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

@jacobsdad2000  The DAC I am demo'ing has no usb connection, because it is too old! This will prove to be a considerable detriment to usage as it cannot really connect to today's better streamers, along the lines of what you post. It does have Co-ax, which I am hearing differing things about, some folks tell me that Co-ax sounds worse than today's USB, others better?? Nonetheless, since the better streamers use usb only, it is not a connection option. 

.... some of the lowest price DAC’s are to be had from yesteryear.

WRONG

And many new cheapies out perform most of the 20th century designs.

Only for enjoying music.

@daveyf Hey it's what works for you. Digital wise I have used them all and AES/ Balanced, Optical, USB and SPDI/F Coax, key is use a good 75 ohm cable.  Signal makes some fine digital cable as do DH Labs. Better yet buy used. Look here and on USAM. 

Lots of DAC threads recently.  I agree, the better new cheap DACs are better than the esoteric from only a few years ago.  Much has been learned in the filters implementation. 

Based on my listening, all the Chinese mass-produced DACS are excellent and all sound almost the same. Splitting hairs. Just returned a Qutest as it is more detailed on only a couple tracks, but edgier than my JDS, Topping, Schiit, SMSL, and Sabaj DACs. 

I don't know what is different if you jump to the $4000 and up range or if you have access to true DSD or ultra high bit rate that actually has more information, not just the format. Almost all of my music is old enough to have been mastered on tape, so there is no such thing as highly detailed.  

The above is for just listening, If you want to get your microscope out and look for the tiniest of details, then you will find them.  I have a new test.  If I listen to a piece, walk out of the room and something is changed, or not, and I come back in, do I hear a difference reliably? If not, any difference is irrelevant.     If you goal is ultra perfection, audible or not, or bragging how much you paid, then none of this matters.  If I had to buy another DAC,

PS: Older DACS with only SPDIF rely on the host clock. Newer DACs with USB, if well done, use the DAC clocking which can be far more accurate.  A "good" DAC will have  a galvanic isolated USB to prevent any host or cable interference.  The Qutest does, as do the newer Schiits. 

Excellent post and i concur with your experience...

Most people had no idea about the acoustic concept of timbre for example and the conditions of his experience in a room ...

Then when we dont know by understanding and experience what is "timbre" acoustic definition and perception what can we do ?

We focus on "details" for the sake of details as a alleged  meaningful artefact induced by the dac superior design ,  not on our controlled experience of "timbre" in the relation between our ears/speakers and the room and we forgot that the dac/ amp is only a small part of this experience so important they could be for sure  ...   ...

We focus on gear then  and on upgrade at all costs and we are the ideal candidate victim of mass market because the price tag  will  always tell the story for us , not   the acoustics basics and learnings and experiments so impactful they could be  ... And anyway other embeddings control may impact way more than a  dac, if this dac is already good to begin with , as the ratio of signal/noise in the house/room or the speakers vibrations and resonance ...

Lots of DAC threads recently. I agree, the better new cheap DACs are better than the esoteric from only a few years ago. Much has been learned in the filters implementation. Based on my listening, all the Chinese mass-produced DACS are excellent and all sound almost the same. Splitting hairs. Just returned a Qutest as it is more detailed on only a couple tracks, but edgier than my JDS, Topping, Schiit, SMSL, and Sabaj DACs. I don’t know what is different if you jump to the $4000 and up range or if you have access to true DSD or ultra high bit rate that actually has more information, not just the format. Almost all of my music is old enough to have been mastered on tape, so there is no such thing as highly detailed. The above is for just listening, If you want to get your microscope out and look for the tiniest of details, then you will find them. I have a new test. If I listen to a piece, walk out of the room and something is changed, or not, and I come back in, do I hear a difference reliably? If not, any difference is irrelevant. If you goal is ultra perfection, audible or not, or bragging how much you paid, then none of this matters. If I had to buy another DAC, PS: Older DACS with only SPDIF rely on the host clock. Newer DACs with USB, if well done, use the DAC clocking which can be far more accurate. A "good" DAC will have a galvanic isolated USB to prevent any host or cable interference. The Qutest does, as do the newer Schiits.