I have not owned the REF 50, but I have not been happy with B&K components that I have owned. From my point of view, B&K did very well with signal amplification, but not so well with component control & switching (preamp stuff). Anthem has a good reputation in the price/performance category, so I would opt for Anthem. I haven't heard the Anthem AVM20, however. Good luck.
B&K Ref 50 or Anthem avm20
I'm quite limited on good equipment where I live and it boils down to these two preamps. I am using the Anthem MCA5 and MCA2 for my amps and klipsch RF7 speakers. The two stores we have in town both have great sales pitches. I am hoping for some outside input on which would be better