tube amp will drive von schweikert VR4-jr?

I think these speakers like power. I've tried all sorts of amps and they always seem to come alive with more power. Tubes are great with them. They sounded terrific with the VTL 450 amps (tubes) and the Parasound JC-1 (solid state) both similar power, 400 watts. They sounded a little weak with the Pass Aleph 2s (100 watts) and the Linn Classik (70 watts) Tubes, yes, but I'd look for amps with at least 100 watts if it were me.

I'm running my JRs with a BAT VK60 for the moment and it is working out extremely well. No signs of compression or strain, even at moderately high volumes.

Being only moderately efficient, I think the speakers can benefit from being fed more power, but they do very well with less. They manage to make do with what you give them.

The Stereo Times reviewer used the Almarro A50125A with the VR4s, can give it a try.