So I just got the HD6xx and the Schiit Heresy and Modi stack. I put in my RCA cables from the Modi to the Heresy and then plugged in the usb from the Modi to my pc. I plugged the headphones in and everything sounds great. However, there is this static and some pops in the left driver of my headphones when I'm using it. I don't want to jump to conclusions and think I have a faulty unit so I'm wondering if something is wrong with how I set everything up.