Snake oil of the year?

Linus Tech Tips is a reputable YouTube tech channel. They’re currently investing a lot of money in a new facility so they can test different electronics / accessories.

It’s no surprise that a blind test showed that the claims AQVOX makes about improvements to sound quality are without merit. As the video states, we’re dealing with digital data. If there were audible changes in the sound, then the data must be different when received by the DAC.

You can test this yourself. Connect a PC to your audiophile switch. Select a music file to copy. Create a SHA-512 hash of the file (see below for some tips). Copy that music file to another PC on the switch, network attached storage, or even Google Drive (if you can reach the internet through the switch). Then copy that file back to a different location on the PC. Create a SHA-512 hash of the copy. Compare the SHA-512 ’fingerprints’. If they match, then you know the switch isn’t the source of the change in sound quality.

Generating a SHA-512 hash...

on Windows (at command prompt):

certutil -hashfile [file] sha512

on macOS (using Terminal):

shasum -a 512 [file]

on Linux

sha512sum [file]

@wsrrsw 

I find it hard to take seroiuly folks who haven’t tried equipment they excoriate but haven’t used or been around. Ah the internet.

Well that's good news because In the video, they compared the AQVOX vs. the standard D-Link switch with blind listening tests. Out of two rounds of testing with 10 participants, the AQVOX was selected as the better sounding option once, the standard D-Link switch was selected 4 times, and the rest of the times there was no difference heard. You watched the video, right?

There's no reason why a network switch whose only purpose is to move data without error from point A to point B should change the sound. This is the beauty of digital data. No matter how many times data is moved through the switch, a perfect copy is made on the receiving end. This is fundamental to how digital audio and systems (i.e. PCs, streamers, the internet, etc.) work. Otherwise, none of these things would be usable.

So with that fact in mind, the only way the sound would be different is if somehow the data payload bits were being changed by the switch. That means if you copied a file from one device to another using that switch, it would be different on the receiving end. You can test this yourself with tools built into all the major operating systems in use today. No measurements needed.

Try it with your JCAT switch vs. a normal switch (perhaps on the cable modem or wi-fi router supplied by your ISP).

@thyname 

I'm not sure I follow what you mean by 'leakage'. Do you mean noise?

If so, the minds behind the Ethernet spec thought of this. That's why the cables use twisted pairs of wires and the physical connections are transformer coupled. Additionally, signalling is differential. This is all to reduce noise and ensure error-free data transmission.

Clock phase noise (i.e. jitter) will cause bit errors if at a high enough level. Fortunately, you can check for errors by using the 'netstat -e' command on Windows or the 'netstat -i' command on macOS. On my Macbook Pro, it currently shows zero errors out of ~3.8 M frames received.

@wsrrsw 

I'd like to believe you, but I'm afraid it just doesn't make any sense. If a PSU could improve the performance of a switch, don't you think the Cisco Systems of the world would advertise PSU upgrades for all their switches to get the 'best performance' and sell more product? I'm sure they wouldn't mind the additional revenue.

Here's a test you should try if your family is game - have someone switch out (see what I did there?) your JCAT one day without you knowing. Let them keep track of whether or not you heard a difference over ten trials. Could be fun.

@wsrrsw 

If I'm ever in your neck of the woods, I'll be sure to take you up on the offer!