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.