What is the EL12 vacuum tube?

The EL12 (EL12 / EL12 Spez) is a pentode vacuum tube designed for power (se/pp) applications. Telefunken Spezial. Klangfilm cinema sound..

What are the key specifications of the EL12?

Amplification factor μ ≈ 18, transconductance gm ≈ 15 mA/V, plate resistance rp ≈ 30.0 kΩ, max plate voltage 250 V, max plate dissipation 18 W, heater 6.3 V / 1.2 A.

Is the EL12 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the EL12 as Rare 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 EL12 sound like?

Telefunken Spezial. Klangfilm cinema sound.. 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.

EL12 EL12 Spez Pentode Vacuum Tube

Power pentode delivering up to 18W in pentode, UL, or triode mode

PentodeHeater 6.3 V · 1.2 A8-pin Side Contact Y8A + Top CapTelefunken 1938

Plate dissipation: 18W
Max plate voltage: 250V
Max screen voltage: 350V
Max cathode current: 90mA
Transconductance: 15mA/V

EL12

Characteristics

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

HeaterIndirectly heated

Specifications of EL12 — Heater
Heater voltageVh	6.3 V
Heater currentIh	1.2 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of EL12 — Limiting values
Plate voltageVa max	250 V
Screen voltageVg2 max	350 V
Plate dissipationPa max	18 W
Cathode currentIk max	90 mA
Grid resistorRg1 max	1 MΩ
Heater–cathode voltageVhk max	50 V

Mechanical

Specifications of EL12 — Mechanical
Base	8-pin Side Contact Y8A + Top Cap
Rarity	Rare
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of EL12 — Small signal
Transconductance	15 mA/V
Plate resistance	30 kΩ
Amplification factor	18

Capacitances

Specifications of EL12 — Capacitances
Input	15 pF
Grid–plate	0.7 pF
Output	8.5 pF

Charactereditorial reading, not a measurement

Specifications of EL12 — Character
Gain	18%
Power	45%
Drive	70%
Linearity	91%

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

Typical operation

Conditions published by the manufacturers, one row per condition. Nothing is computed.

Typical operation
Setup	Va	Vg2	Vg1 / Rk	Ia	Ig2	Load	gm	μ	Source
Class A, single-endedpentode connection	250 V	250 V	-7 V	72 mA	8 mA	25 kΩ	15 mA/V	8	read on the sheet Philips · 1948 · transcript

Using this tube

No interactive loadline model for this tube yet — download a SPICE model below to simulate it in LTspice or ngspice.

Applications

Power output

Generic pentode power (se/pp) stage

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : Telefunken EL12 (radiomuseum.org)

Manufacturer datasheets

4 manufacturer datasheets cross-checked for EL12 / EL12 Spez4 verified

EL12 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: Telefunken EL12 (radiomuseum.org)
Reviewed: 2026-05-29
Status: DataModelCalc
Model: under review

Context

The EL12 is a indirectly-heated pentode from Telefunken, introduced around 1938. It provides a gain factor (μ) of 18 with 30.0kΩ plate resistance. Commonly used in power (se/pp) applications. Telefunken Spezial. Klangfilm cinema sound.

History

Introduced: 1938
Manufacturer: Telefunken
Era: Pre-War

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