What is the 6973 vacuum tube?

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

What is a 6973 substitute or equivalent?

Direct equivalents to the 6973 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 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.

By Jean-Michel Falligan Devergne · Reviewed May 29, 2026

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6973 Tetrode Vacuum Tube

Tetrode6.3V / 0.45A9-pin NovalSPICE

Sourceaudit-us_a (CLEAN — matches canonical datasheet)Reviewed2026-05-29StatusDataModelCalcModelKoren pentodePDF

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

Datasheet ↗SPICE

6973 — RCA·Sylvania — tetrode vacuum tube — (1960)

73.0kΩ

4.8mA/V

9.0pF

0.4pF

6.00pF

GAIN0%

POWER30%

DRIVE27%

LINEARITY75%

SPECIFICATIONS

Heater6.3 V · 0.45 A

Max Plate Voltage440 V

Pa max12 W

Gain Factor—

gm4.8 mA/V

rp73.0 kΩ

Inter-electrode capacitances

Cgk9 pF

Cgp0.4 pF

Cpk6 pF

Pinout9-pin Noval

Era1960

RaritySought-after

HEATER6.3V / 0.45A

MAX PLATE440V / 12W

BASEnoval

Source datasheets

1 manufacturer datasheets cross-checked for 6973

1 verified

EXECUTIVE SUMMARY

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

Introduced1960ManufacturerRCA·Sylvania

Late Production

6973 Datasheet

Local mirror · PDF

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METRIX TESTER

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