What is the 6GM8 vacuum tube?

The 6GM8 is a triode vacuum tube designed for preamp applications. Low voltage dual triode..

What is a 6GM8 substitute or equivalent?

Direct equivalents to the 6GM8 include ECC86. 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 6GM8?

Amplification factor μ ≈ 14, transconductance gm ≈ 2.6 mA/V, plate resistance rp ≈ 5.0 kΩ, max plate voltage 30 V, max plate dissipation 0.6 W, heater 6.3 V / 0.33 A.

Is the 6GM8 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 6GM8 as Moderate 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 6GM8 sound like?

Low voltage dual triode.. 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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6GM8 Triode Vacuum Tube

Dual triode6.3V / 0.33A9-pin Noval

SourcePhilips ECC86/6GM8 low-V datasheetReviewed2026-05-29StatusDataModelCalcModelunder reviewPDF

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

Datasheet ↗

6GM8 — Philips — triode vacuum tube — (1960)

5.0kΩ

2.6mA/V

3.0pF

1.3pF

1.80pF

GAIN14%

POWER2%

DRIVE95%

LINEARITY93%

SPECIFICATIONS

Heater6.3 V · 0.33 A

Max Plate Voltage30 V

Pa max0.6 W

Gain Factor14

gm2.6 mA/V

rp5.0 kΩ

Inter-electrode capacitances

Cgk3 pF

Cgp1.3 pF

Cpk1.8 pF

Pinout9-pin Noval

Era1960

RarityModerate

HEATER6.3V / 0.33A

MAX PLATE30V / 0.6W

BASEnoval

SECTIONS2 (dual)

Source datasheets

1 manufacturer datasheets cross-checked for 6GM8

1 verified

EXECUTIVE SUMMARY

The 6GM8 is a dual indirectly-heated triode from Philips, introduced around 1960. It provides a gain factor (μ) of 14 with 5000Ω plate resistance. Commonly used in preamp applications. Low voltage dual triode.

APPLICATIONS

Voltage amplifierLine stagePhase splitter

Generic triode preamp stage

• Hi-Fi stereo

HISTORY

Introduced1960ManufacturerPhilips

Late Production

6GM8 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.

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