What is the 6GB5 vacuum tube?

The 6GB5 (6GB5 / EL500) is a tetrode vacuum tube designed for sweep / power (se/pp) applications. European sweep tube. Good audio pentode..

What is a 6GB5 substitute or equivalent?

Direct equivalents to the 6GB5 include EL500, PL500. 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 6GB5?

Transconductance gm ≈ 8 mA/V, max plate voltage 275 V, max plate dissipation 17 W, heater 6.3 V / 1.38 A.

Is the 6GB5 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 6GB5 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 6GB5 sound like?

European sweep tube. Good audio pentode.. 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

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6GB5 6GB5 / EL500 Tetrode Vacuum Tube

Tetrode6.3V / 1.38A9-pin Magnoval

Sourceaudit-us_a (CLEAN — matches canonical datasheet)Reviewed2026-05-29StatusDataModelCalcModelunder reviewPDF

Beam power tetrode rated at 17W for high-power output stages

Datasheet ↗

6GB5 / EL500 — Mullard·RCA — tetrode vacuum tube — (1960)

8.0mA/V

12.0pF

0.7pF

8.00pF

GAIN0%

POWER43%

DRIVE50%

LINEARITY75%

SPECIFICATIONS

Heater6.3 V · 1.38 A

Max Plate Voltage275 V

Pa max17 W

Gain Factor—

gm8 mA/V

rp—

Inter-electrode capacitances

Cgk12 pF

Cgp0.7 pF

Cpk8 pF

Pinout9-pin Magnoval

Era1960

RarityCommon

HEATER6.3V / 1.38A

MAX PLATE275V / 17W

BASEmagnoval

Source datasheets

2 manufacturer datasheets cross-checked for 6GB5 / EL500

2 verified

EXECUTIVE SUMMARY

The 6GB5 is a indirectly-heated beam tetrode from Mullard·RCA, introduced around 1960. Commonly used in sweep / power (se/pp) applications. European sweep tube. Good audio pentode.

APPLICATIONS

High-power output

Generic tetrode sweep / power (se/pp) stage

HISTORY

Introduced1960ManufacturerMullard·RCA

Late Production

6GB5 Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

SPICE model not yet available. Loadline calculator requires calibrated Koren parameters.

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