Interesting discussion @curiousjim. I presently am running two network switches in sequence between my CAT6 router and my Network Acoustics Eno Ethernet filter on the way to my server. The first switch is an inexpensive 5-port D-Link that is connected to an 8-port $200 commercial grade Cisco network switch by a $70 Audioquest cinnamon ethernet cable. Both switches have iFi iPower Elite SMPS’s that are plugged into my AQ Niagara power conditioner. Ideally the cleaner the signal you send to your DAC the better the music will sound in your system. RFI and EMI are the real enemies of internet music streaming IMO.
The simple test that I tried and convinced me of the efficacy of using a network switch was to first use an inexpensive switch between my router and my server. The $50 D-Link switch and a $20 L-Com ethernet cable were enough for me to notice that the music sounded less digitally harsh and smoother. Of course the amount of money you can spend on anything in streaming audio can get pretty outrageous. But you don’t have to go crazy to get positive results. I think it’s definitely worth a try.