Thanks for all of your input.
XS137 - a couple months ago I talked to Musical Concepts/Design and they were doing B&K mods.
i just lept on a chance for an in home trial of a used Rogue Cronus Magnum II this afternoon, and raced up I-5 to snatch it. At least I can experience tubes without making a purchase. It’s hooked up, biased, and I’m starting to listen. No hum or hiss. Subs are running high level, and I might have to back them off a bit. Certainly has as much power as the B&K’s 200W. I haven’t listened enough for a verdict yet.