I already have an Audiobahn A4002T powering a 12" Audiobahn woofer(No Audiobahn sucks answers cause this is an old setup from an old car that I still love.) Well, I installed my Kicker Zx200.2 amp and some Kicker KS comps in the front doors. I have absolutely no noise while the car is off but I get a slight hiss and the alternator whine when I turn the car on.

Now, this is how I have it all wired. I have the stock HU and am using the high-level inputs into the Audiobahn amp. From the Audiobahn RCA outputs, I have RCAs connected to the Kicker amp's RCA inputs. I have the power wires going through a distribution block and each wire is 4 guage(prepping for when I update the Audiobahn stuff). I have the Audiobahn grounded to the nearest strut bolt on the passenger side. I have the Kicker grounded to the nearest strut bolt on the driver side.

Today, after looking at a few threads and whatnot, I went out and disconnected the RCAs and the whine went away. I plugged them back in and turned off the HU and the whine is still there. It only goes away when I unplug the RCAs.

Is it the RCAs? Also, is it good to have the grounds at two different points? Should I ground them at the same point(I read to do this on another website but it was for AC and didn't know if it applied here as well.)?

Anything else I should look into? I've looked into the ground loop isolators and whatnot but I believe I should be able to make it a clean setup without the use of isolators.

If you think it's because of the high level input and rca combo, then let me know because I will have a nav unit in a month or two.

Thanks,
Steve

 

throw some ground loop isolators on there. I have 2 pair if you need em. it can at least eliminate the whine. if you feel that the sound quality is lessened, then you can take it from there, but I didn't feel that way when I threw em on. In fact, I have a satellite radio hooked up via an auxiliary cable - although the cable is a ground loop isolator because that was where my alt whine was coming from.

 

Thanks man. I might take you up on the isolator offer if I can't figure this out soon. Might head to a couple different shops around here and get an opinion.

 

Well, for me, I only made all my ground wires thicker and shorter. Connect it to the chassis and remove the paint to make sure there is a solid connection. Also avoid running signal wires with power wires. You can run them perpendicularly but not in parallel with each other. That will for sure eliminate the alternator whine without using ground loop isolators.

And about the hiss sound, just lower your amp's gain to a moderate level.

I hope this helps.

 

Thanks for the input. None of my wires are running parallel. I knew that rule. I have 4 gauge going in and 8 out. I guess the only thing to do is try to shorten up the ground and go to 4 as well or make the power 8 since its not a high amperage amp.

 

make sure your power/ground wires are the same. you never want to mix gauges, it can cause all kinds of power/amperage/currant draw problems. could also be a source of your noise. personaly i would ground them seperately, scrape the paint, and use like 3 or 4 screws to make sure its secure.

later down the line you might want to think about changing out the headunit, so you can run rcas right into your amp. ive never been a fan of high level inputs on amps, but i duno if thats causing the problem, thats just me lol

 

This is a myth of car audio wiring practices. If the ground is "good", this won't be an issue. The alternator whine is an "A/C" noise that's bleeding into the system from the EMF, created by the power wire (+) and chassis (-). There should be NO A/C in these wires to begin with! Even at high current demands, the EMF is smaller than you think, and wrapping the RCAs around the power wire shouldn't make a difference. IF it does, the terminations/connections aren't good enough.

There's nothing wrong with mixing gauges. Ideally, you'll want to use the largest wire you can. Ground loops are created by different grounding points (re: distances) from the battery. My guess is that with one amp grounded on one side, and another amp grounded to the other side, and the RCAs connecting the two amps together is causing your noise problem. You should also upgrade your "big 3". Sand down to the bare metal where your amplifiers are grounded, and use a "regular" screw - NOT a zinc material, as found on "rated hardware" (ie: shock towers, seat belt bolts, etc.). If possible, ground the amplifiers to the frame of the car.

Amps grounded w/ 4 ga. to the frame:




Under the hood - part of the "big 3":

 

Could I place this between the two amps through the RCAs to kill the ground loop?

http://www.crutchfield.com/S-OmpmjUi...loop&i=127SNI1

 

Yep, that'll probably do it. I have 2 of those (different brand) sitting around that were use for like 2 weeks. They are in perfect shape, so let me know if you want em. I can save you some money over $15 a pop plus shipping

 

Sweet....I'm down for that deal. Shoot me a PM with the paypal and $ and we'll get this deal rollin cause this whining noise is absolutely disgusting.

Steve

 

PM sent.

~Jay