I don't know much about the DNA-500, other than its good reputation. I wouldn't, however, include an Ayre in the mix. While, IMHO, good sounding amps, they seem to have difficulty with complex speaker loads and can sound clean and extended, but somewhat constrained. I am told that they use smaller power supplies, which limits their applications. With easy-to-drive speakers, they sound great though. I think it will be very difficult to surpass the huge power supplies used in Moon and Pass amps. Although an older design, check out the Rotel RH-B10 "Michi Series", if you can find one. No relation quality-wise to what they build today. They're extremely rare, sell fast, and sound amazing, though not quite up to the league of the Moon/Pass. However, I would put the B10 ahead of the Ayre. Again, it's all relative to what kind of sound you want.
