Mike - Curious what you mean when you say "vintage". DACs are a somewhat newer technical development. "Newer" being truest, I suppose, relative to them as standalone devices. I usually associate vintage with something old...say, mftd. 25 years ago or more. Since DAC technology has been advancing rapidly, I'm not certain how well served you would be with a "vintage" DAC, whatever that means. Of course, giving an idea about your budget will help with better quality suggestions. Regardless, this link might be of some interest.
http://www.head-fi.org/t/404357/old-dacs
If small, affordable and newer is of any interest, you might find a device from Audioquest (Dragonfly), iFi or Schiit a good choice.
Good luck in your search.
http://www.head-fi.org/t/404357/old-dacs
If small, affordable and newer is of any interest, you might find a device from Audioquest (Dragonfly), iFi or Schiit a good choice.
Good luck in your search.