As Steve would point out products like the BC Thingee, and HagUSB use the same PCM2704 USB chip already used in many consumer DACs. So the benefit of one of these would be negated. That's where the Bel Canto converter box is superior... not quite to the Empirical level but an improvement over the common units.
I believe the old Waveterminal U24 used the TAS1020A chip, though details are sketchy. A newer version is available as well, though again details are lacking. It's closer to $200.
I believe the old Waveterminal U24 used the TAS1020A chip, though details are sketchy. A newer version is available as well, though again details are lacking. It's closer to $200.