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The TNT K-Sox

a cool DIY sock made with Kevlar for your tubes...

[Italian version]

Product: TNT-Audio K-Sox tube dampers
Manufacturer: Not for sale, do it yourself!
Approx. price: 3 $/meter
Author: Mimmo Cacciapaglia

If you are a tube sound hardcore addict, you surely know tubes are microphonic, i.e. tend to capture airborne vibrations and amplify them through your system.
The HiFi market is crazily full of HiFi accessories that should help minimizing this annoying problem on tube preamps and power amps. Normally, they don't come cheap.
So here comes your beloved TNT-Audio online help :-)
We'll tell you how to home-build your own Kevlar dampers for your tubes at a cost that will make your wallet sing and dance (5 $).

Now, I'm talking about Kevlar here, so the first thing to do is FIND the Kevlar fibers...no, don't fret, this is going to be EAAAASY...

What you need is just this...

Just go to your nearest boating supplies & sailing hardware store and ask for a piece of Kevlar-core line for halyards (6 mm). Even if you don't know what you're saying, don't worry, they'll understand what you mean :-)
Even better, show some deep knowledge in the field and ask for Marlow Ropes stuff...(IMHO, the best ones)
The salesman will think you're a real expert and will go on asking you "Which kind of boat do you have???" Now you should answer: A Sovtek EL 34 :-)
The guy will argue you're talking about a fine 34 feet sloop and will treat you gently :-)
The next question will be: "How many feet/meters do you need?". Now, have a look at the rope, it should have a yellow core (that's pure Kevlar!!!). If so, ask for just 2 meters. The guy will suddenly understand you will use it for something else, but the price will remain the same: 3$ per meter, more or less. The same stuff will cost you an arm and a leg at your HiFi dealer ;-)

Pure Kevlar for less

If you live near the mountains and sailing hardware isn't all that easy to find...ask at your nearest mountain supplies & hardware store, they should have Kevlar-core ropes in stock as well. If you leave far from the mountains and far from the sea...well, please don't ask me where to find this stuff...:-)

And now let the fun begin: start to "extract" the Kevlar core out of the rope, a light traction should do the trick.
You will get several strands of Kevlar fibers, braided together, probably three by three. Just pick one long fiber up and you're done: you have exactly what you need to build your own TNT K-Sox.

Wrap it, dude!

Take your tube and start to wrap the Kevlar fiber around it, starting from the bottom. Keep the "wrapping" as tight as possible, so that the Kevlar fibers remain well "packed" and pretty close to the tube.

Once you've reached the top of the tube you need to go down again, so to properly cover any blank space left out while going "up" the first time.
Now that you've finished you need to glue the two ends together. Do not try to make a knot, because Kevlar fibers are HARD to be knotted. So use a drop of cianoacrylic glue and cut any excess of fiber with strong scissors. You've been warned: Kevlar fibers are tough, my friends!

If you're good enough at "wrapping" the end result should look like the picture on top of this page. If it looks like something else (an ancient ugly egyptian mummy, for example) you need to start again. Patience is the key.

Do the K-Sox work?

The Kevlar fibers DO dampen the tubes. Whether this can improve the sound of your tube gear or not is a differemnt story. Some audiophiles refer the sweet sound of the tubes to be caused exactly by their microphonicity. So you need to experiment by yourself, each tube gear and each tube is different, so personal testing is the key.
On my gear they work just great, let me know your findings, as usual.


Almost any tube damping device can eventually make the tube temperature rise (less dissipaton, that is). So while this is not a real problem with line stage tubes since they run cool, it can be a problem with power tubes and rectifiers, which generally run pretty hot.
As usual, we're not responsible for damages to your gear (or yourself) while using the TNT K-Sox. If in doubt about tubes' temperature and/or if you think it is going too high (a good pro thermometer may help here), stop using the TNT K-SoX (or any other similar device).
Build your K-Sox only when the tubes are COLD and do not touch the tubes when hot.


Before trying expensive commercial tube dampers, give the TNT K-Sox a try. For few dollars they get the job done and even the building procedure takes just few minutes.
Let me know your findings.

Copyright 2000 Mimmo Cacciapaglia - www.tnt-audio.com

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