Can the quality that can be obtained by connecting my Mac to the DAC via Audirvana in UPnP mode be considered very high quality?
Not being able to use the direct USB connection between the Mac and the Atoll MS 120, I would like to ask the more experts if this type of protocol (UPnP) can be considered equal to the quality of the USB connection
Thanks to anyone who can help me understand better 
Hi @M_Billy,
They are high-quality connections; when you are using USB or UPNP, there is no compromise over quality. However, if you use Airplay, Bluetooth, or Chromecast, you will be limited in terms of quality.
Thanks Antonio for your attention.
In principle I agree with you and I still don’t have absolute certainty, but I have the impression that the same high resolution files sound better if loaded onto an external disk connected directly via the USB port.
These are still impressions and I’m still doing some tests, but at the moment I have this impression…
Good day:-)
@M_Billy
Audirvana is providing a very high-quality signal to the output bus controllers (USB, Ethernet)… From this point, to the DAC, subjective sound-quality is inherently dependent on the transmission path and the electronic-mechanical and power/ground/earthing, EMF and RF potentials that can and will influence the integrity of the digital-audio code in that transmission. The object of any digital-audio transmission scheme is to mitigate the influence of these non-linear potentials on the signal.
The construct of “very high quality” is a subjective interpretation of the sound-quality of the final audition on a given amalgamation of system components and the electro-mechanical, power/ground/earthing and acoustical environment in which this subjective assessment is made.
Secondary is the implementation of the transmission protocol, whether this is USB or UPnP… We can presume the USB digital-audio protocol is codified in ubiquitous implementation across the spectrum of DAC manufacturers… We see that UPnP is not so well implemented as is found with the implementation of digital-audio transmission via USB .
Given the need for long-distance transmission requirements (apparently in your case), the community has been made aware of a fiber-optic USB transmission system that may be a solution for you… The advantages of decoupling the computer from the DAC on the transmission path, simplifies (to some degree) the implementation of this system and the rejection of transmission based noise gremlins. (It has been noted that using a low-noise power-supply at the receiver is beneficial to performance)
I managed to speak directly with the manufacturer Atoll, I explained (very carefully) my problem, he himself told me that the UPNP transmission quality is absolutely not inferior to the direct USB connection, in fact, according to him I would also be a slight superiority.
Personally, when listening, I find the direct USB solution to be more performing and qualitatively better, it is difficult to explain why this happens, I believe that the signal path in the UPNP connection is evidently not as direct as the USB option.
There isn’t much difference, it’s just a matter of sensations, but, despite the various and repeated listening sessions, this sensation remains confirmed at the moment.
However, I thank all the people who paid attention to me!
I forgot one important thing, there is no possibility of physically connecting the Mac Studio output to the Atoll DAC (Atoll MS 120 streamer) the UPnP connection system remains the only possibility of dialogue with the Mac studio.
The possibility of exploiting the direct USB input of the streamer allows the direct use of music in high and very high resolution.
In this case the solution proposed above is not practicable.