Tacoboy

Any DAC can be part of a DAC/Amplifier setup for your Q701 headphones. What budget did you have in mind? What headphone amplifier did you have in mind?

I'm assuming this USB DAC is so you can get audio from gaming on the PC & PS3. The Astro Mix-amp. and Turtle beach DSS both come with optical input and can process Dolby Virtual headphone. You can also daisy chain an external headphone amplifier to then, if needed.