Agree the lower purity copper of both items is a strike or two against them. However what has encouraged me to experiment with these as simple ground box cable substitutes in the first instance is my very positive experience with 5cm and 2.5cm wide copper foil tape I shared previously. It very audibly complemented the 14Awg X2 wires, being run in parallel to the ground box. The purity of that copper tape wouldn't have been that high either. Only reason I've since removed the copper foils from the OCK-2 is the messiness. I still have them on my LHY switch but they'll be coming off there too. A tube or sleeve appeals in this respect (neatness) and may have audible electrical advantages if one believes the theoretical ideal.
The other reason for trying it, is as stated, to explore the tube as ideal conductor concept. Admittedly this could be done to a higher standard with Mundorf foils or wires and I may also try this, but I'll start cheap.
Additional reasons - for the braided sheath at least - is that I have read in several places that braided cables are - for some reason - favoured for grounding. The exterior cross section of the Shunyata ground cable I referred has a quasi braided topography (photo below). Also, the 8m earth cable from my Puritan Ground Master to my dedicated ground rod is - by chance - a braided old copper speaker cable, the twin conductors equivalent to say 9-10AWG. And it sounds very good. Connecting the earth rod up brought a significant lift to my system. Though I concede I have not AB'd it to another non-braided 8m length...
If both of these (the tubes and the braid) turn out to be inferior as ground box cables then nay bother - they're cheap. They could also be repurposed for cable shielding experimentation. Or potentially, for the largest gauge of braid (2cm wide - approx 6AWG per the 3M spec for their equivalent sized braid) as my earth cable from my Puritan Ground Master to my dedicated ground rod where for the long run the low impedance path likely becomes more paramount. It also gets a little pricey running higher purity cables in a high gauge, though I shan't rule out trying say a 5x 10m stack of Mundorf foils one day
![Smiling face with sunglasses :sunglasses: 😎](https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f60e.png)
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I acknowledge the subtleties and fine balance of grounding cable design you've experienced. I am going off piste on a slightly different direction focussed on thin film conductors, in my own style, and I may make useful discoveries, or I may not. The process is what I find interesting and as stated I am encouraged by my experimentation with foils to date in this context.