I use a Cary 94 preamp with their 2A3 Monoblocks and the upgraded Bel-Canto Dac-1. I tried several hi eff. speakers, 90dB, 92db, 94dB, sound was OK but the 2A3's did not do their magic until I switched to a 98dB or higher speaker. I use a Klipsch KLF 30 tower speaker 102dB. If you can, demo your speaker selection first with the 2A3's.
Good Luck, let us know what you do.
Good Luck, let us know what you do.