The AC power input of the power adapter comes with K11 supports AC power between 100V and 240V.

The specification of the DC port for K11 is 5.5x2.1mm.

The DC output of the power adapter comes with K11 is 12V/2A. You could use 12V3A power supply as well. It is recommended to use the power adapter that comes with the K11 or FiiO linear power supply PL50.