So not terribly long after I got everything connected and working, (but not immediately) I began having some intermittent noise in the rear channels. I noticed at first it would happen on cold/wet days and would frequently seem to come and go with bumps and/or shifts in the car's momentum.
It gradually got worse. After a while it began doing it pretty much every day when it was cold and/or wet out, and didn't go away unless it warmed up or dried out. That summer, the problem largely went away except for when it rained. Now, I know everybody is thinking "obviously there's water getting to something, somewhere..." but I checked thoroughly. Everything is bone dry, and all the signal cables were brand new and fairly high end. Furthermore, as winter came on again, it pretty much became constant. Didn't matter how dry it was. (much less humidity in the cold) Eventually I disconnected the rear speakers and have lived with it like this for some time. Essentially at it's worst, it comes and goes pretty much based on temperature and humidity. Last time it was hot and dry I connected the speakers to it and it worked great.
The sound is a screeching sound, like what you sometimes hear on AM radio frequencies. It does not modulate or change based on rpm's or use of any accessories in the car. The volume of the sound does NOT change as I adjust the input volume level at my receiver, but I can hear the music underneath of it getting louder. I swapped the inputs on the amp, and it did NOT follow the inputs. Still rear speakers only. The amp has nice plastic sheilds where the speaker wires connect, so there aren't any stray strands of wire touching the chassis. I'm not 100% certain my ground connection is the best ever, but the fronts never falter and play VERY strong. It could be the amp itself, but it does work fine in some circumstances, and I can easily see through the casing that there are no obvious signs of distress like venting capacitors or burnt leads.
Does anybody have any thoughts? The guy at a local audio shop suggested that there might have been too much power and the voice coils on the speakers themselves are shorting out from partial damage, but it seems to me like it wouldn't play normally SOME of the time if that were the case. He also gave me the spiel about too little power blowing speakers, which I already knew, and it would be fairly ridiculous to suggest that 123w rms is too little for polk 6.5's. (they're just rear fill and keep it 75% in my jl components up front)
Any suggestions would be greatly appreciated!
