The Luxman 590ax has a Subsonic Filter, Tone Controls and Only Distortion Negative Feedback (ODNF) that might help with your recordings. See:
Subsonic Filter
A subsonic filter is also easily accessible from the remote control in order to remove unwanted low frequency noise while you are listening to a record. When the stylus hits the groove, you might notice the woofers modulating in and out, even though there is no music playing yet. This is due to the ultra low frequency information (below the music), this unnecessary information places a strain on the amplifier and is best filtered out. A mono switch is also available for both loudspeaker setup as well as mono record playback. Both the Mono & Subsonic filter are accessible from the remote control.
Tone Controls
The tone controls might seem like an anachronism in this day and age of minimalism, but they can be remarkably effective in bring to life a less than perfect music collection. We all have music gems in our collection that are sonicly challenging. A lot of the 1980's CDs are quite harsh sounding and the digital glare can be quite fatiguing. Reduce the treble slightly and while the harsh CD is not going to suddenly sound like a reference recording, at least it will now be perfectly listenable. Sit back relax, enjoy the music & forgot about the HiFi. When you want to bypass the tone controls, just engage the Line Straight switch, either from the remote control or from the front panel.
ODNF
Luxman nowadays use a distortion reduction circuit called Only Distortion Negative Feedback (ODNF). This system works by isolating noise & distortion at the output from the music signal and sparingly applying negative feedback to suppress them. Conventional negative feedback systems can have an adverse effect on the music, introducing phase distortion. "The circuit features such an ultra-wide range, ultra- high slew rate and ultra low distortion that it does not use phase compensation for the music signal amplifying circuits." This new technology also ensures that need for a DC servo circuit is alleviated, again improving sound quality.
Click here for more details:
http://www.onahighernote.com/luxman/?c=&id=56
I agree with Jriggy above that you should call the distributor or dealer for a demo of this amplifier.