Looking to upgrade amp, need help.

I am currently looking to upgrade my amplifier. My current system is:
Focal 836v's
NAD C375Bee
NAD C546 cd player
Project debut carbon with Ortofon 2m bronze

I listen to both vinyl and CD's. Mostly classic rock but also a wide variety of music at times.  

My budget is $1500-$2000, probably purchase used to get more bang for my buck. I don't have a preference between SS or tubes, but don't have experience with tubes (but think they would be a good match for the Focals).

Any input is greatly appreciated!!

Thanks,

Joel