User 211, consider one of the higher powered Rowland amps for your Duettas. I lived with a pair of Divas for thirteen years, initially driven by a small pair of Rowland Model Ones and later an 8T which I still use with my Summits though it may be a waste of power. It is true that Krells drive Apogees well but that is not exactly the same thing as a a synergistic musical match.