I've been running the same setup for around 2 years and suddenly after restarting my computer I'm having an issue. My setup is Computer USB port->fiio e7->Hifiman HE-300. I've tried several USB ports to make sure thats not the issue and plugged in the hifiman to the direct headphone port to make sure its not a headphone issue but using the USB->E7->HE-300 setup Im not getting any sound transmitted. Ideas? Update: The E7 wont work in a iPhone->E7->HE-300 or iPod->E7->HE-300 configuration either. Update2:Fixed it by shoving a paperclip into the reset hole.