used Integrated tube amp under $1500 for Klipsch Cornwall III's?

I would place it on the piano.  You run the risk of the tubes picking up the vibrations from the speakers and feeding back when on the speaker (microphony).  Some amps are more susceptible to this than others.  

I have used my Decware mini torii 4 wpc with my Klipsch Quartets and they rock, almost too loud at times.  The decware is very well built. Not flashy finish but not cheap.
I also used a Grommes PHI-26 2/6 watt with the Klipsch and sounded great.

the piano is for show
its not that I don't like the fortes but I want to experiment, a pair of mint  used cornwalls became available at a good price

interesting that many people are recommedning both for and against low powered set's
at some point i will try both

Decware as I mentioned, and others on this thread, is excellent sounding gear. It may look utilitarian but far from cheap. If great sound, synergy with your speakers, pickup the phone and speak with builder/designer, and lifetime warranty - may not be your cup of ☕️

Keep in mind, tubes are microphonic, both mechanically, and acoustically....