RCA Cable Quality

If your system is the same as you posted earlier thread... including a 1969 produced ITT GSX-500 tube receiver, and Fluence Turntable. Then it is probably the quality of your components that is presenting the challenges in hearing the differences in cables. You need a certain level of high resolution components before differences in cables become obvious. 

In the systems I have been assembling for the last fifty years the difference has been noticeable to jaw dropping depending on the components and overall system. 

Cables are like the ultimate audio conundrum.  If you can afford it and like playing around, you can do that, and I have no argument with it.  On the other hand, just being reasonable means sticking with a quality manufacturer with a good rep and a reasonable cost structure, then ensure the connectors are top quality and off you go.  Also, if you're using a MM cartridge, low capacitance would be nice, and mine are from Blue Jeans, "sound" great, and there you go.  This is a funny business, and a profitable one, it would seem if you look at how many manufacturers there are.  I'd stick with someone who's been around for a while.

Have you tried Cardas Clear?

@jimbennet I was not as fortunate to be able to get access to the awesome cable used by the presenter in the Link, but when I followed the same format for their cable test my own finding were identical.

Watch the Link to get the very good advice and the Tutorial.

 https://www.youtube.com/watch?v=iDVoRBjqdek

Mogami 2964 (Cap. 20 pf/ft; 75 ohm)

Belden 1694A (Cap. < 16 pf/ft; 75 ohm)