Thanks for the nice feedback, folks! The system is sounding wonderful, although I'm at a loss to describe exactly what has improved in moving to the new amplification. The music seems more "alive," in general. Instrumental textures are more palpable, individual instruments have more "air" around them, and other things I can't quite articulate in words. But the system has definitely taken a huge leap with the new electronics, proving, I guess, that the Ohm's benefit from better associated gear.
It's also very satisfying that Audiogon has made all this possible. I saved a total of about $1400 on the preamp and amplifier over retail. The power amp was brand-new in an unopened box, at one half off retail -- the only thing I lost is the factory warranty. The preamp was, just as the buyer had claimed, "without a single mark on it," and it's a beautiful piece of equipment. That's another great thing about Audiogon: I have yet to have dealings with anybody here, either as a buyer or a seller, who wasn't a pleasure to deal with. It feels much safer buying here than in the wild and woolly world of eBay, for example. So, here's to AudiogoN, and to the bargains it makes possible. :-)