thump and groumd loop or rca problem

[PittViper 10+ year member]

Hi

I am running the front RCA out of an Alpine hu to the front input of a punch 400-4.

I am running the sub out f the Alpine to the rear in of amp. Front out of amp runs

Front speakers. Amp bridged for sub.

Sometimes I have thump and smetmes I don't. I thought the power wire

Was too close to ground but that doesn't seem to be it. Could it be something loose.

If I remove front RCA inputs problem is still there. But of I remove the sub

Input which is the rear RCA input the sub flutters wildly without any input.

What could be the problem. How should I troubleshoot this.

I need to fix this ASAP.

Thanks

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[keep_hope_alive Premium Member]

i ground my HU to the chassis to reduce resistance between amp and HU grounds.

But it sounds like you may have an amp issue.

In the future, don't mess with RCA cables or other wiring when the system is on.

swap the speaker and sub and RCA's to see if the problem is related to the rear amp channels/input.

 

[bgowdy 5,000+ posts]

sounds like to me its your rear rca cables because i currently have the same problem with my truck. my back rca's well one of the rca is going bad. i just got to replace them

 

[keep_hope_alive Premium Member]

except when he unplugs them the amp acts up. the amp shouldn't have output without input.

swapping the RCA's should help identify if it is them or not.

i developed this to help when one channel doesn't work. same concept applies for Front/Rear.