What is the 6CG7 vacuum tube?

The 6CG7 (6CG7 / 6FQ7) is a triode vacuum tube designed for preamp / line applications. Same as 6SN7 in miniature..

What is a 6CG7 substitute or equivalent?

Direct equivalents to the 6CG7 include 6FQ7. 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 6CG7?

Amplification factor μ ≈ 20, transconductance gm ≈ 2.6 mA/V, plate resistance rp ≈ 7.7 kΩ, max plate voltage 300 V, max plate dissipation 3.5 W, heater 6.3 V / 0.6 A.

Is the 6CG7 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 6CG7 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 6CG7 sound like?

Same as 6SN7 in miniature.. 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.

6CG7 6FQ7 Triode Vacuum Tube

Also known as 6FQ7

Medium-gain triode for driver and line stage applications

Dual triodeHeater 6.3 V · 0.6 A9-pin Noval2 sectionsRCA·GE 1955

Plate dissipation: 3.5W
Max plate voltage: 300V
Amplification factor: 20
Transconductance: 2.6mA/V
Plate resistance: 7.7kΩ

6CG7

Characteristics

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

HeaterIndirectly heated

Specifications of 6CG7 — Heater
Heater voltageVh	6.3 V
Heater currentIh	0.6 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of 6CG7 — Limiting values
Plate voltageVa max	300 V
Plate dissipationPa max	3.5 W
Cathode currentIk max	20 mA

Mechanical

Specifications of 6CG7 — Mechanical
Base	9-pin Noval
Rarity	Common
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of 6CG7 — Small signal
Transconductance	2.6 mA/V
Plate resistance	7.7 kΩ
Amplification factor	20

Capacitances

Specifications of 6CG7 — Capacitances
Grid–cathode	2.3 pF
Grid–plate	4 pF
Plate–cathode	2.2 pF

Charactereditorial reading, not a measurement

Specifications of 6CG7 — Character
Gain	20%
Power	9%
Drive	92%
Linearity	90%

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

Typical operation

Canonical operating pointSPICE model2 availableModel

B+: 300 V
Load: 12 kΩ
Va: 180 V
Ia: 3.9 mA
Vg: -6.6 V
Pd: 0.70 W
Gain: 20.4 dB

At Q: Ayumi Nakabayashi · 2 engines
μ: 19.4
gm: 1.82 mA/V
rp: 10.6 kΩ

Design a stage →

Using this tube

Applications

Voltage amplifier
Phase splitter

Dynaco PAS preampFisher X-100 driver

Hi-Fi stereoHeadphone amp

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Active model : Ayumi Nakabayashi · 2 engines

Manufacturer datasheets

2 manufacturer datasheets cross-checked for 6CG7 / 6FQ72 verified

6CG7 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: RCA·GE
Reviewed: 2026-05-29
Status: DataModelCalc
Model: Ayumi Nakabayashi · 2 engines

Context

The 6CG7 (6FQ7) is a noval-base dual triode electrically equivalent to the octal 6SN7, designed as a miniature replacement when the industry transitioned to 9-pin tubes. It shares the 6SN7's mu of ~20 and plate characteristics, making it a compact alternative for line stage and driver applications. The smaller bottle and noval base sacrifice some of the 6SN7's reputed sonic spaciousness, but the 6CG7 offers practical advantages in chassis layout and availability. RCA clear-top versions are the most popular NOS variant, valued for an open, detailed sound quality.

History

Introduced: 1955
Manufacturer: RCA·GE
Era: Golden Age

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