Intereference with 2005 Dode Magnum

Need some assistance or advice if someone could please.

I have a 2005 Dodge Magnum that is getting a completely new stereo system, head unit, speakers, amplifier. However we are running in to a problem with a lot of noise in the system when ignition is on. The head unit, a Pioneer 8600 is grounded at the same location as the amplifier, an Autotek Super Sport 4 channel.

As it sits I have the stereo in the back of the car (where the battery is) with the power directly from the battery via a fused 8 gauge wire. The ground for the amp and radio is directly connected to the battery as well (i've tried other ground locations as well). The front speaker wires are running down the center of the car, away from any other car wiring. The rear speaker wires are also away from any other cables. The noise sounds like a digital noise, from a computer or something.

Originally I had the stereo up front, getting power from the harness for the factory stereo. The noise was the same at that location.

Any suggestions on what might be causing this noise, and what could be done to elliminate it? I've tried different RCA cables, Stereo cables, Power cables, and ground cables. I've tried the radio in a different enviroment with no problems. I've also tried a different known good 4 channel amplifier with the same results as the autotek.

Any help / advice would be greatly appreciated.

Thanks!

forbidden wrote:

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I generally will lay blame for a noise problem like this with the internal ground plane design of the Pioneer cd player. Do you have any other cd player that you can try? By trying a different amp you have eliminated it as the source. Take another set of speakers as well and temporarily hook them up near the amp with new wire, is the noise present? Try muting plugs on the amp, is the nosie still present?

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An update, I unplugged the radio, took it out of the car. If I power up the amp and then touch the center pin of the rca, I get the noise in the speakers.... If I touch the center pin to the negative terminal of the battery, noise. If I touch the center pin to where the battery grounds to the car chasis, I get even more noise.

I took the speaker outs of the stereo, connected them to the hi-level imputs of the amp, same noise.
I took the speaker outs of the stereo, hooked them to line level converters in to the amp, same noise.

I took the amp out of the system, connected the speakers (polk audio 6.5" components and polk 6x9 3-ways) directly to the radio, and there is no noise...

So it's not the radio, the noise is present even when the radio is not in the car... It's not the amps because I tried 3 different ones with same results. Also tried different rca, power, and speaker cables. It's like this car's b+ is very noisey...

I'm going to bed now, will continue in the morning. Maybe just end up putting in the speakers and head unit for now.

about ready to give up...

Even if I have the speaker disconnected from everything, mounted in the door with the wire laying in the floor, I can hear the noise faintly in the speakers...

For now I just hooked the speakers directly to the head unit and there' s no noise.. Unfortunately this means we can't hook up the subwoofer and it's amp.

Here's a link to a divx encoded video where you can hear the noise:

https://onitap.com/videos/2.avi

The speakers are Polk Audio 6.5" components up front, and 3-way 6x9's in the back.

However, as you can see in the video I disconnected the Polk's and was using the stock Boston Acoustic (cheapy) speakers, and the noise was still there.