Alternator Whine - iPod

[AlterEgo99 5,000+ posts]

Hello everyone, I'm new to this forum and have read many of your threads on alternator whine and ground loops. However, I have traced my issue back to my iPod and am at a bit of a loss as to how to address it.

Here is my current setup:

2008 Chevrolet Silverado X-Cab LTZ 4WD 5.3 Liter with Bose and OnStar

Head Unit - Alpine CDA-9887

Front Speakers - Polk Audio db6501 6 1/2" Component System

Rear Speakers - Polk Audio db5251 5 1/4" Component System

Rear Subwoofer - Custom Enclosure under rear bench seat - 2 10" Polk Audio MM2104 Subwoofers wired in parallel

Amplifier for Front and Rear Speakers - Alpine PDX 4.100

Amplifier for Subwoofers - Alpine PDX 1.600

Using 12 AWG StreetWires Ultra Cable for speaker wire.

Using (3) StreetWires Zero Noise 5 Stereo Patch Cables (6.5 Foot).

Using 4 AWG JL Audio MetaWire for amp power and ground.

The CDA-9887 has an iPod Direct Connection mounted on a 4" pigtail on the rear panel. This is connected to my iPod (located in the glovebox) via the KCE-422i Alpine Full Speed Connection cable.

When the HU is on the Tuner source or the CD source (no disk) and the volume is turned up loud there is no alternator whine. However, when the iPod source is selected, there is a noticeable hiss and some alternator whine.

The amplifiers and HU are all grounded to the same chassis ground, which has been tested to be a very good ground point. The power wires have been routed well away from both the speaker wires and the RCA cables.

I have tested several other iPods and get the same result. It appears to be a ground loop issue either with the KCE-422i Alpine Full Speed Connection cable or the iPod itself.

I have searched the net but cannot locate any ideas as to how to eliminate alternator whine with an iPod source, other than purchasing some ground loop isolators (yes, I know, they only "mask" the problem, but this is the source I typically use the most - heck, if I used the CD source at all, it would be sweet as that source is quiet as a church mouse, even at full volume!) and place them on the RCA cables running to the amps.

If anyone has any pointers or can point me in the right direction, please let me know. Otherwise, I will be posting any results once the ground loop isolators arrive and I try them out.

Thanks!

Click to read more...

 

[denali804 10+ year member]

Pac audio

http://www.crutchfield.com/S-LwA6dcx8DFs/p_127SNI135/PAC-SNI-1-3-5-Noise-Filter.html?tab=review

 

[AlterEgo99 5,000+ posts]

That would probably work if the iPod was connected via the auxiliary port, but it is not. As I stated in my original post, the iPod is connected to the HU via a KCE-422i Alpine Full Speed Connection cable.

 

[BassAddictJ 5,000+ posts]

probably the cable. try wiggling the cable a bunch and see if the whine cuts out at all. try a new cable. its worth a shot but try to incorporate a $20 ground loop isolator at walmart, sometimes those things are just what you need if you can find the source of the problem

 

[AlterEgo99 5,000+ posts]

Yeah, I wiggled the iPod cable at both ends and where it connects to the pigtail on the back of the HU I actually got it to sound worse a couple of times...so it may be the cable connection...my ground loop isolators will be arriving shortly and for less than $20 per I am going to try that first...if they don't work then I will see about purchasing a new high speed iPod cable...that will cost about $30 but again pretty cheap money.

 

[AlterEgo99 5,000+ posts]

Replaced the full speed iPod cable with a new one from PAC...no change. Tried a couple of Stinger SGLI RCA Ground Loop Isolators...no change. Guess I am just going to have to live with it. //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

If anyone has any ideas, let me know. If you need specifics about my install, it is all contained in my original post on this thread.

 

[drpeeb 10+ year member]

Replaced the full speed iPod cable with a new one from PAC...no change. Tried a couple of Stinger SGLI RCA Ground Loop Isolators...no change. Guess I am just going to have to live with it. //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif
If anyone has any ideas, let me know. If you need specifics about my install, it is all contained in my original post on this thread.

Right now I am running my iPod Nano straight into my amp, and I do get a very slight whine, but only when the 12V power charger is plugged in.

When I unplug it the whine is totally gone.

I think I'll try one of those PAC noise filters, though, just so I can just plug the iPod charger in and forget about it ... I never listen to the iPod anywhere else.

 

[AlterEgo99 5,000+ posts]

I installed a noise filter on the constant 12V power lead to the HU and that appears to have done the trick...I can barely hear the whine now and not at all when the truck is movin' down the road. I may still test wiring the 12V constant directly to the battery and see if that totally eliminates the whine but right now it seems quite acceptable.

 

[AlterEgo99 5,000+ posts]

I wired the HU constant 12V wire directly to the battery today...with the in-line noise filter still there it sounds about the same, maybe a bit better. Definitely not anything you can discern when cruisin' down the road. So, it looks as though I'm done for now! //content.invisioncic.com/y282845/emoticons/cool.gif.3bcaf8f141236c00f8044d07150e34f7.gif