So I am looking into headphone amps and have my eyes set on the e9. But how exactly do I set it up with my desktop? Do I need to have a line in on my sound card? I currently have the XFI titanium Fatal1ty Pro which only has the 5 analog inputs for 7.1 speakers, but thats it. Does the e9 simply go through the USB? Or am I going to need a sound card with line in ports?