Ground Loop - can't I just go direct to terminal?

**Red_Beard** · 01-04-2008, 09:02 PM

I'm trying to eliminate my ground loop, alternator whine problem and I'm thinking I'll buy a bunch of wire, and just connect the ground of my P1900 directly back to the battery, i shouldn't hear anything, right? Just the sweet sound of music, correct? I mean, there's no better ground than "ground" itself. (Aside from having RF interfence, but that's a different story)

**crooper** · 01-06-2008, 04:15 PM

You need to do some more reading. The "quality" of the ground connection isn't the problem, it's having signal wires in close proximity to power wires and getting crosstalk. Unless you're using like 0 awg wire I don't think there's any real advantage to having wire returning to the battery instead of good bare metal chassis grounds. If you're worried about having good grounds, you could do the Big 3 upgrade in your engine bay.

**djtaz** · 01-07-2008, 11:24 AM

I had a problem with the buzzing sound and i purchased a 'ground loop isolator' for 15 euro that completely solved the issue i was having. Im in Europe so i dont know of places that sell them there , but google it.

**toymachine** · 01-07-2008, 03:54 PM

Originally Posted by crooper

You need to do some more reading. The "quality" of the ground connection isn't the problem, it's having signal wires in close proximity to power wires and getting crosstalk. Unless you're using like 0 awg wire I don't think there's any real advantage to having wire returning to the battery instead of good bare metal chassis grounds. If you're worried about having good grounds, you could do the Big 3 upgrade in your engine bay.

Yes i agree that this does cause interference, but i understand a ground loop is something different. When finding ground, the audio signal is taking the easiest route, which sometimes may be the same route as something else that is drawing power varying power...or something like the alternator constantly changing is power due to revs.... hence it causes interference. so why would a shielded cable straight back to the battery not fix this?? I have only heard good things about ground loop isolators too.

anyone shed some light?

**pokki** · 01-07-2008, 04:17 PM

hence it causes interference. so why would a shielded cable straight back to the battery not fix this??

DC power cables are not shielded - never seen a sheilded one in my life.

As for why not to run a earth to the boot:
1) Price: you will need to use suitable think cable over a long length as to not cause voltage drop.
2) Difference: with the other electronics grounding to the chassis a direct ground to the battery may have a significantly different level of restiance. Increasing the chances of electrical interference.

In a moderate powered system I'd always ground to the chassis and make sure i've upgrade my battery to chassis ground, and alt to chassis ground to compensate for the additional current draw.

**billmee** · 01-08-2008, 06:49 AM

Power ground - noisy components, pc headunit amp, to the same spot.
Signal ground - the shield of the shielded cables, audio video etc.

Ground loop - when path to ground is found thru shield to a different components power ground thus picking up a lot of noise

**Punky** · 01-13-2008, 02:52 PM

i never believe in ground loop isolator because its just a high pass filter really, and it does not eliminate the problem, it just hides it. This works better imho http://www.electronixwarehouse.com/c...e-sup/ns10.htm another thing is grounding the computer case worked for my case.
Also, cross talked between signal and power wire has never happened to me, even if i used cheap RCA cables that are not at all shielded. The problem has always been ground and not clean power.