Try connecting the gnd to the chassis, bare the metal with some emery paper first. The -ve post is a terribly noisy place to gnd your amp!
Run your RCA signal wires at least 12" away from your power wires, preferably on the other side of the car, power + and - can run side by side no probs.
ground your head unit and amp at the same place , this will help to stop ground loops.
The capacitor on the alternator could be replaced with a std electrolytic of about 4.7uF, at least 20V. solder or crimpsome wire on to the cap, then connect -ve side to ground
and positve side to alternator output.
good luck!

Not all alternators had the capacitor on them. Go to Radio Shack and pick up a coil and capacitor set that filters out the alternator noise. Tell the clerk the problem you are
having and he will fix you right up.

Mareo

Well Mareo, you are the second person to tell me about the capacitor. My alternator doesn't seem to have one. The engine I'm using is an A-14 from a B-210, I've looked under
the hood of another and it didn't have one either. Has anyone here ever had to replace (or just place) one of these? If so, where can I get one?

You need to check the little external capacitor that goes on the alternator. The best way to alleviate that problem is to go to your local Radio Shack and pick up a choke circuit
for your car. The choke is comprised of a coil and a capacitor that wires into your radio wiring. They filter out noise from the elecrtical system and are relativelt enexpensive.

Mareo

As I alluded to in an earlier post, I'm putting a stereo in a 1200. The problem I am encountering is a bad engine whine or buzz through the amp. I've run the signal leads and power
leads to opposite sides of the car and have 4 guage power and ground leads going straight to the battery. Does the A-series alternator put out dirty power and if so what can be
done about it? Would Fanta help in some way?