In answer to several questions, I compared a single DNA 1 Deluxe to a single DNA .5 Deluxe. Both had Cardas speaker posts and the usual internal upgrades of the deluxe package. The only difference in the two amps was the 1 had Cardas input RCA's and the .5 had WBT input RCA's. I have used McCormack amps for a lot of years. I have felt and still feel there is a slight degradation to the purity of the highs as you go up the DNA line. Yes, there is a power difference but it really doesn't show that much. You have to double power for a 3db increase in volume. The DNA 1 being 185/ch and the .5 being 100/ch. So in absolute terms the DNA 1 would play louder. Other than the high frequencies, these amps sound very much the same. I always felt the micro power amp sounded the best through the mids and highs but it didn't have the bottom authority of the bigger amps.
In comparison of a single DNA 1 to a biamp pair of .5's, I take the .5's hands down everytime. To me, it just sounds better. But I'm sure there will be conflicting opinions(aren't there always?)
I also tried the SMC revision A DNA .5. It is a very nice sounding amp and I'm sure a lot of folks would like it BUT for the money, I'll take the Deluxe.
As I previously said, I do not like the newer McCormack's as well. I really think the input DC blocking capacitor in the signal path imparts a slight grain to the sound.
The quick bottom end and sonics of the McCormack's really match the Vandersteen's well. You could spend a lot of money and only make a VERY small improvement. One amp I'm really wanting to try is the Theta Dreadnaught on the Vandersteens. Heard it in a store and perked my interest. Got to hear it in my system before I can really say anything.
BTW---in my last post, that was suppose to be HIGHER powered Mccormack's. Hope the spell check guru's don't hit me!