I thought I should list my setup first to clarify what i'm dealing with.
I've got two amps and a passive EQ in my system. The EQ uses the two rear channels off the radio as it's input after they go thru a spkr to line level converter, radio has no line level outputs. The EQ is powered from the radio's ign switched power line and grounded on the radio's ground line. The front spkr amp is located under the pass. seat and grounded there. The rear spkr/subwoofer amp is in back, mounted on the subwoofer baffle and grounded on the rear wall. All the (heavily shielded) patch cables coming from the EQ's outputs are run down the pass. side of the trans hump, and the power cables for the amps are run down the outside edge of the pass side.
What's resulting from somewhere in all of this is an alternator whining and a loud pop when I hit the brakes. Is there something I should do differently with this stuff?

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D.R. Stevens
1984 Trans Am 305HO L69
all the usual external/free mods, original engine
1991 Firebird 305 L03
2 free mods and a K&N,
otherwise stock

 

I assume you sanded away the paint at the ground for good connections? I do not know if it necessary but I do.

 

What happens when you mute your amps?

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1989 IROC-Z 5.7L
NOS 5151 150HP kit
ProBuilt 700R4, PI Vigilante 2800 stall lockup
Baer Brakes 12" Sport System

 

Neo: All the grounding surfaces have been sanded away, clean as I could get them.

Omar: I don't have an actual mute function on these amps, but if I turn the volumes all the way down the noise disappears with it. However the noise stays constant when volume at the head unit is adjusted.
Hmmm...would this mean I should be looking at the EQ unit for trouble?

 

First step is to try and eliminate some variables. Try to hook up your deck through the line output converters to each amp. If your amp still makes music, it might be time to get another deck, one with a high voltage preout.

If no noise, than hook up your EQ and see if that does it. If that does it, I might want to play around with the grounding on the deck (where do you have it ground? to metal or through the harness on the radio?)

Juan

 

Both the deck and the EQ are on the radio harness ground. Should I try a metal ground instead?

 

Yes. Try a clean piece of metal. Should be places in the dash or behind the console I believe.

Juan

 

What you can do is unplugthe RCAs from the amps to isolate them. If the noise persists then it's the amps. To deal with that, best way is to get a power filter. Other options are to re-rout the power and put the ground somewhere else close. Sometime there are other problems elsewhere in the wiring, like around the alt.or something to cause more noise in the system. If it goes away when you pull the RCAs off the amps, then you have a problem with the EQ or Deck. Try grounding them seperately. The EQ takes the full speaker out from the deck and grounds them out using a large resistor.to take the power down to RCA level. Simple as that. Anyway, unhook the high level inputs to the EQ (with the RCAs hooked to the amps) and see if the sound again persists. If it does then it's the EQ, if not then the deck.