@keithr
Thanks for your suggestions. Nothing I've heard about Zu makes me think they'd be better than some of the others, here. Classical is a *must* for me. My brother in law loves rock and so he's really headed for Zu. I would love to hear Zu but local options are limited.
I don't think I'm headed all the way down to SET. I am trying to land in the middle, with tube amps running either KT66 up to KT 150 and/or a Pass XA 25 (25 to 50w on peaks).
There are many very good choices available to suit your objectives.
Thank you for those recommendations. This thread is becoming *everything* I hope for in a forum. Not just recommendations of the usual brands — though hearing personal experiences is very valuable and of course I might actually be able to hear them — but other "under the radar" options. That's how I initially found Salk and Fritz's bookshelves.
One thing I'm learning is that certain makers just aren't *oriented* toward one kind of amplification or another. Not just that their speakers' sensitivities are mostly under 90db, but that even if they have one or two speakers with greater sensitivity, they don't really design with tube amps in mind. That's ok, but it's not exactly easy to glean from the way they describe themselves.