Best amp for Sonus Faber Amati Homage?

From what I know, the Krell mates very well with the speakers. You may need to try changing the speaker placement.

The only amps that i have heard that make the Amatis truly sing are CAT JL-1 monoblocks....these tube amps are magical!

My Electa Amator IIs are beautiful, fast, and musical mated with my Edge NL-10. At 225/side w/plenty of high current muscle, the low-end is tight and low (they're acoustic suspension).
This is a special amp, a Golden Ear (TAS) winner a year or two ago. For about half, you can have an M8M, with less power and a tad less musicality. There's one of each currently listed on A'gon (one at auction).
I am no way connected w/the company or any models for sale...). Oh, they are also the most beautiful ss out there (the two brilliant crimson lasers of the NL-10, as seen through the clear acrylic top,are VERY cool).

I would try and get a listen to the new CJ Premier 140 monoblocks with these speakers.

Are you aware that any Sonus Faber speaker is very touchy to room placement? A good starting point is to make sure their close together. I find that all Sonus speakers like to be closer together than what your probably used to doing. They should be closer to the centerline of the room than to the outer boundaries on the side walls. Beautiful wood grain finish on those speakers.