I was directed to this site by a friend recently. I use Wi-fi for my streaming and home networking needs, so ethernet connectivity is not something I have any interest in tangling with.
I like Eric’s approach with his measurement techniques. I vaguely contemplate finding a way to doing my own measurements, but in the end it’s a low priority.
Many years ago I spent a lot of time investigating the use of clip-on ferrites with USB cables.
My original recommendations on this topic appear here:
https://www.head-fi.org/threads/does-chord-dave-system-need-a-dcc.809287/#post-13799263
which was a result of many experiments.
Along the way I learnt that it is possible to create sound quality problems:
- Toroid ferrites with multiple windings
- Some, but not enough ferrites: 8-10 ferrites
In both cases these bring some improvements but also cause some peculiar “etched”, “false detail” effects.
Toroids with multiple windings cause a “high Q” resonance where the strongest filtering is applied, which corresponds with “false detail” and “fizzy stereo image”.
Clip-on ferrites, due to their air gap, introduce an unwanted resonance too. The use of more ferrites eventually seems to tame this resonance though. I ended-up recommending at least 20 ferrites on a USB cable, luckily the Topnisus ferrites are extremely cheap.
After much research and experimentation I found that it’s simplest to cover the full length of a USB cable in ferrites, all of the same type, and all close together.
When treating a cable with ferrites, it’s worth noting that the impedance at each end is relevant to the overall effect of the filtering. When this fact is ignored, some frequency ranges will be made worse by the use of ferrites:
https://youtu.be/jYR49UghNj4?si=RU3O39K47drSHEPK
Naturally, I have read Jim Brown’s (K9YC) guide to ferrites. And many many more documents and videos from that community.
The discussion of ferrites with Chord DACs goes back to here:
It transpires that discussion of ferrites on the Head-fi forum is much much older than these postings I’ve linked. Common-mode RF noise has been a well-kept secret for an annoyingly long time, but it’s getting good exposure now.
I treat my BNC cables and power cables, both alternating and direct current, with complete coverage of clip-on ferrites from end to end.
I hope you don’t mind me using English.
Jawed