Thread: Induced noise/Ground loop trouble shooting guide.

alright so tomorrow i'll ground everything to the seat belt and see what happens without the filter right?

can you suggest me of any types of wires that are recommended for in-car use?

edit : cables for grounding. somewhere i read that ground cables must be measured by a mathematic type but i cannot find any links

There's no special cable type for grounding. The ground wire should be the same size or larger than the size of the cable supplying power. So, if you have a 14GA wire for power, you should have a 14GA or larger wire for the ground.

i see! And what about EMF (Electromagnetic field) ? Is there any tip to avoid interference? Maybe cover the cables with an insulation material?

Insulation won't stop EMI. Why are you concerned about it? Do you have or suspect something that's going to cause it? The first post in this thread talks about ways to handle EMI.

No i dont think so. The problem which has remained to solve is the noise i get from the amp while pc boots. In fact for as long as the sound card is not initialized by the computer drivers i can hear noise through speakers! As soon as windows boots and sound card is initialized everything runs perfect!

I'm suspicious about the sound card. I did read somewhere in a forum (maybe that forum) that with external sound cards like sound blasters everything runs smooth!

In any ways now i'm in a very good path to solve all the problems. That's my feeling. What do you think?

Tomorrow i'll ground at the same point AND i will connect the rear speakers directly to the amp and not via the ISO port.

Should i install any GLI to the B+ cable of the amp or the whole system must run smoothly without any GLIs??

I agree that the noise during boot is annoying, but until there's audio being output you will get that. You can either deal with the noise, or you can use a power supply that turns on the amp after a certain delay. I think there's a new USB device that also can control your amp - check the review section for the info. Personally I keep my carpc in sleep mode so I don't have to hear any noise, but that's just me.

I would make sure everything is grounded properly and do some testing before I added a GLI between the computer and the amp.

It's not a problem for me to hear that sound for a few seconds. I just want to be sure that everything's ok. It's not only noise. I can hear the car alternator and its RPMs, but as soon as sound card initializes everything is ok but i repeat EVERYTHING IS OK BECAUSE I USE A RCA GLI between amp and computer!

I asked if i should put a GLI specialized for power supply cables. Not RCAs

I would fix your grounds first before doing anything else. Here is another excellent troubleshooting guide for amplifiers that you might want to read:

http://www.termpro.com/articles/noise.html

thank you!!!! This seems very useful! Oh i almost forgot. There's also another issue with noise. Whenever i drive and want to steer right or left i can hear a quick noise from the speakers! This is because of the steering wheel ground. My steering wheel system is electrical too!!! i hope tomorrow to solve all my problems!