Amp buzzing my front and rear speakers
 

I ran an 8 gauge power wire to my jbl 4 channel amp. Fused with a 50a fuse. Grounded to a bolt in my trunk that I drilled to the metal. Everything sounded good, had my sub and front speakers hooked up. Decided to buy a mono amp to power my sub. So I hooked up my rear speakers into the mix. Upgraded to 4 gauge power wire running to distribution box, which then has two fused 8 gauge wires running to the amps.

Well, my jbl went bad for some unknown reason, I heard a pop in the speakers, so bought another amp to power my front and rear speakers. Now all I hear is a buzzing sound when I turn accessory on, and when I turn the car on, the buzz goes with the engine rpm. It is so loud almost unbearable! I unhooked my amp and just had my headunit power them and they're good. I also tried my friends 2 channel mtx to run just the fronts and I get the same noise!

It's so weird when acc is on when I turn on my headlights the pitch gets higher. Or when I use anything electric in the car it changes the buzz pitch.

Any help suggestions? Anything!? Thank you

do your RCA cables run the same path as your power cables? If so, you need to split them apart, or buy better shielded RCA cables.

Otherwise - I think there may be filters you can put on to take the whine out. I don't have any experience with those personally...

Edit: Something like this, if rerouting the wires isn't an option. Generally try to keep audio wires on one side of the car, and power on the other side.
http://www.lesscoelectronics.com/GLI...ject_p/gli.htm

Are your power and signals wires running down the same side of the car? Separate any power wire from RCA.... try changing your grounds, run a reference ground from the deck to the amps, get rid of your fused distribution block and split with a regular unfused distribution block - just fuse the main supply line running front to back - add up the amperage of both amps draw and place appropriate fuse inline in fuse holder under the hood.

Sounds like a ground loop to me... try any or all of the above and see if it resolves the issue... you can get ground loop isolators but they're more of a bandage rather than fixing the problem.

Hope this helps,

Nick

It is most likely ground loop. If you are running the power or ground close to the RCA's that is your problem.

I have my power wire running down driver side, and everything else on passenger side. I also plugged just my 4 channel up with no distribution box and I still got the whining noise. I've messed with the grounds I have them all grounded into my trunk, would that be my problem? So I should run a ground from my h/u to my amps?

Should I get a ground distributor?????

still stuck!

I'd try a ground distributor for the two amps. Apparently having two grounding points can cause an issue like that. Or disconnect one amp at a time, and see if that solves the problem altogether.

Short of that - go to radio shack and pick up one of those ground loop isolators to try out.

What headunit are you using? If you adjust the volume of the headunit, does the buzzing get louder or quieter? If you adjust the amplifier gain, does the buzzing get louder/quieter? Another thing you can try is take a spare set of rca cables. Cut the ends off. Short the two leads together. Hook up the shorted plugs to the INPUT of the AMP and see if the noise goes away. DO NOT HOOK THE SHORTED PLUGS TO THE OUTPUT OF YOUR HEADUNIT.

DON'T get an unfused distribution block on the power side. You can very feasibly have an issue with a single amplifier that will fry the amp, but not blow the fuse under the hood. The fuses in the distribution block are to protect the amplifiers. The fuse under the hood is to protect your car/power wire from a failure upstream of the smaller fuses.

Sony headunit. If I turn volume up the noise stays the same. It goes with my engines rpm, up and down, also when I turn on my headlights the noise changes pitch. If I turn up or down the gain the noise remains the same.

do I just splice the rcas together? I don't get it

Used a ground distributor and also brought my head unit ground back to my trunk and still the damn buzzing. Is there a ground on the main harness? It's all white so I can't tell the color

Pretty much. Cut the plugs off the cable, leaving a couple inches. When you strip the wire you'll see two conductors for each plug. Strip them back and twist them together. Doing this you are shorting the inputs of the amplifier. After you do this, and if it still makes noise, than the issue is amp related.

I'm thinking if you've swapped amps around and the noise is still there, than your headunit may be the culprit. Whatever happened to the previous amp (or the amp may actually not have been bad), could have fried the RCA outs and you wouldn't hear it through the speaker outputs.

To each their own... but I think fused distribution blocks are garbage... along with glass fuses... for high current systems they just don't cut it. Create more resistance and issues that they do good.

I would still suggest running a reference ground from the deck to the amp, try 8 ga, try 4 ga... if the noise gets less with the thicker guage wire, then keep stepping it up. I know it sounds stupid but I have seen vehicles that you just can't get rid of the engine noise and in one case I had to run a 4 gauge reference ground from the back of the deck to the amp.

Also try running a ground (4ga or more) from the battery to the amp (outside the car - just to test), try running another set of rcas from the deck to the amp just over the seats to test it out. Unfortunately, there are a lot of factors that could be affecting this and it's trial and error until you figure it out.

I've known some pioneer headunits to have issues with grounding of the rca outputs... you may want to look into this for your headunit as well. For the heck of it... try another headunit if you have one kicking around.

Hope this helps,

Nick

where is the reference ground located?