3DJ3 Vacuum Tube

Note: The product photo is a representative example. Actual tube appearance — including label style, glass envelope shape, and getter position — varies by manufacturer and production era.

A Rare Subminiature Tube for Specialized Applications

The 3DJ3 is a subminiature vacuum tube — a pencil-style triode designed for compact, low-power applications where space was at a premium. Subminiature tubes like the 3DJ3 were developed for military, hearing aid, and portable electronics applications in the late 1940s and 1950s, where the bulk of a standard octal or noval tube was simply not an option. Today they are sought by restorers working on the specialized equipment that used them, and by builders who appreciate the engineering ingenuity of this miniaturized format.

Tested and Ready to Install

Every 3DJ3 we sell is individually inspected before it ships — checked for emission, shorts, and noise. You receive a tube that is ready to install and perform. The subminiature wire-lead construction is consistent with the original specification. One tube per order. Inquire about specific brands at a 20% premium, or ask about tested used tubes for a 20% discount.

For the Specialist Restorer

Subminiature tubes are not commodity parts — they are specialist components for restorers who know exactly what they need. If your equipment calls for a 3DJ3, this is the correct replacement. Stock your bench with the right part and restore your equipment to its original performance standard.

Specifications:

• Type: Subminiature triode (pencil tube)
• Base: Wire leads (subminiature)
• Application: Portable electronics, military equipment, hearing aids, specialized audio
• Condition: Tested and inspected
• Includes: 1 tube per order
• Premium brands available: +20% (inquire)
• Tested used tubes available: −20% (inquire)