What is the EL34 vacuum tube?

The EL34 (EL34 / 6CA7) is a pentode vacuum tube designed for power (pp) applications. British voice. Marshall tone..

What is a EL34 substitute or equivalent?

Direct equivalents to the EL34 include 6CA7. 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 EL34?

Amplification factor μ ≈ 11, transconductance gm ≈ 11 mA/V, plate resistance rp ≈ 15.0 kΩ, max plate voltage 800 V, max plate dissipation 25 W, heater 6.3 V / 1.5 A.

Is the EL34 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the EL34 as Common 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 EL34 sound like?

British voice. Marshall tone.. 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.

EL34 6CA7 Pentode Vacuum Tube

Also known as 6CA7

Power pentode delivering up to 25W in pentode, UL, or triode mode

PentodeHeater 6.3 V · 1.5 AOctalMullard·Philips 1955

Plate dissipation: 25W
Max plate voltage: 800V
Max screen voltage: 500V
Max cathode current: 150mA
Transconductance: 11mA/V

EL34

Characteristics

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

HeaterIndirectly heated

Specifications of EL34 — Heater
Heater voltageVh	6.3 V
Heater currentIh	1.5 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of EL34 — Limiting values
Plate voltageVa max	800 V
Screen voltageVg2 max	500 V
Plate dissipationPa max	25 W
Screen dissipationPg2 max	8 W
Cathode currentIk max	150 mA
Grid resistorRg1 max	700 kΩ
Peak plate voltageVao	2000 V
Heater–cathode voltageVhk max	100 V

Mechanical

Specifications of EL34 — Mechanical
Base	Octal
Rarity	Common
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of EL34 — Small signal
Transconductance	11 mA/V
Plate resistance	15 kΩ
Amplification factor	11

Capacitances

Specifications of EL34 — Capacitances
Input	15.2 pF
Grid–plate	1.1 pF
Output	8.4 pF

Charactereditorial reading, not a measurement

Specifications of EL34 — Character
Gain	11%
Power	63%
Drive	85%
Linearity	95%

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	B+	Va	Vg2	Vg1 / Rk	Ia	Ig2	Load	Pout	THD	gm	μ	Source
triode connection, single-endedclass not stated · fixed bias		250 V		-15.5 V	70 mA	15 mA				11.5 mA/V	11	read on the sheet Mullard · 1964 · transcript
Class A, single-endedpentode connection · fixed bias		250 V	250 V	-14 V	100 mA	15 mA	2 kΩ	10 W	5%	11 mA/V		OCR, to be checked Svetlana Electron Devices · 1997 · p. 2 · transcript
Class AB, push-pullpentode connection · cathode bias	375 V			130 Ω	75 mA	11.5 mA	3.4 kΩ a-a					OCR, to be checked Philips · 1949 · p. 5 · transcript
Class B, push-pullpentode connection · fixed bias	425 V	420 V		-38 V	30 mA	4.4 mA						OCR, to be checked Philips · 1949 · p. 3 · transcript

Design a stage →

Using this tube

Applications

Power output

Marshall JTM45/JCM800Dynaco Mark IIIMullard 5-20

Guitar amp

Featured in these amplifiers

Classic circuits

Mullard 5-20
Hi-Fi Classic20W
Classic Mullard 20W push-pull ultralinear design. Published 1955. Smooth, warm British tone with excellent linearity.
PPUL 43%Vb 425V · Vg -14.5V · Vg₂ 425V · RL 6.6kΩMullard Application Note
Marantz 8B
Hi-Fi Classic35W
Saul Marantz's refined 35W stereo power amplifier. EL34 ultralinear push-pull with meticulous power supply. Warm, authoritative American hi-fi.
PPUL 43%Vb 410V · Vg -14V · Vg₂ 410V · RL 5kΩMarantz Model 8B Schematic

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : Mullard·Philips datasheetActive model : Norman Koren

Manufacturer datasheets

11 manufacturer datasheets cross-checked for EL34 / 6CA711 verified

Triode-connectedMullarddata sheets dated January 1964 (D1, D2), April 1962 (D3, D4), January 1960 (D5 + curves)

Va: 250 V
Vg1: -15.5 V
Ia: 70 mA
gm: 11.5 mA/V
µ: 11

EL34 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: Mullard·Philips datasheet
Reviewed: 2026-05-29
Status: DataModelCalc
Model: Norman Koren

Context

The EL34 (6CA7) is a power pentode that defines the sound of British high-fidelity and guitar amplification, from Marshall to Mullard. In pentode mode it delivers 25W per pair in push-pull, with a rich, harmonically complex midrange that distinguishes it from the more linear American 6L6 family. The EL34's strong second and third harmonic content gives it a musicality and vocal-like quality that has made it the default output tube in European hi-fi amplifiers for decades. Mullard Blackburn production, Siemens, and Telefunken are the benchmark NOS types; current production from JJ, Tung-Sol (New Sensor), and Shuguang varies significantly in character.

History

Introduced: 1955
Manufacturer: Mullard·Philips
Era: Golden Age

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