What is the 12E1 vacuum tube?

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

What is a 12E1 substitute or equivalent?

Direct equivalents to the 12E1 include None. These share the same pinout and operating envelope, so they can usually be swapped without circuit changes — though batch-to-batch variations between manufacturers (NOS vs current production) may shift the sonic character noticeably.

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.

By Jean-Michel Falligan Devergne · Reviewed May 29, 2026

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12E1 Tetrode Vacuum Tube

Tetrode12.6V / 1.6AB9GSPICE

Sourcevinylsavor 12E1 / vacuumtubes.ioReviewed2026-05-29StatusDataModelCalcModelKoren pentodePDF

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

Datasheet ↗SPICE

12E1 — Ediswan/Mullard/STC — tetrode vacuum tube — (1955)

14.0mA/V

23.0pF

0.8pF

8.00pF

GAIN5%

POWER88%

DRIVE50%

LINEARITY95%

SPECIFICATIONS

Heater12.6 V · 1.6 A

Max Plate Voltage800 V

Pa max35 W

Gain Factor5

gm14 mA/V

rp—

Inter-electrode capacitances

Cgk23 pF

Cgp0.85 pF

Cpk8 pF

PinoutB9G

Era1955

RarityModerate

HEATER12.6V / 1.6A

MAX PLATE800V / 35W

BASEoctal

Source datasheets

2 manufacturer datasheets cross-checked for 12E1

2 verified

EXECUTIVE SUMMARY

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

APPLICATIONS

High-power output

Generic tetrode power stage

• PA/public address

HISTORY

Introduced1955ManufacturerEdiswan/Mullard/STC

Golden Age

12E1 Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

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