I believe most of the ones that are available use solid-state plate amps. I'm not saying this can't work well, but if you wanted to use a nice sounding tube amp you'd be out of luck.
That said, depending on the particular speakers, you might be able to use a decent sounding tube preamp to sweeten the sound a bit.
That said, depending on the particular speakers, you might be able to use a decent sounding tube preamp to sweeten the sound a bit.