Cotton

[Prune]

I want to use cotton as insulator for my DIY interconnects. I have two questions: where can I get unbleached cotton, and what's the best material to seal the cables airtight, so the cotton doesn't absorb moisture?

 

[Magura]

Hmmm....thought of this??



Unless you do some calculations of the pressure increas vs. temperature increase vs. pressure test of cabinet to at least 3 times that, id strongly advice against an airtight cabinet. Its simply a bomb in your livingroom.

Magura

 

[Richard C]

Exploding interconnects

 

[Prune]

Say what? What cabinet? I'm talking about sealed interconnects.

 

[Magura]

Nope...an air tight cabinet....as would be the only way to keep moisture out of the cotton. I find it hard to believe you would be able to seal each wire on its own. The only other option i can think of is polyolefin heat shrink with an inner liner of glue, but its not enough to keep the cotton dry. The only possible way to seal such to a reasonable extent would be to use ptfe heatshrink (terribly expensive) and then dip the whole thing in a silicone compound to seal it off.

Under any circumstances im still to meet the person with adequately golden ears to be able to tell the difference between the isolation type of the wires in a blind test !

Magura

 

[Prune]

I need the cotton to space out the shield far enough from the signal wires (I have lots of EM interference at home), as I can't find large enough Teflon tubing.

BTW I'm all for blind tests, but I'm just maxing this out for fun, to satisfy my fancy eqipment fetish.

 

[Prune]

Heat shrink is not moisture proof?

 

[Richard C]

perhaps you could soak the cotton in some kind of oil.

 

[Magura]

Heat shrink is not moisture proof. Its VERY hard to make anything moistureproof....even by dipping (look at the polycarbonate caps...they suffer from such probs).

I have bought ptfe tube from RS components for a not all that outreageous price, it comes in many sizes. I think id choose that over cotton fiddle faddle, or even worse an air tight cabinet.

Magura

 

[Magura]

Actually you will find that there are very few types of plastics that are reasonably moisture proof. Polyefin isnt one of them. PTFE is closer to be, one of the reasons its a goos isolator. PVC is also not bad, but have a bad tendensy to destroy everything around it at elevated temperatures.

Magura

 

[Prune]

The cables are balanced, so the shield doesn't carry a signal, and thus I'm not worried about what the outermost cover is.

Anyway, let me change the question then: how can I space the shield several milimeters away, if not cotton? Teflon tape is too thin. Some kind of foam, maybe? And of course, where can I get it?

 

[Magura]

As i wrote in an earlier post: PTFE tubing, if you need bigger distance, use several tubes around one another. PTFE tube can be bought in many diametres from RS components.

Th RS number for 1.91mm bore is 399833. For 3.05mm bore its 399849.

Magura