[sudo-discuss] weird power supply

hi, i found a digidesign 882 i/o audio interface on the sidewalk this weekend w/o a power supply. the specs for psu: Input: 100-240 Vac EING 50/60 Hz 1.0A Max Output: +5Vdc/3.0A +15Vdc/2.0A -15Vdc/0.5A 36W Max UMEC AC Adapter UP0403A-03P can i just use an inverting op amp on a 5v 12v power supply & be done? or is 3v too big a difference (15v may just be for balancing the analog signal)? on the other hand, if anyone knows where to get a psu matching the above specs, that would be stellar too! thx