Which amplifier

@mfdamon Though I'm sure both are outstanding integrated amplifiers neither in my opinion are an appropriate match for a Cornwall. You might be better served, have better sound quality and save a great deal of money by looking at something along the lines of a Luxman SQ-N150 integrated for around $3500 new https://luxmanamerica.com/product/sq-n150-integrated-amplifier/  plus have all the benefits of a factory warranty, dealer support as well as the reliability you’d get from the McIntosh and the Accuphase. If your budget can stretch, this might be even better https://luxmanamerica.com/product/lx-380/. This is what I’m currently using with my Cornwall IVs and I’m completely in love!

Of the two, I would go for the McIntosh.

Tough Choice. Two really great amps. I think both would drive those speakers with ease. I think I’d pick the Mac. Luxman is a solid choice as well. The build quality on the Luxman and Accuphase would be slightly better as Japan tends to do this exceptionally well. I have not heard the amps with your speakers….

I had a pair of Cornwalls driven with a Coda CSIB. It was a great tonal combination, big soundstage, exciting but not bright. I felt the Cornwalls wanted a bit of power. I demoed them with the small Luxman tube amp and just didn't feel that combo. I also used an Audio Note amp but the Coda was on top IMO.

Never heard the Accuphase, maybe look into damping factor combo for these speakers.