What is the 6AH4GT vacuum tube?

The 6AH4GT is a triode vacuum tube designed for driver / otl applications. Driver/OTL medium power..

What are the key specifications of the 6AH4GT?

Amplification factor μ ≈ 8, transconductance gm ≈ 4.5 mA/V, plate resistance rp ≈ 1.8 kΩ, max plate voltage 500 V, max plate dissipation 7.5 W, heater 6.3 V / 0.75 A.

Is the 6AH4GT still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 6AH4GT 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 6AH4GT sound like?

Driver/OTL medium power.. 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.

6AH4GT Triode Vacuum Tube

Low-mu triode with excellent linearity for driver and line stages

TriodeHeater 6.3 V · 0.75 AOctalRCA 1950

Plate dissipation: 7.5W
Max plate voltage: 500V
Transconductance: 4.5mA/V

6AH4GT

Characteristics

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

HeaterIndirectly heated

Specifications of 6AH4GT — Heater
Heater voltageVh	6.3 V
Heater currentIh	0.75 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of 6AH4GT — Limiting values
Plate voltageVa max	500 V
Plate dissipationPa max	7.5 W

Mechanical

Specifications of 6AH4GT — Mechanical
Base	Octal
Rarity	Common
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of 6AH4GT — Small signal
Transconductance	4.5 mA/V
Plate resistance	1.8 kΩ
Amplification factor	8

Capacitances

Specifications of 6AH4GT — Capacitances
Grid–cathode	7 pF
Grid–plate	4.4 pF
Plate–cathode	1.7 pF

Charactereditorial reading, not a measurement

Specifications of 6AH4GT — Character
Gain	8%
Power	19%
Drive	98%
Linearity	95%

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	Vg1 / Rk	Ia	gm	μ	rp	Source
triode connection, single-endedclass not stated · fixed bias	250 V	-33 V	5 mA	4.5 mA/V	8	1.8 kΩ	OCR, to be checked Sylvania · 1953 · p. 1 · transcript

Using this tube

Applications

Push-pull output
Headphone output

Generic triode driver / otl stage

Headphone amp

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : RCA RC-19 6AH4GT · amplifiedpartsActive model : Ayumi Nakabayashi · 2 engines

Manufacturer datasheets

3 manufacturer datasheets cross-checked for 6AH4GT3 verified

6AH4GT DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: RCA RC-19 6AH4GT · amplifiedparts
Reviewed: 2026-05-29
Status: DataModelCalc
Model: Ayumi Nakabayashi · 2 engines

Context

The 6AH4GT is a indirectly-heated triode from RCA, introduced around 1950. It provides a gain factor (μ) of 8 with 1780Ω plate resistance. Commonly used in driver / otl applications. Driver/OTL medium power.

History

Introduced: 1950
Manufacturer: RCA
Era: Golden Age

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