211 PSE /40w of power zero NFB 

They are delicate and sweet sounding amps. Very nice!

I think there is a great deal of wisdom here: what drives differences in sound? Single ended, parallel, push pull? Dht vs pentode driver tubes? Feedback? Damping? Transformers? I’m enjoying listening to these demos and it’s got me questioning my assumptions

it's pity that No one can See what Kind of Loudspeaker you use for your Test. The monos Sounds outstanding ! Congrats

AUDIO RESEARCH, CLASSIC 120. UNSUNG HERO.

what's your music player?

What album/artist please?

looks like 5670 + 6sn7+211