Your kidding, right? Berkeley's own converter rates very high.
http://www.computeraudiophile.com/f6-dac-digital-analog-conversion/15-universal-serial-bus-industry-standard-cables-connectors-and-communications-protocols-between-computers-and-electronic-devices-spdif-converters-shootout-15327/
http://www.computeraudiophile.com/f6-dac-digital-analog-conversion/15-universal-serial-bus-industry-standard-cables-connectors-and-communications-protocols-between-computers-and-electronic-devices-spdif-converters-shootout-15327/