What is the 6973 vacuum tube?

The 6973 is a tetrode vacuum tube designed for power applications. Hi-fi output. Magnavox classic..

What are the key specifications of the 6973?

Transconductance gm ≈ 4.8 mA/V, plate resistance rp ≈ 73.0 kΩ, max plate voltage 440 V, max plate dissipation 12 W, heater 6.3 V / 0.45 A.

Is the 6973 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 6973 as Sought-after 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 6973 sound like?

Hi-fi output. Magnavox classic.. 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.

6973 Tetrode Vacuum Tube

Beam power tetrode rated at 12W for high-power output stages

TetrodeHeater 6.3 V · 0.45 A9-pin NovalRCA·Sylvania 1960

Plate dissipation: 12W
Max plate voltage: 440V
Transconductance: 4.8mA/V

6973

Characteristics

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

HeaterIndirectly heated

Specifications of 6973 — Heater
Heater voltageVh	6.3 V
Heater currentIh	0.45 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of 6973 — Limiting values
Plate voltageVa max	440 V
Plate dissipationPa max	12 W

Mechanical

Specifications of 6973 — Mechanical
Base	9-pin Noval
Rarity	Sought-after
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of 6973 — Small signal
Transconductance	4.8 mA/V
Plate resistance	73 kΩ

Capacitances

Specifications of 6973 — Capacitances
Input	9 pF
Grid–plate	0.4 pF
Output	6 pF

Charactereditorial reading, not a measurement

Specifications of 6973 — Character
Gain	0%
Power	30%
Drive	27%
Linearity	75%

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	Ia	gm	Source
Class A, single-endedpentode connection	250 V	46 mA	4.8 mA/V	OCR, to be checked RCA · 1960 · p. 1 · transcript

Using this tube

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Sources

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

Manufacturer datasheets

1 manufacturer datasheets cross-checked for 69731 verified

6973 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 6973 is a indirectly-heated beam tetrode from RCA·Sylvania, introduced around 1960. Commonly used in power applications. Hi-fi output. Magnavox classic.

History

Introduced: 1960
Manufacturer: RCA·Sylvania
Era: Late Production

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