SRT710You need a DAC (digital-analog converter) with a USB input. It converts the digital USB signal to an analog signal. You then connect the DAC to this amp using RCA interconnects. DACs can be found at all different price points, ranging from under $100 up to $30,000, if not more. For this amp, I probably would look for a decent but inexpensive DAC from Audio-gd or Schiit Audio.
TomomoI already use chord Mojo, I think you're wrong, each stage influences the quality of the audio, if you use a better DAC you will get better results.
Alberto_TSure each stage affects the audio quality but thats not the question he asked. Your answer gives what would be an UPGRADE to what he has now... He asked how do you plug it in to a pc.