The AQ Dragonfly would probably be a good choice for what you're trying to do. They sell them at Best Buy, so if you don't like it you can always return it.
USB Driven DAC for 2nd System
I am currently using a Music Fidelity V-Link MK2 into an original MF V-DAC for my 2nd system. I use this system outside and set it up with each use. I am happy with the sound of MF V combo however it would simplify things if I didn’t need the Wall Wart power supply on the DAC. What might make for a equal quality USB driven DAC to replace the MF combo? I am looking to buy used and willing to explore market until a suitable replacement is found. Budget is <$300. Thanks in advance for your thoughts!