Yes just to add my 2 pennies worth here. I have a raspberry Pi with a switch mode PSU, I have a Devialet 400 (soon to be 800) which has a switch mode PSU and Magico S5 speakers. If I turn the volume up to +30 on the Devialet with nothing playing and put my ear against any of the drivers there is utter silence. Considering that I run an IT business from home with servers, router (with SM PSU’s) NAS PC’s with noisy internals all running on the same mains network I begin to doubt the noisy PSU assertion.
If I actually played music at that level in my room I would literally be pinned to the wall with the sheer volume of sound, even at 0 on the volume my wife comes in, gives me one of those looks and shuts both the doors!!!
The background noise level is about -36 dB according to my Netatmo.