The new A21SE is rated at 21W but remember Class A is a different ball game.
May be a different ball game, but still not in the right ball park in my experience. Two of the SS amps I've tried with my 89db SR17's were class A. The Aleph 5 putting out 50wpc, and the Bedinie 25/25 putting out, you guessed it, 25wpc. Both class A amps. In a larger space both could put out a fairly satisfying volume, but if you ever wanted to push it with dynamic music, again the results were less than satisfying in comparison to more powerful amps. In a smaller room you may be fine. But I'd still say you'd be on the borderline. $3k+ is a whole lot to risk...I'd see if you can get to audition them in your system before dropping that kind of coin.
Marco