What is the 6AH4GT vacuum tube?

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

What is a 6AH4GT substitute or equivalent?

Direct equivalents to the 6AH4GT include None. 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 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.

By Jean-Michel Falligan Devergne · Reviewed May 29, 2026

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6AH4GT Triode Vacuum Tube

Triode6.3V / 0.75AOctalSPICE

SourceRCA RC-19 6AH4GT · amplifiedpartsReviewed2026-05-29StatusDataModelCalcModel2 enginesPDF

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

Datasheet ↗SPICE

6AH4GT — RCA — triode vacuum tube — (1950)

1.8kΩ

4.5mA/V

7.0pF

4.4pF

1.70pF

GAIN8%

POWER19%

DRIVE98%

LINEARITY95%

SPECIFICATIONS

Heater6.3 V · 0.75 A

Max Plate Voltage500 V

Pa max7.5 W

Gain Factor8

gm4.5 mA/V

rp1.8 kΩ

Inter-electrode capacitances

Cgk7 pF

Cgp4.4 pF

Cpk1.7 pF

PinoutOctal

Era1950

RarityCommon

HEATER6.3V / 0.75A

MAX PLATE500V / 7.5W

BASEoctal

Source datasheets

3 manufacturer datasheets cross-checked for 6AH4GT

3 verified

TYPICAL OPERATING POINT

SPICE model(2 available)2 .subckt available ↓

Va250V

Ia20.49mA

Vg-25.021833512584706V

Pd5.12W

RL6kΩ

Av16.7dB

EXECUTIVE SUMMARY

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.

APPLICATIONS

Push-pull outputHeadphone output

Generic triode driver / otl stage

• Headphone amp

HISTORY

Introduced1950ManufacturerRCA

Golden Age

6AH4GT Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

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