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

Here are my initial results of my head-to-head in-home test of the McIntosh MC452 vs Bryston 4B3, tested with McIntosh C2500 and Bryston BP26/MPS2 preamps:
Results:
-If I had to pick between the McIntosh and Bryston power amps, it would be the Bryston 4B3, by a small margin.
-The McIntosh 452 unsurprisingly did a better job at midrange, but unexpectedly (for me) had a more dominant mid than the Bryston 4B3.  The McIntosh's midrange was fully rounded out in the lower mids, with the Bryston's mids, including vocals, being "leaner".
-The Bryston 4B3 did a much better job at bass response, dynamics, pace and timing.  This resulted in a more musically engaging experience (for me at least).  There was a punch, attack, and engagement level that was missing from the MC452, and not just in the lower frequencies.  Even though the 4B3's vocals were not as fully developed as with the McIntosh, the 4B3's vocals seemed to pop out more and have more "air" around them.  Underneath that was a solid foundation of drums and bass which carried and exceptional rhythm and drive.  The 4B3's the overall presentation of the 4B3 seemed more cohesive as a result, and, unexpectedly, was more "musical".  For me at least.
-Soundstage was pretty much a draw.  But, I will say that the MC452's soundstage was more noticeable simply because there was more meat to the lower mids that simply was not there with the 4B3.
-Between the two preamps it was no contest - the C2500 beat the BP26 easily.  The BP26 was harsh and difficult to listen to.  Sibilant 'Sh" vocals were rough.  Could be just the difference between a tube preamp and solid state?
In summary, I do miss the MC452's fully developed mids in the Bryston 4B3, but ultimately the 4B3's pace, rhythm, drive, dynamics, and bass made for a more musically engaging experience. Not to mention the Bryston is half the cost, and of course comes with the 20 year warranty.  Another aside is that I really like the Bryston's speaker terminals which made for a rock solid locked-in connection, whereas I did not like the McIntosh's spring-loaded mushy feeling connectors which didn't feel as secure.  Another aside is that thinner or poor recordings sounded better with the MC452, since the mid was more fully-fleshed which provided a bit of balance to such recordings.  Overall, the result was not what I expected - I thought I'd like the McIntosh's sound more than I did.  Ideally, if I could combine the strengths of both amplifiers into one, that would be my perfect amp.  The dynamics, pace, attack, rhythm, drive, and bass of the 4B3 with the effortless fully developed mids of the MC452, in one single amp - that's what I need to find now that I've analyzed these two...  Based on everything I've read, I'm hoping I'll find what I'm looking for in the Gryphon Diablo 300 - which I will be testing (in a store) vs McIntosh C2600/MC462 next weekend.  The MC452 is definitely a great amplifier, but for anyone looking at the 4B3, to me it just seems an exceptional value with awesome build quality, with sound that at least for me, beats the MC452 sound by a small margin.  That said, I can absolutely see how someone else might prefer the MC452's sound for the effortless and more developed midrange.

Diablo needs at least 100 hours of burn-in time in addition to 80 I think factory hours. Make sure of that. Also, Gryphon matches well with Gryphon and better Purist Audio cables and cords, I suspect it does well with some others too but don't know it. Start by plugging the Gryphon in straight into the wall if possible, no conditioner, it's got one in it. Still it might sound better with some conditioners in certain situations, this part is tricky. Look forward to your report and final decision.

nyev
Excellent review! I am looking forward to your next installment w/ the Gryphon.  Happy Listening!

Diablo 300 is becoming quite popular because it represents great audiophile value. Sure, Gryphon separates would be much better, but excuse me, that kind of money is beyond the reach of 99% especially if you want top of the line. But even 'entry level ' separates are way too much for most. Used is possible but hard to find with North American voltage, and even with European not so easy, and is still expensive unless 25-30 years old.

Thanks inna for the tips.  The Diablo is a demo unit the shop is getting from Gryphon, so presumably it should have some miles on it.  Good point on avoiding power conditioning - I’ve seen stories of conditioning causing issues for the current-hungry Diablo at shows.  While I was aware of this I am pretty sure the shop has conditioning built into the walls of their listening room.  So I’ll have to ask how we can avoid this during my audition.  

And yes, from what others say, it seems I would need to spend a lot more than the cost of a Diablo 300 to get equivalent or better performance from separates.  That said, there is the issue of subjective taste.  An example is with a lot of high end cables I find to be very impressive, but often there is one small thing that ruins it for me in terms of balance, being too warm/cold etc.  I expect to recognize all the qualities of the Diablo that others mentioned after I test it on the weekend.  But it doesn’t there won’t be that one thing that makes it not work for me.  We’ll see.  If the Diablo doesn’t work out, to be honest I’ll be happy with the 4B3 and will need to move my search to a suitable preamp that’s a bit more lively and has more drive and excitement vs the McIntosh C2500 that I tested the 4B3 with.  The C2500 wasn’t bad at all, but I’m sure I could find a more involving preamp to go with the 4B3.  Maybe Simaudio 740p Or AR Ref 6.  Or even the Bryston BP-173, but it would need to be far superior to the terribly thin sounding BP-26.  I couldn’t believe how the BP-26 came from the same company that made the excellent 4B3 to be honest.