I tried this with a Wadia 321 also, but had bad results. I think I got a bad one, because it just was not right. It was just missing depth, size, punch. I returned it.
Then I went to a Schiit Freya+ preamp (no DAC). It was decent, but I ended up selling it.
Currently I have a mid 90’s Wadia 15 DAC that is going directly to my Pass XA60.5s. Call me crazy, but I prefer the Wadia 15s DAC to the Bryston BDA-1 DAC that it replaced. I should say that I only listen to 16/44, so Qobuz and Tidal won't work here. I am very pleased with the results, but I think long term I will return to a preamp in the chain. Probably Audio Research.
The Wadia 321 really did look the part. Very nice looking piece of equipment. Yes it does have a large footprint as mentioned above. Think a large pizza box. I still scratch my head on why this didn’t work out.