Alternator Whine...HELP!

[MeanGreen03]

I just installed my system and I'm getting that evil whine. I have a 4 channel amp and it is only occuring in my rear channels. If I plug the rear channel RCA into the front channel and vica versa the whine happens in the front channel. Could it be a bad RCA cable or what should I look for and test?

 

[Thumper8302]

i honestly think ur rcas are groundin somewhere.... try another pair and see if that helps u any

 

[thehoe92]

make sure your RCA's are ran on the opposite side of the power
maybe that one is close to some power wire

also you could try grounding the shield of your RCA's on the back of the head unit and see if that helps

make sure you have as few grounding points as possible

 

[MeanGreen03]

The RCA's are ran on the opposite side of the power. I have 3 sets running together and thats the only one it's happening on. So grounding the sheild of the RCA will show what? Do I ground it with the RCA's plugged in? What do you mean as few grounding points as possible?

 

[Boomer73]

Sounds like a ground loop. Just get an RCA ground loop isolator from radio shack for $12 and be done with it.

-B

 

[MeanGreen03]

I gounded the RCA shields at the back of the HU going to the rear channels and it made a loud buzzing noise. If I move that RCA wire close to the power wire by the amp it amplifies the whine but it doesnt do it with the other RCA's. I switched both of the RCA's so that the front is the rear and the rear is the front and the buzzing/whining still occured in the rear. I cant tell if my subs are getting the feedback too(I can hear a slight static noise if my ear is really close to them), but it is definitely not comparable to the rear doors. The RCA's do run along the power (around 1.5ft) as that is inevitable as they all have to run up into the amps.

 

[solored]

Just run your front rca's, hook all your 4 speakers to the front, thats what i did.. I had a hifonics zeus 440 4chan, also changed my rca wire as well...I only have the one rca wire thats why im running of the 2 chans... I have 3 sets total, 2 sets are cheap, the good one is a knu koncepts one... if you have crappy rca's they have very little resident sheilf on them... the ****** ones i have are the blue monster ones GARBAGE get some good high quality ones from knu koncepts. Also if your running 8awg wire to your amp (power grnd) that could be another fault.... run atleast 4awg... good luck with her! do tell when you figure it out... try to avoid a ground loop isolater as it will just lead to another problem... there is a reason why it is doin what it is doing, correct and dont add something to counter act the problem... thats your last step...

 

[MeanGreen03]

I have 0awg running to distribution blocks and from there 4 awg to the amps. I'm running the better Rockford Fosgate RCA's. What are the best RCA's out there that have the best insulation? I was thinking about getting a 6-channle RCA wire so that way the wiring would be much simpler. I'm going to try to re-route the power wire when I have some time to see if I can reduce the length of the power and RCA's running along each other. Any other advice is greatly appreciated!!!

 

[solored]

http://www.knukonceptz.com/productDetail.cfm?prodID=KRY4.4M

Thats what I am going to be running, I have those but just the 2chan normal rcas not the 4, they are super heavey duty.... yeah try everything BEFORE a ground isolater... even sometimes re grounding the amp... like i had a 4 chan and 2 chan alpine amps running off same ground and what not (not my install came with truck) they didnt have any noise coming through... and the wiring set up was just ******, like i dont even know what the guy was thinking, but it worked.. so i re wired everything right, and im using a hifonics zxi440 4 chan amp.. and hooked up the same i got bad whine through the speakers... most time is a faulty ground, but i just used a different rca and ran 2 chans off the 4 chan amp and it was fine... i was told to if the gains are to high you could get that noise as well.

 

[01TX_Tahoe]

i would replace the RCAs or trace them out to make sure they're not pinched anywhere. they could be grounding out somewhere in the truck... i've had that problem before. i ran the RCAs to the back seat and someone else put the seat back in without adjusting them... needless to say they got pinched and had to be replaced..

i've tried to use Streetwires RCAs for most of my projects. i've never been disappointed with them.

 

[MeanGreen03]

I zip tied all 3 of them together to make sure they were easier to run. I don't think any of them were torn into to ground out but that is something I'm going to have to check. This is frustrating since I took my time to make sure everything was right. I'm not looking forward to tearing everything back apart but it's a must! I'm out of town for business for a while so that sucks since I can't get to it right away...

 

[solored]

Just use 1 rca cable and run 2 chans (front rca, all 4 speakers((if you want)).. guarntee it wont annoye you for now... check your gains... all the simple things you can do off the amp...

 

[MeanGreen03]

I'm pretty sure I set my gains right....turned the volume to 75% of max then turned the gain up until there was distortion and turned it back down until the distortion went away. I'm a little over half on the gain. Maybe I can turn the volume up to 80% to lower the gains some. I did notice the woofers of the rear channels jumped more than the front so I don't know if this could be correlated.

 

[Tahoejoe]

The problem was answered by your very first test. Once the same rca cable had failure on both channels (front and then on rear) you need to deal with the one issue you know is solid.

As stated earlier you could have a pinch.

While running the cable did you cable catch a piece of sheet metal and damage the cable?

RCA failure at grounding brackets. The entire metal piece surrounding the center pin ensures a proper ground per most RCA designs. Check ends (on both end of the cable) Loose? Bent etc.

Your head unit could have a faulty pre-out. Pull the deck and switch the cables to the RCA preout without the whine and you know works properly. If the whine continues you know the head unit is the source. Not sure what you have but Pioneer head units are horrible with this quality issue.

If you using Rock Foz cable your RCA is shielded just fine. If shielding was an issue the problem would be present on all of your cables being ran in the same location. Knu-Concepts is great equipment but replacement is not the issue yet from what I have read.

 

[MeanGreen03]

Thanks for the reply. My setup is a Kenwood DNX9140 H/U, a RF T600-4 going to 4 6.5" Infinity Kappa Perfect Components, and a RF T1500-1bd going to 2 12" T1's wired @ 2 ohms. I have 0/1awg running to the back with a distribution block with 4awg running to the amps. The grounds are 4awg from the amps going into a distribution block then 1 0/1awg grounded on one of the seat studs.

I know I didn't pinch the wires (unless I zip-tied them too tight) anywhere or catch them on anything. I think there may be interference from the power b/c if I move that RCA around close to the power wire it gets worse. The only thing that doesn't make any sense is that if I move the other RCA, that I'm not having any problems with, close to the same power wire it doesnt have any affect. I made sure the connections were tight (I even squeezed a few of the shields so they would fit tight). I re-wired my H/U with a new power and ground.

Here's a quick diagram that I drew of how I ran the wires:

 

[Tahoejoe]

Well from what you have said and looking at your wiring I would say one of 2 things. (noise issues are such a pain.) My last truck I ripped everything out only to find the issue was a bad ground shield on my AudioControl line driver.

1. An easy quick change would be to move the power distribution to the center under the seat so it is isolated to the power side of the amp. Dont think it is the issue but you got a shot. You can also dig a bit more metal on your seat ground and re-set your ground wire on the seat bolt. (use a copper washer under the connector and on top where it meets the bolt. Small change but will help anyway.

2. I still think the issue is with your head unit pre-out or RCA cable. If you have the buzz on your rear speaker RCA and your front is fine try switching the RCA cables at your head unit leaving only the RCA cable without issue hooked up. After switching the cable at the head unit to front and rear pre-out and you have no issues you can pretty much assume the cable has a failure point. (it happens)

 

[MeanGreen03]

Hmmmmm....After thinking about it, it might just be the pre-outs. Here's why:

1. Starting with RCA wires hooked up correctly.......ONLY rear whined.

2. I switched the RCA's @ the amp so the rear channel was the front channel and the front channel was the rear channel (rear channel pre-outs went to front channel of the amp)...........ONLY front whined.

3. I switched BOTH RCA cables to test the cables themselves without having to buy new ones. So the RCA cable in question was now the front channel (front channel pre-outs went to front channel of the amp)....ONLY the rear whined.

So now I could switch the front channel and rear channel again on the amp to see if the front whines so that will pinpoint it directly to the rear channel pre-outs on the H/U.

IF it is my H/U pre-outs.....Why would moving the RCA closer to the power wire in the back cause the increase in whine? Does that have to do with a bad ground RCA??? (i.e. would act like the RCA isn't sheilded at all??)

My H/U doesn't look like most H/U pre-outs....it has a pigtail pinned plug connection so the RCA's are plugged into this short cord and that cord is plugged into the H/U.

 

[Tahoejoe]

The whine gets more intense the closer you get them due to the increasing EMI from the bigger current loaded cable and yes without the RCA connection being solid it will compound the issue.

The head unit pigtail should be able to be replaced pretty cheap and easy. Call Kenwood if the deck is newer. It will connect to a pin connector just inside the deck case so easy if you get the part.

For now you can pick up 2 RCA Y connectors (1male2Female ends) and use the one good one you have left for both RCA runs. Still split them at the amp just adjust your fade on your head unit.

 

[MeanGreen03]

So you wouldn't think it would be something inside the unit rather than the pigtail?? I guess the pigtail would be the quick and easiy method to check and make sure.

---------- Post added at 07:23 PM ---------- Previous post was at 06:34 PM ----------

How can the voltage be checked coming from the pre-outs?? My H/U is suppose to be 5v. So if there is something wrong I could tell from this, right?

 

[MeanGreen03]

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When I grounded the rear (left and right) RCA the whine went to the front channel. When I grounded both front and rear channels the whine was in both front and rear. The loundness of the whine went down just a little. I'm going to have to try and reroute the wires or something I guess and see what that does. When I had the RCA's disconnected from the H/U and the amps on, the whine was in both channels and louder than normal.