So I've heard good things about the sound quality of NFB-11. However, I've also heard a lot of reports about problems with the USB drivers in Windows. Does anyone know what particular USB chipset the NFB-11 uses? Other Amp+DAC units I'm considering list the specific chipset they use, for instance the Schiit Modi 2 and the Lovely Cube, both of which use the C-Media CM6631A which seems to have better driver support than whatever the NFB-11 uses. I'm really conflicted over which to choose between the NFB-11 and the Lovely Cube. Then there's the NFB-15 as well, which further complicates the decision. I guess I like that the AGD models provide SPDIF connections, whereas the Lovely Cube only supports USB and analog input. However, if the AGD devices have shoddy USB support, that is also quite undesirable. Does anyone have experience with both the Lovely Cube and the NFB-11 (and/or NFB-15 as well)? I'm looking for an Amp+DAC to drive a pair of Sennheiser HD 650 or 600 headphones. Of course, even the headphones choice is a decision that is confounding me a bit, since the HD 600s are also very attractive (and cheaper). I may have to give them both a trial. However I'd like best possible amp for the job so both of the headphones I'm interested are properly represented. I expect either pair would be a substantial upgrade from HD 555s I'm currently using, unamplified and driven by an onboard Realtek ALC898 chipset. Someday I'll probably try my hand at building a Bottlehead Crack (which will pretty much render the HD 600 vs 650 choice I make now moot, since I hear either pair sound exceptional with the Crack), at which point I'll also get a new DAC and move whichever Amp+DAC I choose now over to my Harman/Kardon AVR 1700 which has absolutely horrendous headphone output.