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

whether it’s worth looking into old dac such as
Spectral SDR 2000,
Mark Levinson No.35 (36)
or so Sonic Frontiers Sfd-2 Mk2 DAC.

Digital audio is the fasted moving, now improving category out there
Because to this day they have no usb connection or other options.
But is it necessary?
Or is it better to still focus on a truly time-tested sound?

(sorry for my English)
Classic Statement , 
  In controlled A/B tests nobody can distinguish a $100 DAC from a $1000+ one. Try a PeachTree DAC It.  to a  low priced Schite Audio DAC   many examples Borris,  listen to a Audio Quest Dragon Dac to a  Small Beater 
And a Good day to you Sir 

What dac you have that uses the 1543 chip?
I wish I never threw away my casette tapes😃

What dac you have that uses the 1543 chip?
A french dac  with an internal battery,a NOS one, designed by Christophe Mariac, bought on EBAY... Starting point systems dac....

Look for one used anything below 200 bucks will be the right price...
About 10 years ago I purchased a NuForce uDac for my 2011 MacBook Pro. I distinctly remember it sounding much darker (and worse) than the internal dac on the Mac.

Fast forward to about a year ago. I purchased an Emotiva BasX Stereo Dac Pre something or other to try to replace my Oppo-BDP105d + miniDSP + UPA-200 combo. Again, it sounded “dark” compared to what I was used to with my current setup. 

In that case it could have been the optical input or the amp, dunno, but it sounded distinctly worse than the pricier separates. Even my wife chimed in that it sounded inferior and she liked the idea of a net profit from selling audio gear. 

Poorly designed dacs sound poor I guess. 

Why anyone would throw a ton of money at a dac at this point is anyone’s guess. The specs I see on even $200ish dacs are better than my Oppo’s at this point and with multiple outlets testing equipment these days instead of just word vomiting audiophile speak, you can visually see if what you think you hear lines up.

I’m considering picking up one of these $300 Topping or SMSL units to see what the fuss is about with DSD and MQA. Formats are kind of a wildcard I guess since it’s about what they’re converting not the hardware used to convert. It’s inconvenient because Tidal is built into the Oppo and easy to control from an iPad, but I’d like to know if these newish formats actually improve the listening experience.
As an aside, the Oppo has paired perfectly with everything I’ve ever thrown at it from tube pre’s/amps to tube/ss combos and so on. Backbone of my system ever since it was released.