Thread: Induced noise/Ground loop trouble shooting guide.

When you hook up the ipod, are you running it off of the ipod battery or do you have it powered by the cig lighter?

If its the first, its telling you that the head unit is producing noise outside of ground loops, which it is not. If its the later, im amazed

You have a ground loop between your PC and HU. No way around it. Grab a ground loop isolator and test it. If the noise goes away then its 100% a ground loop between the PC and the deck

But then the problem is which is the culpret?

I would yank the deck, connect it to the same power source as the PC and leave the deck right on top of the PC. Hook it up to a speaker and a very small RCA. Check if the noise goes away. Ground the chassis of the deck to the same point, check to see if the noise goes away. If the noise is still there, then we are in trouble.

I'm going to go out on a limb and say that the rampage deck's internals are pretty crappy. They have not isolated the aux in on the deck from chassis gound forcing a ground loop no matter what you do. Your only choice is a new deck or ground loop isolator to make up for the bad design.

Maybe its time to invest ina new deck with a decent design? Any available on the classified forum?

Originally Posted by Will Albers

When you hook up the ipod, are you running it off of the ipod battery or do you have it powered by the cig lighter?

If its the first, its telling you that the head unit is producing noise outside of ground loops, which it is not. If its the later, im amazed

By the ipod battery, so I guess you not amazed

Originally Posted by Will Albers

You have a ground loop between your PC and HU. No way around it. Grab a ground loop isolator and test it. If the noise goes away then its 100% a ground loop between the PC and the deck

I'm tending to think that is the case.

Originally Posted by Will Albers

But then the problem is which is the culpret?

I would yank the deck, connect it to the same power source as the PC and leave the deck right on top of the PC.

Well, they ARE taking power and ground from the same wires in the same physical location.

Originally Posted by Will Albers

Hook it up to a speaker and a very small RCA. Check if the noise goes away.

I'll try a different, single speaker on the HU, but the car is 10 years old, and I am almost sure that there is no crossover or external amp to cause problems. Can I use an 8 ohm speaker, or do I need a 4 ohm one??

[QUOTE=Will Albers] Ground the chassis of the deck to the same point, check to see if the noise goes away. If the noise is still there, then we are in trouble.

Well, I grounded the HU chassis to the same wires that ground the carputer and the HU, it made no difference. Only grounding the carputer chassis helped with the RFI a little, but I am more concerned with the engine whine.

[QUOTE=Will Albers]I'm going to go out on a limb and say that the rampage deck's internals are pretty crappy. They have not isolated the aux in on the deck from chassis gound forcing a ground loop no matter what you do. Your only choice is a new deck or ground loop isolator to make up for the bad design.

Then a GLI it is. I am fine with a bandaid, as long as the booboo goes away.

Originally Posted by Will Albers

Maybe its time to invest ina new deck with a decent design? Any available on the classified forum?

Hmmmm, I will think about it, but chances are, unless it is ACTUALLY the HU, I will still have engine whine.

Hi All,

I am having the same problem. I am connecting the output of my sound card to the HU. I get the aeroplane sound. Tried sound card to headphones and its ok then tried using PDA to Hu and it is also ok but when I connect sound card to HU the problem is there again. I ask around about the noise isolator and the sales person tells me that it will reduce the bass level if I install the noise isolator. Any way to fix this? Pls. help..

Many many thanks

So, the GLI fixed the problem.

Thanks
Michael

Originally Posted by nemo1

Hi All,

I am having the same problem. I am connecting the output of my sound card to the HU. I get the aeroplane sound. Tried sound card to headphones and its ok then tried using PDA to Hu and it is also ok but when I connect sound card to HU the problem is there again. I ask around about the noise isolator and the sales person tells me that it will reduce the bass level if I install the noise isolator. Any way to fix this? Pls. help..

Many many thanks

if you check my post a few threads above u will see i had similar problems.. what did solve my problem is that I removed the ground from the HU ISO plug and i ran a 12 AWG ( i wish i had 10 awg..) from the HU case to the PC case.. that took away most of the noise.. then i bought a ground loop isolator which did not effect the sound quality at all.. i feel that it is even better (as it removed the noises even those that u don't notice) and bass is even better. and that removed all the remaining noises.. so veeery happy now.
I tottaly disagree that isolators effect the sound quality.. if u think of it they are just magnetic transformers with a 1:1 ratio..they let music pass through (magnetically) but DC current is blocked.

Thank You Nomader...I will try it out and post the outcome...

Nomader...after reading your threads, I noticed that you are using a Blaupunkt HU. I am also using a Blaupunkt HU, there are many cables running out from the HU ISO plug, how do you know which one is the ground?

thanks again

As far as I know all Blaupunkt HU use the ISO plug.. it is the black cable (usually) DO NOT run the unit without any ground cable at all.. very dangerous it will burn your HU or cables as it will ground itself through any other cable it will find (speaker etc.).

take your time.. remove the connectors cut the small ground wire in the ISO plug. then ground it either on the pc case or into the same position you have grounded your pc (this cable sould be as short as possible and as thick as possible) try which gives you less noise. try to remove as much noise as possible before using the isolator. (sounds easier saying it than doing it)

you can download the manual of your HU from the blaupunkt site, if you don't have it. it has the diagams..if it is different than this one

Originally Posted by Wiredwrx

So, the GLI fixed the problem.

Thanks
Michael

Thats good, sort of. Its a ground loop between the deck and PC, the GLI is a band-aid. I would still like to know the culpret (deck ) but if its workin, let it be and enjoy!