Best pre-owned 2-channel amp for under $2000??

Ok so I really could use some help directing me to a pre-owned 2 channel solid state amp to replace my Adcom GFA 555. I am open to the newest generation of Class D amps, but that would be a new purchase, most likely, and I am trying to stay in the used market for value and price purposes.

I have an Integra DHC 9.9 pre/pro, and I listen to alot of rock, blues, jazz, and female vocalists, on CD. My most recent - and largest investment by far - the Dynaudio Contour S3.4s, which I purchased new a year ago for about $5K, seem like they are asking for more and better sounding power.

I was considering the McCormack DNA-225, or the Classe CA-300, which I am sure will be a noticeable step up, but I would like some additional recommendations that more experienced audiophiles might have, based on what would pair best with my existing gear. I need to keep it under $2000 (used), and preferably closer to $1500. Thanks!

Fred