Hi guys, I recently purchased 2 headphones: the Massdrop Hifiman HE4xx and the Beyerdynamic DT 770 Pro (250 ohm). I also got the O2 amp from Massdrop. My soundcard is the Asus Xonar DX and I work on Windows 10 x64 Pro. Now the questions: 1. What standalone DAC under 250$ would you get for listening to music and playing computer games that would pair well with those components? 2. I don't know how a DAC works in terms of connectivity. As far as I know, the DAC is connected to the PC via USB, and my question is: should I disable my PC soundcard? Will the DAC ignore the soundcard? Would the DAC benefit if I have the soundcard enabled? Thanks in advance..