I would suggest that you need at least 100W with a transformer that can drive the bass woofer. I have a pair of JM Lab Alto Utopia and tried a few tube amps. Then I found that a hybrid amp is the best for these speakers.
I am happy with my Counterpoint NP100 platinum: 100W at 8ohm and 200W at 4ohm.
I am happy with my Counterpoint NP100 platinum: 100W at 8ohm and 200W at 4ohm.