Ground loop/alternator whine - Opus 250w

**notion** · 12-27-2007, 10:47 PM

Hi guys,

I was wondering what kind of noise suppression people were using on their high wattage PSUs. I have the Opus 250w which I love, but I'm having trouble isolating alternator whine/ground loop noise making it into my system.

I did have an in-line supporession circuit but it was choking the ampage getting to my PSU causing it to shutdown on crank, once I removed it the PSU is fine.

Can anyone recommend a good solution for my setup?

Thanks

Notion

**DarquePervert** · 12-28-2007, 06:04 AM

Moved to Car Audio.
This is not a PSU problem.
There is a FAQ all about troubleshooting noise here: http://www.mp3car.com/vbulletin/advf...iew&advfaqid=8

**Mylt1** · 12-28-2007, 08:23 AM

start with the basics. where is your power wire run, where is your ground, did you sand off the paint to bare metal, what other wires are run an where are they run(for an amp or other electronics), have you used any cheap spark plug wires or the "high performance" type wires or coils?

**notion** · 12-28-2007, 10:53 AM

Well, my car is a 350z so everything in it is "high performance" I guess.

I have run the main live feed directly from the battery via housing electrical solid core down the outside of the passenger door well to a space behind the passenger seat. The ground for the unit is attached right there in the installation area via a bolt drilled directly into the chassis.

The audio cable runs back from the computer down the center of the car past the gear shift to the stock head unit aux-in.

I used to have the computer set up on an inverter with pretty much the same wiring setup and no whine, but now with the Opus it's pretty noticable.

**Mylt1** · 12-28-2007, 12:38 PM

is the whine a steady whine or does it increase as the revs of the motor increase?

**notion** · 12-28-2007, 01:14 PM

It definately rises and falls in sync with the revs of the engine.

**Mylt1** · 12-28-2007, 01:33 PM

i would say upgrade your grounds in the engine compartment and see if that helps. also, any way to move your power wire farther from the alt?

**notion** · 12-28-2007, 01:43 PM

Not sure what you mean. I dont run any grounds to the engine compartment from the car computer, I kept the ground on that as short as possible grounding it in the actual compartment where the computer is installed.

The main live wire runs straight through my bulkhead to my battery which is at the back of the engine bay close to the windsheild, so I can't really move that any further away.

**DarquePervert** · 12-28-2007, 02:25 PM

I'm pretty certain he means the ground from the battery to the chassis.

**Mylt1** · 12-28-2007, 03:12 PM

yes, the ground from the batt to the chassis as well as from the engine to the chassis. just dong that will help eliminate some if not all the problem. one quick question, is your power wire any where near you cars ECM?