Recommended USB DACs and USB Audio Interfaces
Both within the context of HiFi / high-end audio as well as for recording studios there is now a wide range of high quality DACs available. As long as you reduce the requirements for a USB audio interface to those that are really essential (high quality conversion of the USB signal up to 192 kHz / 24 bit or more, very good analogue output stage, a high quality converter chip, such as ESS Sabre, Burr Brown, XMOS, Wolfson or the like, and maybe playback of DSD / DXD audio files), you can get a very cheap high-end DAC with a top sound.
When choosing the right device, let your ears decide and not the technical specifications: You don’t need an asynchronous mode. Adaptive converters provide great sound-neutral results for little money. Up-sampling can be expensive as well, and is worth it only when consistently implemented. Since HD audio files with more than 192 kHz / 24 bit are still quite rare and the improvement in sound negligible, a 24/96 converter will do just fine
Below you can find a selection of devices for high-end and studio technology, all of which can be easily purchased at Amazon.
You can buy the matching USB audio server here.