What is the RS241 vacuum tube?

The RS241 is a triode vacuum tube designed for power (se) applications. DHT transmitting triode. Wehrmacht heritage..

What is a RS241 substitute or equivalent?

Direct equivalents to the RS241 include 4C5. 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 RS241?

Amplification factor μ ≈ 17, transconductance gm ≈ 3.5 mA/V, plate resistance rp ≈ 5.0 kΩ, max plate voltage 400 V, max plate dissipation 15 W, heater 3.8 V / 0.6 A.

Is the RS241 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the RS241 as Collector 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 RS241 sound like?

DHT transmitting triode. Wehrmacht heritage.. 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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RS241 Triode Vacuum Tube

Triode3.8V / 0.6A4-pin European

SourceTelefunkenReviewed2026-05-29StatusDataModelCalcModelunder reviewPDF

Power triode delivering 15W for push-pull and SET designs

Datasheet ↗

RS241 — Telefunken — triode vacuum tube — (1932)

5.0kΩ

3.5mA/V

6.5pF

9.0pF

5.00pF

GAIN17%

POWER38%

DRIVE95%

LINEARITY92%

SPECIFICATIONS

Heater3.8 V · 0.6 A

Max Plate Voltage400 V

Pa max15 W

Gain Factor17

gm3.5 mA/V

rp5.0 kΩ

Inter-electrode capacitances

Cgk6.5 pF

Cgp9 pF

Cpk5 pF

Pinout4-pin European

Era1932

RarityCollector

HEATER3.8V / 0.6A

MAX PLATE400V / 15W

BASEb4-eu

Source datasheets

1 manufacturer datasheets cross-checked for RS241

1 verified

EXECUTIVE SUMMARY

The RS241 is a directly-heated triode from Telefunken, introduced around 1932. It provides a gain factor (μ) of 17 with 5000Ω plate resistance. Commonly used in power (se) applications. DHT transmitting triode. Wehrmacht heritage.

APPLICATIONS

SET outputPush-pull output

Generic triode power (se) stage

• Hi-Fi stereo

HISTORY

Introduced1932ManufacturerTelefunken

Pre-War

RS241 Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

SPICE model not yet available. Loadline calculator requires calibrated Koren parameters.

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