I have a Pioneer DEH-3600MP connected to amp by RCA. When i power up the system there is a very strange sound coming from speakers. Problem gets MUCH worse if i start up the car engine. The problem dissapear when i connect a speaker by normal speaker connection. I replaced the HU with an older Pioneer and everything is back to normal. What is the problem? Can i fix it?
Of course you can fix it. It's a matter of finding what the problem is first. My guess is that you had some loose wires (prob negative) or you had some wires touchin eachother.