This may be of little help, as the MA 6500 and 6900 are different animals indeed, but I had the 6500 and a 400xi in my system recently, and found the Krell much more dynamic, but sometimes to a fault (little midrange bloom). That being said, I upgraded (IMHO) further to a used Musical Fidelity Tri-Vista Integrated, and for the same price of a new 400 or 6500, it is in a totally different sonic league, in my system. Not colored, laid back nuetral sound. Not sure of the relation of MF with Wilsons, but I would not write of the upper-end MF integrated gear. Good luck. BTW, I like the Mac sound as well - yes, it is colored, but it's all in what your ears and mind enjoy. My old MA5100 is a gem coupled with an MR65 tuner.
Krell 400xi vs. BAT VK-300x vs. McIntosh MA6900
I'm considering 1 of these 3 excellent Integrated Amplifiers to power my newly aquired Wilson Sophia Speakers. My Source Component will be either the Krell Standard or BAT VK-D5. Installing in a mid>large size living room. I'm looking for a smooth, full/robust, easy- on-the-ears sound. I'd rather not have to buy all 3 for an at home a/b/c audition, though I know that this is the preferred method of evaluating Components. Thought that I might give this post a try, to at least narrow it down to 2. Thanks!