I'm surprised nobody from PreSonus has answered this one yet. This question was posted almost 2 years ago and should be easy to answer for PreSonus staff. This should have been specified in the Owner's Manual Specifications section but it's not.
So I have the same question. The voltage should be 5VDC but how many mA this Studio 24c requires to operate? Or in USB language, how many unit loads (1 unit load = 100 mA).