A DAC, or digital to analogue converter, is the component responsible for turning the digital audio data stored on a computer or phone into the analogue electrical signal that headphones or speakers actually need. Every device with audio output has some form of DAC built in, but a USB DAC is an external unit connected over USB instead.
People often add an external USB DAC to bypass the built in audio hardware of a laptop or phone, which can be limited in quality or affected by electrical noise from other internal components, aiming for cleaner sound or support for higher resolution audio formats and higher power headphone outputs.
A USB DAC typically relies on the standard USB Audio Class to work without special drivers, making it straightforward to connect to most computers and many phones through a simple USB cable or adapter. See our guide to USB audio for more on getting the best sound over USB.
