What is the 6CD6GA vacuum tube?

The 6CD6GA is a tetrode vacuum tube designed for power applications. High-current sweep..

What are the key specifications of the 6CD6GA?

Amplification factor μ ≈ 4, transconductance gm ≈ 7.7 mA/V, plate resistance rp ≈ 7.2 kΩ, max plate voltage 700 V, max plate dissipation 20 W, heater 6.3 V / 2.5 A.

Is the 6CD6GA still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 6CD6GA 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 6CD6GA sound like?

High-current sweep.. 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.

6CD6GA Tetrode Vacuum Tube

Beam power tetrode rated at 20W for high-power output stages

TetrodeHeater 6.3 V · 2.5 AOctalRCA 1955

Plate dissipation: 20W
Max plate voltage: 700V
Transconductance: 7.7mA/V

6CD6GA

Characteristics

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

HeaterIndirectly heated

Specifications of 6CD6GA — Heater
Heater voltageVh	6.3 V
Heater currentIh	2.5 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of 6CD6GA — Limiting values
Plate voltageVa max	700 V
Plate dissipationPa max	20 W

Mechanical

Specifications of 6CD6GA — Mechanical
Base	Octal
Rarity	Common
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of 6CD6GA — Small signal
Transconductance	7.7 mA/V
Plate resistance	7.2 kΩ
Amplification factor	4

Capacitances

Specifications of 6CD6GA — Capacitances
Input	22 pF
Grid–plate	1.1 pF
Output	8.5 pF

Charactereditorial reading, not a measurement

Specifications of 6CD6GA — Character
Gain	4%
Power	50%
Drive	93%
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	Vg2	Vg1 / Rk	Ia	gm	rp	Source
Class A, single-endedpentode connection · fixed bias	175 V		-30 V	75 mA	7.7 mA/V	7.2 kΩ	OCR, to be checked RCA · 1956 · p. 1 · transcript
pentode connection, single-endedclass not stated · fixed bias	175 V	175 V	-30 V	75 mA	7.7 mA/V	7.2 kΩ	OCR, to be checked Tung-Sol · 1962 · p. 2 · transcript

Using this tube

Applications

High-power output

Generic tetrode power stage

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : audit-us_a (CLEAN — matches canonical datasheet)Active model : Koren pentode

Manufacturer datasheets

3 manufacturer datasheets cross-checked for 6CD6GA3 verified

6CD6GA DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: audit-us_a (CLEAN — matches canonical datasheet)
Reviewed: 2026-05-29
Status: DataModelCalc
Model: Koren pentode

Context

The 6CD6GA is a indirectly-heated beam tetrode from RCA, introduced around 1955. It provides a gain factor (μ) of 4 with 7200Ω plate resistance. Commonly used in power applications. High-current sweep.

History

Introduced: 1955
Manufacturer: RCA
Era: Golden Age

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