Chord Electronics Chord Electronics Mojo 2 might be just the amplifier you need to elevate your audio setup. This model has an USB port to let you connect other devices.
From HiFix
"Chord Electronics Mojo 2 Portable DAC and Headphone Amplifier"
Audio Sanctuary
Chord Electronics Mojo 2 Portable DAC / Headphone Amplifier
This product is also available at 4 unverified merchants.