PS Audio's Digital Link III gives you warm, spacious, and open sound you don't associate with DAC. It also offers 192 kHz upsampling and a USB connection.
You can plug a jump drive loaded with MP3s right into the USB port of the Vincent SA-96 preamp and, using a row of front panel buttons, navigate to the song you want to hear.
Benchmark's DAC1 USB is a reference-quality, 2-channel 192-kHz 24-bit DAC featuring Benchmark's Advanced USBAudio technology for your computer, UltraLock clock system, and HPA2 headphone amp.
You'll give the PS Audio GCHA headphone amp an A+ grade for its exceptional sound. The design features 'Class A' output, a USB connection, and digital / analog signal sensing.
The NuForce Icon HDP is a very high performance headphone amplifier, DAC, and preamp for integration with your home audio system. It features built-in DACs for its USB and SPDIF digital inputs.
HRT's Music Streamer II Pro USB DAC provides the professional audio market with a pristine performance bridge between a computer-based music library and a professional audio playback system.