Hi GAP,
but I would preferably use an ordinary usb-hub to power the DAC
The question is, what is a "ordinary usb-hub"?
If it is a powered one then you do not need a special power supply for the Pi.
The Pi3 on the other side consumes more power than its predecessors.
The Pi Foundation approved power supply has 5.1V with max. 2,5A.
Frank