Gio wrote:
Teflon tubing seems to be the common high-end approach with pure silver wire.
Hi.
Per above progation velocity order chart, Teflon is forth best insulation material, next to foamed PE which is commonly used as the dielectric insulation for all coaxial cables. Unlike foamed PE which must be factory extruded to form a
constant thick dielectric required for any coaxial cable centre conductor, Teflon is a thin & solid material, which can be handled easily by us DIYers.
That's why Teflon is a pretty common hi ranking insulation material for electronic uses, e.g. exotic caps.
Silver, like Teflon, is an expensive metal which should go together with a high performance insulation material, e.g. Teflon, to get the best result. Of course.Teflon can also be used to insulate copper too.
I always use Teflon tubing, simply for its high propagation velocity (v.c.), fast signal transit time (=1.45mS/1,000ft vs 1.06mS/mft of free air) & low low dielectric constant (2.00). This is strictly a scientic choice.
Gio wrote:
what about oxidation of the silver in the loose tubing?
In fact Allan Wright asked me similar question years back as he told me his silver grounding foils tarnished so quickly.
I've chosen loose Teflon tubing because of the air trapped inside the tube. The air foams the 2nd best (next to vacuum) primary dielectric for the silver wire as the wire is now 99% surrounded by the air trapped inside the tubing. The 1% is the tiny point contact between the silver wire & the Teflon tubing inside wall.
Now the conductor inside the flexible tubing is 99% insulated by air which unlike Teflon tubing which cost us money. Air is free to us !!
The very small quantity of air trapped inside the tubing would not tarnish any silver as silver is only attacked by the sulphur oxide gases found in polluted industrial airs which tarnish the silver.
The bare silver wires used in my interconnects & even power cords do not tarnish at all.
The trick is how to make sure the cable is
AIR-tight so that the little trapped inside the loose tubing is kept in & out of the outside polluted air. Once air-tightening is done properly when the cable is built, it should be OK for good unless the end termination of the cable is broken.
So my ideal cables are built with fine metal (Ag) & very best insulation dielectrics (air & Teflon).
c-J
PS: only copper is oxidized by air. So air-tightening for copper cables should be done very carefully.
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