now I found NAD m10 V3 demo verzion (he played fo 10 hours all together) for 2150€ and I think that this is good price.
This is a good price - if - you plan to use the internal amplifier. If not, I still think something like the ICON or a miniDSP SHD with Dirac for example, would be better and cheaper options.
a big problem with ground loop via XLR and filter problem in DAC (by Amir).
There is a humming with ‘some’ amplifiers using XLR. It depends on how the amp is grounded. My M66 with my Audiolab 8300XP has the same hum, but it just requires the ground lug terminating to the amp chassis. On the ICON there is no ground lug like there is on the M66, so the easiest option is to use an RCA to do the grounding for you. And you can still use XLR to carry the signal just fine with an extra RCA connected for grounding.
I am told they do nut hum if you use an M23 amp…. So it very much depends on your amp grounding if the ICON (and M66) will hum or not.
As for the filter…. Well that same forum thread that showed the ultrasonics in the filter, also showed that the ICON Qrono filter had especially good timing accuracy, better than the other ESS DAC with standard filter. (Read the whole thread you will find the info in there).
For me personally, I don’t see the filter as being a problem, the ultrasonics are something like -60dB down and in the inaudible part of the spectrum.
Whereas the timing accuracy it showed is more likely to create a perceptible benefit, as that is at all volumes and across the whole audible spectrum.