In high-quality audio products, power supply design is critical. Our design goal was to utilize the power in the USB interface, which comes from the computer or server, without significant compromises in sound quality.

Essentially, the Audiophilleo comprises two independently powered, and electrically isolated subsystems:

  • The USB interface and digital signal processing microprocessor
  • The differential S/PDIF output stage and clocks.

This approach is important for minimizing jitter, and requires two independent power supplies:

  • A regulated supply dedicated to the “front-end” (the USB interface and processor)
  • A multi-stage regenerative power supply dedicated to the “back-end” (S/PDIF clock and output circuitry)

The regenerative power supply has these advantages:

  • Critical S/PDIF output circuitry is isolated from noisy USB power, insuring consistent sound regardless of the computer used
  • It provides galvanic isolation, so the output stage couples to the DAC without requiring a transformer.

For the dual 12v trigger, we include an external power supply. The trigger usually need quite a bit of current—more than one would typically want to draw through a USB interface. This external power supply is also galvanically isolated from the rest of the device and cannot influence sound quality.