I'm coming in later here and I've not read every post.
I also have the D9.2's and run them off my C2700 and MC275 like you and frankly they are disappointing in my room. What I'm getting is a very detail but tipped up presentation the tweeters are just to hot IMO. they also do not play well at lower volumes. They are lacking in bass at lower levels and don't really come on song until your up above 75db. I find them very picky on position as well.
I'm going to try different tubes in the MAC's as i feel the stock tubes are rather bland sounding maybe a bit bright too and that's not helping the hot top end of the D9.2's. I know new production tube can sound like that so i'll hunt down some nice NOS 6550 to try.
But over all they do some great things in the midrange and soundstage but bass extension and tone are not really there and the top end is IMO too hot.
Note I have a very difficult room so many of my issues could be the room. as i demoed them in a fully treated room and they sounded significantly better in that room.
Glen
