Damn it... I just PM'd you right before I saw this. I'll have my simplified thoughts and info the on the parasound d/ac-1100 and transdac up in a bit.

I think anything that's no longer in
How old does it need to be to be "vintage"?

How old does it need to be to be "vintage"?

Meh, it doesn't really matter. The focus will probably be on vintage stuff, but if there's some cool newer multibit DAC worth talking about, feel free.

How does it sound?

I stayed up way too long searching eBay for dacs from that list 

If we think there is correlation between DAC chips and good sound (PCM63?) that list could easily be narrowed down.

There is, but to some limited degree. There are quite a few variables involved. Filter and output stage design can make or break these old dinosaurs. In general, Ultra-analog 20400A/PCM63/PCM1702 DACs means that *at least* the DAC itself won't be the limiting factor.

Some older DAC chips have been out of circulation for so long and/or have had such infrequent implementations that it's hard to say just what role the chip itself is playing in the overall sound (ex. the old Crystal DACs in the Angstrom 200, the PCM67 hybrid chip in the Theta Basic, Prime, and Progeny, etc).

I've spent a bit of time buying, reselling, and occasionally keeping DACs using that list. I use the original version here http://www.dutchaudioclassics.nl/the_complete_d_a_dac_converter_list/ - the site still updates it as new information comes in. Sometimes DACs that you'd expect would sound good based on their chips sound pretty rough (ex. the Denon PCM1702 DAC). Others sound decent on their own, but need mods to shore up a deficiency or tighten up the sound (ex. the Adcom GDA's). Some surprise you with just how good they are *despite* a DAC chip that's less well regarded or really not mentioned at all (ex. the Assemblage 2.6 that I heard, with it's PCM1704, surprised me because to my ears it lacked the general 1704 "syrup" or "softness" that gets mentioned around this site; the Theta DS Pro Progeny sounds great out of the box despite it's budget PCM67 chip).

I guess what I'm saying is that it's probably a good idea to stick to dealing with vintage R2R's on a case-by-case basis. That list - while a great resource - is a bit of a pandora's box.