Are "vintage" DAC's worthwhile, or is this a tech that does not age well

Just ask yourself the question whether you would buy a 15 year old PC: there is your answer....

....most likely no asynchronous and certainly no high speed USB, no precision clocking, no DSD or high res decoding. All of this matters because you ideally want the DAC to slave the source to minimise jitter.

@devilboy 

yes, you read it correctly. You would however forego the opportunity to slave the server’s to the dac‘s clock as well as DSD and higher resolution formats. Using a OCXO or rubidium clock on the dac via USB has major benefits on the server. Alternatively there are reclockers for the USB connection only (e.g. Innuos Phoenix); they however do not benefit the dac.

My dac progression went from Audio Alchemy to Theta Pro Basic to Audio Aero Capitole 24/192 to Antelope Zodiac Gold +Voltikus to Zodiac Platinum + Audiophile Clock. They all were converting bits but they don‘t sound the same.

@minorl 

you make a very important point: the analogue section of a dac is actually a preamp. In most cases a simple attenuator will suffice to regulate volume to the power amp. Ideally therefore, the manufacturer of the dac should include analogue rather than digital lossy attenuation. 

This might lead one to conclude that rather than endlessly speculate on delta-sigma vs R2R technologies as well as the merits of various DAC chips, more focus should go to the quality of the analogue stage. 

It would be very interesting to analyse DACs with a digital out via a reference preamp vs their own analogue stage. While one would still have to speculate about the implementation quality of the digital out- and inputs as well as the cable, it would become a very worthwhile route to better focus on the analogue stage, which after all is the source of most RFI/EMI as well as ground level distortions in dacs.

If there ha been progress in DAC technology in the last few years, it hs been in the quality of clocking and the implementation of I2s or USB ports. The basic chips or ladder designs are maature. That said, significant progress in these 2 areas has material benefits. A well designed asynchronous USB port with high quality clocking (whether OCXO or Rubidium) through the slaving of the server/player is clearly superior to synchronous implementations of yore.