Curious if anyone from the dCS Tech team would care to comment on this 
Seems to me that’s like asking if the university president wants to attend frat-house parties. 
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Not sure, but dCS team posted a comment on that kind of discussion in another thread. If I remember well they said that you can use whatever switch you want to, but you have to pay attention with professional switch that are “managed”…With sophisticated firmware which perform some operations that can impact either the sound or the operation of Mosaic.
Sorry for being so vague, but may be someone can find that thread and explain better than me…
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Sure, let’s have polite discussion about this
I translated the article you linked to (sent you a copy to verify that I’ve not missed anything), there are a number of issues mentioned in the article, but let’s start with the most critical one;
IMHO, there’s no argument that some Ethernet Switches will be noisier than others for whatever reasons be it Power Supply or poor Engineering. So, that’s a given. Resulting in a question of whether such noise affects the DAC and how (knowing full well that it doesn’t affect PCs to the extent that no applications are affected… more on this later).
The jitter problem they allude to is however inconsequential as the physical Ethernet stream is completely terminated on an Ethernet PHY chip (immediately after the Ethernet Pulse transformer at the port); with a Qualcomm Atheros AR8030 on dCS platforms. While data is assembled from IP Packets reconstructed by a separate CPU and networking stack; the TI Sitara ARM CPU/Linux on the dCS. Both the PHY chip and the ARM CPU/Linux are closely-coupled and isolated on the S800 board.
So, the issue is just one of noise, and the key question then becomes;
(a) Can such noise affect the sound of the DAC? (Enough to be heard)
(b) Can such noise be easily mitigated (without having to spend $2,000 on an Ethernet Switch)?
The answer to (b) is simple. There are any number of ways to eliminate noise from a noisy Ethernet Switch; fibre based isolation being one. The problem domain then reduces to just the Media Converter at the far-end where one can focus on cleaning things up. Most Media converters are built on a single chip coupled with a PSU, it’s trivial to produce noise-free Ethernet to attach to the DAC. The pictures in the linked article seem to suggest they measured both the Ethernet Switch directly and with a Fibre media converter, but they don’t show any of the measurement results. Maybe I’m missing it somewhere.
As for (a), let me put this thought experiment in your mind;
Take the cheapest/crappiest PC you can find. Attach it to the noisiest nastiest Ethernet Switch you can find. If you were to download an Excel spreadsheet, would you agree there is zero chance that the spreadsheet will have any error?
So, somehow, Ethernet noise has zero effect on the cheapest nastiest PC and application, but it affects the dCS platform & application (D-to-A)? Do you actually believe that the dCS Compute board is worse than the cheapest PC? 
Back to the article you linked to; there’s no explanation or demonstration of what they measured on the Metrum Streamer/DAC with the Wavecrest - unless I’m somehow missing it - they don’t show or explain the measurements, but they jump to this critical conclusion;
Does a switch affect the clock in a streamer or dac?
Yes: 100%. We have now proven that, we hope.
…
However: in terms of phase noise, we find 10 dBc/Hz quite significant. In addition, the audible influence is also quite significant between a router supplied free of charge compared to a decent Netgear or Dlink.
What have they proven exactly? They didn’t show any measurements.
Also, am I mis-reading this? They’re suggesting that the noise or jitter from the physical Ethernet stream causes phase-noise on the DAC’s CLOCK?? 
Within dCS DACs, the Ethernet stage is so far removed, in terms of stages, not physical distance, from the DAC’s Clock, that frankly, it’d be ludicrous to suggest that Ethernet noise or Ethernet physical layer inter-symbol jitter can affect it. Plus, with dCS’ hyper-focus on Clocking, do you actually believe they’d engineer the DACs to allow Ethernet to affects the D-to-A Clock?? Come on!!
My question/suggestion, did you truly honestly blind test yourself when you heard the difference?
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Thanks Anup, I have the same doubts as you as of their statements.
They do provide full measurements, but they are behind a pay wall. Unless you donate (Patreon), they are not shown. Their investigation took several months.
I did not donate. But from posted comments they suggest this is a time domain issue. Also they seem to have demonstrated that port isolation on a switch is not 100%, and also that galvanic isolation is not.
My old switch is just under the new Cisco. After listening on the new one I noticed a difference. It is not big, I switched back and forth, I still can hear it. I estimate it as big (or small) as half that of listening with or without a Rossini Clock.
P.S. Thanks for the translation you have sent. Maybe you want to post it here, so others can read it. Again, the measurements are only available after a Patreon donation.
Yes, with a managed switch you need to know how to configure it. If you have no clue, don’t get one.
However, it is not rocket science. Just to give you an idea, here is the Easy Setup Guide of my new switch. Now you can decide if you can do this:
Cisco_Catalyst_2960-L_Easy_Setup_Guide_20161105.pdf (2.6 MB)
I believe you, I was just trying to remember what was said in that kind of thread some time ago (on this forum, obviously).
I think this one:
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Ahhh. Actually, I wouldn’t mind paying to see the measured results, unfortunately the open parts of the article doesn’t read with much credibility. For example, they totally lost me when they quoted Hans Beekhuyzen as a source of information on Jitter. That’s a joke. If you’re going to quote someone about understanding Jitter in the context of Audio systems, then there’s no one better than Julian Dunn.
I briefly look at the comments section. While it’s true that galvanic isolation is not 100%, the issue is parasitic-capacitance which is easily mitigated with a proper Pulse transformer. Jaap is suggesting that the Ethernet noise can “penetrate” the Pulse Transformer, the PHY chip, the ARM CPU (with it’s networking stack and the RAM buffers), all the way through to the D-to-A stage… Honestly, that’s quite laughable
By the way, this one particular comment stood out.
Michael wrote:
11/02/2023 AT 12:38What I wonder is if I remove the internet plug from the switch, the streamer continues to play and I hear no difference in sound change.
How about now exactly?
And Jaap’s response;
Jaap wrote:
11/02/2023 AT 12:50
Hi Michael,It’s not that easy to compare. You empty a buffer that already includes the effects of the switch. You could compare directly in the router and via the switch where you restart the track. Then you could notice differences.
On the one hand he says data integrity is 100%, but on the other hand he’s saying that the data in the buffers are affected; that tells me he has no idea how Ethernet & TCP/IP works.
If what he says is true and Ethernet Switches have that kind of impact, then there’s absolutely no way the dCS Firmware update could possibly download successful! 
I would still recommend you do an honest blind test on yourself - you might be surprised that you can no longer tell the difference. The mind is a tricky thing, it’s easily fooled.
Translated version of the article attached (hopefully I’m not violating any Copyright in posting the translated piece, original article URL included 
);
How a Network Switch Affects Audio Playback - An Extreme Deep Dive (no pics).pdf (419.3 KB)
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That’s a good post well worth reading, in particular this excerpt:
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Jaap measured the influence of a switch powersupply at a DAC’s clock, seems to me it’s not all “voodoo”
I have purchased another powersupply to give it a try on my Melco S100 switch, an Ifi elite smps this time, again the sq differences are there compared to the Plixir lineair power supply I was using.
Just give it a try if you like tweaking the streaming side of your system.
The noise isn’t affecting data, it’s affecting other parts of the system.
If you use Toslink to transfer data via S/PDIF over a cheap optical cable bent into a figure 8, you’ll see no difference in the extracted data, but the clock jitter will be absolutely off the charts bad.
Would they allow in their design? No.
But might it have an effect they didn’t expect? Of course.
dCS has stated several times they see no need for expensive clock cables, yet it’s obvious to any who actually listen that there are significant audible differences between say the Apogee Wide Eye and Cardas Clear, Audioquest WEL and more recently, Transparent clock cables.
No one disagrees that the Ethernet data transfer is bit perfect, but we’re still struggling to understand why bit-perfect interfaces like Ethernet switches do in fact sound different from one another, and it’s not due to “bias.”
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Indeed, with that I am struggling now. I hear a difference. Will do more (blind) testing.
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It’s funny how it’s always companies that struggle to understand how stuff works that sell you the “upgrade” products.
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I accept what you say you hear, but how do you know this? What have you done to eliminate the variable of bias from your evaluations, in a way to provide a third party confidence in the assessment? Insisting in bold type there is no bias is a meaningless assertion without demonstrating its removal from the evaluation process.
Just as you say that without the Clock, your Rossini does not to your ear reproduce your test tracks as well as your former Wadia DAC, I can accept that assessment as a subjective evaluation. But unless you’ve taken steps to remove cognitive bias from the evaluation, please don’t ask anyone else to accept it for more or less than it is.
I don’t expect you to accept anything I have to say any more than I expect to ever agree with Anupc’s objectivist leanings.
I don’t double-blind, I do all my evaluation completely sighted, and I believe I control for bias given how often I don’t choose to purchase products that are very highly reviewed by magazines and others. A great example is I recently demoed a Simaudio MOON 810LP phono preamp, which is very highly regarded throughout the industry, and it took me all of thirty seconds to hear that it paled considerably compared to my Audio Research Ref 2 Phono SE. (Likewise it took about the same time to hear how much better the Ref 3 Phono SE sounds when I recently had an opportunity to trade up, and I did.)
You can choose to accept what I have to say or not, but I certainly would never, ever want anyone to make a purchasing decision based upon what I say.
Rather, as with magazine reviews, I would hope at best my words would help others to narrow down what they want to audition, using whatever methodology they choose. (I also only read reviews to determine what I want to audition, and don’t think I’ve ever spent more than a few seconds looking at Stereophile’s published measurements except to check whether amplifiers meet their rated power output.)
If others measure or listen and find no differences and consider me under the influence of snake oil peddlers, so be it; I know what I hear, I do my own testing and select products that make improvements in my system.
Likewise I find myself most often purchasing products from companies that use measurements to determine why what they’ve experimentally determined sounds better sounds better and those that listen to each product to make sure it sounds right before it leaves the factory.
Wadias actually almost always measured poorly in some way, but they were the DAC that previous to my Rossini + Rossini Clock sounded the most like… music, and were the first DAC I heard that ever did, something I never realized listening to earlier CD players until I heard it.
I’m just relating my experiences, feel free to place me in whatever category you choose.
This is just down to electrical noise, which can be bypassed by using an optical connection. There is nothing mystical about it. Clocking Ethernet, and jitter affecting the dac clock is just bs. And the sad part people keep quoting some “measurements” behind a paywall, but no sight of them, and no interpretation.
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Well it’s easy enough for anyone interested in an audio-rated switch to test using a pair of Ethernet to fiber media converters; I recently installed a pair for lightning protection on the Ethernet output from my cable modem.
I can’t say whether they affected sound quality or not as I don’t ever stream audio except from a local file server, and even that’s rare which is why I’ve never tried an audiophile switch for my LAN.
Update:
iFi just released the LAN iSilencer which also galvanically isolates Ethernet but does so in a much. more compact form factor for just US $89, about the same price as a pair of media converters, a pair of SFPs and a fiber optic cable.
And where are your measurements ?