I use a Bryston BP6 with my McCormack DNA 0.5 Rev. A and it's extremely neutral and allows the amp to display all the 3D imagery it's capable of. Really just sounds like the proverbial straight wire with gain. Passive also sounds like an interesting idea. I was going to suggest Placette but not sure how it would compare to the much less expensive Schiit mentioned earlier. Best of luck.
