What is the 12E1 vacuum tube?

The 12E1 is a tetrode vacuum tube designed for power applications. British military pentode..

What are the key specifications of the 12E1?

Amplification factor μ ≈ 5, transconductance gm ≈ 14 mA/V, max plate voltage 800 V, max plate dissipation 35 W, heater 12.6 V / 1.6 A.

Is the 12E1 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 12E1 as Moderate availability. NOS (new-old-stock) examples from RCA, Mullard, Tung-Sol, GE, Sylvania and Telefunken trade among collectors; modern production where it exists comes mostly from JJ Electronic, Electro-Harmonix, Tung-Sol (New Sensor), Genalex, and a handful of small-batch makers.

What does the 12E1 sound like?

British military pentode.. Sonic character also depends heavily on the circuit operating point, the surrounding tubes in the stage, and the output transformer when present — use the interactive loadline calculator on this page to explore the trade-offs.

12E1 Tetrode Vacuum Tube

Beam power tetrode rated at 35W for high-power output stages

TetrodeHeater 12.6 V · 1.6 AB9GEdiswan/Mullard/STC 1955

Plate dissipation: 35W
Max plate voltage: 800V
Max screen voltage: 150V
Transconductance: 14mA/V

12E1

Characteristics

Datasheet values, once each. Every value cites its sheet.

HeaterIndirectly heated

Specifications of 12E1 — Heater
Heater voltageVh	12.6 V
Heater currentIh	1.6 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of 12E1 — Limiting values
Plate voltageVa max	800 V
Screen voltageVg2 max	150 V
Plate dissipationPa max	35 W

Mechanical

Specifications of 12E1 — Mechanical
Base	B9G
Rarity	Moderate
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of 12E1 — Small signal
Transconductance	14 mA/V
Amplification factor	5

Capacitances

Specifications of 12E1 — Capacitances
Input	23 pF
Grid–plate	0.85 pF
Output	8 pF

Charactereditorial reading, not a measurement

Specifications of 12E1 — Character
Gain	5%
Power	88%
Drive	50%
Linearity	95%

datasheet cited · model or editorial reading · catalogue value, no citation attached yet · nothing invented

Using this tube

Applications

High-power output

Generic tetrode power stage

PA/public address

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : vinylsavor 12E1 / vacuumtubes.ioActive model : Koren pentode

Manufacturer datasheets

2 manufacturer datasheets cross-checked for 12E12 verified

12E1 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: vinylsavor 12E1 / vacuumtubes.io
Reviewed: 2026-05-29
Status: DataModelCalc
Model: Koren pentode

Context

The 12E1 is a indirectly-heated beam tetrode from Ediswan/Mullard/STC, introduced around 1955. Commonly used in power applications. British military pentode.

History

Introduced: 1955
Manufacturer: Ediswan/Mullard/STC
Era: Golden Age

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