@bluethinker - Nothing but love for the VK-255SE. I used tube amps most of my life (now 70). Audio Research Classic 60, VT-100, VT-100 Mk-III, two Almarro low-power amps. I've concluded that tube amps, as good as they are, tend to homogenize textures making things too smooth sometimes.
The VK-255SE does everthing I want, is not crazy priced (used) and mates well with my VK-33SE. Read about the design of this amp on BAT website for more info. They say converting to mono doesn't increase wattage much but doubles the current. Would like to hear that sometime. Thanks