Noise interference from auto air adapter

**hardcoreracing** · 03-13-2008, 12:27 PM

After hearing what people had to say about using an inverter vs an auto air adapter, I decided to take my inverter out and replace it with an auto air adapter made specifically for my laptop. Here's my setup:

IBM T42 thinkpad
Port Replicator II docking station
1/8 audio out to RCA plugs - connects to aux in on my head unit.

When everything was powered by an inverter, I got no noise or screen interference at all. The only noise I got was the little fan on the inverter which keeps the inverter from overheating.

After switching to the auto air adapter, I noticed a few lines of interference during bootup on the screen, and noticeable noise interference when I bring up road runner. The noise interference is like a wave, fades in then fades out repeatedly. When I play an mp3 which is a ballad, it becomes more noticeable.

I read threads where people were having the opposite effect, interference with an inverter but none with the auto air adapter, but never the other way around. The only change I made was the adapter. My question is, is anyone else experiencing this, and if so, what could be done to suppress the noise interference?

**hardcoreracing** · 03-13-2008, 04:30 PM

Okay here's an update. After reading more threads on how people were using a ground loop isolator to solve their noise interference problem with an inverter, I decided to try it with my problem with the auto air adapter.

Results? It seems to have worked like a charm, noise interference is gone! The one I used is from best buy for $17.99 although you can find cheaper ones elsewhere.

The isolator has male/female rca plug connectors along with two wires that need to be grounded. I just grounded them to the same place my head unit is grounded.

**mikeeps2** · 03-13-2008, 11:27 PM

hello , what adapter you used , what is the number parts on best buy , thanks

**hardcoreracing** · 03-13-2008, 11:46 PM

I bought this one:

http://www.bestbuy.com/site/olspage....=1122655296186

But you can find a similar one at radio shack or circuit city for cheaper.

I connected it between the aux input jacks of my head unit and the cable which has rca plugs on one end and a 1/8 plug that goes to the headphone jack of the thinkpad.