another ground loop issue thread

[Divvy]

Hello! Last week i bought some new speakers for the rear. The install went well but when i connected the rca in the amp, the speakers started making a ground loop noise.
There is a whining noise that follows the rpm and a static distortion.
Now i know there is a sticky theread on this, and ive tried every suggestion in it, but the sound is still present.

I've currently tried: temporary grounding the engine, alternator and battery with jumper cables, new ground for H.U, new H.U, changing amp ground location (yes, its bare metal), changing car battery, starting the Hu off a separate battery, new rca's (separate from the power wire), grounding rca output to H.U, moving the rca's and removed the stock amp in the car. all to no avail, the noise didnt even change.
The distortion only comes on when all four rca's are plugged in, but emits from all four speakers. Without the ignition on, it plays silk smooth. The sub is currently uninstalled, but there was no noise when it was hooked up to a separate amp with same grounding location.

The car is an audi a4 b7 avant
Amp is dls ca-p44
And ive tried 2x sony and one pioneer headunits
Any suggestions would be greatly appreciated, before i ram the car in a wall and buy a new one

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[1aespinoza 10+ year member]

Any suggestions would be greatly appreciated

Before this, were 2 RCAs the only signal input? After all you have tried, only common factor is the amp.

 

[Divvy]

Before this, were 2 RCAs the only signal input? After all you have tried, only common factor is the amp.

Yeah, i only had the front hooked in, i can unplug the front and drive with the rear speakers without any issue. I feared it was an amp issue myself, but wouldnt the amp send the signals to the speakers regardless of the rca’s if it was struggling?

 

[dragon.breath 10+ year member]

Being the front two channels are quiet, try connecting the front rca and speakers to the rear channels to the rear channels. If it makes noise, the rear channels of the amplifier are bad. If it is quiet, you still have a install problem. Either rca interference or a pinched speaker wire causing feedback to the amplifier.

 

[Divvy]

Being the front two channels are quiet, try connecting the front rca and speakers to the rear channels to the rear channels. If it makes noise, the rear channels of the amplifier are bad. If it is quiet, you still have a install problem. Either rca interference or a pinched speaker wire causing feedback to the amplifier.

the noise emits from both front and back as soon as i plug the rear in. i currently have the rca cables running over the seats while troubleshooting. i havent checked the speakerwires tho, will definitely check it! thank you.

 

[1aespinoza 10+ year member]

wouldnt the amp send the signals to the speakers regardless of the rca’s if it was struggling?

It will, but very low since there nothing to amplify. You can bridge the rear and front speakers, and use only the front RCAs to see if it solves your issue. Pioneer decks are notorious for this issue. When bad, if you use 4 RCA outputs, you will get the exact issue you got. Use only 2 RCAs, problem solved.

 

[Divvy]

turns out it was the rca's all along .. the pair i swapped in was apparently not as shielded as i thought despite thier thickness. thank you all for suggestions tho!