Hello I don't know if I understood you correctly but when I connect the ma-23 to the preout front outputs and put pure direct and for my ears little difference to the pure direct of the internal amplifiers of the 8500 where a better sound is noticeable is pc + dac nuprime + ma -23 the only disadvantage is that in this way I cannot use audyssey and in my living room it helps me a lot! The problem is that something happens when I connect it to the 8500 that loses the punch of the ma-23 and if I use them externally they sound great.
What I mean is, if you play your music this way:
Music play on PC, PC output to Nuprime DAC input, then Numprime DAC output to the MA23, your PC, or the DAC is doing the volume control
Now if you play the music the other way:
Music play on X8500H with its own internal amps, then the X8500H is control the volume.
So you can see that it is not an apples to apples but oranges to apples comparison, to compare the X8500H amps to the MA23 amps in a fair and real sense, you have to have everything exactly the same, leaving only the power amps inside the Denon, and the MA23 as the difference.
That's why I suggested you should do it this way:
A) When using the Denon's own amp:
you play music with your PC, output from PC to input of the Numprime, then output of the Numprime to the Denon's analog input, select direct or pure direct so it bypasses the Denon's own ADC/DAC and go directly through the preamp volume control and then to the power amp.
B) When using the MA23,
you must do the same, that is, play music with your PC, output of PC to input of Numprime, then output of the Numprime to the MA23.
You can see that the signal path A) and B) are the same, and you will be effectively comparing:
Denon's preamp+power amp to the Numprime preamp+MA23 power amp. And you only then have to make sure you level match the two, so that one way is not louder than the other, otherwise the louder one will most likely sound "better" to you, especially the bass.
If you do it like that you will not lose the bass when the Denon amps are used, guarantee!!
I hope this is clear, if not, you need to use a better translator from you language to English.