Makes tubes less microphonic and lowers distortion
Duende Criatura tube rings or tube dampeners considerably reduce distortion and self-oscillation from audio tubes. They have to be slid around the top part of the tube where they reduce mechanical vibrations in the tube. You will notice improvement of three dimensional picture, a more controlled bass and cleaner sound stage.
Duende Criatura tube rings are made of pure teflon and titanium. Simply slide the ring over the top of a vacuum tube. They reduce mechanical vibrations and stabilize the operating temperature of the tube's filaments. This not only creates better conditions for the operation of vacuum tubes but also improves the tube's longevity.
The precision-machined teflon base ring is very dense which provides excellent damping properties. They can withstand temperatures of up to 260 degrees, which is much higher than the operating temperatures of vacuum tubes ranging from 160 to a maximum of 220 degrees. A pure titanium clamp is used to provide a strong and stable pressure over the teflon ring to increase the effect. Titanium has been used because tube circuits are sometimes sensitive to eddy currents. Titanium, unlike other metals do not carry induce eddy currents. Duende Criatura tube rings are very durable and last indefinitely.
All vacuum tube types and sizes in any part of a circuitry will benefit from Duende Criatura tube rings. For proper effect the rings should be placed around the top of the tube as shown in the photo. This will allow the tube to properly dissipate heat.
Audio Candy by Paul Candy @ 6moons.com (November 2004):
We all know that vacuum tubes are vulnerable to air and structure-borne vibrations which can have negative effects on music playback. Duende Criatura's Tube Rings are simple Teflon rings that are slit to expand slightly while slipping over a tube. There's a groove around the outer portion which contains a Titanium retainer clamp to ensure a tensioned fit. Lightweight and flexible, the manufacturer (who makes jewelry in his non-audiophile life) claims that Titanium will not induce eddy currents into sensitive tube circuitry. You simply slide these dampers over the tube and seat them at the top portion roughly where the getter resides. The Teflon can withstand temperatures up to 260 degrees and will not melt or stick to the tubes (hey, it's Teflon!). Nor will it accumulate any dust or alter color. Providing you position the ring correctly, it will not affect the tube's ability to dissipate heat nor alter its operating temperature.
Just sliding the rings on the input and phase splitter tubes of my Stingray created immediate benefits. The soundstage was slightly wider and deeper and gained sharper focus and greater separation between performers. It was easier to pick out subtle details in the music to offering a more involving listening experience. These effects were immediately audible even during A/B/A comparisons. The result was magnified yet again when I slipped these thermionic prophylactics on the Manray's EL84s, with the added bonus of deeper, more powerful bass and a greater sense of dynamic agility.
Roy Gregory @ Hi-Fi+ (issue 28 December 2003):
Anybody with a tubeamp, especially an open chassis model should investigate these plain looking little rings immediately...
...They're now considered essential as far as I am concerned, and bring new meaning to the term ‘Simply The Best’."