Something about " reclock " & "dejitter ", which I couldn't comprehend...

Thanks for the references haha, I did buy a Silent Angel Bonn N8, which was also reviewed by Hans.

You don't need to understand. Trust the science and give them your credit card.

HAHA, I'm trying to convince my friend to do the same!

I haven’t watched the video but to add to the issues, as far as Ethernet, there is galvanic isolation, and Ethernet cable grounding that have made a huge difference on my system.  And we thought vinyl was tweeky?  I think digital is far tweakier.

You friend is correct and old Hans doesn't know what the crap he's talking about. As long as the DAC can lock on the signal you're good. 

“I was speechless lol, because I didn’t know about this, and I bough a network switch myself actually, so I seriously would like to prove my point to him!”

So you buy stuff without researching and validation…good going! That’s the exact sort of thing fuels the ASR and archimago disciples 😂

Everything your friend should show you about ethernet. 

http://archimago.blogspot.com/search?q=ethernet

The only two devices that can provide a significant, and if so positive change IMHO are:

• Galvanic USB isolators.  Depends on a lot but $30
• Asyncrhonous Sample Rate Converters.  Their benefit really shines with older DACs that sound a lot better at 96 kHz.  New DACs do a better job internally.

Best,

Erik

But the Bonn N8 actually improves the SQ of my system though, or I'm just being hypnotized hahaha,,,

Perhaps it does improve the SQ. Have you level matched your system with and without the Bonn and listened blind and picked out better than chance with or without? If not,  then I'm glad you enjoy it but I can't take seriously that it really does anything.