Hi all. 1981 Camaro Z-28. Gear:

• Sony head unit
• Legacy Amp
• Shielded RCA cables
• Low level noise filter (4 channel RCA)

I am getting engine noise through my rear speakers (we will deal with this first). Even with head unit disconnected from amp, I can hear severe engine noise from speakers. With head unit connected, the noise does not increase with volume, ie, I have to crank the music so I can no longer hear it. I have run a power cable from battery, but I think the deck and amp share it. I also ran a NEG cable from battery to see if it would help but it didn't. I can try other stuff if anyone has any suggestions, such as separate wiring for amp & deck, etc...but I don't want to waste time either.
I am really good with home audio, but recently learned more about car wiring and audio. I have a meter and can make some new wire runs if needed. Thanks.
~cape

 

When you disconnected the head unit where did you unplug it? Try it by unplugging at the amp so the RCA inputs are open. Then listen for the noise again. If it persists, measure the AC voltage across the amp's power input terminals while it's powered on (but still no input signal). Let us know what you find. If your power input is good and you have nothing else connected to the amp's input then your amp must be at fault. If you have another or can borrow one try swapping it in to see if it goes away.

 

wow...I never would have thought of that. You were right...when I plugged in the RCA from the ground loop isolator, the noise returned, even though the other end was NOT plugged into the deck. So then I thought, "what happens when I plug in the new RCA cables directly from deck?" Seemed to be no noise. Instead of trying one thing at a time, I replaced the RCA cables from deck to amp AND installed the isolator, together. Who would have the the ground loop isolator would do the OPPOSITE, and actually introduce noise?? I will have to hook everything back up and fully test it out with the new cabling...I will post back. oh yeah, and THANK YOU

 

No problem and nice car btw. Which powertrax did you get? How do you like it? I have a 12 bolt with posi and apparently there isn't one available to replace my carrier.

 

Huge difference...LOADS of traction. Combined with those tires, very difficult to "burn out" even if I try...