-Yz-

I just hooked up my amp and components today. Ran the power up the pass side, and the remote on/off, RCA's, and crossover cables through the center console. Everything sounds great.

Anyhow, there's this damn ground noise that fluctuates with throttling meaning higer revs equals change in pitch of the ground buzz. The ground buzz goes away when the car is OFF and is only evident when I start the car. It also goes away when I put the car in reverse I checked and re-checked almost everything and it all looks good. Even re-grounded the headunit and amp a few times. I also noticed that if the ground is not plugged into my amp, the amp will continue to run. double I grounded the amp to the cross memeber in the trunk right where the spare tire is to the right. maybe you guys have an alt. place to ground or something else to check???

And oh yea, I couldn't run the amp wires directly to my crossovers in the doors through the door gromets so I tapped into the stock speaker wires which I doubt is the problem?

PJK3

oh... how weird is this one...


how is the amp mounted? and what is the amp mounted to?

try disconnecting the RCA's at the amp, and see if the noise is still there.

-Yz-

The amp is mounted in the trunk and I bolted it to that sway bar looking thing right in front of the gas tank. I grounded it to the bolt that keeps the swaybar thing in place on the pass side. I swapped RCA's, still got the same sound, did as much as I could with a better amp ground, but all the same sound. I ended up having to fine tune my amp to limit the noise, but it's still there a bit. I may be picky, however I'd like it to be clean music if possible.

modifry

The change in pitch of the noise means the noise is alternator whine, but the part where it goes away when the reverse lights come on is very strange. I can't imagine the car shuts off the alternator every time you go into reverse. However, I could imagine there might be some connection betweent the two if the reverse lights were on the same circuit (fuse) as the HU, but they're not even close.

One idea comes to mind to try - does the noise go away if you put it in reverse with the back-up bulbs removed? (or just unplugged)

Also, it's not a quick fix (or guaranteed) but you might try disconnecting your head unit from the factory ground wire and make sure it's not grounded anywhere else. Then run a HU ground wire back to the same place the amp is grounded.
.

PJK3

what kind of amp is this?

is it screwed directly to the metal or is it on MDF?

try unmounting the amp and see if that doesn't fix it. take the amp off the wall and sit it on the carpet or some other non-coductive surface. it's rare, but i've seen an amp or two in the past have weird noise problems when they were grounded to the chassis through the body of the amp. they should be ok w/ having a conductive path through the amp case, but i have seen that be a problem in the past. also, how old is this amp?

also, along modifry's thoughts... pull the bulbs from the reverse lights and see if the noise comes up when the car is in reverse. you could have a short somewhere that's being completed through the reverse light circuit.

this one is really bizarre. i'd continue to double check grounds though.