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

I have also heard dacs sound different from each other. I even had an old dac upgraded and it became much better.

Regarding the question I would guess that something like a ML dac that was very advanced for its time still sounds good. Maybe not as good as the latest equally advanced and expensive dacs. If you can get it for a good price it may be worth it.

On the other hands there are now dacs for $1k - $2k that are said to sound great. You would probably have to compare the old and the new next to each other to hear which is best and which one you like the best.

Here is an example of a somewhat affordable dac:
https://www.stereophile.com/content/okto-dac8-stereo-da-processor

If you for some reason don't trust Stereophile it also got a great review at ASR
https://www.audiosciencereview.com/forum/index.php?threads/okto-dac8-stereo-dac-review.14705/

Apart from ageing parts i do not see any reason for not sounding excellent in redbook. I bet a SFD2 can show a clean pair of heels and then some to modern dacs. And yes there is a big difference between a 5k to a 0,5k value dac.

G

Firmware Updates to CD/SACD/Blu-Ray players.

I typically update my camera's firmware, but for audio use of these?

I just bought a 2009 Oppo BDP-83SE (special edition, improved audio).

https://hometheaterreview.com/oppo-digital-bdp-83-universal-player-reviewed-1/

It has Firmware Updates, I suspect only for minor video issues. 

If all the initial reviews said very good audio, never found an audio 'problem' mentioned, why do/risk it?

Any recommendations?

thanks, Elliott

Why would it not age well? If you bought a cd player 10 years ago of good quality, it also contains a dac inside. If it still works, then what is the issue? Honestly, the only dac you need is the musical fidelity v90 dac. $299 and worth every penny. Sounds just as good as a $1000 dac. Small form factor, well designed, plenty of connection options, a burr brown chip, and it’s a stereophile class A component. To spend much much more on a dac is ridiculous. I've owned my v90 dac for 2 years now, it sounds wonderful. I use it in conjunction with both a Marantz hd cd1 cd player/transport, as well as with the audiolab cdt6000. I also have my grace digital internet radio connected to it, as well as my topping bc3 bluetooth module. Great versatility. 

Myself and two buddies had a DAC "listening test" at one of their homes.
All Rogue tube gear and Martin Logan with a USB feed from Roon.
Three DACs: Chord Qutest, Mytek Brooklyn+ and Bryston BDA-3.

Honestly didn't have to go past one track (Linda Ronstadt: What's New) the difference was so obvious.  Please don't bother trying to punch holes in the test or say it wasn't fair.  If your ears work you would have had to agree. BTW the order of DACs above was the way they sounded from
good to better to best. 

To the OP,  If you like the sound of an older DAC and you can be assured that it can be repaired if needed, then I say go for it.  Can't comment on any one in particular as I have no experience with them.

Regards,
barts