What is the 6GU7 vacuum tube?

The 6GU7 is a triode vacuum tube designed for preamp applications. Clean driver..

What is a 6GU7 substitute or equivalent?

Direct equivalents to the 6GU7 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 6GU7?

Amplification factor μ ≈ 17, transconductance gm ≈ 3.1 mA/V, plate resistance rp ≈ 5.5 kΩ, max plate voltage 330 V, max plate dissipation 3 W, heater 6.3 V / 0.6 A.

Is the 6GU7 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 6GU7 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 6GU7 sound like?

Clean driver.. 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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6GU7 Triode Vacuum Tube

Dual triode6.3V / 0.6A9-pin NovalSPICE

Sourceaudit-us_a (CLEAN — matches canonical datasheet)Reviewed2026-05-29StatusDataModelCalcModelNorman KorenPDF

Medium-gain triode for driver and line stage applications

Datasheet ↗SPICE

6GU7 — RCA·Sylvania — triode vacuum tube — (1960)

5.5kΩ

3.1mA/V

3.4pF

3.0pF

0.44pF

GAIN17%

POWER8%

DRIVE95%

LINEARITY92%

SPECIFICATIONS

Heater6.3 V · 0.6 A

Max Plate Voltage330 V

Pa max3 W

Gain Factor17

gm3.1 mA/V

rp5.5 kΩ

Inter-electrode capacitances

Cgk3.4 pF

Cgp3 pF

Cpk0.44 pF

Pinout9-pin Noval

Era1960

RarityCommon

HEATER6.3V / 0.6A

MAX PLATE330V / 3W

BASEnoval

SECTIONS2 (dual)

Source datasheets

3 manufacturer datasheets cross-checked for 6GU7

3 verified

TYPICAL OPERATING POINT

Va165V

Ia6.9mA

Vg-7V

Pd1.14W

RL11kΩ

Av24dB

EXECUTIVE SUMMARY

The 6GU7 is a dual indirectly-heated triode from RCA·Sylvania, introduced around 1960. It provides a gain factor (μ) of 17 with 5500Ω plate resistance. Commonly used in preamp applications. Clean driver.

APPLICATIONS

Voltage amplifierLine stagePhase splitter

Generic triode preamp stage

• Hi-Fi stereo• Headphone amp

HISTORY

Introduced1960ManufacturerRCA·Sylvania

Late Production

6GU7 Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

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