Whenever I use the butchered cd changer input there's a whining noise as you rev the engine, probably stemming from the noisy alternator. I'm guessing it's a grounding problem, how to fix? Do you need to solder that screw in the cd changer back? Could I hook it up to the radio ground?

 

Hi Jago-
Are you still using the PIE AI-AUX that you modified the grounding on? I think you just found out why the grounding was originally wired the way it was .

In any event, this may work for you:
http://www.myradiostore.com/noise-fi.../grloisei.html

Radio Shack has them also:
http://www.radioshack.com/product/in...LAID=107597266

 

Tried to open up the cd changer, unscrewed the power ground and made sure it had no connection to the chassis of the changer. Didn't help. Made sure power ground had a direct connection to the chassis of the poweramp, didn't help.

Actually, it turns out when I connect the jack of the iphone output the noise goes down a lot, but doesn't dissapear completely. I.e. hooking the cd changer up to my output ground removes a lot of the noise, but not all.

Do you think the ground loop device could help fix this?

 

btw, i broke the aux switcher, so im using the plain vanilla butchered cd changer.

 

If you are still having alternator noise, yes, I think the ground loop isolator will likely help....and it is not a very big investment to try it.

 

I've dealt with alternator whine on a few occassions with the jag, and sometimes a new ground is required. Sometimes, relocating 'audio' signal wires away from any hot wire also helps eliminate it. I have to be pretty careful when I repack the radio into the dash after working behind it. (remember, I have an aftermarket, with multiple RCAs headed to the rear thru the tranny tunnel)

 

ill try the ground loop eliminator to see if that works, it's not unbearable as is, just annoying

 

I tried the radioshack ground loop isolator between the iphone and the cd changer, the whining might have improved a bit but is still noticeably there.

How do you make a new ground?

 

Before you mess with the grounds, try one simple test. With the ignition off, unplug the power connector from the power antenna. Then turn you car on and see if the whining is now resolved with the antenna retracted.

If this works, then install the antenna switch described on this forum.

On my car I noticed that I get mild whining with the antenna extended when using the Aux, it is completely gone with the antenna retracted.

 

Disconnected both the motor and signal cable to the antenna, no difference.

The ground loop isolator makes no difference either. What's next?

 

Jago-

At this point it would be helpful if you could post more details of your 'plain vanilla butcher the CD changer' mod. Which exact cable did you cut ? Exactly what else did you modify? What kind of cables did you use for your AUX interface. Where is your iPod powered from? Where in the car are the wires routed? Can you post some photos of the wiring? The more info the better.

 

I cut the cables exactly as the mod proposes. Perhaps I'll redo them, but the multimeter states everything is in good nick.

There are two phono cables from an iphone dock in the front, running along with the rest of the cabling (center console, seat) to the trunk. (The noise is there even with the cables disconnected, I think, will double check).

The ipod is powdered from the cigaretteadapter (it's power source doesn't affect the noise)

The noise with the iphone disconnected is much much worse, so the grounding works, but it's just not good enough to eliminate the noise.

 

How did you break the Aux switcher? Do you still have what's left of it?

I was wondering if it might be combined with the one I have to make a good unit again.

 

Please explain how pin 5, signal ground on the AI-Net cable is connected? Did you cut the pin 5 connection internally to the CD changer and just connected the AUX ground to the AI-Net cable pin 5? Or is pin 5 also still connected in the CD changer as well as the AI-Net cable ?

Also is pin 5 connected somewhere to the power ground (pin 2) or power ground somewhere else in the car or did you keep it separate?

Sorry if these questions seem redundant, but I cannot help unless I am sure about what you have wired.

 

Ground is shared between the two RCAs. Can check AI net cable going out from the cd changer

 

Is that shared ground a wire or a braid on the RCA cables? If it was a braid, was there foil there also, or just a few thin copper strands? You may need to upgrade to high quality coaxial RCA cables if it was just a wire or a very lightweight braid.. After all, compare it to the AI-NET...there is a a good quality shielded coaxial for the audio, plus another outer shield in the AI-NET cable as a whole.

Also just for grins, unplug the CD changer connector in the picture and see if that helps at all.

One last question, does the whine get louder when you turn up the volume control, or is the whine independent of the volume control level?

 

Yep, shared ground, and it's a wire. That being said, unplugging the rca cables that go into the changer doesn't remove the noise. I can try to unplug the connector and see.

The whine is linearly louder with louder volume.

 

The fact that that filter did not fix it, and the noise get louder with volume implies the problem is probably not a ground loop issue.

If unplugging the internal CD changer cable does not fix it (I am not betting on it, but it is an easy one to try), then I think you would need to upgrade to high quality shielded audio cables. Running dedicated power direct from the battery to the iPod, with a chassis screw connection as close as possible to the iPod as ground, might also be necessary help quiet things down, but I think the unshielded cables are the major culprit here. I would not expect unplugging the cables would help....even a few inches of that unshielded cable is probably enough to cause problems.

 

But the noise issue is there with the signal cables disconnected from the cd changer.

So you suggest to ground the iphone signal RCA ground to the chassis close to it? Shouldn't its ground be close to or shared with the power amp?

I can make a cable shield for the cable stubs in the cd changer and see if that helps, also ordered an 12 amp alternator noise eliminator I can play with.

Also, the noise is still there if connecting the iphone in the trunk (running on its batteries).

 

Is the noise there WITH the engine on as well as when it is OFF?

If it is present when the engine isn't running, the whine isn't alternator induced.