@erik_squires for the Yamahas, the 2000 greatly influences the as 3200. With the AS-3200 by itself I do not like it. It has to be with the 2000. They go really good together.
I have not messed with any preamps for the Luxman. I figure for the price, if it's not good enough standalone then I don't want it. I am on the fence on selling my Luxman 595. I will eventually buy the MacIntosh 12000. I might sell it down the road if I find I do not use the Luxman enough. It's hard to give it up... it does sound better than other amps for Jazz music.