I had a VTL ST-85 power amp for a few years, & used it in roughly a 10x10 office room with fairly efficient speakers. It only had so much power, & pretty much "crapped out" in a larger room, or with less efficient speakers, but it had it's tube-y charms.
As far as: "an occasional hardness in the treble(at louder levels)and wouldn't mind a little more warmth in the midrange", if VTL gear isn't giving you enough warmth (!?), I'd look for a diff. brand of speakers, like Merlins perhaps.
Or go to a SS amp, & stick w/Dynaudio's.....just my 2cents.
As far as: "an occasional hardness in the treble(at louder levels)and wouldn't mind a little more warmth in the midrange", if VTL gear isn't giving you enough warmth (!?), I'd look for a diff. brand of speakers, like Merlins perhaps.
Or go to a SS amp, & stick w/Dynaudio's.....just my 2cents.