Installing my new amp got rid of my constant alternator whine, and replaced it with an intermitent noise issues... In addition to installing a new 4-channel amp, I also put in a 1 farrad capacitor.

The first time we fired the system up, I heard weird noise as the empeg booted up. It was as I could hear the empeg accessing data on its hard drives. Once the system was on however, it seemed to be fine...

But now, my system goes from being noisy (picking up alternator whine and "bus" or "drive" noise) to being sound free. I'm still in the process of tweaking the gain on the amp, so I'm not sure if that's an issue. Also, this might be coincidence, but it seemed as if noise was not an issue if the car was running for a while before popping in the empeg. Maybe the capacitor being charged prior to booting the empeg makes a difference?

I'm still trouble shooing this, so I'll post more as I find it out, but I've never had noise that wasn't alternator whine, so I really don't know what's up.

Other issues: I get the battery icon and occationally the player will reboot itself while playing. My car has one of those aftermarket power pulleys that sends less power to the AC compressor and alternator. That may have made things worse.

Hrm. Man i wish someone would come out with a drop in replacement for the wimpy 70amp alternator in the WRX. A number of guys on the boards have said that they've had to replace their alternators every 3 to 4 months running 1000watt systems. I've been debating on putting in a cap or a yellow top... i'll be watching your outcome closely! =]

Thanks Loren.. I'm begining to think my Vishnu Power Pulley is only adding to the problem...

I spent a few minutes in MS Paint and came up with this...

Thanks for the wiring diagram, that's VERY helpful.

Just for the heck of it, try these two things:

1. Remove the capacitor and see if the noise disappears.

2. Try sending the rear RCA's straight to the infinity subwoofer, and the front RCA's straight to one pair of channels on the four channel amp.

If that second thing gets rid of the noise, you can use the amp's front passthrough, chain it to the rears, and have the front fader be the regular speakers and the rear fader be the subwoofer level. Adjust the front/rear fading of the regular speakers by adjusting the amp gains.

wow. If you're having power issues running a 200W sub and a 4x45... I'm in trouble. I'm going to be running a 500/1 and a 300/2 JL Audio.... 800 Watts total, and I was planning on going the Vishnu path myself next Spring. I may have to end up tossing another battery in the trunk.... blech.

Yeah, i'd go with what Tony suggested. Take the Cap out of the equation first and see if that helps.

I really wonder what is causing your power issues though... that's the odd one. Where did you ground out to? I'm going to upgrade grounds from the battery to the alternator and the chasis eventually so everything has the same potential through 4 gauge.

Tony, Loren, thank you! I'll play with it somemore tonight. That diagram was both fun and a pain in the butt to do in MS Paint!

Loren, did you just ask me where I grounded to? Didn't you study the slide?!? The empeg and the amps are grounded straight to the battery. I'm also redone all of my factory grounds in the engine bay as well as add two more fo the strut tower bars.

Mod wise, my car is a mutt... I have Godspeed Up and Downpipes, Prodrive Axel Back exhaust, K&N drop-in, Vishnu IC hoses, removed intake resonator, TurboXS MBC, Vishnu Underdrive pulley and I'm looking to get a Stage 2 Cobb reflash. Vishnu is okay, but too expensive for my tastes (given the alternatives). I'm almost certain I'll be pulling that UD pulley if taking out the CAT or rewiring the RCA's doesn't help.

Damn, I just put my interior back together too!

Hahah. doh. Yeah, i guess i figured that just meant you used the car as a dist block. doh.

I'm going with Vishnu for one reason, they are 45 minutes from my door. Easy access to dyno tuning and help should it be needed! Pricey, but from what i've seen their products are rock solid. The exhaust is the only one i'll have a really hard time shelling out for.

keep us posted. =]

Okay... getting weirder!

1. I got in the car, turned the key to Acc. and started the player up. NOISE (like a modem hearing the empeg do its thing).

2. Started the car. NOISE.

3. Allowed car to run for awhile (perhaps to let the alternator charge the capacitor). NOISE.

4. By-passed capacitor. NOISE.

5. Turned off car. (No need to charge the Capacitor anymore). NOISE.

6. Re-crimped empeg's ground connector at battery (what the hell, why not?). NOISE.

7. Laid self in front of car and released parking brake. NOISE.

8. Un-plugged both RCA's to 4-ch. amp. NO-NOISE.

9. Plugged in only rear RCA's. NO-NOISE. (got a big THUMP because I left everything hooked up and turned on).

10. Plugged in fronts (and rears) NO-NOISE. (Huh? didn't this combo give me noise just a few moments ago??)

11. Re-connected capacitor. NO-NOISE.

12. I then did a combo of pulling the player from the sled, turning the car on and off a bunch just for the hell of it - NO NOISE.

At this point, I don't get it. Maybe that "thump" from the RCA's getting plugged into a live amp gave the system the slap upside its head that it had coming to it! I also have a gut feeling that if I go out to the car tomorrow morning, I'll be back to NOISE.

Here's one thing, I don't think that my low power issue has anything to do with my noise. After I turned the car off, the player started giving the battery icon a bunch of times and my annoying "self-reboot" - a sure sign that the battery was getting low from the audio testing. Yet, as time went on, the noise went away.. So low power didn't add to my problem.

I would only run the amp off of the cap.and better battery's make a huge difference.I just put two orbital battery's in my truck yesterday and man it made my hole system sound better.I'm using a alumapro 15 farit cap.my other battery poweres my head unit and empeg.

The guy that was helping me install my system said that the cap should go to the sub and not the 4ch amp. But he didn't say why... he has more experience doing car audio, so I just went with it. You think I should swap the cap over to the 4ch amp?

no leave the cap the way it is,I ran all my amp's thru the cap because they pull alot of power,1500sub,800 front,500 rear.maybe it was your rca's since playing with them has seemed to fix the problem.are your rca's running next to your power cable.

Dodgy ground somewhere between the battery and the empeg. Check the sled contacts and wiring.

Thanks genexia... I'll give that a shot. Maybe I just got lucky and pushed the player into the sled a little harder one time? Maybe the car was warming up and that helped? I keep thnking that the empeg must be the culprit this time because of the "data" noise being transmitted through the speakers.. so this makes sense.

My next experiment will be to see if wiring the player directly to the battery will help the battery icon. Are "performance" batteries really expensive?

Optima Yellow Tops can be had for around $150 or so.

And I can definitely recommend the optimas!

But reading you guys complain about alternator output makes me so happy to have the manual throttle in the 101 - it's actually intended to keep the idle high enough to produce enough power from the alternator. That electronic warfare stuff sure uses power

Here's a theory I have (and I admit I'm no good at electronic ever since plugging my ErectorSet motor into the wall outlet and waking up sometime later...)

I was having a bad ground connection from the empeg to the battery (either at the battery, the dock or a connection) so the empeg grounded itself along the RCA's. Once I pulled the RCA's and restarted the player, it was forced to use its "dodgey" ground to the battery. Once this ground was being used, re-connecting the RCA's had no effect. Does this makes sense? Will a device change where it's getting its ground from?

Off to do more testing.

That is in fact the DEFINITION of a ground loop. So yeah, that makes a lot of sense.

Sometimes just running a ground wire to the sled casing is enough.

Well, everything is fine now (knock on wood). Maybe I just had to re-do my empeg ground to the battery and disconnecting the RCA's "forced" the emepg to start using the proper ground? (shrugs)

Funny... you get so conditioned to hear that alternator whine that it's almost odd not having it around....

Just took a look at this today, and that's DEFINITELY a possibility. It's what I was thinking was a problem right before I got to your actual question on it.

I had something similar in an old Mercury Tracer (no relation to me - haha). I had installed a head deck and amp, and long story short, it turns out that the piece of metal in the dash that I had grounded the head deck to was in fact isolated from any other metal parts in the car. The head deck grounded itself through my RCA shields. I could tell once I realized that when I disconnected them and plugged them back in I could see a tiny spark!

Properly grounding the head deck took care of it. I suspect your empeg is done the same way. Obviously it has a wire available leading right to the battery, but - I would spend some time making sure the empeg is actually using that ground path and not something else.

I believe the empeg's (RioCar in my case) metal body (the box containing the electronics) is happier (at least in my situation) when also properly grounded through the metal shell of the sled.

The sled shell itself must be properly grounded, AND the metal bumps on the inside of the shell must make decent contact with the empeg's casing. I have found that if wear, corrosion, or dirt have allowed the empeg to be inserted without the casing being in solid electrical contact with the shell around it, then I will hear electrical noise (hard disk accessing, general buzzing).

When this was happening to me, jiggling the unit would sometimes reduce the noise, as would some re-insertions. Adjusting the pressure points inside my (now well grounded) sled to increase contact pressure eliminated all the noise.

I discovered this after spending time with a decent digital meter looking for ground problems, and not finding anything of significance at the sled docking connector. I then thought about electrical paths other than the docking connector, which led to me looking at the ground path for the body of the unit.

This may or may not be a factor in your case, but I think it is something to keep in mind.

I'll second that. I had some low level engine noise which only went away when I re-grounded my sled to my beefy (10 gage) common ground line instead of the ground line on my cigarette lighter (which isn't small either).

-Zeke