engine whine w/o rcas plugged in

[brocken 10+ year member]

I just installed a system in my wife's car and I'm having trouble figuring out the problem. It's an '06 Murano. I know it's not the head unit or my PAC audio adapter because the front speakers still make the noise when the RCA's are unplugged(from the HU and/or amp). It only happens with the engine running. It doesn't matter if the stereo is on or not. I tried different grounds for my amps and they're solid connections directly to the frame. I have a Kicker zx450.2 running the front comps and a Memphis ST250d running the sub. The whining seems to be coming from both tweets which are mounted in the dash.

Without ripping the car apart again to see if the speaker wires are stripped or crimped what else might be the problem? How likely is it that the Kicker amp is causing the problem? It's a brand new amp.

I suppose I could try installing another amp and see if that fixes it but I'm trying to find simple things to try first.

Thanks!

Click to read more...

 

[PESteele 10+ year member]

what hu have you tried new ground for it. Also the rca signal transfers slightly through the air when unplugged if its like a foot away

 

[azbass 5,000+ posts]

where did you ground the amp?

 

[knukonceptz 10+ year member]

Did you ground the PAC?

 

[forbidden 10+ year member]

And where are the crossovers mounted?

 

[brocken 10+ year member]

I did not reground the HU but I've also removed that from the list of problems since I totally disconnected it and the whine is still there. And I didn't ground the PAC either but that shouldn't be a problem if the noise is still there when the RCA's are disconnected.

The amps are grounded to seperate frame bolts in the trunk. Yes, I did sand the paint of the surface, there's good contact. These are better grounds than most other cars I've used before and those didn't have noise.

The amps and crossovers are all mounted to a large board. The crossovers are several inches away from the amps and no power wire is running near them.

I did try one troubleshooting step that lowered the noise. I turned the gain down on my stereo amp almost all the way and the noise is all but gone. You can just barely hear it now. I tried that first with the engine running and the RCA's disconnected and my wife could hear the whining diminish as I turned the gain down.

I turned the PAC adapter outputs up a little to compensate for the level.

Does that sound like it's something in the amp? Where else might I be picking up the sound? It would be too much of a coincidence for both sides of wires to pick up the same noise.

Thanks for the help!

 

[Decipha 10+ year member]

alt whine does not come from wires! in all my experience with installs i have yet to blame alt whine on wires! if someone can prove me wrong on this i'll give them a fukin popsickle... turn the gain down

 

[brocken 10+ year member]

gee, thanks for the helpful post.

I was hoping somebody could post something constructive. The noise has to be coming from somewhere and having to turn the gains almost all the way down to alleviate it is not a great solution.

 

[ga12r 10+ year member]

You say you have the amps grounded to two seperate bolts? You might try gronding both amps plus the headunit to the same point(either to a distribution block that runs to a bolt, or all the grounds to one bolt). You probobly have a ground loop.

 

[brocken 10+ year member]

thanks for the idea but I really doubt that's it. I completely disconnected the second amp(power, rca, ground) and the whine was still there. This is with the headunit disconnected as well.

 

[Goldenknob 10+ year member]

try a different amp. to me it sounds like it could be a amp problem.

 

[Decipha 10+ year member]

believe it or not it may be due to your alternator going bad... i did an install in a 94 chevy astro and less than a week later it had a bad case of alt whine i couldn't figure out what was causing it for the love of life... then a couple days later the battery light on the cluster came on... after i swapped out the alt haven't had a problem with alt whine... may be something to consider if all else fails

 

[knukonceptz 10+ year member]

If all you have is an amp with no input signal and no other added electronics (amp, electronic crossover etc) and the amp is connected to power, ground, remote and speakers it would have to come from the amp as the amp is the only thing in line with the speaker. Swap amps using the same power/ground connection. If amp 2 duplicates the issue, you have a bad ground. If it resolves it, bench test the amp to verify the noise. Amps should not "make" any noise, they amplify what is in the stream.