How different between B&W 804s & B&W 805s????

I think that is the right way to go. Please let us know what you think of the 805 with the new amp.

I've heard MA6900 pair with this 805 before at a hifi shop. It sounds amazing even the room is big and room acoustic not so good, I believe MA6600 can do better than that. Once again thanks all of you for sharing experience, i'm sure those experience cost you alot of money in the past

I currently use a Mac MA2275 tube integrated amp with a pair of 805s's and a TAD subwoofer in a large 20'x 27'room. Being a log home all the walls are (naturally)wood with a carpeted floor. The sound is excellent and there is plenty of volume available. I run the speakers direct with no crossover. Driven by the preamp outputs the subwoofer with crossover set @ 45hz is only for fill at lowest octave and is virtually unnoticeable it does not color the mid bass at all. I was never really a B&W fan but these speakers lack the brightness that in the past characterized B&W speakers to me. Female vocals are exquisite. The 804's on the other hand sound congested & boxy to me lacking both the smoothness and open sound of the 805s's. I originally auditioned both speakers driven by a C220/MC275 combo in pretty good dealer showroom. Hope this helps.

I run the speakers direct with no crossover.

What do you mean by this Gerald?

BTW, I am a fellow log home owner.

I have 805s's and originally ran them with a marantz sr8001 untill i put the money together for the MA6900. That was a huge jump for me and by far the equiment upgrade that stands out in my memory as having the largest effect. My marantz AVR has nice bells and whistles for home theater but just didnt do it for 2 channel. I continue to struggle with the pros and cons of either trying to integrate a sub vs full range speakers but I echo the others who suggest that your weak link might be amplification. (Mine was anyway...)
I have since moved on to seperates but still remember that MA6900 fondly. I hope that you enjoy yours as much as I did mine.
On the cable front, I tried about 6 or 10 different choices from the cable company in the US. My fav's for the ma6900 / 805s combo were Purist Audio Design.
Good Luck!