DAC's from the past, are any of them really worth much today?

You are right in my book in spite of my  limited experience with dac ...

Current lower end DACs almost definitely have eclipsed a lot of the high end offerings from the past decades. The DAC is absolutely the wrong piece of gear to consider using most anything from the past unless one of the really high end and well reviewed pieces show up as a drop-dead cheap bargain ;-

 

cleeds,   

I don't listen to the "wrong material". I listen to what I like, not find music that shows of the kit.  I don't "train my ears" as some have suggested to find defects. A recording or mixing engineer would, but I want to enjoy music, not pick it apart. 

All of my music is Redbook.  I think I made it clear my analysis did not include true high bit rate original mastering. Don't have any. That may make a bigger difference though when demonstrated to me in stores, it did not. A 24 bit/192 remastered file of some worn out old tape or early digital is no better than a 16/44 as the detail is not there no matter how many bits you pad it with. 

Much of what I listen to preceded even Dolby A. 80 dB dynamic range about max on the masters, but likely less as the target was LP with only a 60 dB dynamic range.  Then mixed on boards that by todays standards would be bettered by a Berhringer semi-pro.  Even into the 80's boards were mostly NE5532's.  Then the first generations of digital. 14 bit Sony,  took a few years for the 18 and 24 mastering, as well as a big learning curve.  Adding the loudness wars where modern music has less than 60 dB dynamic range.  Let's not forget the pitch boxes.  Garbage in, garbage out even if you carry it in a gold plated bucket and wear rose colored glasses.  Fortunately that garbage can be totally involving music!

I do want to call out domestic small businesses that make the extra effort over chasing specs and actually listen to their products but don't add an ego price tax. Geselli, JDS, and Schiit for examples. There may be others.  They also provide support. Good luck getting that from China-Inc. 

I agree that DACs have made a lot of progress… but be careful. There is no question there are significant differences in budget DACs and high end DACs. Taking for example Schiit Yggdrasil as a budget DAC and >$5K (depending on exact brand) like Linn, Berkeley, Audio Research, etc. Real high end stuff sounds a lot more like real music.

As an example over the last week I compared Schiit Yggdrasil, Schiit Gungnir.  Linn mid range Selekt, Audio Research 9, and . The Schiit DACs were far inferior DACs. The treble was primarily high frequency hash, the brass not natural sounding and the bass, muddled together three bass line notes onto one. 

Aesthetix Pandora….. was and still is a giant killer….. HRS isolation, tube outputs, custom, FPGA filters, faraday cage, galvanic isolation…erc……. Jim White…. an engineer w ears….

We should talk about specific models and not in broad terms. For example, Dcs Bartok, even in apex variant (with R.Nucleus) is product that does not come close to Dcs Puccini (playing discs)...I think, like in many other things, (except perhaps with new d class amps) 'new is better' is only a marketing slogan