What is the EL84 vacuum tube?

The EL84 (EL84 / 6BQ5) is a pentode vacuum tube designed for power (pp/se) applications. Sweet, musical. Vox AC30 soul..

What is a EL84 substitute or equivalent?

Direct equivalents to the EL84 include 6BQ5. 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 EL84?

Amplification factor μ ≈ 19, transconductance gm ≈ 11.3 mA/V, plate resistance rp ≈ 38.0 kΩ, max plate voltage 300 V, max plate dissipation 12 W, heater 6.3 V / 0.76 A.

Is the EL84 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the EL84 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 EL84 sound like?

Sweet, musical. Vox AC30 soul.. 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.

EL84 6BQ5 Pentode Vacuum Tube

Also known as 6BQ5

Power pentode delivering up to 12W in pentode, UL, or triode mode

PentodeHeater 6.3 V · 0.76 A9-pin NovalMullard·Philips 1953

Plate dissipation: 12W
Max plate voltage: 300V
Max screen voltage: 300V
Max cathode current: 65mA
Transconductance: 11.3mA/V

EL84

Characteristics

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

HeaterIndirectly heated

Specifications of EL84 — Heater
Heater voltageVh	6.3 V
Heater currentIh	0.76 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of EL84 — Limiting values
Plate voltageVa max	300 V
Screen voltageVg2 max	300 V
Plate dissipationPa max	12 W
Screen dissipationPg2 max	2 W
Cathode currentIk max	65 mA
Grid resistorRg1 max	1 MΩ
Peak plate voltageVao	550 V
Heater–cathode voltageVhk max	100 V

Mechanical

Specifications of EL84 — Mechanical
Base	9-pin Noval
Rarity	Common
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of EL84 — Small signal
Transconductance	11.3 mA/V
Plate resistance	38 kΩ
Amplification factor	19

Capacitances

Specifications of EL84 — Capacitances
Input	10.8 pF
Grid–plate	0.5 pF
Output	6.5 pF

Charactereditorial reading, not a measurement

Specifications of EL84 — Character
Gain	19%
Power	30%
Drive	62%
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	Pout	THD	gm	μ	rp	Source
Class A, single-endedpentode connection · fixed bias	250 V	250 V	-8.4 V	36 mA	4.1 mA	7 kΩ			10 mA/V	19		OCR, to be checked PHILIPS · 1953 · p. 3 · transcript
pentode connection, single-endedclass not stated · fixed bias	250 V	250 V	-7.3 V	48 mA	5.5 mA				11.3 mA/V		38 kΩ	OCR, to be checked MULLARD · 1961 · p. 1 · transcript
triode connection, single-endedclass not stated · cathode bias	250 V		130 Ω	44 mA	5.1 mA	5.3 kΩ	5.4 W	12.5%				OCR, to be checked MULLARD · 1961 · p. 3 · transcript
Class A, push-pullpentode connection · cathode bias	250 V		270 Ω	34 mA		3.5 kΩ a-a						OCR, to be checked Ei-RC · non datee (style "www.eierc.com" -> annees 1990s/2000s) · p. 7 · transcript

Using this tube

Applications

Power output

Vox AC15/AC30Fender Blues JuniorMatchless DC-30

Guitar amp

Featured in these amplifiers

Classic circuits

Mullard 5-10
Hi-Fi Classic10W
Mullard 10W push-pull ultralinear amplifier. Compact, musical design widely cloned. Sweet midrange character.
PPUL 43%Vb 300V · Vg -7.5V · Vg₂ 300V · RL 8kΩMullard 5-10 Circuit
Vox AC30
Guitar Amp30W
Vox AC30/6 with Top Boost. Four EL84 cathode-biased push-pull. Chimey, jangly cleans with rich harmonic overdrive. Beatles, Queen, U2.
PPVb 320V · Vg -8V · Vg₂ 320V · RL 8kΩVox AC30 Schematic

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : Mullard·Philips datasheetActive model : Koren v1

Manufacturer datasheets

12 manufacturer datasheets cross-checked for EL84 / 6BQ512 verified

EL84 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: Mullard·Philips datasheet
Reviewed: 2026-05-29
Status: DataModelCalc
Model: Koren v1

Context

The EL84 (6BQ5) is a miniature power pentode delivering about 6W per tube in single-ended or 14W per pair in push-pull, developed by Philips/Mullard in the early 1950s. It is the output tube of the Vox AC15 and AC30 amplifiers, giving those amps their chimey, harmonically rich character with a distinctive Class A compression. The tube's compact size and modest power supply requirements make it ideal for small to medium-power amplifiers. Despite its diminutive stature, a well-designed EL84 push-pull amplifier can drive moderately efficient speakers with surprising authority and musical engagement.

History

Introduced: 1953
Manufacturer: Mullard·Philips
Era: Golden Age

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