Vacuum Tube LEDs: Miniature 7-pin Tubes With a Bottom Shield

Apart from the Bakelite bases on octal tubes, I figured there should be no problem shining a light up through the glass envelope. Come to find out that some of the tubes with Miniature 7 bases have an electrostatic shield (?) across the bottom that pretty well blocks the light.

This 6BJ6 has a neatly trimmed octagon:

6BJ6 - octagon shield

6BJ6 – octagon shield

The shield plate, if that’s what it is, doesn’t have a standardized shape. This 6CB6 sports a simple square:

6CB6 Square Shield

6CB6 Square Shield

The Box o’ Hollow State Electronics contains one 6BE6 tube (a heptode with five grids connected to four pins) without a shield:

6BE6 - Clear base

6BE6 – Clear base

Yeah, those pins are rather grotendous.

And another 6BE6 with a semitransparent smudge not connected to anything else; it would look accidental if it weren’t inside the tube:

6BE6 - Tinted Base

6BE6 – Tinted Base

All the shielded tubes are pentodes, for whatever difference that makes.

These tubes may be a bit too small compared to the hard drive platters; Novals will work just fine for my simple purposes.