Tube amp recommendations to drive Joseph Audio speakers

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 !

The ARC Ref 2 I'm currently using was a big improvement on the solid state Classe preamp I had been using.  The Ref 2 I've owned for over a decade, it is definitely not lean tonally; if anything, it's slightly on the warm and "tubey" side.

I've inserted an Audio Research VT100 into this system as an experiment.  The VT100 is vintage 1995 or so but has been updated with new caps and a set of KT120 output tubes.  Sounds very good, but has more fan noise than I expected.

So at a crossroads presently.

FYI, Jeff Joseph recommends using an amp of at least 60 wpc for the Pulsars.

I’m using Lab12 Integre4 MKII. In the process of auditioning it, I also auditioned Lab12 Suara and Lab12 Pre1. They sounded largely identical to my ears. You can consider the Suara, although if I am you I would consider selling your ARC pre and getting the more expensive integrated Integre 4 MKII instead simply because it runs cooler and the biasing procedure is painless (took me less than 5 mins to bias 4 KT170 tubes with the built in LED screen). Lab12 stuff really deserves to be more well-known, their tube amps compare favorably with the best SS class A amps out there. They are some of the best amps money could buy.