What is the 274B vacuum tube?

The 274B is a rectifier vacuum tube designed for rectifier applications. Designed for the WE 300B amp. Premier WE rectifier..

What is a 274B substitute or equivalent?

Direct equivalents to the 274B include 5U4G, WE274A. 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.

Is the 274B still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 274B as Legendary 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 274B sound like?

Designed for the WE 300B amp. Premier WE rectifier.. 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

←274B

← 27 2A3 →Compare → 5U4G

274B Rectifier Vacuum Tube

Rectifier5V / 2AOctal

SourceWestern ElectricReviewed2026-05-29StatusDataModelCalcModelunder reviewPDF

Full-wave rectifier for vacuum tube power supply designs

Datasheet ↗

274B — Western Electric — rectifier vacuum tube — (1935)

5.5pF

6.0pF

4.50pF

GAIN0%

POWER0%

DRIVE50%

LINEARITY75%

SPECIFICATIONS

Heater5 V · 2 A

Max Plate Voltage550 V

Pa max—

Gain Factor—

gm—

rp—

Inter-electrode capacitances

Cgk5.5 pF

Cgp6 pF

Cpk4.5 pF

PinoutOctal

Era1935

RarityLegendary

HEATER5V / 2A

MAX PLATE550V

BASEoctal

EXECUTIVE SUMMARY

The 274B is a directly-heated rectifier from Western Electric, introduced around 1935. Commonly used in rectifier applications. Designed for the WE 300B amp. Premier WE rectifier.

APPLICATIONS

Power supply rectification

Generic rectifier rectifier stage

VS 5U4G

Full comparison →

HISTORY

Introduced1935ManufacturerWestern Electric

Pre-War

274B Datasheet

Frank's Electron Tube Pages · 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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