Luxman tonality

Completely agree with OP. When I first went to audition the Luxman 590AXII, I was expecting this warm, lush, rolled off sound. Why? Because that's what I had read about them. I was completely wrong!

Compared to 509, the 590AXII tilts towards warm, but only by a smidgen. After living with it for a few months now, I would say the 590AXII is fairly neutral with just a hint of warmth. And as Eric said, the extension on both ends is really amazing. 

Previously, I had the Audio Research GSi75 which is renowned for its wide soundstage. Let me tell you that the Luxman has a soundstage that would rival, if not outdo, the soundstage width of ARC. It controls the woofers of my speakers much better. However, the one area where the ARC had a leg up was palpability and the extra air around instruments that only a good tube amp can give you. But in all other areas, the Luxman takes the cake.

I thought this was a very good description of the tone of the Luxman.

https://www.tonepublications.com/review/the-luxman-l-509x-integrated-amplifier/

For argument and sake of reference point, if you were to put Boulder amplifiers (and we still had the 1100 series here for comparison) as straight-up natural at 12 o’clock – adding nor subtracting nothing, with no sense of added tonal saturation, our reference Pass XS Pre/XA 200.8 is probably at about 10:30. With going to the left a bit on the warm/saturated side. The Luxman 900 series was about 11:30, with our tube references the PrimaLuna EVO 400 and VAC i170 coming in at about 9:00 and 9:30. I’d put the recent Esoteric integrated about 12:30 – slightly to the cold side, and the last few Simaudio amplifiers we’ve reviewed about 1:00 – even more clinical. The L-509x, like it’s larger separates has that same touch of warmth/saturation, without being slow or non-resolving. I wish I would have had the ability to listen to them both side-by-side and suspect that the L-509x comes very, very close to the 900 series in terms of sonic performance.

I heard the 509x and 900 series side-by-side and the 900 series was a lot better to my ears. A lot more expensive too.

Neutral? Maybe. Sterile? Hell, no. The thing that always impresses me is the detail, across the board, along with what I believe is very good bass control. And to be clear, I'm talking about the L-590AX. All of you have had more gear than me, I'm sure, so judge my opinion accordingly.

Gotta disagree on the 'euphonic' thing, miller. "agreeable in sound" is just a throwaway, it couldn't be a more vague or inept description. I think far too many manufacturers of audio gear are tweaking it with this in mind, pushing the mids forward, etc, and well, 'adding audio crud to the system'. Perhaps not truly crud, but they're altering the sound, rather than shooting for an accurate reproduction of it. Perhaps because their gear isn't up to that task.

It is not me you disagree with, it is literally the definition. That's why I say don't take my word for it, look it up. Your disagreement then is with reality. I know nowadays we each are supposed to be able to have our own reality. Good luck with that. Me, I'll stick with the actual, you know, reality.