alternator whine, 88 vette

just got done installing a mtx 4 channel amp <new in box> in a 1988 vette. pioneer din & 1/2 source unit. ran 8 ga. power and ground to battery. everything is fine until i plug in the factory antenna to the back of the pioneer, then i get alt. whine, unplug the antenna and noise goes away, any suggestions?. this is a new one to me, ive never had this problem with alt whine going away when i unplug the antenna. and also, the head unit is grounded to the amp ground point, i did not use the fact. ground for the source unit

This is an antenna grounding issue.  Your antenna mount to the car body is not providing a ground.  You'll need to ground it.Support the12volt.com

Um, did you say that you ran the ground to the battery? If you did, then I have to point out that amp grounds should not be longer than 3 feet. If the ground is running all the way to the front, then try grounding the amp to a piece of bare metal, preferably double metal, but it must be scrapped clean of paint. See if that helps double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer

it's a little tougher on those vehicles as the chassis is mostly fibreglass.... sometimes going right to the battery is the only way to get a good ground potential... i remember working on them when they were new cars and seem to remember encountering loads of ground issues.....Kevin Gerry

Certified Electronics Technician

MECP First Class Installer

Owner/Installer

Classic Car Audio

since 1979

thats why i ran the ground to the battery, because of the fiberglass body issue. im going to try using a different antenna and see what happens. ive only worked on a handful of vettes and every one was a pain in the ass

I totally forgot about the boddies being complete fiberglass. I understand why you went to the battery know. Have you tried using a "bandaid" on the RCA's. I mean a noise filter on the rca lines. Plug the filter in right after the deck and see if tha works. I dont like using them but it may be just what you need.double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer

customsuburb wrote: Could he just ground the antenna to the battery?

Yep.  Or to any ground bus connection.

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one crutial point i forgot to mention is that the deck the guy had in there was an old school din and a half pioneer with no preouts, so i had to feed hi level from the deck into the amp, which normally wouldnt be a big deal because ive done it before with these mtx amps and never had a problem, but in this vette ive got nothing but problems, so im thinking about temporaly hooking up an alpine deck ive got sitting here with 5 volt preouts and using rcas to the amp and then see what happens. there might be a problem with the pioneer deck, who knows?.....

My bet is that it is the ground plane in the Pioneer cd player. I would still run a new ground from the base of the antenna to the battery and also look at a new ground from the cd player to the battery as well.Top Secret, I can tell you but then my wife will kill me.