I tried The MA6900 with my 805s and tried real hard to like it but went with the Sugden Masterclass and am very happy.
The Accuphase E530 is equally pleasing.
The MA6900 a fine machine and you may be very happy with it. The equalizer would be fun to play with. The hyptnotic good looks and tank like build always attracted me.
The MA6900 on ebay always gets alot of bids so you could sell it in a heartbeat for $3,000.
Have you tried the MA2275?
By the way I noticed a huge improvement removing the grills on the 805s, like opening a window, dramatic difference.
The tweeter grills are held on with magnets and pull off with a slight tug.