Bryston 4B3 vs Mac MC462 vs Pass Labs X250.8, OR... GRYPHON Diablo 300?

Gryphon makes their own speakers and probably doesn't support anyone. Look up their discontinued Atlantis on ebay, as an example.

Bubb, unfortunately the shop didn't have the 803 D3's for me to test with the Diablo, as they said they sell so many 804's and 802's they don't need to demo the 803.  I should be clear I'm not even slightly saying the 802 or D3 line is bad - it just has a less relaxed mid than I prefer.  I agree it is an excellent speaker and I believe others may specifically like it better for how revealing it is.  I've extensively A/B tested my 803 D2's with the 804 D3 and I've heard the 804 D3 in other systems as well with the same qualities detected in the midrange which are simply not to my liking.  Regarding the typical analysis of dynamics, timing, attack, decay, etc, as I said I was unable to get a good read on these during my test of the Diablo.  Sorry to fail in my typical reviewing abilities!  Another way to put it is that the sound was so unique in my experience, that I admit I lost my sonic bearings a bit and I spent most of my time trying to get them back!  Again this was due to the soundstaging (it was like, how can I test this amp when there is a singer right in front of me distracting me from the test!) and the "control" aspect which I found very different.  With the vocals it is like a disembodied voice is planted right in front of you.  I've seen others say this about how pinpoint the Diablo is with vocals.  By "control" and "muscular" I mean that you get the sense that the speakers are doing EXACTLY what the amplifier is telling them to do, and not leaving any leeway for the speakers to do anything else.  It is hard to described in terms of typical descriptors of dynamics, attack, decay etc.  It is more a sense of being completely "dialed-in" and "focused". That's what gave me the feeling of using high-end headphones while I was listening.  The only difference being the soundstage was in front of me instead of left/right and in my head as it is with headphones.  That is what I am working through, whether I'll grow to enjoy this as a sonic benefit.  I think I will - it is a really cool effect and I think it is just my ears are biased to what I'm used to which is most definitely not this!  Sorry, I didn't get a chance to listen to The Chain, as I was working through my own sense of experiencing sonic discombobulation.  Realized when I left the audition I was quite dehydrated too so that didn't help.  I am thinking of going back next week which is my nearest opportunity.  Also of note - the room was medium sized, I was maybe 8-9 ft from the speakers, and it was set up to be an equilateral triangle between both speakers and me.  The room had a lot of dampening - which could have added to the "control" factor.  I typically like a bit more energy to come from the room to liven it up (but not much).  I did request they bypass the power conditioner they had and plug the Gryphon directly into the unconditioned wall outlet, so there shouldn't be any issue there.  In terms of burn-in, it was a "distributor demo" that had just arrived at the shop.  They said they expected it had some heavy use on it but they said there'd be no way for them to know for sure.  The did offer the demo unit to me (with DAC and phono modules) at a very aggressive price so I'm thinking it can't possibly be new if they can do that.

I think, you definitely need another audition. One thing about Gryphon you certainly got right. It has a great grip on speakers and you feel the amp's presence. In a manner of speaking, it is quite authoritarian. 

That is a perfect way to describe it “you feel the amp’s presence”.  It is difficult to describe this effect in a non-subjective way.  It is like the amp is curating the music for you, the way it wants to  (and doing a very, very good job of it).  What I’m wrestling with is whether I like this effect vs an amp that “disappears”.  No one I’ve seen has commented on this control element being a negative factor, so maybe I would be able to stop focusing on it so much after some extended listening sessions.  I doubt that can happen over an in-store audition.  On one hand I really like the effect.  On the other, I seem to notice it a bit too much and it’s distracting.  Now that I think of it - I did see one person on another forum say it was too controlled and not free-flowing enough for them.  But that’s the only one.

nyev, you have a great perception of the sound. This amp/speakers interaction is a complicated thing. I myself like speakers that are slightly loose and give me a somewhat 'bluesy' sound. But this kind of speakers need an amp with a firm grip not to get out of control. It should be a right balance, and it can be a matter of preference. It appears that this Gryphon/B&W pair does not strike the right balance, though it does certain things very well. That's why you are so ambivalent. Just don't buy if you are not sure.
What I also know about Flemming, I watched a number of interviews with him, is that he likes large scale music. This influenced his designs.
I understand what you call "flow" of music. Again, it's interesting and not simple. For example, and that's not about amps or speakers, it is about the sources, both analog in this case. My Nottingham turntable overall sounds much better than Nakamichi cassette deck. But, music has more coherence and flow when played on tape, tape recorded off vinyl played on the same Nottingham. I also once noticed the disruption of the flow with a wrong interconnect cables.