What is the EL156 vacuum tube?

The EL156 is a pentode vacuum tube designed for power (pp) applications. Legendary Telefunken power pentode. Studio icon..

What are the key specifications of the EL156?

Transconductance gm ≈ 11 mA/V, plate resistance rp ≈ 20.0 kΩ, max plate voltage 800 V, max plate dissipation 50 W, heater 6.3 V / 1.9 A.

Is the EL156 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the EL156 as Legendary 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 EL156 sound like?

Legendary Telefunken power pentode. Studio icon.. 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.

EL156 Pentode Vacuum Tube

Power pentode delivering up to 50W in pentode, UL, or triode mode

PentodeHeater 6.3 V · 1.9 A10-pin Y10ATelefunken·Siemens 1956

Plate dissipation: 50W
Max plate voltage: 800V
Max screen voltage: 450V
Max cathode current: 180mA
Transconductance: 11mA/V

EL156

Characteristics

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

HeaterIndirectly heated

Specifications of EL156 — Heater
Heater voltageVh	6.3 V
Heater currentIh	1.9 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of EL156 — Limiting values
Plate voltageVa max	800 V
Screen voltageVg2 max	450 V
Plate dissipationPa max	50 W
Screen dissipationPg2 max	8 W
Cathode currentIk max	180 mA

Mechanical

Specifications of EL156 — Mechanical
Base	10-pin Y10A
Rarity	Legendary
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of EL156 — Small signal
Transconductance	11 mA/V
Plate resistance	20 kΩ

Capacitances

Specifications of EL156 — Capacitances
Input	19 pF
Grid–plate	0.5 pF
Output	7.5 pF

Charactereditorial reading, not a measurement

Specifications of EL156 — Character
Gain	0%
Power	100%
Drive	80%
Linearity	75%

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	Ia	Ig2	Pout	Source
Class A, single-endedpentode connection	350 V	250 V	120 mA	15 mA	15 W	read on the sheet Telefunken · 1965 · transcript
triode connection, single-endedclass not stated	500 V		120 mA		30 W	read on the sheet Telefunken · 1951 · transcript

Using this tube

Interactive loadline calculator not available for this tube yet — it needs calibrated Koren or Ayumi parameters.

Applications

Power output

Generic pentode power (pp) stage

PA/public address

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026

Manufacturer datasheets

2 manufacturer datasheets cross-checked for EL1562 verified

EL156 DatasheetFrank's Electron Tube Pages · PDF

SPICE models

Revision and verification status

Source: Telefunken·Siemens
Reviewed: 2026-05-29
Status: DataModelCalc
Model: under review

Context

The EL156 is a indirectly-heated pentode from Telefunken·Siemens, introduced around 1956. Commonly used in power (pp) applications. Legendary Telefunken power pentode. Studio icon.

History

Introduced: 1956
Manufacturer: Telefunken·Siemens
Era: Golden Age

METRIX TESTER