Rockpanther: I cannot answer all your questions. In my opinion, based on listening on my system, the Luxman 590ax has a smooth treble and plenty of bass on my Sonus Faber Olympica II Speakers. It is a very musical sounding amplifier and its mid-range is terrific.
I have not heard the McIntosh 6900 and Luxman L-590AX on the same speakers. I compared the Luxman 590ax to the Luxman L-550A II and, in my opinion, felt the 590ax sounded much better and worth the extra cost (for me).
I do not know how the 590ax sounds on harsh or bad recordings. Again, in my opinion, in my system, my 590ax sounds great on the recordings I play. I hope you can audition the Luxman 590ax so that you can hear yourself how it sounds.
As I said above, I like my Luxman L-590ax because of its Class A design, it is fully balanced and I really like how it sounds. In my opinion, the Luxman 590ax is a terrific sounding integrated class a amplifier. If you are having trouble making a decision, please review other comments on the 590ax in AudioGon and look for reviews of the 590ax. I hope this helps.
I have not heard the McIntosh 6900 and Luxman L-590AX on the same speakers. I compared the Luxman 590ax to the Luxman L-550A II and, in my opinion, felt the 590ax sounded much better and worth the extra cost (for me).
I do not know how the 590ax sounds on harsh or bad recordings. Again, in my opinion, in my system, my 590ax sounds great on the recordings I play. I hope you can audition the Luxman 590ax so that you can hear yourself how it sounds.
As I said above, I like my Luxman L-590ax because of its Class A design, it is fully balanced and I really like how it sounds. In my opinion, the Luxman 590ax is a terrific sounding integrated class a amplifier. If you are having trouble making a decision, please review other comments on the 590ax in AudioGon and look for reviews of the 590ax. I hope this helps.