This circuit is pre-eminently suitable for PCs and laptops that are not equipped with a built-in sound card but do have a USB interface. However, the ‘mini PC sound card’ can also be useful for other applications and various experiments.The introduction above provides a nearly complete character outline for the circuit under consideration. In brief, it is a 16-bit stereo version of a digital to analogue converter with USB interface. The converter may be used for a range of audio applications. But the first thing that comes to mind is an external sound card for PCs and laptops without such a card, or as an expansion card in the event a second one is desired.The circuit is conspicuously compact and simple by design, because it consists mainly of an integrated D/A-converter supplemented by two opamps. This simplicity however, does not imply that the quality of this ‘USB audio-DAC’ has been compromised. On the contrary, we would like to say.