It is interesting how certain things affect the sound we perceive. I struggle with the use of copper alloys having less than half the conductivity of copper as connectors when audiophiles make such a big deal about OCC vs. OFC wire, which has a conductivity difference of only about 1% IACS. The Furutech GTX-D receptacles use pure copper blades, as does the Cardas receptacle, which may explain why those have been so well received in the audio community for so long. Below is from the Furutech literature:
Of course everyone would love to make pure-copper receptacles, but its malleability – lack of stiffness – makes pure copper a poor choice. That’s why you’ll find less conductive metals such as beryllium copper, phosphor bronze, or brass in some receptacles. Furutech’s intense engineering scrutiny has resulted in an industry-first, a technique allowing us to use special Furutech 24k gold- or rhodium-plated α (Alpha) pure copper conductors strengthened and sprung by our innovative nonmagnetic Stainless Steel Conductor Spring System that keeps a firm grip yet won’t damage male connector blades or their plated surfaces. Even the screw-down pressure plates are curved to maximize contact area. The GTX receptacle can be summed up in a word; virtuoso!