I am considering pre-owned 5-channel amps from all of the above brands. The intended speakers are Dynaudio 52's (L+R), 122C, and surrounds to be defined (must be in-ceiling). The pre/pro will likely be a Rotel 1066 or a B&K ref 30. Any comments on the above choices for amps? Any others to add? Would like to spend under $1000 on the amp (Rotel 1075, B&K AV 5000, etc.), so I will look to pre-owned.