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.

6HJ5 Pentode Vacuum Tube

Also known as 6DQ5 (no plate cap)

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

PentodeHeater 6.3 V · 2.25 A12-pin CompactronRCA·GE 1965

Plate dissipation: 24W
Max plate voltage: 770V
Transconductance: 10mA/V

6HJ5

Characteristics

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

HeaterIndirectly heated

Specifications of 6HJ5 — Heater
Heater voltageVh	6.3 V
Heater currentIh	2.25 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of 6HJ5 — Limiting values
Plate voltageVa max	770 V
Plate dissipationPa max	24 W

Mechanical

Specifications of 6HJ5 — Mechanical
Base	12-pin Compactron
Rarity	Common
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of 6HJ5 — Small signal
Transconductance	10 mA/V
Plate resistance	5 kΩ
Amplification factor	4

Capacitances

Specifications of 6HJ5 — Capacitances
Input	16 pF
Grid–plate	0.8 pF
Output	11 pF

Charactereditorial reading, not a measurement

Specifications of 6HJ5 — Character
Gain	4%
Power	60%
Drive	95%
Linearity	95%

datasheet cited · model or editorial reading · catalogue value, no citation attached yet · nothing invented

Using this tube

Interactive loadline calculator not available for this tube yet — it needs calibrated Koren or Ayumi parameters.

Applications

Power output

Generic pentode sweep / power (se) stage

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : audit-us_a (CLEAN — matches canonical datasheet)

Manufacturer datasheets

2 manufacturer datasheets cross-checked for 6HJ52 verified

6HJ5 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: audit-us_a (CLEAN — matches canonical datasheet)
Reviewed: 2026-05-29
Status: DataModelCalc
Model: under review

Context

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.

History

Introduced: 1965
Manufacturer: RCA·GE
Era: Late Production

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