I've spent quite a bit of time listening to the various B&W speakers over the years, including the 800D. I believe the current retail is $23k for the 800D vs $26k for Sasha so it is a very fair comparison.
While the Krell amps actually help the 800Ds in this comparison by having better control over the bottom end which can be overly ripe with many amps and 800D combo, the Krell would not be my first choice with the Sasha.
I've heard the Sasha with various amps, inlcuding Krell, Ayre MX-Rs and my own Lamm M1.2s. They do sound quite different with different amps driving them so the synergy of amp/Sasha is important.
The openness, dynamic liveliness and effortlessness, soundstage capabilities as well as imaging and focus persists with many amps/Sasha but Sasha will allow the more "musical amps" to shine through like very few speakers out there.
I've heard my own amps/preamp with the 2x more expensive Avalon Isis ($60k) speakers and the Sasha sounds much more natural, open and engaging with my amps.
The Krell/Sasha combo, imho, will "impress" but ultimately is not a very "musical" combo. The Ayre MX-R/Sasha and even more so, the Lamm M1.2/Sasha is a pairing that is very musical and engaging, sounding natural without a trace of harshness.
While the "extra sparkle" up top with the 800Ds is impressive at a first listen, ultimately the Sasha tweeter is more refined and more natural sounding of the two metal tweeters. It doesn't draw attention to itself like the 800Ds diamond tweeter and is more forgiving and smoother while giving up virtually nothing in either detail or extension.
The midrange is very impressive for both speakers and is a toss up depending on taste and what one "perceives" to be the more natural and neutral voicing.
The bass is obviously better with Sasha, not only reaching deeper (-3dB at 20Hz vs -6dB at 25Hz for the 800D) but is also more coherent, articulate and much better integrated/balanced. The Sasha is also much easier to position in most rooms to get a flatter bass response vs the 800Ds which can often sound bloated, thick and have peaks that are very audible.
While the 800D is great at imaging and throwing a spacious soundstage, the Sasha's ability to recreate a 3 dimensional acoustical space that exists on the recording is simply unmatched. The ambiance and air the Sasha creates completely allows one to peek into every corner of the space and "feel" the separation/layering of instruments front to back as well as side to side. The palpability factor of the images is also up there with the very best speakers.
Wait until the reviews of the Sasha start coming in.
It is a very serious speaker that conveys the emotion of music to the last degree while treating you to a very realistic presentation and
unforgettable listening sessions. I am simply in love with this speaker!
Yes, $26k is not exactly chump change but in this case, it is completely worth it.