noise problem in front speakers

Here is the setup: 2005 Mercury Mariner, Pioneer AVIC-D1 head unit to MB Quart RAA 4200 to MTX TXC 6.0 and 6.1 components. It is a high pitched noise that is present at all times the amplifier is on. It changed pitch and was almost eleminated when I moved the signal cables so I though there was induced noise from another wiring harness. I disconnected the signal cable and ran a new one outside the vehicle but the noise persists. I have ruled out the head unit because the noise also occurs if you touch your finger to the positive of the signal cable. Am I right to believe it is the amp and if so, do I need to have the amp looked at for a faulty component that would be causing the noise. This one has really stumped me so any direction would appreciated. Thanks in advance.Good Luck!

-Thad

Not sure if you have already, but have you checked the grounding points?

I checked the grounds. I have an MB Quart RAA1000 and the 4200 running (8ga.) to a distroblock and then that (0ga) to ground. I tried adding the ground to the RCA but that did not eliminate the noise. Any other thoughts?Good Luck!

-Thad

make sure your rcas are not run nexty to any speakers wires or power wires... this inculdes stock wiring. If and when your RCAs need to cross a power/speaker wire,make sure it is at a 90 degree. this will help eliminate noise.

Read and implement nouseforaname's post. New Project: 2003 Pathfinder

Read and implement nouseforaname's post...lol