Headphone AmplifierPHA-3AC

Turning the power on

Connect the headphone amplifier to your booted computer using the micro-USB cable (supplied).

  1. Rotate the power/volume knob clockwise.

    The POWER/CHG indicator flashes in green then lights up.

    Rotate the power/volume knob further clockwise to increase the volume.


  • The headphone amplifier contains a rechargeable lithium-ion battery though the headphone amplifier can only be used when it is connected to an AC outlet with its DC IN 5V port via USB AC adaptor (supplied) and micro-USB cable (supplied). The rechargeable lithium-ion battery supports power supply from the USB AC adaptor and improves the sound quality. When the headphone amplifier is turned off, battery charging will start and the POWER/CHG indicator will turn up in red.