The output specification of the PSU-3 power supply is 12 VDC, 2.5 A maximum, 43-60 Hz. The size of the output connector is 5.5x2.5 mm (DC plug, power at center). Input connector: IEC320-C8 (2 prong). An equivalent PSU is an AC to DC adapter which outputs 12-14 VDC, >2 A, into a 5.5x2.5 mm circular plug with power (+) at centre. Do not use a 3 prong (safety grounded) adapter as this may seriously lower the audio quality.