With this circuit it is possible to provide a coaxial digital input for the headphone amps HPA V100, HPA V181, HPA V200, HPA 220 and HPA 281.

The coaxial digital input can be used to connect a digital device with a coaxial digital output (often called "S/P-DIF) like CD/DVD-Players or computers. PCM coded 2-channel digital data with sampling rates from 44.1 ... 192 kHz are supported. The electrical characteristics meets the S/P-DIF standard while the incoming data may be "professional" or "consumer" coded.

The built-in digital receiver forwards the data to a separate D/A converter offering 110 dB dynamic range and 100 dB THD N.

The converted digital data has priority over all other analog inputs and will mute these when valid data is received.