What is the 211 vacuum tube?

The 211 (211 / VT-4C) is a triode vacuum tube designed for transmitting (set) applications. Transmitting triode. Mighty bass..

What is a 211 substitute or equivalent?

Direct equivalents to the 211 include VT-4C, 242C. 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 211?

Amplification factor μ ≈ 12, transconductance gm ≈ 3.3 mA/V, plate resistance rp ≈ 3.6 kΩ, max plate voltage 1250 V, max plate dissipation 100 W, heater 10 V / 3.25 A.

Is the 211 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 211 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 211 sound like?

Transmitting triode. Mighty bass.. 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

←211

← 20B-EmissionLabs 250TL →Compare → VT-4C

211 211 / VT-4C Triode Vacuum Tube

Triode10V / 3.25AUX-4SPICE

SourceGE·RCA datasheet · cap audit 2026-05-09Reviewed2026-05-29StatusDataModelCalcModelKoren v1PDF

Power triode delivering 100W for push-pull and SET designs

Datasheet ↗SPICE

211 / VT-4C — GE·RCA — triode vacuum tube — (1929)

3.6kΩ

3.3mA/V

5.4pF

14.0pF

4.80pF

GAIN12%

POWER100%

DRIVE96%

LINEARITY94%

SPECIFICATIONS

Heater10 V · 3.25 A

Max Plate Voltage1250 V

Pa max100 W

Gain Factor12

gm3.3 mA/V

rp3.6 kΩ

Inter-electrode capacitances

Cgk5.4 pF

Cgp14 pF

Cpk4.8 pF

PinoutUX-4

Era1929

RarityModerate

HEATER10V / 3.25A

MAX PLATE1250V / 100W

BASEux4

Source datasheets

1 manufacturer datasheets cross-checked for 211 / VT-4C

1 verified

TYPICAL OPERATING POINT

SPICE model(2 available)3 .subckt available ↓

Va750V

Ia35.83mA

Vg-45.41V

Pd26.87W

RL4kΩ

Av15.7dB

EXECUTIVE SUMMARY

The 211 (VT-4C) is a directly-heated thoriated-tungsten power triode originally developed for military radio transmitter service. Running at plate voltages of 800-1250V, it can deliver 15-25W in single-ended Class A with a fast, dynamic, and slightly forward presentation compared to the warmer 300B. The thoriated-tungsten filament runs at bright incandescence and gives the tube exceptional transient speed and high-frequency extension. GE and RCA NOS examples are the standard, with current production from Shuguang and Psvane offering more affordable alternatives.

APPLICATIONS

SET outputPush-pull output

Audio Note OngakuCary CAD-805

• PA/public address

VS VT-4C

μ 0%Rp +0%Pd +33%Full comparison →

HISTORY

Introduced1929ManufacturerGE·RCA

Pre-War

211 Datasheet

Local mirror · PDF

↗

METRIX TESTER

Test this tube on a Metrix

CLASSIC CIRCUITS

Single-Ended Triode

211 SE Classic

16W

VT-4C/211 transmitting triode in audio service. High-voltage SE with commanding dynamics and visceral impact. Thunderous bass authority.

SEVb 750V · Vg -72V · RL 10kΩ

GE 211/VT-4C Datasheet

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