This is a well known producer of audio related accesoires, amplifiers and more. Amongst these are teflon sockets, precision machined out of exotic materials. Body is CNC milled oout of teflon and the adjustable pins are available in two different materials: Silver plated bronze and Gold plated bronze. These sockets provide a tight fit for the tubes' pins and guarantee a good contact. Worth the money...
Luciano is an Italian who also makes CNC milled sockets a la Yamamoto style, be it that Luciano makes the body with greater outer dimensions and he uses Tellurium Copper for the, also adjustable, pins.
Tellurium is a rare metal and the combination with copper creates unique specifications when used for machining. Taken from the internet: "As a free machining copper tellurium copper is a superior alloy in all applications where products are drilled, turned or machined in some way. Both manual and automatic product lines’ efficiency is several times higher than in the case of traditional pure copper, which is a very ductile metal. For example, the cutting properties of copper can be significantly improved by alloying copper with half a percent of tellurium. The electrical and thermal conductivity and ductility of this free machining copper are only slightly altered. Copper telluride precipitations in the microstructure break up the turnings into chips thus enabling a much higher machining speed than is possible with pure copper. On a machinability rating scale with 100 being for free cutting brass and 20 for copper, tellurium copper is rated at 90."
See these photos (by Luciano) which speak for themselves...
Comparing UX4 sockets.
At first a comparison with Yamamoto: The body has greater outer dimensions making it possible to mount them in (almost) all existing holes by standard UX4 sockets. Ceramic sockets by Johnson and others, have often a greater waver thus mounting holes are further apart. The UX4 sockets from Luciano allow direct use in these holes as well, Yamamoto not. See photos for comparison:
Using Luciano's sockets.
As said, these sockets are easily mounted. Also soldering the pins is no problem and UX4 tubes have a really tight fit, even after numerous tube changing.
When comparing these sockets soundwize, I can not simply state that one sounds better than the other: Soundcharacter is about the same. The Tellurium Copper pins, however, have an effect on focussing. A slightly better focus on instruments and voices is obtained when swapping Yamamoto's Silver for Luciano's... Also staging is a bit more wide, not deeper.
These benefits along with the for direct replacement possibility because of the greater dimensions, makes these UX4 sockets really interesting: Worth the money!
Luciano is willing to make some for you as wel (these are promotional prices):
You can contact Luciano at: jakeband-at-gmail-dot-com (replacing at and dot, you know the drill)