@ozzy62 is right. You need a speaker in the 90db range for sensitivity. Klipsch heritage series are one option to consider. No direct experience with Omega that @rar1 mentioned, but full rage speakers are often a great option for tube gear. These often do very well in terms of imaging and midrange reproduction. The Omegas are crazy efficient at just short of 95db/watt/meter.
High Efficiency Options?
I’m thinking about assembly a pretty modest second system based on tubes. I think for a basic el34 amp most speakers 85db or higher would satisfy but I’d like to play with low powered tube amps. System will be in a small bedroom and I won’t use it to listen loud often, so I’m thinking anything in high 80db range will work. To give you an idea of my taste I use Harbeth c7s with Primaluna seperates fed from my Audio Mirror Tubadour and Auralic Aries. I don’t have a large budget for speakers, probably 1,000-1,500, and I’ll buy used. I have decent grasp of what’s available for the most part, but not really when it comes to high efficiency speakers. I know of Zu and Tekton but don’t find what I’ve read about them too appealing. Outside of those two I’m not really sure what’s out there in my price range. Any ideas or recommendations would be much appreciated.