I have tried many passive, direct dac, and active preamp,and vacuum tubes do
Sound more realistic and natural per dollar then a solid state model ,there too there are exceptions if you gave the $$.vacuum tubes give you more bang for the buck.
Active gain stage on a good quality preamp over $3k has better detail and
Dynamic range when the volume goes up the whole performance should stay rock steady. I have listened to transformer based passive preamps that are very good
Like U.K based Billington and Steven's very good but over $4k.
Having the ability to operate a audio store while in Europe and play with all the options was very interesting. I have yet to hear a direct feed from digital converter
That has the slam and control as with a quality preamplifier, DCS Edgar another exception great build and sound quality but pricy.