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Connections & formats

USB audio

Also called USB DAC, USB Audio Class, UAC2

USB audio sends digital audio from a computer, phone or streamer to a DAC over an ordinary USB cable. It is the most common input on modern DACs, carries the highest sample rates and DSD, and needs no driver on most operating systems.

Computerclock unusedDACBufferDAC clockaudio datarate feedback
In asynchronous USB audio the computer sends audio data in packets and the DAC’s own clock sets the timing, telling the computer how fast to send, so the computer’s clock plays no part and jitter stays low.

Almost every DAC made today implements USB Audio Class 2, which macOS, Linux, iOS and Android support natively and Windows has supported since 2017. Unlike optical or coaxial, most USB DACs run in asynchronous mode: the DAC controls the timing and pulls data from the computer, which removes the computer’s clock from the picture and keeps Jitter low.

USB also carries power, so small dongle DACs run from the phone. The flip side is electrical noise from the computer reaching the DAC’s ground, which better DACs isolate. Expensive USB cables are a recurring argument; measurements have not shown them to change the audio data, and errors on a USB link show up as obvious clicks or dropouts, not as subtle changes in sound; the data otherwise arrives Bit-perfect.

Where you’ll see this on tonistry.

  • USB is one of the connection types members pick when they draw a signal chain.

Related terms