What is the 6BQ5 vacuum tube?

The 6BQ5 (6BQ5 / EL84) is a pentode vacuum tube designed for power (pp/se) applications. American EL84..

What is a 6BQ5 substitute or equivalent?

Direct equivalents to the 6BQ5 include EL84. 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 6BQ5?

Amplification factor μ ≈ 20, 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 6BQ5 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 6BQ5 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 6BQ5 sound like?

American EL84.. 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

←6BQ5

← 6BL7 6BQ6GTB →Compare → EL84

6BQ5 6BQ5 / EL84 Pentode Vacuum Tube

Pentode6.3V / 0.76A9-pin NovalSPICE

SourceAmperex datasheetReviewed2026-05-29StatusDataModelCalcModelKoren v1PDF

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

Datasheet ↗SPICE

6BQ5 / EL84 — Amperex — pentode vacuum tube — (1953)

38.0kΩ

11.3mA/V

10.8pF

0.5pF

6.50pF

GAIN20%

POWER30%

DRIVE62%

LINEARITY90%

SPECIFICATIONS

Heater6.3 V · 0.76 A

Max Plate Voltage300 V

Pa max12 W

Gain Factor20

gm11.3 mA/V

rp38.0 kΩ

Inter-electrode capacitances

Cgk10.8 pF

Cgp0.5 pF

Cpk6.5 pF

Pinout9-pin Noval

Era1953

RarityCommon

HEATER6.3V / 0.76A

MAX PLATE300V / 12W

BASEnoval

Source datasheets

3 manufacturer datasheets cross-checked for 6BQ5 / EL84

3 verified

EXECUTIVE SUMMARY

The 6BQ5 is a indirectly-heated pentode from Amperex, introduced around 1953. It provides a gain factor (μ) of 20 with 38.0kΩ plate resistance. Commonly used in power (pp/se) applications. American EL84.

APPLICATIONS

Power output

Vox AC15/AC30Fender Blues JuniorMatchless DC-30

• Guitar amp

VS EL84

μ +5%Rp +0%Pd 0%Full comparison →

HISTORY

Introduced1953ManufacturerAmperex

Golden Age

6BQ5 Datasheet

Local mirror · PDF

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METRIX TESTER

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SIMILAR PENTODES

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12SJ7Preamp 307APower/Output 310APreamp 35LR6Sweep / Power 47Power/Output 4P1LPower (SET output) — DHT pentode 5639Video / wideband (power)5654RF / Preamp

6BQ5 6BQ5 / EL84 Pentode Vacuum Tube

Source datasheets

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