Best Vintage Dac??

Museatex Bitstream is my fav DAC. About 25 years old. I purchased it few months ago and enjoying it very much. 

A vintage DAC is not something you might want.  It was in its infancy and had many problems in the early years.

Museatex Bidat or Bitstream dac.  I will never get rid of either of them.  The Bidat is in the main rig and have been using the Bitstream on the cans.  

genez and infection: sure, modern DACs have impressive numbers on paper. However, the best SOUNDING dacs are all vintage. Here they are:

Forsell Air Reference, Melos MAX-1, Meitner Bidat, EAD DSP-9000, dcs Elgar plus, Levinson 30.6, Theta Gen.VIII, dcs Delius, Sonic Frontiers SFD-2, Metronome C20 Signature, Theta Gen.5, Nakamichi Dragon.

Some good modern DACs:
Nagra HD-DAC (if you’re not on welfare), NAD M51 (if you are)

I would highly recommend looking for Audio-gd DAC-19MK3.
About 10-12 years old now.
It uses the now unavailable  micro DF1704 digital filter and PM1704UK chip set. It sounds terrific. Very musical!
Good luck.