Well I finally got the replacement amp from wooferstec and now I'm having some other problems. First there is really bad alternator whine which gets worse with revving. The other thing is the front enclosure I made for the 6.5 Rainbow Germaniums must really suck for them because they sound muffled, flat, and almost like the volume is half or 1/3 of the rear speakers. The rear Rainbows sound amazing, I was very impressed. So the alternator whine problem has be stumped as everything in the system is hooked to a 0 gauge wire coming from the battery negative, any suggestions? I dont get any whine with just the sub amp (JL 1000v2) hooked up, but it starts when the Zapco is hooked up.

1994
Avic Z1 Head unit
Zapco 1000.4 to Rainbow Germaniums front and rear (Symbilink)
JL 1000v2 to 12W7 (RCA)

 

Could have created a ground loop issue if the Zapco links are too close to each other.

 

From what I understand about ground loops, those are caused when you have a difference of potential between two grounding points but everything is grounded to the battery negative. What do you mean by the Zapco "links"?

 

If you place the Symbilinks too close to each other you will cause a ground loop. I had the exact same problem and had to call Zapco to get the answer.

It might be your problem or it might not, it was mine.

 

I don't see how they can be placed so they're not close together, I mean just at the head unit they can be practically touching. Do you mean to keep them separated when you run them only? Is it ok if they're close together for a short distance like at the head unit?

Also just realized you probably can't hear alternator whine through a sub (so maybe the whine was still there when I had the JL amp hooked up but couldn't hear it).

 

I ran a ground wire from my high amp ground to my head unit and all my engine noise disapeared. It worked for me.

 

Was that the only ground the head unit had? And did you ground it to the body of the head unit or the negative wire going to it?

Also I just checked something else, I unplugged everything from the head unit and only left the 2 Symbilink cables, with the car off and the headunit and Zapco amp on I get the whine which gets worse when you turn up the gains on the amp. Does this still point to the Pioneer as the problem or the Symbilinks?

 

Never mind guys, looks like Woofersetc screwed me again, this amp just died after about 30 minutes of playtime. I knew something was up when they said they were sending me a new unit in an old box. It seems very unlikely that 2 "new" Zapco amps are defective... this sucks so bad I waited almost 50 days to receive this replacement from them

 

I was going to say, no way your going to get alter whine when the car is off,

 

Did you say you have your amps grounded to the battery???

unless your amps are mounted in the engine bay, you should change your ground. They "should" be 12-18 inches from the amp

 

That's if you are grounding to the chassis, the battery negative is the best place to ground amps in a Vette.

 

Doing this should eliminate noise in the system because you only have 1 grounding point and no change in potential between two points. Its also using 0 gauge wire so the "long" run isn't that bad.

 

Taken from "How To Design and Install High-Performance Car Stereo"

"Ground loops are insidious. They are caused by the non-zero resistance of the wire used to interconnect the equipment. Typically ground loops are created by a piece of equipment having multiple connections to the grounding system.

In auto sound, this problem is exacerbated by the rather callous belief by automakers and certain other folks that the metal frame of the vehicle makes a good ground. While this may be true for cigarette lighters and taillights, applying this belief to audio systems is a gilt-edged invitation to disaster.

Generally, the audio wiring has higher resistance then the power wiring. Since the electrical system of the car uses the body/frame structure as it's negative return, the non-zero (yes, it's small, but not small enough!) resistance of the car body allows small voltage drops to be created between various points in the car body.

The alternator in the battery charging system makes things worse because the frequency of its AC output (alternating current…that's why it's called an alternator, not a generator) is easily within the audible range. The low impedances involved (high available current means low impedances) make filtering out alternator noise even more difficult. Anyway, these voltage drops occurring between various points in the car body usually have alternator noise riding on them, which gets into a sound system via a ground loop.

Here are some ground rules to help you avoid noise in your system:
1. There should be one, and only one, path to the negative side of the vehicle electrical system. If you elect to use the vehicle body as this point, scrape the paint from under the contact point, and use a lock washer on both sides of the terminal lug.
In extreme cases, you may need to run a heavy-gauge wire to the battery's negative terminal. Alternately, you could use the point where the battery negative hits the vehicle"

 

acording to MECP, 12-18 inches for safety, not ground loop.


also, did you use crappy rca wires? where are they in respect to the power wire? normally alt whine is in full range amps as opposed to low range amps

 

The Zapco has Symbilinks, it doesn't use RCAs.

 

Bought my Focal speakers from the house you mentioned with no issues. I didn't buy my Zapco from them being they are gray market. I paid $200.00 more from a local dealer.

 

That's because the chassis has high resistance compared to the copper that is in the ground wire so yes for safety you need to keep it short when running a ground to the chassis but its not as important when you run it back to the battery because copper conducts much better than steel and you don't get the high resistance.

 

I agree that the ground should not be run to the battery. That is one FOR SURE way to get alternator whine....

Not to argue, but that is install rule # 2. One should never run their ground directly to the battery....

A good chassis ground is all that is needed.

From what I've read about C6 installs, a jumper from the deck ground to the chassis ground is the cure for most whine issues. Keeping your signal cable away from your power/ground wire is another must...

 

Can you please explain how its possible to get noise from running to the battery? It's well known among installers that know what they're doing that running back to the battery will give you the best ground in some cars, especially a Corvette.

 

There are tons of threads about grounding to the battery, if you don't believe me, here's one:

http://www.caraudio.com/forum/showth...battery+ground (don't know if I can post this link if not please delete it mod)

The chassis is an easy way to get a decent path to the battery negative (ground), so if it's easier go for it but it will not cause noise in itself and you get the best ground connection going back to the battery. Running to the chassis, now thats a way to introduce noise into the system, especially if you have multiple grounding points!