My car stereo is driving me CRAZY! When I hook up the preamps to my amplifier and turn the car to "On"... BUZZ

Question

So, in my belief, I have tried everything.

But first, let me tell you a couple things. This head unit is is a high end, Pioneer DEH-P6900UB I paid 300+ for at circuit city a couple years ago. I'm almost dead positive there is nothing wrong with it in particular. Whenever I send sound out the speaker hookups on the head unit directly to the speakers, the sound is near perfect. However, after buying a new rockford 4 channel amp, I hooked up the preamps for the four speakers from the head unit to the amp and the speakers BUZZ. It's annoying, and it only happens when the car is on. "Road Noise" "Ground Loop" my friends have suggested them all.

I have:

Tried 5 or so different grounds for the amplifier

Hooked the head unit up DIRECTLY to the battery, so it's not a power issue there.

Ran the RCAs outside the car, inside the car, every possible way.

Hooked up a CD player to the amp: PERFECT sound (does this mean the power/grounds for the amp are OK? I'm assuming).

Any help would be awesom

Answer 1

Bravo Cyniclos! I would have to agree...But before you go thru all that trouble...Did you say you ran the RCA wires or pre amp wires seperately?In other words are there ANY wires that may have power(12-14 volts)that are NEXT to the RCA/Pre-Amp wires?I know another common mistake people make is running power along side with the RCA wires.This is a no no.The current that flows thru the wire can sometimes be heard thru The RCA cords.

If you did run them seperate,I would have to agree thats its internal of the head unit.I hate using "ground loop" isolators...They cut down on sound quality tremendously.I also feel that you should NEVER need one UNLESS you are using CHEAP products....Ive noticed that CHEAP decks and amps sometimes pick up noise....Ive never encountered any noise from any name brand electronics unless the wires were ran together.

Oh,1 more thing...did you check the rca wires?Grab another set and try them and see if it still doing the same.Maybe the RCA are bad??

Answer 2

this is a very common problem with all the pioneer headunits. this happens because the ground fuse on the stereo is blown. pioneers are very easy to mess this up. this usually happens when the person is messin with wires while the stereo is on.

there are several ways to fix this. one is buying a "ground loop isolator" but will reduce the sound quality of your system. radio shack should have them.

another one is getting a speaker wire. in one end, connect it to a good ground source. on the other end, loop the wire around the outside of the RCA's that will be used behind the stereo.

notice i said outside of the RCA's. the outside part is what carrys the ground on them. the hole of the rca's is what carrys the signal. since the stereo does not have good grounding on the rca's, this will fix it very easy.

if you do this, try to do it as clean as possible.

the other way to fix this is by contacting pioneer and try to get the grounding fuses replaced. they are inside of the headunit and are very small. i think the fix is around 50 bucks... cant really remember as this happend to a friends pioneer stereo early last year and he wanted to use the warranty on the stereo. so they fixed it for free.

ive fixed several stereos using the 2nd method cus ppl for some reason connect and disconnect the wires or rca's while the stereo is on. usually this will create static and travel to the stereo through the rca's and ends up blowing the internal ground fuse. the result is a buzzin sound when the car is on only. very annoying too lol and it gets louder if you step on the gas.

Answer 3

Before going through too much, I would try to ground the pioneer direct to the chassis bare metal, not to the factory ground at the harness, this usually solves most ground loops. And double check your ground at the amp, should be solid, and to bare metal. Other than that, get rid of the junk pioneer, and get an alpine or clarion.