Best U.S. made integrated tube amp under $2500?

Hmmm. I would look into the Manley Stingray and the Rogue Cronus. I assume 40-50 tube watts is more than enough to drive the Dulcets. What I would buy for the price, and better than all of them in my opinion would be a Lightspeed Attenuator and Music Reference RM10MKII for $2,500 total, new. Don't think any of the other three options would be as good - but not an integrated and while the RM10 is handmade in California, the Lightspeed comes from Australia, but handmade by the owner so certainly not the product of "cheap" labor. The RM10s have enough power for my Merlin VSMs (89db, 8 ohm) so its's 35 watts might be enough to drive the Dulcets if they are not to be played to loud, in a smallish room like yours; I assume if you own Dulcets, you are not a headbanger....that would be a significant step forward IMHO. I think you would be more than impressed with what the Lighspeed/Music Reference could do for your wonderful speakers - the combo is cheap, but SOTA for a 35 watt amp.

Might also might be able to hit that price point with CJ or ARC used.

VAC Avatar, though an older piece of gear, is well built and would power your speakers nicely.

I sure enjoy my Cary gear.