Mechanics

HOW TO GET RID OF ALTERNATOR WHINING THROUGH SPEAKERS....

2000 Chevrolet Monte Carlo • 103,000 miles

Alternator whine through speakers hooked up to 4 channel amplifier? Aftermarket cd player. Already tried noise filters and re routing RCAS and tinkered with the grounds on the cd player? Help Please, has been the case for last decade.
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Chevyforever1986
June 4, 2012.




Have you change the alternator?

Sometimes, there is no cure for these aftermarket amps.

Roy

No not on this particular car but on my previous car (1997 Olds Cutlass Supreme) it did the same thing even after spending extra money on a high output alternator. And the amplifiers, im not sure it would make the noise with all 6 or 7 amps ive tried including high end brands like MTX Audio or Rockford Punch. Ive gotta be wiring something wrong, well thats my assumption anyways, obviously im not sure lol. Thanks for the incite though

Tiny
Chevyforever1986
Jun 4, 2012.
ASEMaster6371 is right. Since the '87 model year GM has had a real poor generator design. They develop huge voltage spikes that can destroy the internal voltage regulator and diodes, induce spikes into computer sensor wires, and, . . . and, . . . show up as static on AM radio stations. When you hear it through a cassette or cd player, the spikes are coming in on the power wires.

It is real common to go through four to six GM generators in the life of the car. The way to reduce the number of repeat failures is to replace the perfectly good battery at the same time unless it's less than about two years old. As they age, they lose their ability to dampen and absorb those spikes. The old battery will work fine in an '86 or older car with the better generator.

The excessive whine in the speakers suggests your generator already has a defective diode. That will reduce the output capacity to one third of the unit's rating, and "ripple" will be very high. That ripple will also cause a whine in the speakers. Here's a better description of ripple at the bottom of the page:

http://randysrepairshop.net/charging-systems.html

Before you spend any more money to cover up the noise, have a load test performed on the charging system to see if that is causing it. The typical generator should produce around 90 amps or more. If the test finds closer to 30 amps max, it will show high ripple too. Professional testers show ripple not as a voltage but as high or low on a bar graph.

If you need a new generator, don't waste your money on one with higher output. That will do nothing to reduce noise. It is very rare to need the full generator output. It will deliver exactly as much current as is needed by the electrical system regardless of its maximum capacity.

Caradiodoc
Jun 4, 2012.
Ah wow, thanks for the info. Well that kinda sucks I guess. Umm so the only way to do anything about it is to replace both at the same time? And that will only possibly reduce it? And is there any cure for it at all? I have an extra battery and a couple capacitors as well if that would be any help. Thanks again for the help guys

Tiny
Chevyforever1986
Jun 5, 2012.
Simply replacing the generator and battery on principle is not the answer. You need to have the generator load tested, THEN replace it if it proves to have a bad diode, and replace the battery to prevent failure of the replacement generator.

In the unlikely event the noise is still there with the new generator or if it tests okay with low ripple, unplug the small connector on the side while the engine is running. If the noise is still there, it's not related to the generator. Look at the ignition system instead.

Caradiodoc
Jun 5, 2012.
Hi, I came to a conclusion after the numerous years of frustration. It had nothing to do with he charging system. I was looking more toward the head unit and my personal wiring because that wasnt the case in my old car with a yellow top optima and fresh alternator and completely different amps. All along through out the years I had pioner/sony head units. Pioneers always had the whine, sony did not. Pico fuse blown in pioneers? Idk, but then the rcas I think arewhere it all lies my reasoning because they are wally world (schoshe) brand. I seen on u tube a few guys grounding the rcas (shields) by stuffing a wire in the the shield part of only ONE of the two rcas and grounding it to the deck. By god it worked! Totally happy! I actually soldered the little ground wires to the shields on the rcas. Affter everything kist find ime
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Tiny
Chevyforever1986
Jun 20, 2012.

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