Vintage DACs. Do they hold up over time?

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?
Alan

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

MARK LEVINSON No36
Wadia25
Threshold
Sonic Frontiers
Then both EAD's.

Cheers George