I’ve used and still use some very good Cisco switches in my network. For my audio systems, I isolate with a combination of fiber, GigaFoil 4, and EtherRegen. I view these as noise reduction/problem prevention devices, not devices that improve any other aspect of audio reproduction. Switches themselves have no apparent impact. Switches simply cannot change the sound of the bits passing though them. If they do, they’re doing something wrong or something else before them was. I’m not of the “1s and 0s” school. I know that switches can inject noise into a system, and I suppose a bad enough switch could contribute to packet loss that might cause a problem. I know that “1s and 0s” are voltage swing interpretations of digital information. This is a process that can be done badly, but if your DAC is receiving a bit perfect file, and its Ethernet port is properly constructed and isolated, it’s inexplicable from an engineering perspective what sound difference a network switch can cause. I’ve been an ahdiophool long enough to know that sound differences have often been heard before they’ve been understood, measured, and quantified. I am open to the possibility that something is being heard that we don’t yet know how to measure. But even testable hypotheses are lacking.
When one looks at what’s inside of so-called audiophile switches, one sees zero explanation for alleged SQ improvement. They are generally not as well made as a Cisco Catalyst. That’s not to say that Pete and others don’t hear what they hear, but my hypothesis is that what is happening is that the audiophile switch is fixing a previously undiagnosed problem with the switch and/or cable it replaced. Not that there is anything magical about an audiophile network switch.
Whenever I hear an SQ difference, or hear one reported by another audiophile, I always ask: “why should this be?”. There must be a reason. If the reason is anything other than expectation bias, there has to be an engineering explanation. I am amazed how many times people tell me they “don’t care what the reason is; it just sounds better.” The reasons that SOtM and Melco give for the “sound” of their switches are not engineering reasons. Even a lot of the stuff proferred by Uptone Audio on behalf of ErherRegen is more hypothesis than proven engineering (a solution in search of a problem as someone put it), but at least they offer some design detail that makes sense, e.g., fiber isolation (as opposed to most of the others).
I believe in using quality switches and employing fiber isolation. The latter is more luxury than may be necessary. Properly certified and unshielded Cat6 cable seems all that dCS equipment requires. A GigaFoil 4 (hasn’t worked for everyone here in the Community, but I have two working flawlessly) or EtherRegen can supply the isolation one needs to protect the DAC from upstream noise, if any. Other than that, I’d be looking at my power, power cables, audio cables (as opposed to digital), and the most my budge or patience can tolerate for the best equipment I can sensibly afford. I’d always rather pour as much into the speakers and audio electronics as possible.
Just my two cents.