I am using a Consonance Cyber 880i tube amp. Rated at 100W with KT88’s but mine has KT120’s and not sure how much that would affect output. My Spatials are the Triode Master version (M3) so designed for (but not limited too) low power amps.
Keen to hear your impressions of Spatials if you do go down that path. As always, best if you can try them at home with your own gear/room to see how they sound to you.
I heard those speakers at last year’s RMAF. One of my favorite rooms.
The efficiency rating on Spatial M series speakers is a bit misleading and requires that you read the fine print. That stated efficiency rating is only for frequencies above 200 hz. I have never been satisfied with my M3TS’s or TM’s with lower powered amps and that includes 40 wpc ones. Closest was the Rogue ST-100 but too much heat for me. They like power especially if you are using them in a room much bigger than a spare bedroom. Just my opinion after three years of ownership starting with the M3TS’s.