The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

The New Hotness

  • Metal-case 5T4 Vacuum Tube Opened

    I’ve always wondered what’s inside a metal-case vacuum tube:

    Dual rectifier tube 5T4 - metal case opened
    Dual rectifier tube 5T4 – metal case opened

    The cutter last saw action on the EMT used in the MPCNC, so it’s intended for use on steel tubes. I thought about parting the case off in the lathe, but a tubing cutter sufficed for a first attempt, even if it couldn’t cut quite as close to the flange as I wanted.

    A 5T4 tube is a full-wave rectifier with two sections:

    Dual rectifier tube 5T4 - upright
    Dual rectifier tube 5T4 – upright

    Unsurprisingly, the guts resemble those of glass-envelope rectifier tubes in my collection, like this 5U4GB:

    5U4GB Full-wave vacuum rectifier - cyan red phase
    5U4GB Full-wave vacuum rectifier – cyan red phase

    The metal case would be far more rugged than a glass bottle and, perhaps, the flange locked the tube into its socket against vibration.

    The filaments surely weren’t thoriated, so it’s all good …