I just got a power line filter for my empeg. Alternator whine. Should a power line filter be connected to the yellow or the orange wire on the empeg wiring harness?

The filter has 3 wires. 1 is for power from car 1 is for power to HU and the 3rd is for ground. Still not sure if I should splice that into the ground that is hooked to the mpeg or find my own ground...

Depends. Most of the time you would need to filter the constant power wire. But I can envision situations where the ignition wire might need to be filtered, depends on your situation.

Also note that power wire filters do not cure ground loops. They help mask noise, but that simply reduces the amount of engine noise being propogated by the ground loop.

In some cases, you will need to filter both the power to the empeg as well as the power to the amplifier. This will require a Hugh Jass filter on the power line between the amp and the battery.

One of the Service Technicians here (he is responsible for teaching 1000's of mechanics a month) told me to also run an extra wire from the alternator to a ground point. He said some cars' alternator don't have a good ground.

Where should I hook the ground on this thing?

You're welcome to mess with the alternator's ground yourself, but don't involve me or my advice in the process. I don't buy into the idea that the most important part of the car's electrical system would be flaky on modern vehicles. I think it's bad advice to mess with the alternator wiring.

Oops, I should have been more clear (my car is in the parking lot with the dash all over the inside of the car). I wasn't asking for tips on the alternator's ground. I was wondering where to ground this filer - A: into the car's connector or B: to a new ground point. I realize that if the answer is B then I'll have to find that point myself.

He wasn't suggestiong messing with any existing wires on the alternator. He just meant loosen a bolt somewhere on the alternator (like for a bracket) and attach a new wire there and to ground. I think I'll pass on that.

Just noticed that the yellow wire already has an inline filter... could there be any problems running two?

I'm gonna cry, I'm gonna f'ing cry..... I've had alternator whine since last fall, just when it was getting too cold to work on my car... so I put up with it. Now, I've been trying to fix it with no success.... I ripped out a good part of my interior and re-routed all my RCA wires thinking I was getting noise from them... I wasn't. Then I pin pointed it to the the head unit. I regrouned that. Didn't work. No I added a filter to my yellow wire - didn't work. All I've managed to do is make my empeg harness about 1.5" inches shorter and piss off my co-workers by running out the parking lot every time I get a break (worked 60 hours this week - wife doesn't like me to work on toys at home but I spend 8 hours in my car M-F...)

I may try the orange wire... after that, I may drop this thing off at the shop..:(

The only additional advice I can offer is what's already in the FAQ, and I'm sure you've already gone through all of the flowcharts linked there.

Yeah I did... It keeps leading me back to noise getting in at the head unit...

Thx Tony. I'm heading home now. Maybe I'll EQ it out.

Did you say you were running a two-head-unit setup? No amplifiers, crossovers, or equalizers?

Grab a ground wire and start touching things to the chassis. The empeg case, the headunit case, the RCA cables connecting the headunit to the empeg, etc. See if it changes.

You might be surprised. Most alternators are grounded purely by the mounting bolts, and more than once I have found a high-inpedance or entirely open circuit due to corrosion, or simply the bolt being a little loose. I spent a very cold day with my sister over christmas when my car stopped charging the battery, and we kept having to get jumpstarts from people all the way home to get a little power into the system, then drive as fast as possible to get home before it ran out

Had to do this four times over a 20 mile journey, in the snow. Bit of a pain.

It turned out to be a salt-corroded bolt that had such a high surface resistance the alternator was effectively isolated from the engine. When I cleaned it, everything started working perfectly, so I ran a heavy copper strap from the alternator body to the engine to make sure it wouldn't happen again.

Of course, normally the positive output is fine, but without a good ground you get all sorts of odd results, as you know.

Patrick

Now you've got me discouraged. I'm heading outside now to drive to a random parking lot and work on my alternator whine because I don't trust the people at the shop to tie their own shoe laces. I've never dealt with any sort of noise before, and i'm hoping it'll just be regrounding the amplifier.

Matthew

Like Tony asked, we need to know your setup.

I have my CDplayer, empeg, and both amps powered directly from a capacitor which is attached directly to the battery. Also, each one of these items has a seperate ground wire all brought back to a single point under a giant bolt in the trunk. I did this from the outset to make sure I had no ground loops, and it appears to have worked.

You might try running extra wires around the car... get a hundred feet of lamp cord and just start trying things - connect each item's power right to the battery. Connect each item's ground directly to the battery. Try running RCA patch cables over top of the seats to any amps that you might have. Basically, run everything like you would on a bench, and see if the noise goes away. Then replace each wire one by one until you find the culprit. This approach has worked for me in the past.

Also, depending on the setup, could you be picking up inducted noise into an RCA cable, possibly by having it run too close to something else? I had a pretty bad noise in my last car until I realized my patchcord ran next to the heater blower motor.

Just some ideas to try.