Hello ,
Do we know if the Mini Usb (Usb Audio) is workable ?
Does anyone has connect PC to this USB to play music ?
Do we need drivers to be installed to PC ?
According to the SA30 manual page EN-9 there is only an standard USB-A slot suitable for audio playback from pen drives:
I think there is no other USB type of slot (mini or standard B) available on the backside of the SA30 for audio playback. Furthermore I think it is not possible to connect a pc to the available USB slot and play music from the PC on the SA30. I think it should be possible to connect an usb drive to it too.
Page 9 of the manual mentions the usb for audio playback.
Guys if you check the SA30 from behind you will find it next to the Serial Port.
Also the remote has PC USB source
I didn’t know there was a USB mini connector on the back the SA30, I cannot move mine to have a look. Since the USB mini isn’t documented in the manual I guess is for service / support purposes only.
As far as I know the PC USB button is an undocumented feature to switch to ARC input source 
Arcam was planning to implement usb dac into SA30, and they even made the port and remote button.
But somewhere between first presentation, prototypes and mass production for some reason they ditched this option, and no one knows why. If one asks them why the port and the button are present, they will just tell you, that this option is not there, and port is for “servicing”, and button for arc 
No one knows why they left the port on the device. It’s inactive, seemingly not connected to anything, yet they need to pay for it. Makes very little sense.
Anyway to summarize this long post: it was supposed to be there, hence the port and the button, but in the end it’s NOT there. Period.
That button was supposed to switch to USB DAC, but since they canceled this option, button was not doing anything for a long time. They only added arc function for this button later, cause customers where complaining, that they cannot switch to arc manually.
So, unfortunately no USB DAC.
As i understand ARCAM needs to find a Software team to invest inhouse .
Otherwise they can also implement existing software’s likes BlueOS.
To be honest I think they are outsourcing big part of software development.
As far as I understand streamer part is provided by Airable (former TuneIn), DSP at least partially by Dirac. I don’t know if basic amp controls and integration of those parts is done in-house or also outsourced.
BlueOS is not feasible, as it’s proprietary to NAD’s mother company and can only be found in their products. They are not licensing it.