When using a speaker in the low-mid 80's sensitivity region, I prefer at least 100 watts/channel. Interesting phenomenon: It doesn't take much power to drive these at relatively low volumes, such as casual light listening. About 5-8 watts/ch. BUT- if you prefer to listen even at moderate levels, soaking up 20-40 watts per channel is easy. That means for good sound some headroom is required. No less than 80w/ per channel and ideally 100. You can get by with 40 watts/ch, but it could sound flat and lifeless when power demand increases.
Yes, I know you said a **tube** amplifier only. This can be done with 100 watt mono blocks ideally. However, the more economical approach is a hybrid system.
