Well, I pulled the 6581. It WAS a very early chip from a C64 of unknown problems....
I replaced the model with a 8580R5 I scavenged from a known good late edition C64c I had sitting around. Figured no harm in testing, right?
Well, I socketted the 8580 on the Catweasel board, hooked back the 4 prong AUDIO, left the 4 prong unknown connector alone, and installed the card back in my computer.
Booted up..... and tested ACID 64.... SUCCESS!!! Perfect C64 sound! :-)
Now, that leaves the question.... Is my 6581 damaged, or does the Catweasel Mk3 not like the early 6581 chips? I'm not sure how to answer this one, without finding more SID chips. I'll have to search my closet more... (I need to anyhow, now.... I have to find a SID that'll work in my 64c. ;-) I'd hate to part out a computer that actually has nothing wrong with it, other than the fact I stole a chip out of it!)
@redrumloa-
Sure... I'll snap some pics and assemble you something... You want it as a simple HTML or something? E-mail me... :-)