Alternator Whine Options

[GTS13]

Hey guys,
I just finished installing my new 6 channel amp but now have alternator noise. I've already redone my ground on the amp moving it to a different location even and that didn't fix it. I also bought a couple Ground Loop Isolators and those didn't fix it either so I returned them. Any other ideas on what to do? Only other thing I can think of would be to replace my alt with a bigger one?

The amp is a JBL GTO 755.6 II.

Thanks!

[GTS13]

Ok, that's a lot of stuff Davey. I have my head unit hooked up that I did about a year ago and it has the ground that connects to the stereo's wiring harness. And then I just ran the RCA cables from my head unit to my amp along with the signal wire. Then there's a ground coming out of the amp and grounding to another part of the car.
So you're saying the ground for my head unit and amp should be connected?

[BloodyStupidDave...]

So you're saying the ground for my head unit and amp should be connected?

That is a thing to try, yes. As pittfirefighter said, a common cause of alternator whine is a difference in potential between the ground at the amp and the ground at the headunit. Because bodywork and wires have an electrical resistance, when things are connected to different ground points, there is a possibility of there being a small voltage difference between the different ground points. My reply above gives a number of different strategies to check that all the metalwork and the ground points on different bits of your audio setup are all at the same voltage.

But the point that jester (and the other point that pittfirefighter) makes is equally valid: alternator whine can be induced in the RCA cables if any power wires run close to the RCA wires. This is where the various shielding strategies I outlined come into play: rerouting the RCA cables away from any power or any other signal wires is important. Alternatively (or additionally), replace your RCA cables with ones offering better shielding characteristics or supplement the shielding on your existing cables.

This post has been edited by BloodyStupidDavey: Aug 5, 2007 - 4:46 AM