I know this an older thread, and I rarely post, but I bought the L-590AX MKII three months ago, and it is the single best piece of equipment I've ever purchased. I'm 56, and have been pursuing great sound since I was 15.
I've been disappointed more often than not. Not with the Luxman. The best way I can describe it is in terms of photography... It's as if suddenly the exposure, the film, the processing, and the printing were done really well. There is no comparison, and people notice.
After 34 years, my wife has latched on to this piece like none before.
Yes- it does throw off some heat, and needs ventilation.
It is most likely my last amp, and I have had quite a few.
Flowery prose off- PM me with any specific questions.