Probably a dumb DAC question

Not all tube pre amps sound the same and not all DACs sound the same[ some of us would say none of them do]. Look for a DAC with the kind of sound you like; I assume you did that with the pre. If you are worried about compatability check with the manufactor of your pre but in general about any will work together. I have tube and SS pre amps and have never had problems with the ones I have used.

From my experence with the Focal Titanium tweeter, I had Mini Utopias and my friend has Wilson Sasha, I would stay away from "hot" sounding DACs. You might look at the new Rega DAC, it has a choice of several filters which make slight differences in the sound according to what I have read. It has gotten good reviews and lists for $995.