Okay I will give this a shot. I have a CD player with variable output and a preamp with both a main attenuator and gain trim controls. If I were you I would start by defeating the variable output control in the digital source. I do this on my CD player by turning the control fully clockwise or full output. For the amps I would do the same to start. For the preamp I would leave the gain knob at its standard setting and just use the volume control to start.
Now play some music. Make sure the preamp volume control is at the lowest setting, fully counter clockwise, to start. As the music is playing slowly increase the volume until you get to your optimal listening level. Note where the volume control is positioned. Ideally I like to see the volume control operate at optimal listening levels between the 11 and 2 o'clock positions, maybe a little further along. If you can accomplish this right off the bat you are set. If not, then use the gain control on the preamp to attenuate the gain until the main volume control can be used in the range I mentioned. This is how I set it up in my system. Depending on the recording I may have to trim some gain but for the most part do not use the controls at all.
Before I address the amp review the link here:
http://www.thevintageknob.org/luxman-M-2000.html
BTW, they have information on your preamp as well.
From what I can tell the attenuators on the amp are used to adjust the meters so the level is between -10dB and 0 dB. So after you have done the adjustments on the preamp, then try making the adjustments on the amp, although I do not think this is critical. In my case I run my amps at full gain so you should be okay.
Finally, unless you absolutely have to, do not attenuate the variable output on the digital source. It should stay at full output for best results. You should be able to make all the necessary adjustments on the preamp and amp. Let me know how this works out for you.
Now play some music. Make sure the preamp volume control is at the lowest setting, fully counter clockwise, to start. As the music is playing slowly increase the volume until you get to your optimal listening level. Note where the volume control is positioned. Ideally I like to see the volume control operate at optimal listening levels between the 11 and 2 o'clock positions, maybe a little further along. If you can accomplish this right off the bat you are set. If not, then use the gain control on the preamp to attenuate the gain until the main volume control can be used in the range I mentioned. This is how I set it up in my system. Depending on the recording I may have to trim some gain but for the most part do not use the controls at all.
Before I address the amp review the link here:
http://www.thevintageknob.org/luxman-M-2000.html
BTW, they have information on your preamp as well.
From what I can tell the attenuators on the amp are used to adjust the meters so the level is between -10dB and 0 dB. So after you have done the adjustments on the preamp, then try making the adjustments on the amp, although I do not think this is critical. In my case I run my amps at full gain so you should be okay.
Finally, unless you absolutely have to, do not attenuate the variable output on the digital source. It should stay at full output for best results. You should be able to make all the necessary adjustments on the preamp and amp. Let me know how this works out for you.