I test cables without electronic testing equipment. I’m sure my high end system is junk to professionals although I’ve appraised 27 SoCal & San Fran recording studios in my former profession. I must say, the recording engineers had hearing deficiencies by the time they were 50 and result in non-flat sounding studio audio setups in many of them. Luckily, I’m friends with some remastering engineers with superb hearing, Kevin Gray, Steve Hoffman and Robert Pincus. I also do recording and remastering for a local orchestra, choirs, chamber orch., etc.
Back to my testing. I receive up to four versions of a cable, differing sometimes as little as having a 26 gauge versus a 30 gauge conductor or return wire or a copper, silver or rhodium connection difference. I won’t seriously compare them to the current, burned in version until I’ve cooked them as they generally (90% of the time) sound worse to start with. Sometimes, the newest version is better sounding than the current model due to significant changes in the design, such as when the new version reduced capacitance by 50% through additional teflon shielding over conductors and/or returns.
I don’t care that a machine will tell me that they all test the same other than for capacitance, inductance or resistance. The manufacturer tests for the basics. What we do is determine if sonically, we prefer the current version or the new version, usually its the current version. When multiple changes have occurred in the new version and it is significantly better, the manufacturer renames it. This has happened a half dozen times in the past 15+ years. A high percentage of the time, the cables do not meet up to the current version. The manufacturer is continually tinkering with his formulas, design and materials to produce the best cabling he can (although his speaker cables have only seen three or four versions in 20 years and A/C cables maybe three versions in 10 years).
We also test other upscale cables to his cables to see how they compare on at least two systems, mine and his. We’ve tried High Fidelity, Magnan, Kimber, Furutech, Nordost, Audioquest (not all of their cables but a selection over the years) as well as others he has tested on his own. He also take his cables to shows and upscale audio systems locally to compare to their current cabling. Never have compared them to Transparent Audio cabling which retails for 50X more for speaker cabling or Masterbuilt at 100X more. I heard them replace Siltech, Triode Wire and Shunyata as well as shows.
I don’t know what the manufacturer finds as far as the three electrical testable variables in his cables before and after he burns them in/tests them. I or the both of us compare the cables at my house and at his factory for a sonic evaluation. I don’t have any other relationship with the manufacturing of the cabling.