Tube amps under $7500

If the requirement for balanced design limits choices to much, I would ditch that criterion.  There are MUCH more important things at play than the relatively trivial advantage of balanced design.  You do need to somehow hear various amps and make a choice entirely on the sound, not on any specific design choice, topology, type of tube utilized, etc.  There are a number of suggestions made above that are based on sound and disregarding your balanced criterion that you should use to make your target list. 

Way back in this thread, a dealer who sells Legacy mentioned the Synthesis amps he also sells. If you can, you should get to hear their amps even if the black color is out of the question because their amps are great examples of warm sounding tube gear that is also punchy, alive, dynamic, and clear sounding all at the same time.  That will set a tough to beat mark, but, I think you will agree it is a worthy standard; I have not met anyone who has heard their amps that did not like the sound a lot.  I know someone who traded in two month old $60k amps for a pair of their $18k monoblocs.  I like the monoblocs, but they are really only slightly better than their $8500 integrated amp that includes a fantastic DAC.  Some pretty exotic DACs have been traded in for Synthesis DACs; they do know how to make those things well too.

I recently replaced my ST100 “Dark,” which is an excellent amplifier, with a pair of monobloc Odyssey Kismet amps, and I am exceptionally pleased.  Used with my Rogue RP-7 preamp, I think the solid state amps give me better bass response, especially at lower volume levels, better tonal qualities, and better soundstage and imaging. At least with my Fyne F702 speakers.

@mike4597 Equivalent bass response has been my primary concern with the low-mid-level tube amps I am exploring. The behemoth tube monoblocks can definitely go low with realism, but I will never be in the market for those.

Music Reference products, though never trendy and/or fashionable, are (were) very well designed and built by tube expert Roger Modjeski. Roger passed away in 2019, but his amps are well known to run trouble free for years. At one seminar I attended, Bill Johnson of ARC said he built his amps for an expected lifespan of 20 years. Modjeski said his target was 100 years!

Roger designed his RM-200 amp for low impedance loudspeakers, and the amp puts out a little over 100w/ch, with taps for 8, 4, and 1 ohm (!) loads. Both KT88 and 6550 tubes may be used (only 2 per channel), and the amp’s low output impedance for a tube amp results in very little change in frequency response in reaction to loudspeaker impedance characteristics. The amp features balanced-only XLR input jacks.

Michael Fremer reviewed the original version of the RM-200 in Stereophile, after which he kept it and used it as his reference "affordable" tube power amp, and placed it in the Class A/Tube category in the mag’s Recommended Components list. He subsequently reviewed the Mk.2 iteration of the amp, and John Atkinson’s test bench results of the amp were unusually excellent. In his Stereophile review of the earlier RM-9 power amp (single ended/RCA jacks only, 4 EL34 or KT88 tubes per channel, producing 100wpc, 125 in the MK.2 version), Dick Olsher (one of my favorite reviewers) heaped praise on the amp, asking the rhetorical question "Who needs the McIntosh MC75 when we have the Music Reference RM-9 Mk.2?"

The RM-9 Mk.2 typically sells for around $2000 on the used market, the RM-200 Mk.2 around a grand more. Legendary high end retailer Brooks Berdan (alas, like Bill Johnson and Roger Modjeski also deceased) sold Jadis and VTL amps to his well-heeled customers, Music Reference to working class stiffs.

@bdp24 Very interesting. A product that came out during my years away from hi-fi. Seems to check all the boxes and I see a MkII on Shark for $3250. Sounds almost too good. Will inquire further and thanks for the tip.