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

I could not found any defects at all with my very resolving speakers of the NOS battery dac S.P.S. with a single TDA 1543 chip ...

The only people who criticize it speak about more "details" with other more complex architecture and i know for a fact that i hear all details there is with this dac but the organic musicality, the soundstage and imaging and timbre naturalness is spot on also ...

Then why these people spoke so much about way better dac than it because it lack "details" ?

I believe that most people with costlier system had forgotten that the house/room signal ratio level matter , EMI shielding matter too , that speakers resonance is there even if you dont know it and vibrations control is madatory , and i believe that they own system in a living room with not much acoustic controls if there is one ...

In the opposite all that is adressed in my system then i hear what this simple dac is able to do in optimal environment without the need to buy a more resolving useless dac... If i could and want to buyone i will buy only a more musical one and this will be hard and very costly ...

Upgrading often appear silly ...It is often the case when all three embeddings are relatively under controls with a relatively already good system ... I own one ...

There are other companies that build modern DACs around very old vintage chips because they sound better with such chips.  Most of the advancement in chip design has been to make them smaller, make them utilize less power and offer more functions that support there use in mobile devices--sound quality is hardly a priority.  Companies like Audio Note, Naim, and Lampizator horde old chips because they deliver the sound these companies seek.   Whether or not that is your sound too is a matter of personal taste; but one really has to hear such machines to decide this.

One of the things that seems to be a factor with older DAC's, besides their older chip design ( which may or may not be a detriment), is the inability of the older units to support the current connection protocols. For example, the DAC i am demoing has no USB connections. As a result, to connect it to most current streamers is not possible. This severely limits the usability of the unit. Apple are good at consistently changing their connectors in order to supersede and antiquate their older product line. This seems to be a factor here in digital audio as well.

Well folks, I ended up purchasing the Esoteric D-05. It occurred to me that the lack of USB connection, for my circumstance, was really not a big deal. 

Here's the thing, comparing it to a friends almost new Benchmark, the Esoteric essentially ran away in the SQ department and was an eye opener! Possibly due to the synergy with my Esoteric SACD player, but nonetheless, a significant bump up in SQ. Plus, the Esoteric DV60 was no slouch to begin with! 

So, to conclude, it is not always the best way to go with the newer DAC, clearly depending on price paid.