Well I completed my 6LU8 a little while ago, but only played it on tiny desktop speakers. It sounded good, but you know, desktop speakers.
Anyway, I dug up a pair of Advent Graduate (8" woofer, 2" tweeter) and was dissapointed to see they needed a new surround. Well, got the speakers repaired and hooked em up. The 6LU8 is a great amp for these speakers! The power is just about right for my listening room, about 1/3 for normal relaxed listening, and 1/2 for 'louder' listening.
I must say this combo is working well for me. Very nice detail, especially horns, saxes. Percussion and bass are right there, I would not say it was booming bass, but acustic bass sounds like it is in the room.
There is an 'apparent' balance issue. Maybe it is just me, but one channel sounds louder to me. I have a 'weak' tube in teh pair, and perhaps this is it. I will switch inputs, and later tubes to see if it is happening and if so, is it the tube. Not too bad but my soundstage appears to be a little 'lopsided'.