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Archive for March 9th, 2016

Vacuum Tube LEDs: Octal Tube on a CD

Mounting an octal tube socket in a CD requires nothing more than printing one from the same OpenSCAD code that produced the Noval socket:

Vacuum Tube Lights - octal socket - Slic3r preview

Vacuum Tube Lights – octal socket – Slic3r preview

Then apply a 1-1/8 inch Greenleee punch to a randomly chosen scrap CD, match-drill two screw holes, push the knurled inserts into the socket, and screw everything together:

Octal socket in CD - screw detail

Octal socket in CD – screw detail

I totally forgot about the raised ring around the central hole, so the OpenSCAD source code now moves the screws outward to 47 mm OC for a bit of head clearance. The 6-32 screws don’t look nearly so large next to that big Bakelite base.

The 2.36 mm tube pins fit perfectly into the (square!) socket holes without reaming.

This 6SN7GTB would definitely benefit from a ersatz plate cap with an LED shining down on the mica spacer; fortunately, the getter flash is on the side, not the top. You can see the plate cap atop the adjacent duodecar tube diffracted in the grooves, so a CD “chassis” will add some pizzazz to a rather drab tube:

Octal socket in CD - LED diffraction

Octal socket in CD – LED diffraction

In person, you see distinct RGB spots, not a continuous spectrum.

This tube has a completely broken-off base spigot (the keyed cylinder around the evacuation tip), so (I think) more light gets through the base than from a cut-off spigot end. Perhaps the plate cap will add enough light to turn the base LEDs into an accent.

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