Anybody want a laugh?

"Noise suppressing capacitors" as linked to in the article are not high grade capacitors. The only thing special about them is their failure mode.

This is not a "special" capacitor configuration. It is almost a given that the power supply in the Cisco switch already has it, as does most switch mode power supplies with a ground connection.

There are many ways to reduce and suppress this noise - installation methods, shielded cabling, filters, etc. One proven way in electronics design would be to replace lower-grade capacitors with noise suppressing capacitors. Here is an example of a capacitor design that reduces EMI/RFI and would have a measurable reductive effect on noise levels if installed into a Cisco switch:

https://www.illinoiscapacitor.com/pdf/Papers/EMI_RFI_suppression_capacitors.pdf

CD318, the best is this for another product. Basically they figured out if you will fall for the marketing blurb of one, you will fall for connecting multiple in series and that you won’t question why the first one did not do the job.

Cumulative process – there is an increased level of Waversa Audio Processing when multiple WNDR capable units are connected, improving sound quality

On another note, and Ethernet connection is galvanically isolated. There is the potential for analog noise to be conducted over an Ethernet configuration and in a poorly designed DAC, I could foresee situations where it could cause an issue.  Of course you can also transmit 100 megabits per second across a fully isolated barrier for <$10 including support circuitry.

This is about amplifiers but it's applicable to everything in audio. It's from Bruno Putzey paper 'The F-word or why there is no such thing as to much feedback" whether you agree doesn't really matter to the quote.

The avoidance of feedback, specifically global feedback, also meant that longer signal chains quickly accumulated distortion products. A relentless drive for minimalist design ensued. If everything one adds to the signal path detracts from the result, only the smallest number of components will do.
This resulted in the ludicrous situation where fantastic sounding recordings were made with signal chains numbering up to a hundred amplifying stages and replayed on audiophile systems where even a transparent buffer proved an impossibility.

Hi-fi review is a complete shambles. The few magazines that do measure are capable of reprint-ing the most frightening distortion spectra from amplifiers and actually call them good. “Objectiv-ity” got downgraded from “independent of who’s doing the observing” to “not favouring particular brands”. For me personally the affair hit rock bottom when in 2009 two reviewers, one Dutch, one British, independently remarked of the same amplifier (a reasonably priced product with exemplary performance) that it sounded surprisingly musical for an amp with such low distortion. In the 21st century audio engineers build equipment while actively avoiding two of the most powerful tools available to the whole of science and engineering: measurement and error control. The damage to the audio industry and its reputation in the wider engineering world will remain immeasurable until we decide to take control.

As a counter point djones51,  someone proved in a blind test with a significant group of audiophiles, that audiophiles couldn't tell when 2.5% distortion was added to their own system with their typical "listening" methods. On the other hand, in a controlled AB situation, engineers could pick up the difference quickly. It may be best to replace the term golden ears with gilded ears :-)

Not surprising, noone here would consider me a true audiophile and I would probably flunk the test too. 😳