Mine are 19xxx as well, and I just recently got them.
Definitely an annoying peak at around 6k, but bass is pretty nice IMO.
Only got around 130 hours burn-in on them, and probably a good 100 hours of just listening to them so far, perhaps it changes with time.
(Oh, I also tried the Fostex HP-A8C for 3-4 days with the HD800's, and alltho the DAC seemed good I felt it could not drive the HD800s very well, especially the bass response seemed too thin.)
Thanks.. so what is your current favorite dac/amp to be paired with HD800?
I am interested in Luxman because it's much cheaper here as well.