@PeterMusic, @McMan
Thank you both, gentlemen. Your comments are invaluable to me. With regard to new tube gear, I have no concerns about maintenance. My MFA components dated back to the mid 1980's and I ran them for decades. Eventually of course, maintenance became a big issue. I had a closet-full of spare tubes and kept buying more "just in case."
The new MAC tube gear requires far fewer tubes. I've got an adequate tube tester. I suspect I'd be quite happy with the C8 and, being a visual person, I like how it matches the MC275. One of the features of the Luxman 550AXII that I appreciate is the bass and treble controls. I'm not sure the added EQ ability of the C22 would be an advantage for me. Just more stuff with which to "fiddle."
I'm awaiting word from a MAC dealer about what they'll offer me on a trade-in for the Lux. I'm reluctant to sell privately but will do so should I decide to proceed with the MAC gear.
Thanks again.
Best,
P