Headphone amplifiers with coaxial output

Coaxial S/PDIF

— output for transmitting audio signals digitally via a coaxial electric cable. It is similar in capabilities to an optical output (see the respective section), allowing stereo and even multichannel sound through a single connector. However, a coaxial cable does not provide 100% protection from interference, but on the other hand, it is cheaper than fiber optics and does not require special handling.

It should be noted that in headphone amplifiers, digital outputs (including coaxial) serve an auxiliary function: they usually handle the routing of digital signals received at the corresponding input. As a result, models with such outputs are not widespread, and seeking out such an amplifier makes sense only if you intend to use it for that specific purpose — for example, broadcasting music from a USB OTG-connected flash drive (see "Inputs") to the digital input of an external audio receiver.

It is also worth mentioning that the "native" hardware connector for a coaxial interface is RCA. However, this should not be confused with an analog RCA output (see the respective section) as they are fundamentally different standards. In some headphone amplifiers (especially portable ones), a coaxial S/P-DIF is combined with another connector (for example, embedded into a 3.5 mm mini-Jack port), requiring the use of appropriate cables/adapters.