As most people know, Im real anal about mixing...
But this is the one time I don't think a tube preamp is needed. For the simple reason, that if you sample from very old records, it was done with alot of tube and other analog stuff anyway. So I really don't see that much of an advantage. Matter of fact, a tube VST

, would not serve a purpose...
Just stick to a good phono preamp, plust the ASR converters have alot character.
Now if we are talkin about a regular preamp, now that is another story...