Ground Loop Noise From Sub Amp RCAS?

[B1GR3DDD]

So I've been struggling with a ground loop in my car for a good while now, and thankfully, just the other day I finally solved it and got rid of it completely by both grounding my RCAs and upgrading them to a bit higher quality, shielded set.

Now, as of this afternoon, I just got my sub amp installed in there. It powers up and works fine, however, when I connect the RCAS from my 4 channel amp's pass through to the inputs of the sub amp, I start to get some of that annoying loop noise again, but in the door speakers. I then tried taking one pair of RCAS out of the 4 channel amp and plugged the RCAS, which were coming directly from the headunit, into the sub amp. Again, same problem arised.

I'm completely baffled as to why this is happening. The previous sub amp I had, while a bit cheaper than the one I have now, didn't cause this problem whatsoever.

I'm pretty lost as to how to fix this.

Anyone have any ideas?

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[wew lad 5,000+ posts]

reground your sub amp to a better/different location. it could be backfeeding noise due to a ground loop between the sub amp and whatever you connect to it.

 

[keep_hope_alive Premium Member]

How did you ground your RCA cables? Stock or aftermarket head unit?

The reason to address grounds is to minimize resistance between all grounds.

Upgrading the head unit ground to the chassis can help also.

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[B1GR3DDD]

reground your sub amp to a better/different location. it could be backfeeding noise due to a ground loop between the sub amp and whatever you connect to it.

I was thinking about doing this, however I wouldn't know where to move it. I've used a multi meter and checked the resistance from the battery negative to the grounding location before, and got less than 1 ohm of resistance.

 

[B1GR3DDD]

How did you ground your RCA cables? Stock or aftermarket head unit?
The reason to address grounds is to minimize resistance between all grounds.

Upgrading the head unit ground to the chassis can help also.

Sent from my SM-G900V using Tapatalk

I grounded the RCAS by running a bare copper wire around the pre-outs on the headunit to the head units metal body.

 

[wew lad 5,000+ posts]

I was thinking about doing this, however I wouldn't know where to move it. I've used a multi meter and checked the resistance from the battery negative to the grounding location before, and got less than 1 ohm of resistance.

pics of your ground location? not sure if camry bodies are steel and good conductors someone else chime in there

 

[tymoto21 10+ year member]

What if you unplug all rcas from the 4 channel but keep one in your sub amp?

Or unplug the rcas to the front speakers and put them in the rear input then put the rear into the sub amp?

Just checking that deck doesn't have front rear and sub rcas does it?

 

[keep_hope_alive Premium Member]

I've done installs in several Camrys without noise issues (several I owned). I run Alpine head units. No issues with steel when grounding to the floor. I sand paint and use a dedicated ground bolt (no factory bolts).

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[B1GR3DDD]

What if you unplug all rcas from the 4 channel but keep one in your sub amp?Or unplug the rcas to the front speakers and put them in the rear input then put the rear into the sub amp?

Just checking that deck doesn't have front rear and sub rcas does it?

I tired both. When completely unplugged from the 4 channel and plugged just 2 into the sub amp, there was no noise. But when there was even 2 channels in each, the noise was present. And no, my head unit only has 4 preouts. 2 regular, and 2 rear/sub outs.