Tube amp recommendations to drive Joseph Audio speakers

I second the Quicksilver mono amps! 

The Quicksilver amps used tubes penthode, the tonality ad clarity are not as good than tubes 300b or 2a3 but the power and dynamic are better.                              The Joseph audio speakers are not very sensible so it's a better choice to choose penthode amps.

How much power you need of course depends on the size of your room and the listening levels you prefer. Based on a review I read of your speakers by the Part Time Audiophile, he had good results with a Class A tubed amp that output 25W per channel.

The Quicksilver mono amps suggested above run a variety of output tubes to output more power than you might really need.

Consider this alternative. I use Quicksilver Mid Mono amps. 40 Watts but can run the EL34 tubes as well as others and in my experience, the EL34 tube sounds better than the likes of KT88 or most other KT based tubes.

The tubes are biased between pentode and triode and have a good balance of the merits of both. A huge bargain, these amps bested other more expensive amps I have owned. A pair of these would be well under your price point brand new.

I suggest the leanness you are hearing is likely from your preamp- notes from a review:

"Notes on Tonal Structure

I should note that the tonal integration of the Reference Two… the sense of "top-to-middle-to-bottom tonal balance and proportion" was very good. Overall, it’s my distant impression that this preamp does just a touch better with tube amps than solid state—the level of detail delivered to the wrong solid-state amp could definitely err in the grievous direction of dryness, which would be a real shame. High frequency extension was truly excellent; the midrange was neutral; the bass was controlled, though with perhaps a touch of leanness with the Linn Klimax."

The reason I believe this is that I had the XA25 with my Cary Audio preamp and it was too mid bass heavy - so I sold it.

Regardless, possibly one of the best sounding systems I have heard in my audio life is a set of JA Pulsars driven by a Rogue Audio RP-5 preamp and Stereo 100 power amp. Sound was punchy, super clean and refined. Amazing !