@jeffreyw
Having heard the Pass 250.8 and INT-250 with the B+W’s several times, both do a very nice job. I should be up front. I do not love the B+W D3’s. I don’t think they are a bad speaker, but just not my favorites (they are very nice etc).
That said, having heard them with several amps (Pass, Moon, McIntosh, Luxman, Classe).
I felt they sounded best with the Classe and Pass (in fairness the store that had the McIntosh gear literally had them in the front showroom with glass EVERYWHERE).
But both the Classe (previous series) and Pass could drive them to very loud levels cleanly and the bass (and I love bass) was really, really good.
(It’s the highs on B+W that I don’t always agree with), but both the Pass and Classe smoothed things out ever so slightly. I own a 250.8 and while it’s currently paired with a XP22, I’ve run it DAC direct also and not had any issues.
My current speakers are Salk SS12’s which are 84db and can play down to 20hz. I listen loud at times and the 250.8 has NO problem driving them. In fact, it rarely leaves Class A power (the needle on Pass amps indicate you are moving towards A/B power)
This Bi-polar vs mosfet transistor gibberish is a non-issue. The Gryphon, Pass, and many others will drive those without an issue.
Get the one who’s sound signature you feel matches best with your speakers to get you the sound you are looking for.
It doesn’t matter a hill of beans to me if you get a Pass, Gryphon etc... but I wouldn’t rule anything out that you are looking at.
Nice thing with the McIntosh integrated is they have built in EQ, which if you don’t have something like Roon could come in handy for you.
But, if you like Bass, a warmer (or at least not super detailed sound, and with your speakers I would be cautious as that tweeter is revealing). Pass, McIntosh, the Gryphon should all do the trick.
If you go DAC direct, the RME DAC’s are very nice and have all sorts of EQ available also.