Coaxial S/PDIF Input
Coaxial S/PDIF input count identifies the electrical digital audio connections available to receive compatible source signals.
The connector and device-specific counting scope matter. Coaxial digital audio is distinct from analogue RCA audio and from clock signals that may use similar fittings.
Coaxial S/PDIF Input — Headphone Amp
On a headphone amplifier with digital conversion, a coaxial S/PDIF input receives a digital source for the internal audio path. Its connector can be RCA or BNC as specified.
Compare supported input formats and rates with the source rather than relying on connector fit alone. Keep analogue line inputs and optical S/PDIF separate from this count. The number of digital inputs does not describe headphone-output power or the number of listeners supported.
Coaxial S/PDIF Input — DAC
For a DAC, this field counts RCA coaxial S/PDIF inputs; BNC S/PDIF inputs are listed separately. A compatible digital source can feed one of these inputs for conversion to analogue audio.
Compare RCA input count with the sources you intend to connect and check accepted PCM rates separately. A total containing both RCA and BNC sockets should not be treated as an all-RCA count. Ordinary analogue RCA inputs do not belong here.
Coaxial S/PDIF Input — Upscaler
On an upscaler, coaxial S/PDIF inputs receive digital audio before processing. RCA or BNC connections can be used where specified, and the exact connector needs to match the source and cable.
Compare the input formats and rates separately from the output limits. A BNC word-clock socket is not an audio input, and an unspecified S/PDIF connection could instead be optical. Several input sockets do not by themselves provide simultaneous mixing.