Weird Alternator Whine issue

[Bun-Bun 10+ year member]

Ok I have done a search cause I know this is a common issue but I can't find anything similar to my specific problem.

I finished installing my amps yesterday which include running all my power wire and rca's and everything. I used Knu Konceptz Krystal Kables and these things are awesome... and my power wire is on the other side of the car and underneath the car (positive and negative). I have a HC1400 in the trunk with the positive run direct from the alternator to it and the negative run from the alt caseing to it as well. Plus big 3 done for the stock battery. The only thing using the frame as ground is my HU. From the HC1400 I have 1/0 running to a fused distribution block and a ground distribuiton black where then 4ga runs to my amps (~6in of 4ga). All conenctions are solid with Knu Konceptz compression fittings or ring terminals to the battery.

HU is Alpine 9887

Amp is Alpine PDX4.150

Here is the weird thing... I only have alt whine in channle 2 on the amp. I have tried switching the RCA's around (swapping front and rear) and its still channel 2 that has the whine. I took my HU out and it caused every speaker to go staticy and I discovered the RCA ends had come loose (like the caseing was uncrewed a bit) so I tighened all of those up and everythign is making a good solid connection yet stilll... the slight whine is still there.

So its not the HU, not the RCA's (cause it doesnt matter which RCA I use or which channle from the HU I use) so its in the amp somehow. When I pulled off the RCA for channel 2 the connector actually pulled out of the amp but I just pushed it back in and carefully turned the connector off and it stayed in and still sounds great but im wondering if maybe its not grounding correctly because of it? Could I try grounding that connector to my distro block at the amp end? Or what can I do? HELP! lol

Too sum up... alt whine in only 1 channel of 4 channel amp.

Thanks for any advice.

EDIT:

could it be that I have my negative wire from the back battery directly to the alt housing? shoudl I move it to the front batt instead? But wouldnt that mean it would be whining in all speakers and not just the one?

Also with the car off everything is krystal clear...

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[jrwalte 10+ year member]

Negative to alt should be fine. It's a better ground in my opinion, because you're grounding directly to your power source instead of through front bat --> chassis --> alt. But weird things do happen. You should at least move it to to the bat or the chassis as a test.

To clarify, when you moved RCAs you said it was still channel 2 in the amp with the noise. Did you mean the channel or the speaker still had the noise? So did the noise move to the rear speaker that was then connected to channel 2 or did it stay in the speaker where the noise originally came from?

 

[Bun-Bun 10+ year member]

To clarify, when you moved RCAs you said it was still channel 2 in the amp with the noise. Did you mean the channel or the speaker still had the noise? So did the noise move to the rear speaker that was then connected to channel 2 or did it stay in the speaker where the noise originally came from?

I swapped the RCA's that were on channel 2 and channel 4 and then moved my channel 1 speaker to channel 4 (so that both were up front and I could hear better). And I still got whine out of the channel 2 speaker and the channel four speaker (moved from channel 1) had no whine. thus the rca on other channels does not cause whine and other rca's on channel 2 still causes wine.

 

[jrwalte 10+ year member]

That's hard to follow. So originally the speaker on channel 2 was having noise? You swapped RCAs and the noise is still coming from the speaker connected to channel two?

 

[Bun-Bun 10+ year member]

That's hard to follow. So originally the speaker on channel 2 was having noise? You swapped RCAs and the noise is still coming from the speaker connected to channel two?

yes. and also channel two is the plug that I had pull out on me while testing it in my apartment but when I pushed it back into the amp it was secure and it still sounds great. Just now in the car I have alt whine.

Oh and it is definitely alt whine as it whines up and down with engine rev's. With engine off if you turn up the HU with nothing playing the static is constant accross all speakers (just the normal amp static)

 

[jrwalte 10+ year member]

I'd look at the speaker(s) connected to channel two that the whine is coming through. It is possible for a speaker wire to pickup noise. To rule out the amp as the problem, take the speaker with the noise and remove it. Then take another piece of speaker wire and connect it right next to the amp.

If you have no noise, it is your speaker wire or maybe your speaker grounding to your frame. If it's your amp, then you can try grounding the rca at the amp to the ground wire going into the amp. If that doesn't work or it degrades audio quality, look into replacing the amp.

 

[Bun-Bun 10+ year member]

I'd look at the speaker(s) connected to channel two that the whine is coming through. It is possible for a speaker wire to pickup noise. To rule out the amp as the problem, take the speaker with the noise and remove it. Then take another piece of speaker wire and connect it right next to the amp.
If you have no noise, it is your speaker wire or maybe your speaker grounding to your frame. If it's your amp, then you can try grounding the rca at the amp to the ground wire going into the amp. If that doesn't work or it degrades audio quality, look into replacing the amp.

I can't remember because I was dead tired last night when testing this but I am pretty sure I switched the left and right speaker outputs and the whine switched speakers... but I will double check tonight.

Now that I think of it my speaker cable going to the right speaker is resting against the 1/0 power cable going to the amps... if this is the case could I put the cable in something to sheild it? Its just where it goes from the left side to the right side of my trunk that they run along each other.

and no it doesnt degrade sound quality at all... and the whine is very faint. Just bugging me cause I have never had any problems with alt whine in my vehicles.

 

[jrwalte 10+ year member]

I don't know of anything to sheild a wire from noise. Best bet is to reroute one or the other.

Keep in mind it could also be the speaker itself. Maybe a strand of the negative is touching your frame or you have the speaker screwed directly to your frame and it's somehow grounding.

 

[Bun-Bun 10+ year member]

Ok well I guess I have alt wine (and other noises) in all my speakers. The right one is just louder. I never had problems with alt wine before in my beretta so could it just be that I am using the stock harness for my HU? As I said everything else is hooked up directly to the back battery (HC1400) and that is hooked up to the alternator (both pos and neg) so I can see anyother possible ground loop...

I will try moving the cable from the alt to my front batt temporarily to see if that is the problem but if that doesnt fix it I guess it will have to wait till I have time to run some seperate wire to my HU.

 

[enginerd 10+ year member]

Did you ever figure this out? My PDX1.400 is doing the same thing... Help!