I have a customers truck here with an aftermarket head unit and some amps, nothing huge and big, just a bit over stock improvement.

It has some serious electrical interference in the speakers, is there any kind of aftermarket noise filter or any type of device to silent this? Will adding grounds or changing grounds or anything like that help? I would like to tone that noise down some, I dunno if it was there before ( we o/h the engine ) as it didnt run when it came in, but judging by the customers attention to detail, I cant believe he would put up with that.

Any suggestions appreciated.

I'm feeling like an *ss asking you this, Eric, but did you reconnect all the grounds when you installed the engine? Sorry.
Check your grounds..make sure they are all clean.

Has to be a ground problem somewhere I would think, either one of the ones around the engine or the one for the amp.

grounds were my first hunch as well. Blake and I both went over this thing and found nothing.

Tom, FWIW, its the Red Dually....Coe....

I ran a ground wire from the radio ground through the firwall to the large ground strap in the engine compartment and have no whine or radio noise with a SONY X-PLOD deck.

Before that ground was installed the AM radio reception was bad and the XM was not as clean as it is now.

The only time I hear any noise is under high voltage lines with AM radio on.

;)

just a suggestion that's worked for me in the past, run all the stereo equipment grounds to a common point

eric gimmie a call if its still giving you trouble.

grounds were my first hunch as well. Blake and I both went over this thing and found nothing.

Tom, FWIW, its the Red Dually....Coe....

What'd those guys do this time?

Did they run any large power wires up to the batteries? With all the electronics stuff in that truck, it wouldn't surprise me at all.
If so, did you disturb those wires? Its possible you could have shifted the power lead so it runs closer to other wiring.

I bet when the stereo stuff was installed, the RCAs and power wires are run together. If you run RCAs down one side of the truck and power wires down the other, it will clear it up....I don't think it is your problem. It relies on the owner. It is something to look at since I had the same problem with one of my cars. I was even using good RCAs (pheonix gold...sp?)

Figured I'd update this. I pulled the deck out of the truck and there is more crap back there then anybody could imagine. I found some of the RCA's pinched between the back of the radio and some of the dash supports. I ended up pulling the upper dash pad off to route cables and wiring behind it. That took care of the problem.

so eric installs car audio now? soon there will no longer be duramax's in the MA shop, just a bunch of escaladezzz with twenty-fo's and dubs and bumping mad beats on their fresh new stereo, courtesy of dmaxallitech. :D

Ben, you have to see this dually to believe it. Its a sweet rig. Too bad some stereo shop decided to bugger it up.

Congrats on finding the cause, Eric.