Hi all I've had this thing sitting around for a couple of years now, not even sure if it works, but it looks super-clean! It's a Rauland pro204 4 channel mic pre/mixer. The only trouble is, no indication of what kind of input voltage it needs for a power supply. I remember vaguely hearing 24V - but my memory's not trustworthy to risk it. Any advice? Thanks! Mark Alan Miller Slaughterhouse Recording Studio.