How is this possible? alt noise without the power wire connected

[bobo244 10+ year member]

I am getting alt noise without the power wire connected. I had no problems with my system for over 1.5 years, then I changed my battery and all hell broke lose. For more info on that story follow this link:

I have a dual battery setup and disconnected the power wire from the front and rear batteries so the 4 ch amp is running off the back battery only. Yet I am still getting alt whine. I don't understand how this is possible. Is the alt whine coming from the power wire in the deck? I don't think so because when I connect the front batt to the rear batt, the alt whine is much much louder, so I assume that is where it is coming from, but with power wire disconnected there shouldn't be any whine due to that wire. Correct?

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[htownplaya456 10+ year member]

If you low voltage signal(RCA's) are running by any 12volt then it can pick up noise.

 

[outspoken 10+ year member]

try this, my pioneer h/u did the same thing and it took care of it...

http://www.caraudio.com/forum/showthread.php?t=198477

 

[bobo244 10+ year member]

If you low voltage signal(RCA's) are running by any 12volt then it can pick up noise.

Thanks for the idea, but the rca's that are in there worked fine for over a year. I changed my battery and then the alt noise began. So the problem can't be from the RCA's.

 

[duece212 5,000+ posts]

when you changed the batt did you get the ground good and tight/clean?

 

[James Bang 5,000+ posts]

when changing batteries or grounds, The RCAs should be disconnected from the amp because when the grounds is disconnected, the amp may try to ground itself from the RCA.

 

[snakeye 10+ year member]

Thanks for the idea, but the rca's that are in there worked fine for over a year. I changed my battery and then the alt noise began. So the problem can't be from the RCA's.

I had the same problem when I changed out my battery once and this was the solution. its actually not the rca's that are bad, its the internal ground (inside the head unit) pioneer is notorious for this. you can fix it by grounding the rca's like this or you can open it up and all it takes is a drop of solder on the internal ground circuit.

Ground the rca's and see if that ends it.