Can someone help me with alternator whine?

[Timbers]

Hi everyone.

I have done some forum searches, and searches on the net, and found lots of cures to this annoying problem. I am really confused and was hoping one of you could give me some clues as to what is causing my alternator whine. It is pretty loud, and very annoying. Along with the whine, I do get a hiss, and even some spark plug ticking. Yes I get it all! I don't know what to do!

Here is a short example of my setup, in my Lincoln LS:

Electrical components:
Stock radio system, running to a passive line out converter, 1 set of RCAs from that run to a Kenwood Graphic EQ, three sets of RCAs come off that, 1 goes directly to the SUB AMP, and two go to the Crossover. From the Crossover the RCAS go to the FRONT AMP, and the two BACK AMPS.

Wiring:
Battery is in the trunk. Two short 4 gauge wires + and - run off the battery to the + and - power distribution blocks and from there 10 gauge wires run to the amps. The remote turn on is a 20 gauge wire running off of some power wire I found behind the stock stereo. It splits off into 6 components to turn them all on.

All RCAS are nice Phoenix gold shielded cables, all power wires are run away from the RCAS. All components except for the head unit share the same positive and negative connections, off of those two power distribution blocks. The only thing that has it's own power is the head unit, because it comes off the wiring harness of the car, since its stock.

Any clues? I was going to try to eliminate components by using loopbacks to see if I can figure out where its coming in. I know it could be a ground loop, but everything is powered off two 4gauge cables coming straight off the battery and going to the blocks.

What could I try next? I thank anyone who had the patience to read through all this and answer my question. Thanks,

...Tim

[Immo_G]

I guess you could try adding power filters onto the headunit and EQ and crossover, just capacitor - inductor - capacitor.

[maylar]

I honestly don't know why, but alternator whine is usually a consequence of ground loops. I would suggest ripping it all apart and starting fresh...

Amps to speakers only, no input. Got whine?
Add crossover, no eq unit. Got whine?
Add eq, no LLC's. Test again...
Add LLC connection from HU. Test again.

You'll probably find that adding either the crossover or eq unit makes the noise come back. Evaluate your options from there.

[offroadbum]

i don`t know why but i have alot of trouble with whine after adding an eq.
try move the eq ground.it can be a pain,but sometimes you get lucky.
make sure all the cars orignal grounds(motor,battery,ect) are not broken.and try not to ground to the body.

[Timbers]

Concerning grounds,

I run a 4gauge wire off the battery and then branch that off to a bunch of 10 gauge wires going to the amps. do you think it would be better if I didn't run the 4gauge, and took the 10gauge wires right to the battery on their own?

A reason I am probably getting whine is because my head unit is powered from wires off the harness, while everything in the back of the car is powered using fat gauge wires, connected right to the battery -.

If this is the case, do I need to get a ground loop isolater to cancel out this?

Thanks for all the help guys! I will try the eliminate components troubleshooting technique when I get some time, thanks!

...Tim

[maylar]

If you were using RCA preouts from the HU then I'd say the HU ground would be a logical culprit. But with line level converters off speaker outputs you get some isolation from that already.

[jomor]

Either you get alternator whine or not, all your devices should be grounded exactly to the same point. Cut the ground wire that is attached to your head unit, and pass a new grounding wire from your head unit to the point the rest of the devices get grounded.
Good luck

[Dustin Haug]

Don't use a ground loop isolator unless you really can't find the source. Think of it as a bandaid. Is the whine always there or does it only come on once in a while? If it's always there it's almost certainly a grounding issue. If it comes on only say when you're air conditioning or headlights are on, then it could be you just need to reroute your signal cables.

[Timbers]

It is always on. Every component in the entire system is grounded to the same point, except for the stock head unit, which is obviously grounded to the stock wire harness, and probably the shell of the radio is grounded to all the metal that it is screwed into. Since that is the case, I would have no idea how to isolate it.

I will have to run some tests, to narrow down what device could be introducing the noise into the system.

What a pain in the ***!!!! Thanks for the help guys,

...Tim

[Circlotron]

If you were keen enough (or desperate enough) you could always open up the alternator and put RC snubbers across the diodes. Also, a small inductor and then a filter cap on the output, just like in a normal mains transformer power supply.

With an alternator the 3-phase rectified output has in theory about 2% ripple if the stator winding was a pure sinewave. The only one I ever looked at had a slightly flat-topped waveform which was good from the point of view of ripple.

BTW, do you have a nice short, *thick* cable from the engine block to the car body?