I was troubleshooting this with ryan, but i figure someone can benefit from reading this in thread form....
i got my new 6.5s in, and they sound great. but from day 1, there has been a loud "pop" everytime i turn the car off. Obviously, its the amp thats older and doesn't have a soft turn off feature. I could live with that.
Just yesterday, I drove to school with no problems at all (it was nice, windows down some, stereo up louder) but when i got back in, there was a loud hum, which turned to a whine when i was about half way home. I turned the radio up louder to overcome the hum, and it'd start popping intermittantly. So i just straight turned it off.
So the troubleshooting began. All my amp connections are solid (power grounds remotes) i moved my RCA lines as far away from the power lines as i could (still have a big of overlapping for a couple inches before they go to each amp) And ryan suggested to check all the grounding on my h.u, thinking maybe that was the issue. So i moved them to what i'm positive is a solid ground. and its still there.... just as loud.
so i turned the levels down on my amp (powering the 4 corner speakers) and the hum pretty much disappeared. So am i to beleive this is the amp's doing?? I'd much rather replace that then my headunit. (amps are much cheaper...

) The amp i'm using is about 10 years old, and has been in storage for about 8 of those... i'm guessing it probably needs a good internal cleaning and/or replacement of a couple vital parts. but it still won't make it new.
so.. questions, answers, suggestions?