Cocktail Audio HA500H Hybrid Headphone Amp/Preamp/Asynchronous USB DAC (Black)
AudioQuest DragonFly Black v1.5 USB DAC + Preamp + DRAGONFLYBLK
Luxman DA-100 USB DAC, Class A Headphone Amp - On a Higher Note
iFi audio hip-dac Portable USB DAC and Headphone Amplifier
Alpha Design Labs - Stratos USB DAC, Headphone Amp, Phono Preamp | Shop Music Direct
Headphone Amp/DACs at Crutchfield
Cocktail Audio HA500H Hybrid Headphone Amp/Preamp/Asynchronous USB DAC (Silver)
EarMen Sparrow USB DAC PreAmp Headphone Amplifier at AV.com
Douk Audio P1 Tube Headphone Amp Offers Smooth Analog Sounds from USB or Bluetooth Sources
Amazon.com: Fosi Audio Q4 Headphone Amplifier Mini Stereo DAC 24-Bit 192 KHz USB Optical Coaxial to RCA AUX Digital-to-Analog Audio Converter Adapter for Home Desktop Powered Active Speakers : Electronics
Audioquest DragonFly Black USB DAC / Preamp / Headphone Amplifier - The Music Room
Luxman DA-250 Compact Headphone Amp, Preamp & USB DAC