There are a couple of Llano tube hybrids for sale on audiogon at this time in your price range, these will have no problem with your speakers. I don't think you can find a pass X-250 in your price range but I do agree as to it being a good choice. Plinius would also be a good choice but again hard to find at your price. Some people (not me) think Classe amps sound like a tube amp, maybe that would do it for you. I have a Krell Ksa-250 on my Supertowers with a Bent Audio passive for preamp, not tube like but very good midrange and soundstage with the passive in the mix.
Dave
Dave