What is the 6HJ5 vacuum tube?

The 6HJ5 is a pentode vacuum tube designed for sweep / power (se) applications. Sweep tube. 2A3-like in triode mode..

What is a 6HJ5 substitute or equivalent?

Direct equivalents to the 6HJ5 include 6DQ5 (no plate cap). 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 6HJ5?

Amplification factor μ ≈ 4, transconductance gm ≈ 10 mA/V, plate resistance rp ≈ 5.0 kΩ, max plate voltage 770 V, max plate dissipation 24 W, heater 6.3 V / 2.25 A.

Is the 6HJ5 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 6HJ5 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 6HJ5 sound like?

Sweep tube. 2A3-like in triode mode.. 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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6HJ5 Pentode Vacuum Tube

Pentode6.3V / 2.25A12-pin Compactron

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

Power pentode delivering up to 24W in pentode, UL, or triode mode

Datasheet ↗

6HJ5 — RCA·GE — pentode vacuum tube — (1965)

5.0kΩ

10.0mA/V

16.0pF

0.8pF

11.00pF

GAIN4%

POWER60%

DRIVE95%

LINEARITY95%

SPECIFICATIONS

Heater6.3 V · 2.25 A

Max Plate Voltage770 V

Pa max24 W

Gain Factor4

gm10 mA/V

rp5.0 kΩ

Inter-electrode capacitances

Cgk16 pF

Cgp0.8 pF

Cpk11 pF

Pinout12-pin Compactron

Era1965

RarityCommon

HEATER6.3V / 2.25A

MAX PLATE770V / 24W

BASEcompactron

Source datasheets

2 manufacturer datasheets cross-checked for 6HJ5

2 verified

EXECUTIVE SUMMARY

The 6HJ5 is a indirectly-heated pentode from RCA·GE, introduced around 1965. It provides a gain factor (μ) of 4 with 5000Ω plate resistance. Commonly used in sweep / power (se) applications. Sweep tube. 2A3-like in triode mode.

APPLICATIONS

Power output

Generic pentode sweep / power (se) stage

HISTORY

Introduced1965ManufacturerRCA·GE

Late Production

6HJ5 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.

SIMILAR PENTODES

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