Engine noise through power lead...?

[ultimate157 5,000+ posts]

I have a 96 cherokee, and i have two amps, one RFosgate 600w powering my subs, and one 400W Jenson amp powering my 4 5.25's

I ran the wires right next to eachother, the whole length of the car, and i have a high-pitch whine coming out of the Jenson amp through my speakers, and it goes higher when i rev the engine.

is there something i can put in line with the power lead to eliminate this? I had this setup in my Jeep Wrangler at one time, and it did not have any whine to it.

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[johnecon2001 5,000+ posts]

you should attempt to reground the Jensen amp. And your HU as well.

 

[helotaxi 5,000+ posts]

And search this site for a problem caused by a bad ground trace in the Pioneer deck that is becoming quite notorious for causing ground loop noise problems.

 

[ultimate157 5,000+ posts]

i did a VERY extensive search today ... and i've got lots to say.

I ran direct wire from the battery, outside the car, to the pioneer HU (12+ and ground.) I still had the whine. I tried rerouting the turn-on lead and RCA cables, still there.

the weird thing is, the whine does NOT come out through the speakers if directly hooked up to the HU.

I also noticed the RFosgate also whines, i just had low-pass on for my subs.

I tried hooking up the RCA's to an output from inside my house, and i believe it did not whine.

Is this ground loop you're talking about inside the HU?

 

[ultimate157 5,000+ posts]

What kind of head unit do you have? If a recent year-model Pioneer it is possible that you're experiencing the infamous Pioneer RCA output ground trace problem. Apparently if you connect or disconnect the RCAs while the HU is powered on it burns something on the board internally and creates an inescapable ground loop problem that can only be remedied by sending the unit in for repair.

****IT PIONEER ... thanks for your advice guys...

 

[Vestax 10+ year member]

Have you tried switching out RCA's?

If not, try this. Take a couple of 16 awg wire (like speaker wires) and ground the outer shield of your RCA's. That is, for each preout you have, take a piece of wire, wrap the outer part of your RCA's, and connect it to ground, plug the RCA's back into your deck.

 

[Chevyaudio 5,000+ posts]

try grounding the RCA's. I believe that has fixed the infamous Pioneer ground loop

 

[ultimate157 5,000+ posts]

im guessing this will work on either end of the RCA, so i dont have to rip out my dash again ? just ground it at the amp(s)?