Anybody want a laugh?

In a double-blind test, it would be much more difficult to determine any improvement with an upgraded network switch with a system that was not optimized. Comparing a network switch is considerably different than comparing another component - such as a power conditioner.

And I’m asserting that no system, at any price, will make that $500 switch a worthwhile purchase. 

Yup, good for a grin at least....toss some meat into the cage and watch the fur fly over fluff...;)

....but my popcorns' gone cold, so ciao'

While the basic exterior armature is built to resist vibration, the structure itself is also designed to “float”, providing even more effective vibration suppression. This airborne structure makes it almost impossible to transfer vibrations, so there is no sound distortion due to vibration.

Hmmmmmmm...Calling Peter Belt. To his credit, many of his ideas agree or not, did not require a financial outlay. Not as witty as Donald Fagen’s notes on the making of Can’t Buy A Thrill But you get the picture.

4. Jeff Baxter had a theory that one of the secretaries at the ABC offices had several sets of interchangeable breasts which she would alternate wearing from day to day. This turned out to be incorrect.

Kyle would be proud!

I have no idea whether this modified switch will reduce audible noise on a stereo system. However, EMI/RFI noise is a major issue in building physical networks. Here is a link to a Cisco switch install guide, read the part about EMI/RFI. Note this section is included in all Cisco data center-grade switch install guides, because EMI/RFI noise produced by switches is both real and sometimes does interfere with the signal. 

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst4900/4948E/installation/guide/4948E_ins/0...

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

The OP could be correct that the modifications made to the referenced EBay switch will make no audible difference. But, there’s no way to know without actually testing the original and modified devices. 

However, the OP and some other posters are quite incorrect in asserting that switches don’t pass measurable EMI/RFI noise along with the signal - they do, as Cisco warns in their install guides. And, they are incorrect in asserting that it’s not possible to measurably reduce that noise with potential for an audible effect - Cisco gives us a few tips for how to do it, and we know that noise reducing capacitors are routinely incorporated in electronic designs for this exact purpose. 

Phasemonger