The ATX Breakout board V2.0 is compatible with 20 pin and 24 pin power supplies, there is also an extra 4 pin connector to take advantage of the 12V CPU Power for extra current output.

Would appreciate any help on this. I need to replace a power adapter for an old guitar pedal/preamp (H&K Original Tubeman). Now I know the pedal needs a 12V DC 500mA adapter. And I've seen several ...