Maty has linked some pages on the Star Quad architecture and Blue Jeans Cable gives a good brief overview of both RCA and speakers and digital cables from a technical point of view.
Basically, from my point of view, the matter can be summarized as follows:
Balanced cable: is set up with twisted pair or, even more interference-free, with Star Quad
RCA / Cinch cable: should be coaxial cable with the best possible shielding and low capacitance. This means that the higher-capacity Star Quad falls out.
Loudspeaker cable: it is recommended to have a low inductance, shielding is not necessary. Star Quad would be possible here.
Power cables: stay away from do-it-yourself when you don't know what you are doing. For electricians only! But there are many indications for a well-functioning cable ... I built this myself now ...
In addition to the low-capacity RCA cables mentioned here, I came across two other providers who are very interesting here in Germany / Europe.
http://www.funk-tonstudiotechnik.de/Audiokabel-analog.htm and Amazon Goobay 1.5m 2x cinch plug to 2x cinch plug HQ, black
https://www.amazon.de/dp/B000LB7ZMO/ref=cm_sw_r_apan_glt_i_9J86PJ9GK83XRH2GPTYK? psc = 1.
For this purpose
http://www.hifi-forum.de/viewthread-26-24165-2.html
And something else for speaker cables here
http://diyaudioprojects.com/Power/Low-Inductance-DIY-Speaker-Cables/
I like to use amphenol as a plug, I didn't like the Neutrik REAN that much.
With these ingredients you can build yourself snake oil-free no nonsense audio cables or have them assembled. If you then also hear that it sounds better, it is all the more pleasant and if you do not hear anything, you can enjoy a technically good and sensible product that you may even have built yourself. In this respect, it is not bad at all if you are looking for components that you think are of higher quality, I am thinking here of Teflon-insulated cables or 'higher-quality' plugs or the welding process of Blue Jeans cable or silver solder for the connector. All of that makes something, in the worst case a wallet is empty and in the best case you have all the desired effects but the bottom line is that you did it right and that also gives a good feeling ...