I would recommend auditioning these speakers with a different amp/pre combo. Even a Rotel would be a different world of sound for this level of B&W's.
Most Sony, even ES line, tend to sound harsh and un detailed with real speakers like B&W. I have a set of 804's and used to drive with a Yamaha rx-v 1500 receiver. Now am using an audio research SP-16 pre with a 20 year old Krell KSA-250 and listen to the stereo for hours. Bass is no defined and effortless Highs are now open, have depth and are detailed. If you have the money, its worth a try, you can always sell the equipment.
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