As new condition comes with power cord, original packaging and manual. Driver key is not present. (Mac doesnt need and Windows drivers are available on the Bryston website).
Modern DACs have asynchronous USB inputs to connect your computer for playing music files. This results in the bitstream being re-clocked to the outboard DAC’s own clock, which is much more accurate than a computer’s digital clock. However, older DACs, even expensive ones, don’t have asynchronous USB inputs. The Bryston BUC-1 solves this by having a USB input for connection to your computer, and an accurately re-clocked digital output that can be connected to your old, and perhaps very expensive, DAC, giving you the essential asynchronous input. It could also be an accessory for use with your home theater receiver, which doesn’t have a USB input.