I just wanted to weigh in here and say to all those who have low opinions of Class D amps and dismiss them outright, you may be overlooking their potential as a lower cost bi-amping solution for bass when looking for a solution for difficult to drive speakers. Even though you would never use them on the top end or as a single amp solution they do have cost effective applications on the low end, bi-amped.
I have never heard a hi-end Class D amp so won't offer an opinion on their musicality. I do have two Crown XLS 2500 amps (low end Class D amps price wise at $595) pushing the woofers on my Infinity Kappa 9's and even these really delivery on the low end. So much so I have considered upgrading to a better Class D amp just for bass. (Suggestions welcome.) I have mono class A tube amps on the top end that cost over 10x the Crowns and of course there is no comparison. But together they sound excellent and these inexpensive Crowns have helped me avoid having to spend a lot on a big Class A SS amp like a Krell or other high current amp that these speakers need.
I have never heard a hi-end Class D amp so won't offer an opinion on their musicality. I do have two Crown XLS 2500 amps (low end Class D amps price wise at $595) pushing the woofers on my Infinity Kappa 9's and even these really delivery on the low end. So much so I have considered upgrading to a better Class D amp just for bass. (Suggestions welcome.) I have mono class A tube amps on the top end that cost over 10x the Crowns and of course there is no comparison. But together they sound excellent and these inexpensive Crowns have helped me avoid having to spend a lot on a big Class A SS amp like a Krell or other high current amp that these speakers need.