Tube amps under $7500

If bass response, and specifically how the amp handles low impedance (i.e., damping factor) is a high priority, then solid state is the way to go.  Some powerful tube amps with many pairs of output tubes may also have respectable damping factors, but to me, most such amps sound hard and edgy (I prefer solid state to many high powered tube amps).  It comes down to priorities and picking your own set of compromises; nothing is perfect.  My own priorities do place deep, tight bass way down the list.  Getting a rich, saturated sound with good midrange and lively sound at lower volume levels are high on my list which is why I like low to medium powered tube amps.  I sacrifice extreme volume capability, and deep tight bass.

@mdalton Ah. That explains everything.  You have scored some truly classy gear at good value. I  admire, but can't emulate. The stoic good humor alone would make all worth reading. See below. 

@larryi Just so. In a perfect world, I would bi-amp with Aric or such on top and Coda or such on the bottom. But I am old, not to mention tech-lazy, and times are chaotic, and 90% of my listening is casual, which leaves me in the usual compromise state, albeit vastly better informed owing to the wealth of information shared here. Thanks to all.  

+1 @larryi 

My listening values are pretty much the same.  I have no experience of Legacy speakers but I take the OP at his word that they are non-negotiable.  That’s why I suggested the possibility of bi-amping, as one approach to solving these simultaneous equations.  But for me, with my listening values, if I wanted to experience the magic of tubes, I’d think about easier-to-drive speakers.  Having said that, the OP is taking a nicely deliberate approach and might just be able to get it all with the Legacies and the right tube amp.  And I’m enjoying trying to help. 

The MC275 is a great amp once you throw away the junk OEM tubes. Which should he done with immediacy IMHO.

@mdalton 

Bi-Amping is the way, at least for me.

I have two mono-blocked MC275s (running GEC A2900s and KR Audio KT88s or GEC KT88s depending on any  given day) up top and a pair of Pass Labs xa160.8 mono-blocks down under. I love how they sound together.

Speakers are BW 802D4s.