Luxman L-590AX

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.

Luxman makes a great class A product. They tend to be on the the warmer side of neutral, but just a tad bit. Luxman will not rescue a bad recording but so much of todays gear is so sterile and dry that bad recordings hurt your ears. Luxman will always be a part of my system in some form.

Ok. Do you know any amps or speakers that rescues bad recordings?

Thanks for many good answers so far!
Does the adjustable treble and bass works well? Can I play loud even if controls are used?

I still think with system matching the DAC and cables to tastes, you can get this amp to be 'nice' to bad recordings. I found quit warm and forgiving, yet still detailed enough, musical and very enjoyable... You are going to have to hear it yourself to know any more about it....
Call the distributor for a demo.