Interference after adding second power/ground run.

[timma100 10+ year member]

So my mids and highs were dead silent, I've worked for a long time to get them that way. Now, after adding a second run to the trunk of power and ground, (prepping for new alternator and amp http://www.caraudio.com/forums/car-audio-build-logs-cars-trucks-suvs/627904-build-upgrade-2005-altima-3-5-a.html

But now I have interference coming through my RCAs (its audible on highs, mids and sub). Now the second run of power and ground go right along side the existing RCA runs, but DC power doesn't generate much electromagnetic interference, (AC does by constantly changing in polarity and intensity).

So my thoughts to fix this are either get shielded twisted pair RCAs, or find whats inducing this interference into the line. One possible culprit is that this new line runs over the top of the alternator and is nearly in direct contact (Its wrapped in plastic heat shielding). Alternators do generate EMF, so perhaps its being induced there, and the RCAs are picking it up... So, this could be solved by a metallic shielding around the wire where its close to the alternator..

Also considering adding another chassis ground in the trunk because why not..

Edit: most ghetto option that might work, wrap RCAs in aluminium foil...

What are your thoughts?

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[The Camry]

Seems like you know the problem. How exactly were the original runs ran? Alt to front bat to rear bats?

How exactly are the new runs ran?

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[timma100 10+ year member]

Seems like you know the problem. How exactly were the original runs ran? Alt to front bat to rear bats?
How exactly are the new runs ran?

Sent from my SGH-T999 using Tapatalk

New runs go directly from alternator positive lug/negative to rear battery. And run along side the RCAs the entire route (except for under the hood.... because that'd just be silly)

 

[The Camry]

New runs go directly from alternator positive lug/negative to rear battery. And run along side the RCAs the entire route (except for under the hood.... because that'd just be silly)

Thats your issue. You should never run your rcas next your power. EVER.

Em fields are absolutely generated on dc power. There is tons of current on dc power compared to Ac. You can run speaker wire next to power wires but not rcas, even twisted/shielded.

Also you should have your front bat hooked to rear as well.

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[timma100 10+ year member]

Thats your issue. You should never run your rcas next your power. EVER.
Em fields are absolutely generated on dc power. There is tons of current on dc power compared to Ac. You can run speaker wire next to power wires but not rcas, even twisted/shielded.

Also you should have your front bat hooked to rear as well.

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Yeah it was certainly not ideal running them through the same channel but out of necessity. Contemplating lots, and lots, of aluminum foil...

 

[The Camry]

Yeah it was certainly not ideal running them through the same channel but out of necessity. Contemplating lots, and lots, of aluminum foil...

Pull the rcas. Run them outside the car to the amps. Noise should go away. Good way to check. $5 at walmart

or use a aux to rca adapter from your phone. Disconnect rcas from headunit. Plug in rcas from aux and play a song on your phone. Noise should be gone. Both are good ways to test

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[timma100 10+ year member]

Pull the rcas. Run them outside the car to the amps. Noise should go away. Good way to check. $5 at walmart
or use a aux to rca adapter from your phone. Disconnect rcas from headunit. Plug in rcas from aux and play a song on your phone. Noise should be gone. Both are good ways to test

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I actually got off really easy with this one, while I was in the trunk adding a rear chassis ground I took a little time and separated the RCAs from being so close (basically wrapped around) the newly added power run. So, that, plus a really solid chassis ground, and now there's no noise. I'll keep an ear on it for a while and see if it comes back, if it does I'll probably go through and wrap the RCAs in copper shielding, and then ground that shielding to the chassis..