What is the RS242 vacuum tube?

The RS242 is a triode vacuum tube designed for power (se) applications. DHT triode. Smaller RS241 sister..

What is a RS242 substitute or equivalent?

Direct equivalents to the RS242 include E130, RS242X. 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 RS242?

Amplification factor μ ≈ 16.8, transconductance gm ≈ 3 mA/V, plate resistance rp ≈ 5.6 kΩ, max plate voltage 350 V, max plate dissipation 12 W, heater 3.8 V / 0.76 A.

Is the RS242 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the RS242 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 RS242 sound like?

DHT triode. Smaller RS241 sister.. 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.

RS242 Triode Vacuum Tube

Also known as E130 · RS242X

Power triode delivering 12W for push-pull and SET designs

TriodeHeater 3.8 V · 0.76 A4-pin EuropeanTelefunken 1940

Plate dissipation: 12W
Max plate voltage: 350V
Transconductance: 3mA/V

RS242

Characteristics

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

HeaterDirectly heated

Specifications of RS242 — Heater
Heater voltageVh	3.8 V
Heater currentIh	0.76 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of RS242 — Limiting values
Plate voltageVa max	350 V
Plate dissipationPa max	12 W

Mechanical

Specifications of RS242 — Mechanical
Base	4-pin European
Rarity	Collector
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of RS242 — Small signal
Transconductance	3 mA/V
Plate resistance	5.6 kΩ
Amplification factor	16.8

Capacitances

Specifications of RS242 — Capacitances
Grid–cathode	8 pF
Grid–plate	5 pF
Plate–cathode	6 pF

Charactereditorial reading, not a measurement

Specifications of RS242 — Character
Gain	17%
Power	30%
Drive	94%
Linearity	92%

datasheet cited · model or editorial reading · catalogue value, no citation attached yet · nothing invented

Using this tube

Interactive loadline calculator not available for this tube yet — it needs calibrated Koren or Ayumi parameters.

Applications

SET output
Push-pull output

Generic triode power (se) stage

Hi-Fi stereo

Replace or compare

Sources

By Jean-Michel Falligan Devergne

Manufacturer datasheets

RS242 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: Telefunken
Reviewed: —
Status: DataModelCalc
Model: under review

Context

The RS242 is a directly-heated triode from Telefunken, introduced around 1940. It provides a gain factor (μ) of 16.8 with 5600Ω plate resistance. Commonly used in power (se) applications. DHT triode. Smaller RS241 sister.

History

Introduced: 1940
Manufacturer: Telefunken
Era: Pre-War

METRIX TESTER