That does help, thank you. Never heard of HE-5LE's though, but looking them up right now they have much less internal impedance than the PC350's (38 Ohms vs 150). Reading around, it seems they require a fair bit of power to drive though; could that have to do with the sensitivity? I think...
So has anyone tried this sound card with some high (or medium) impedance headphones? I just picked up some PC350's (150 OHM impedance) and have been eyeing this sound card for a while, but not really keen on getting a headphone amp as well. I'm sure there's someone out there that's tried this...