Many wall warts (SMPS) are well designed for audio and quite quiet.
Lifeless can not be overcome with room treatment.
Daisychaining Ethernet switches
Having previously operated an LHYaudio switch followed by a 10m clocked Etherregen after a Draytek router I out of a whim added a humble Netgear GS 305E for not even $50 in the chain ahead of the LHYAudio switch. All Cabling is ONTI with a Xangsane braided silver ethernet cable between Etherregen and Server.
The effect was not subtle: major uplift in bass performance in tightness and definition, ‘being there’ spatiality and impulse rendition. I live in Central London and probably have more incoming crud on the cable, RMI and EFI than more remote locations. Given that I now daisy chain 3 switches and a router to achieve optimal results I cannot but wonder whether any of the individual component designers have fully understood the task at hand in providing an optimum ethernet audio signal to the server. So far as I can make out individual component tests become borderline meaningless. But then some would argue that bits are bits: So not!