Ooooooh! How was the Bottlehead DAC? Do you know if it was close to production? How about the prototype amp?
I really enjoy my Innerfidelity (Anaxilus) modded HD800s out of my Bottlehead S.E.X. and have been really curious about a possible super amp and matching DAC from them.
The Bottlehead DAC was very good. It is close to production, but he did mention possibly switching to a different chipset than the one in the prototype. The DAC sounded warm and musical, and resolving - definitely a good match for the HD800. The amp is very neutral sounding to my ears - it allowed the DAC to shine through. The amp is very well built with high quality parts and versatile connectivity (balanced and single-ended, switchable high/low impedance, stepped volume, etc.
You can find pictures and some more comments about them at the Seattle "quattro de mayo" impressions thread.