Battling alternator noise in stereo? Here's your solution!

[parsonsj]

I have finally eliminated alternator noise from my stereo system. My system is very simple: one 2 channel amp, 1 sub (powered via amp bridge), 2 mids and 2 tweeters, with a crossover per side. My head unit is my iPhone. The iPhone works great as a head unit: PAC makes a powered adapter that connects the dock connector to the amp, and a non-powered volume control.

Now I listen to MLB.com for baseball games, Pandora for radio, or XMSirius, or the iPod app, and (best of all) my Navigon app. That's right: I have a working GPS-based navigation system in my Nova. All because of the iPhone as the head unit.



I use a Bluetooth headset for talking on the phone, since my car is so loud at most cruising speeds.

That's the good news. I've had all this working for awhile (the Nav system for a couple weeks), but the bad news is that I have had significant alternator whine.

I tried different cabling techniques, different grounds methods, and different power methods. No luck. Then I tried power filters and ground loop filters, but found them unsatisfactory... the power filters didn't work at all, and the ground loop eliminators all took my mid-range away. I tried different vendor's products, and nothing really worked.

Then I found this:

http://www.davidnavone.com/cart.asp?14&pid=178

It's an isolated power supply. It uses your vehicle's power, and provides a completely separate output power. It's as if your stereo components are being powered by another battery that is not connected to your alternator.

Alternator whine: gone. There isn't even a trace of it anymore. I've been searching for this for a year!

Anyway, I thought I'd share my discovery.

jp

[oestek]

Great find, John. Thanks for posting that one. Which version of iPhone are you using? My 3GS does not like my previous iPhone's car chargers. I just ran an iPhone adapter out of the headset jack into an RCA adapter to the amp, using the volume buttons on the side of the phone. The cool thing is that it pumps the phone output through the amp, it also becomes a speaker phone you can actually hear. I love the GPS navigation also. Downloaded the AOL Radio app and can listen to broadcast stations all over the country over the 3G network. Did you mount your phone in the car? Post pics!

[parsonsj]

I'm using a 3GS... I got it in July. Love it. The GPS, wi-fi, and 3G networks all give us all kinds of options. The only thing I can see as a problem with your method is battery life. With my dock connector, my phone charges while I'm listening or navigating.

One further thing: once I got the alternator whine solved, I found my new iPhone 3GS has an audible noise floor. You can hear faint white noise when the iPod app is paused, or during silence on the radio station. When the car is running, the engine is so loud that you can't hear it, but it is definitely there. I tested my old iPhone (original): no noise. My niece's iPhone 3G: no noise. Same with all the iPods in the family: no noise.

I tried it in airplane mode: still noise. So I called AppleCare, and they are sending a replacement phone.

If I configure my system to run from the headphone jack of my iPhone 3GS, then the noise is gone. So it's an iPhone dock connector problem with my particular phone.

I should have the new phone today. I'll report back.

Pics soon...

jp

[oestek]

Thanks! I have not heard the noise. I'll check into that dock charger.

[CarlC]

John,

Did you use the two-amp version for your amplifier? The six-amp gets pretty pricey.

[parsonsj]

I used the 2A to power my PAC iPhone interface and to give the amp it's turn-on signal. It's got a built-in relay to get power directly from the battery when it gets the turn-on signal.

I was worried that would result in noise, but it didn't. My alternator whine wasn't amp-originated, it was head unit (iPhone/PAC device) originated.

I guess that means that from the amp's perspective I only have a single stereo ground, which eliminates any ground loops. Yeah. That must be it.

jp

[69LT1Nova]

Thanks for the link! They have some cool iPod connectors - and not bad on the price.

[parsonsj]

I ordered the part last weekend, paid for it via PayPal, and it shipped Monday morning. I had it Thursday.

Very impressive.

jp

[Denvervet]

I'm not sure I understand but sounds cool if I got it correct. So, you are saying that you don't have any kind of inDash stereo unit? Where do you place your iphone? I was planning on stereo unit with connection to ipod in glove box. This setup sound better and who needs CD players anymore.

[parsonsj]

David,

You got it. No head unit. Just the iPhone.

I get in my car, snap the dock connector in place, do my thing with song choice, shuffle, MLB, navigation or whatever. All sound comes out of my stereo via the dock connector. I use an ear-mounted BT setup for phone use.

It works like this: I'm driving around with stereo playing, and navigation working. If I get a call, the iPhone mutes the stereo and switches over to Bluetooth. I talk on the phone, then hang up. The music and nav resume.

No external antenna needed... so wiring is easy. As I said, I battled a significant alternator whine until I discovered the David Navone product. Now it's all high fidelity.

jp

I can dig up part numbers if you want.

[CarlC]

Thanks John.

Were you able to isolate the noise by disconnecting the head unit/iPhone from the amplifier?

It would be interesting to see if the noise persisted if you had a direct connection to the amplifier without having the docking port suppling power to the iPhone.

[Denvervet]

John
It would be great if you posted part #s especially if anyone else here is on the cusp of installing electrical. I will check out the website of power cables you mentioned. I don't need everything yet as I best keep up my body sanding so I can get my ride off to paint. Just orded my new isis electrical system, new efi, so I'll have a number of mental challenges ahead.

Looks like the Alpine stereo I originally bought for my DD truck is going in there afterall.

[CarlC]

CD's? What are those? ;-)

I dumped the changer several years ago. I'm now using my BlackBerry which has many similar features as John's setup.

[parsonsj]

The noise stopped as soon as the iPhone/PAC was disconnected from the amp.

jp

[parsonsj]

The interface cable is a PAC ICAV2 (don't get the AV... you must get the AV2).

The volume control is a PAC PRC1 RCA line level controller.

You connect power to the Navone piece, which powers the ICAV2 and amp relay. The RCA jacks from the AV2 go to the PRC1, and the output from there goes to the amp.

Simple plug and play, works great.

jp

[CarlC]

Much gras JP.

[parsonsj]

Oh, and I have my replacement iPhone now.

That noise is gone too. My stereo system now has fantastic signal to noise!

I guess I'll have to go back to fiddling with the suspension now. Or maybe the cold start.. or a cover for the fuel regulator... or something.

jp

[MikeMalibu]

Thanks for the tips. What amp are you using?

[Steve1968LS2]

The interface cable is a PAC ICAV2 (don't get the AV... you must get the AV2).

The volume control is a PAC PRC1 RCA line level controller.

You connect power to the Navone piece, which powers the ICAV2 and amp relay. The RCA jacks from the AV2 go to the PRC1, and the output from there goes to the amp.

Simple plug and play, works great.

jp

Hmmm.. I will have to get this info over to Tom at Bowler Trans..

I have a lot of noise.. running a Griffin TuneDock as the interface and the PAC gizmo for volume..

[Steve1968LS2]

Actually the whine in my audio is even there if the engine is off.. any ideas?