ok - here's what I ended up having to do in my car (...I can barely hear the alternator noise now w/ the player paused..)

seperate ground wire - ended up running another cable from the amp's ground, to the negative on the headunit.. also hooked up this same ground to the rca leads provided (only on the headunit..) - shielded this ground from reaching the amp using a groundlook isolator..
ALSO had to hook up this negative at the headunit to the CHASIS near the headunit.. (why??? this got rid of 90% of the noise, and the ground-loop isolator got rid of the other 10%)

I'm not even sure why it worked, but it's playing beautifully now w/o hardly any alternator whine

...proud to have one of the first Mark I units