, it would go into protect, then light up again, then go into protect in intervals. I havent changed any of the wiring since i have my friends alpine in a few days ago. Any idea as to what the problem could be?