Back in the early seventies I built a copy of an Ampex 351 stereo tape machine. You can read about it here if you wish. Years later in 1980 I read an article by Walter G. Jung and Richard Marsh called Picking Capacitors. It was this article that changed my thinking on capacitors. (Cables are cylindrical capacitors) I recommend reading it to anyone interested in DIY audio even thirty five years later. Especially the parts on dielectric constants and their related DA.
A couple of years later I tried changing the paper-in-oil capacitors I originally used to ones with a plastic dielectric. I'm not exactly certain just which plastic it was, perhaps polyester or maybe polypropylene but not Teflon. Only coupling caps were changed and the same value was used.
So what happened? Well, the playback equalization changed such that I had to reduce the high frequency response to the limit of the control's rotation. This was using my Ampex standard NAB 15 IPS calibration tape. And the record EQ was also increased and there was not quite enough adjustment to fully compensate. So in essence the high frequency response was boosted over what the PIO capacitors provided. To me this was empirical evidence that a capacitor's dielectric makes a difference.
Actually, the silver is there to protect the teflon.
When polytetrafluoroethylene is hot extruded over copper, some of the fluorine reacts with the metal to create copper fluoride which is not good stuff to have on the wire. Over tin, it creates stannous fluoride which, at those temperatures, is volatile and causes voids to form in the PTFE.
silver fluoride is created when hot extruding over silver, but it's not an issue.
PTFE insulated wire is usually produced to meet a military specification that mostly has to do with resistance to chemical and environmental exposure. The silver plating doesn't enter into the mil spec at all. As cold extrusion methods for PTFE insulated wire have become viable over the last 10 years or so, silver-plated teflon-insulated wire is becoming a thing of the past.
But there is so much of it available as government surplus that there is unlikely to be a shortage.
I like it because the insulation doesn't melt when i solder it. Bought several pounds on ebay ages ago and I'm still using it.
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It's common in instrumentation wiring to use shielded twisted pair for that kind of job.
The signal and return wires are twisted together, and the shield is connected to the return on ONE END ONLY.
It's worth pointing out that apparently when 30ga silver plated stranded PTFE insulated wire was used to rewire phonograph tone arms, people did find that although it's a dream to work with (as super fine wires go), it did attenuate HF a bit.
But that's a much smaller signal through a much smaller wire.
But that's a much smaller signal through a much smaller wire.
But stannous fluoride is good in toothpaste
In a chassis, the lengths of the coax won't be more than a foot or so, so it won't have much effect on the sound beyond keeping the hum out. If it's a new build I'd place the preamp circuit next to the input jacks, and far away from the power supply and output stages and transformers. To make the input signal paths short. If needed, you could place the volume pot nearby, and use shaft extenders to have the control knob be out front of the chassis.
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