got serious feedback from somewhere in car.

luke_ha · 02-22-2004, 11:44 AM

ok here's whats up i have a 37' chevy sedan that i built myself and wired myself. stereo sounds great when car is not running but when it is running there is a loud buzz. It gets louder when i turn up the volume and rev the engine. running power dirctly from alt. to battery to amps to speakers. I have one fear when i bought the amps i went with reconditioned amps. Any thoughts to get me started?

Thomas_A · 02-22-2004, 02:28 PM

Make sure you have a really solid ground. Normally noise is caused by a poor ground. Also check to see if you ran any wires near any thing that could be generating EMF... wich would be electrical items...there are really a ton of things that could cause it..but those 2 have a high %.

good luck. Thomas

Mark gas · 02-23-2004, 10:51 PM

did you run the power wires and rca's together?

Erik.Ha · 02-23-2004, 10:55 PM

sounds like alternator noise... bad ground is possible. More likely the audio wires are not shielded/seperated enough from power and other electrical wires in the car... Troubleshooting and fixing this can be a MAJOR pain in the A$$.

Luckily, if you wired it yourself, you should be able to fix it yourself. I'd start by seperating ALL of the audio wires from any other car wiring and making sure youre using good quality auto shielded cable.

Bob_Bo · 02-24-2004, 06:23 PM

Heya Luke, sounds like a nice ride you've got there.

Is the whine coming from your alternator or from your speakers?

If it's from the alt, then you need to upgrade to a more powerful alternator and a larger capacity battery.

If it's from the speakers, especially from the mids and tweeters, then it's probably residual AC current from the alt causing the noise.

There are a few things you can do for this.
1. As it's been said, make sure you have a good ground. A good test for this is to make up a jumper wire, clip it to the neg terminal of the battery then to the amp and see if the noise changes.
2. Make sure your power wires and your audio wires are separated by at least 8 inches. Better yet run them on opposite sides of the vehicle.
3. Also make sure none of the wires are run along side any other wires (EMF) for any long lengths. Try to cross any other power wires at 90 degree angles if possible.
4. Keep all wires away from any electrical motors, plug wires, coil, distributor and any relays.
5. Finally, you can try a filter on your alternator output to dump that residual AC current. You can find these most anywhere, I know Crutchfield has them.

Good luck.

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Shawn Keeler · 02-25-2004, 09:44 AM

The best way is to make sure the ground for the head unit and amps/processors are grounded in the EXACT same place!!! So you do not get a ground loop. You may have to run a wire back to the amp grounding point. This will eleminate the noise.
Shawn

luke_ha · 02-25-2004, 10:11 AM

i knew there would be a ton of possible problems. This will be a huge amount of work since i installed the interior in before i started up the car again to test the stereo. Made the mistake of thinkin"hey it sounds great lets move on." I was a huge novice at car audio and got all my info out of books and a bit of advice.

well i am working in england right now so i wont be able to do anything for a while. but hopefully when i get home i can get it working out.

Scott L · 02-27-2004, 04:19 AM

Good luck man, I have the same prob. I have shielded name brand RCAs and I seperated everything (power on left, RCA in middle, speakers on right) but I still hear an annoying whine. I'm guessing it's a weak grouund, either from the amps or the HU.

I'll try your advice Bob and test it by hooking the jumper cable to the negative battery post and then clamping it to my amps' ground wires. Then I'll try the HU ground.

If something explodes I'm suing, what's your address?

dave_brogli · 03-06-2004, 08:15 PM

i have this excact same problem. Ive been searching for a clue for close to 3 months. fortunetly its in my 85 lesabre and i can live with it.

Greg_R · 03-29-2004, 08:08 PM

I would amend the 'have a good ground' comments to 'have good groundS'. I installed 3 new 4 gauge ground wires:

- Alt to chassis
- neg battery terminal to chassis
- Amp negative distribution block to chassis

99.9% of the 'whine' problems can be solved with these connections. Be sure that the chassis connections are to bare metal (and not paint). After attaching the cable hit the chassis area with some primer (to prevent rust).

Running the interconnects away from the power wires is also a good idea.