Does that include the midimuso you mention in another topic?
Indeed it says at http://midimuso.co.uk/index.php/octex/ (for the Octex, don’t see this info for the ORAC):
Specifications:
Power supply voltage: 12 volts DC. (max 18V), +ve centre pin (2.1mm)
Power supply current: 500 mA minimum (per board when chaining)
500 milliamps on the +12V bus likely would eat up most of a power supply right there. Yikes.