Vintage DACs. Do they hold up over time?

I'm talking about Dacs from the 90s that were well regarded like the Timbre tt-1, Sonic Frontiers SFD2-MkII, Threshold DAC 2,
Wadia 25, Altis Reference, Levinson 36, Meridian 566-20, EAD9000,
Kora Hermes tube dac etc.
The DAC's you list are very well made. They should continue to work for many years to come.
Hold up? Do you mean quality of sound compared to modern dacs or will they keep working?

If using them for Redbook cd (pcm) replay, then yes if they have true Multibit d/a converters inside.
As Multibit converters have "Bit Perfect" conversion for PCM (Redbook)
They will give better sound if good ones, than todays Delta Sigma based dacs can.

You can do searches to find if they have Mulitbit dacs or Delta Sigma

Cheers George

Had to kill some time so I did it for you.

TIMBRE TT-1 CS4328 – CS8412-CP is Delta Sigma

SONIC FRONTIERS SFD-2 Mk II 2x UA D20400A – PMD100 – UA AES21 is Multibit

THRESHOLD DAC 2 2x UA D20400A – PMD100 is Multibit

WADIA 25 4 x PCM1702-K + DSP is Multbit

Altis Reference is Delta Sigma

MARK LEVINSON No 36 4 x PCM1702-K – PMD100 – CS8412-CP is Multibit

MERIDIAN 566.20 CS4329-KS is Delta Sigma

EAD DSP-9000 PRO 2/4 x PCM63P-K – SM5803APT – CS8411-CP
EAD DSP-9000 PRO SERIES III 2/4 x PCM63P-K – PMD100 – CS8412-CP are both Multibit

Kora Hermes tube dac is Delta Sigma

My pick of these from working and listening to some of them.
For PCM RedBook CD is the

Sonic Frontiers
Then both EAD's.

Cheers George
I think the Vimak DS-1800Mk2 dac still holds up well even today. It is the one of the best Delta Sigma dacs ever made & was designed as an incredibly complex and heavy, all-discrete Delta Sigma architecture designed by the company which invented the Delta Sigma converter, as opposed to the current crop of miniaturized Delta Sigma chips. It was really a sight to behold, wrapped in a thick, heavy copper-plated aluminium chassis with copper-clad C-core transformers in a separate shielded compartment. It was also known to have expensive taste in transports ;) You can see photos of the Mk1 version here.
You surely forget the JADIS JS1 MK1 (tubes unit in 2 pieces), FORSELL DAC REFERENCE and also on a budget CALIFORNIA AUDIO LAB ALPHA. I am pretty sure they are still in the game despite they are nearly vintage ...
I'm still using my Muse Model 2. I do wonder what it would take to better it, other than a better Muse.
Theta has always sounded incredible.
Museatex Bidat?
My Threshold DAC 2 is still holding up just fine.
Still using a Dodson Audio DAC 217 mk 11 which still sounds very good. Was updated with the 218 software which did result in an improvement.
I used to own the Timbre TT-1, talk about a blast from the past, cool looking and good sounding piece. However my system then was a far cry from what it is now so I can't really say how it holds up. Worth checking out perhaps pretty sure I paid $800 for mine used in like 2002 if you can find it now can't imagine it would be much more than $500ish? Worth a flier at that price.
Melbguy1, the Vimak definitely holds up.
This year on Ebay someone was selling the Vimak Audio DT-1000 Transport & DS-1800 DAC for 2900$

This same guy is currently selling the Vimak DT-1000 Transport for 1600$