Extra RCA voltage?

Recently, my 3-yr old pioneer head unit and power acoustik amp showed signs of their age, so I replaced them with a Pioneer DEH-P7400 and a Power Acoustik OV12-1600 amp.

However, after I was done swapping the parts, I began getting alternator whine, which I remedied. However, the subs would give a bump whenever the amp powered on. I checked the amp ground, 0.1ohms. I noticed that when the RCAs were not connected to the subs, the amp would power on normally. I tested the RCAs and when the head unit was off, there was 2.6DCV in each RCA which then disappeared after the headunit/amp powered on. I also changed the head-unit ground and both locations were 0.1 and 0.3ohms.

I'm stumped.

Thanks.

Your new amp may not have the same turn-on delay that the old one had.  You might try a pop-stopper like https://www.autotoys.com/x/cust/product.php?productid=1811&cat=788

I have the amp remote on a switch, it pops even if I turn the amp on several minutes after the head unit. I connected the RCAs from another car to my amp and it did not pop on turn-on. I'm sure the reason is the 2.6v in the RCAs when the head unit is off, I just don't know what could be causing it...

Any suggestions?

You are describing DC voltage.  An amplifier outputs AC voltage, including the amp in the deck.  If you want to know what voltage the head unit is outputting, read AC volts at the amplifier speaker terminals with gain all the way down.  But that isn't the problem, I would bet.  And since you have the turn-on with a switch installed, are we to guess that you have it hooked into ignition ACC and not to the deck remote wire?

First off, thank you for the input.

stevdart wrote:

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You are describing DC voltage.  An amplifier outputs AC voltage, including the amp in the deck.  If you want to know what voltage the head unit is outputting, read AC volts at the amplifier speaker terminals with gain all the way down.

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What I'm saying is there is DC voltage (2.6v) in the RCA lines when the headunit is OFF. There should be zero voltage if the headunit is off. This is my problem...I'm pretty sure at least. Where could this be coming from? Or, how can I eliminate this?

stevdart wrote:

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But that isn't the problem, I would bet. And since you have the turn-on with a switch installed, are we to guess that you have it hooked into ignition ACC and not to the deck remote wire?

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The switch is on the headunit remote wire.

DC voltage present on the RCA (I bet it's on the shield ring) indicates bad pre-amplifier ground plane in your head unit or bad RCA cable shields.  Try swapping cables and also running a dedicated ground for the head unit (not using the OEM wiring harness ground.)  If it still does it the head unit needs repair/replacement.

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I ran seperate RCA cables and ran a dedicated ground....

The head-unit is defective then?

Probably.  Pioneer is not known for excellent quality control... if it's a new HU I'd take it back and get a replacement or a warranty repair.  Sorry.

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Ok, I'll call the store I bought it from and if they give me any trouble I'm calling pioneer.

DYohn: You were right, it was in the outer ring of the RCA.

Thanks a lot guys for the help, I appreciate it.