I got this amp recently.
It is very nice!
Powers the Hifiman HE-6 very well.
A bit surprised there isn't more information around here on the NFB-27... Audio-gd seems very well regarded, and this is one of their TOTL pieces. I loved reading Clem's impressions and feedback-- anybody else feel up to sharing their experiences?? Don't hog all the headphone heaven for yourself ;)
I recently went a bit over the top and purchased an Abyss ab-1266. It was either that working with the nfb-27 or a Stax sr-009 with an electrostatic amp. Since my desk space is limited as is, I decided to give the Abyss option a try, hoping that the nfb-27 would be adequate to power these monsters.
I got some unfounded criticism in other forums regarding the pairing, however, I must say that my ears refute such criticisms.
The nfb-27 powers the Abyss very very well. The overall sound quality is amazing and the bass is very powerful and accurate (speaker like).
My respect for the nfb-27 has grown after this experience.
The headphones that have paired well with the nfb-27 (in order of pairing preference) are:
1) Abyss ab-1266
2) Sennheiser HD800 / HD650 (equally as good overall with different pros)
3) Hifiman HE-6
4) Beyerdynamic T1