What interconnect are you currently using and off the top I would say your preamp is the weakest link, I had the 3800/A65 combo for quite awhile with WW Platinum Eclipse 7 cables. Id try a Audio Research Ref 5se or Ref 6 se . Preamps are the heart of any great system and that great A75 u have will tnk u.
+1 Audiolabyrinth
+1 Audiolabyrinth