Need HELP with alt whine

[grjr]

you say you have ignition whine noise- This isn't clear.

Ignition noise makes sharp ticking sounds, the frequency of these ticking sounds will go up as engine speed increases.

Alternator noise makes a whining sound, the frequency of the whine will go up as engine speed increases.

So do you have alternator whine, ignition noise, or both?

[pityocamptes]

Sorry, alternator whine.

[shagone]

have you checked you spark plug wires? if they are really old sometimes they can cause noise or if thay are the stainless steel core racing type they are bad for sound systems and vey noisy.

also, are youre amps chassis' mounted directly to the sheet metel of the vehicle with metal screws? if so try to isolate the amps chassis' from the vehicle somehow like mounting the amps to a board and then mount the boards to the vehicle or by using rubber grommets where the screws go through the amps to isolate the amps, this may help to stop some ground loops.

[ppia600]

You said its an international.. does it have one of those ancient long generators or a more modern alternator? Also, try plugging the rcas directly into the amps without connecting them to the eq.

[Clipped]

its the pyramid....its always the pyramid...

[grjr]

if you remove the EQ from the signal path does the noise go away?

[pityocamptes]

Originally posted by shagone
have you checked you spark plug wires? if they are really old sometimes they can cause noise or if thay are the stainless steel core racing type they are bad for sound systems and vey noisy.

also, are youre amps chassis' mounted directly to the sheet metel of the vehicle with metal screws? if so try to isolate the amps chassis' from the vehicle somehow like mounting the amps to a board and then mount the boards to the vehicle or by using rubber grommets where the screws go through the amps to isolate the amps, this may help to stop some ground loops.

Spark plug wires are new and the supression type. The amps are mounted over the rubber flooring, but screwed down with metal screws into the floor.

Originally posted by ppia600
You said its an international.. does it have one of those ancient long generators or a more modern alternator? Also, try plugging the rcas directly into the amps without connecting them to the eq.

No, I have the newer internal regulator type alternators. The noise is both from the HU and EQ (if I unplug one and bypass it to the other it makes no difference).

Originally posted by Clipped
its the pyramid....its always the pyramid...

They ain't that bad...

Originally posted by grjr
if you remove the EQ from the signal path does the noise go away?

No, the noise remains the same.

Will aluminum foil wrapped around the power wires with the aluminum grounded shield the induced noise? How about wrapping the HU in foil? I've read where some short wave radio guys do that to the receiver or radio to prevent noise. Thoughts? Thanks!

[shagone]

try moving the location of your amps or not screwing them into the floor directly with metal screws and see if that helps.

you could also try re-routing your rca cables or a spare set temporarily outside of the vehicle to se if your routing is an issue.

i don't think that wraping your head unit with foil will do anything but heat it up faster. it already has a metal case for shielding. wraping power wires with foil won't do much either. just keep your signal wires away from them.

[tsmith1315]

Apologies if this posts more than once, there have been issues with the reply...

The vehicle is an old international scout.

Cool truck, almost indestructible.

I do have to say that the Visonik 12's with the Lanzar amp (1200 watts - 600 watts rms) hits VERY hard. I wasn't expecting it from the setup but DAMN!!!!

Great! The "DAMN factor" is what makes car audio so much fun.

Will aluminum foil wrapped around the power wires with the aluminum grounded shield the induced noise? How about wrapping the HU in foil?

Seriously doubt it. As mentioned aleready, the whine is most likely a result of a ground loop, and not induced. Were the noise induced into the RCA cables, it would get louder as you turned up the volume. In the old days of cassette decks, noise was sometimes picked up by the tape head, but that was normally clicking or ticking noises. Aluminum isn't much of a shield anyway.

I still have a wrinkled sheet of Mu metal and some braided copper tape with thin (nickel or similar) liner from the 80's, both marketed as noise suppression devices. Tried them a zillion times to no avail.

Not to jump on the bandwagon here, but try going straight from the HU to the amps, then disconnect power and ground from the EQ. At least back in the old days, whine was more likely to show up after adding an EQ or cheap crossover than any other single component.

OH, I also have plastic RCA jacks if that makes a difference.

Only if they are defective or damaged. If you have doubts, try new patch cables first, that would be an easy fix.

The amps are mounted under the seats and they are grounded to the same point (star ground). The eq and HU are also grounded in a similiar manner.

The idea of the star grounding technique is to have one and only one ground reference for the entire system. That isn't always possible or practical, but the closer you can get the better.
In the scheme you've described, I see as many as 5 ground references:

1) HU and EQ ground wire connection.
2) HU and EQ physical connection to vehicle chassis.
3) Antenna physical connection to vehicle chassis.
4) Amplifiers ground wire connection.
5) Amplifier physical connection to chassis.

The most obvious thing here is that (1) and (4) should be the same point for a star ground.

(3) isn't practical to change, but it is possible for that to be an issue, so it can't be over looked.

I would start by simply unscrewing the amplifiers, then removing the HU and EQ from the dash lay them on the seat, floor, wherever they won't be in contact with metal.

Then disconnect the HU and EQ ground wires, and run a 12 or so gauge wire from their ground wire to the point where the amplifiers are grounded. If the EQ is powered, make that a 10 ga wire.

Crank it up and check for noise.

If it's gone, reinstall one item at a time, checking after each change until you find the offense.

If it's still there, try running a wire from the HU chassis to the EQ chassis. They should be grounded anyway, but you want to be sure. Check it again.

If still there, try moving the system ground to different places. Some chassis locations can be more noise that others.

Keep us posted.

Tim

[pityocamptes]

OK. I need to clean up some wiring under the dash tomorrow. Will pull the HU and see if it makes a difference. I do know that when I turned on my AM radio to 1400 and listened I could hear LOTS of noise coming from the dash HU area. Right behind the HU is the entire system wire bundle - ignition, power, etc. Really no way to move it as the dash is not that wide or very big.