Help me with my Ground Loop?

easy · 04-14-2008, 06:14 PM

I need help guys.

The PC is connected and powered along with the screen.

Everything is working perfectly (touch wood) but I'm getting interference over the audio.

This is how I rigged the audio up:

The lappy is connected to a connects 2 interface that I replaced the cd changer with.

The audio signal from the laptop is clean when using headphones but as soon as I connect to the line out of the laptop to the connects2 interface see pic. I get a buzzing sound.

Now having done a seach its seems its 99% a ground loop issue as I am hearing alternator whine too.

Now with this setup what would you suggest?

Please don't get to technical as I am a noob so simple instrauctions would be great.I have read the FAQ on ground loops and it all depends on the setup.

As I am using a connects2 interface what would you do to get rid of the noise?

Ideally I woluld like to get rid of the noise rather than bandage the noise up with a Ground Loop Isolator .

Or is a Ground Loop Isolator the thing to use as I have the connects2 interface?

Thanks

nserpa9248 · 04-14-2008, 07:10 PM

you can try grounding the shielding of the RCA cables to the chassis of the car, grounding the case of the connects2 adapter (i imagine it is grounded..possibly), and if you can get a ground from the laptop mobo to the car ground you would essentially be re-grounding everything. Quite a bit of work, but does a good job at fixing certain types of ground problems.

AWehmeyer · 04-17-2008, 08:36 AM

Ground loop isolators aren't a band-aid. Good ones include a prettyhigh-quality transformer that just reflects the inpedance of the next component rather than connecting directly to it. Buy a good one and your troubles will be solved.

easy · 04-17-2008, 10:01 AM

What I have done before I buy an Isolator is to invest in some High Quality shielded cables.And a Creative USB Xmod.

Should be with me tommorow.

The onboard sound jack is right over the HDD in the laptop and is not helping with noise.So I will try these things first to see if it helps.

If I can get distance between the laptop and the soundcard then this should help.These cables work fine in the house but I guess an investment in sheilded cables is a must for a CAR PC. Its a cruel environment for a PC.

If all else fails and I need an Isolator can anyone recommend one that will not impair the sound quality?

Maybe ground the laptops PSU to the car chassis would help?

Thanks

Jantsa · 04-24-2008, 04:01 PM

I'm having same problem. When connecting laptop to connects2 box, whining starts. I found out that if I unplug touchscreen, whining stops. So in my case, problem is touchscreen and its grounding I suppose. What do you think?

AWehmeyer · 04-25-2008, 05:37 AM

Is the laptop running on its battery when you experience the whining? If you have a power supply connected to the car, disconnect it and see if the noise is only present when the laptop is powered by the car.

Jantsa · 04-25-2008, 07:00 AM

I got rid off that annoying sound.

I tested it today, and I found out that it doesn't matter which laptop was connected. Yesterday I was probably so tired, that most of the sound was coming from my head..

I moved laptops place from under the passengers seat to different place and interference wasn't that loud anymore. Then I went to car-audio store, and bought ground-loop isolator.
That was the final cure. Interference is finally gone, and I'm happy.
Thanks anyway..