Picked this guy up today in a junky little music store in Casper Wyoming.
Apparently it's been modded, RC4558 chips instead of the stock 4558 "type" chips originally used.
From what I've read on the Internet since I got back to the room it's a somewhat rare, but not too valuable pedal. Low gain, smooth overdrive. I'm guessing the mod makes it a little hotter. Goes for $30-$90 depending on condition. I got it for $65, but I guess the mod would increase the value a little, as the RC4558 was the chip used in the TS-808 Tubescreamer. And it is in pretty great shape for a pedal from 1987. There are two small scratches, I'd give it a 9/10.
Unfortunately I won't be able to check it out until Friday, because my gear's buried in the back (front?) of the trailer, and we're off tonight and tomorrow. So does anyone know about this thing? Reviews on the web are generally pretty positive, but they're all from guitarists.