We had this debate on connectors used by other respectful brands before - if a manufacturer uses a cheap part because he finds it sounds better I applause him for using it over nice looking perhaps more solid parts. And I have to say I do not see why modern or new technology forcefully results in better sounding cables - in fact I humbly admit I am completely ignorant in cable sound quality - I can not correlate any cable parameter varying within normal ranges with sound quality. But I know that in my system, some sound great and much better than others.
I realize this is the case with most people and it does make things really difficult for me, I can't convey value when it's not recognized!
I can make cables that sound anyway you'd want them to by careful selection of parts. From warm and lush to bright and etched, it comes with experience from building a lot of cables over a lot of years. I can try to make some observations that may be helpful:
Wire:
- Copper is always warm, which is a better trade-off vs bright and harsh so copper is safe and some prefer it because it is warm. But warmth masks detail, especially in interconnect cables. Different types of copper also have different degrees of warmth... The warmest cable will use lower purity copper in heavier gauges with PVC insulation, anything less than 23g will have an effect on the highs making the sound seem even warmer. PVC adds to the effect, more muddy than warm though. Upgrading to higher purity copper, using wire thinner than 23g will and using teflon insulation will all improve the performance of the cable by reducing warmth and increasing resolution. Litz-type copper wire is made of many runs of very thin copper wire that are individually insulated and arranged so there are no inner or outer wires in the bundle, accomplished by twisting and/or braiding the wires, sometimes around a round or flat former. UPOCC copper is also less warm and more resolving vs typical copper and is about 3% more conductive vs the standard ETP copper.
Some cable companies have their tricks to get copper to perform better such as cryo, very high voltage pulses, using UPOCC copper etc... Kubala Sosna, Tara and Jorma have some copper cables that are far better than most, but they are expensive and still not as resolving and neutral as they could be. But for a lot of people this is a good trade off, especially if they own very accurate hard-coned speakers with similarly accurate SS amps. But imo this is more like compensation for speaker drivers with certain resonant problems combined with electronics that don't hide the truth. Somewhere you're going to need to add something to make this kind of system musical, but cables aren't the answer, amplification is... whether preamp or amp. See the recent reviews of Magico showing with tube amps...
- Silver is never warm and can add some very undesirable traits like accentuated leading edges, harshness, grain... basically what people call an "etched" sound. But it is more resolving than copper and some kinds of silver wire manage to avoid these effects. Silver wire needs to be very pure to avoid these issues, 5N silver is usually pretty good but UPOCC silver is 6N+ and is head and shoulders better than typical silver wire, it's by far the best wire for audio use generally available. It has one issue and that is the timbre of vocals and acoustic instruments can seem a bit light weight. This can be avoided by either using much larger gauges than needed, both Wireworld and Siltech use 17g UPOCC silver in their top end ic cables which is huge overkill. I have a custom UPOCC silver/gold alloy made for me, which provides a very realistic timbre and is the most accurate and neutral wire for audio I have ever tried, by far. It's also the most expensive wire in the world not counting pure gold, platinum, etc wire. Finally, Duelund has 5N silver wire with a mineral oil impregnated silk dielectric. This makes for a silver wire that is almost warm, it's very smooth and has a beautiful tone but it's far from neutral and makes for the most love-it/hate-it cable I've ever seen. It is more resolving than copper and if the tone has good synergy with your system you may love it, if not it can be really bad.
Dielectric: Air and cotton sound very good but allow the wire to corrode over time. I built some cables in cotton and oversized teflon tubes and the wire does corrode over the years. Some will say it doesn't matter but imo that's BS. The truth is it's a subtle difference vs regular teflon insulation, and imo it's far better to have a cable whose wire will not corrode over time. I have made prototype cables with nitrogen gas dielectric and this works pretty well but is much more difficult to manufacture.
Geometry: a litz-type geometry using wire smaller than 23g is key. Coax type cables always sound bad. Side-by-side is missing the opportunity to use noise-canceling geometry, usually these are ribbon cables and while they can sound good it's nowhere near as good as a litz braid.
Connectors: For RCA plugs it hard to beat WBT 0102 Ag, imo they are the king of RCA plugs. For a good bit less of a retail price the Furutech FP-108 are excellent, this is rhodium plated pure copper, the same plugs as the very expensive CF-102 but with a brass body instead of carbon/stainless. Then there's the Furutech FP-126(R), probably the best value for the money available. On speaker cable connectors, they make much less of a difference vs ic cable connectors, but it's still worth it to use good quality pure copper connectors, imo Furutech makes some of the best with their FT-211/212 spades and bananas. WBT is very good but expensive and the Furutech carbon fiber/stainless models feature far nicer construction quality vs WBT and the sound isn't much different.