What is the WE437A vacuum tube?

The WE437A is a triode vacuum tube designed for power (se) applications. Holy grail small triode. ~2W SE. Legendary..

What is a WE437A substitute or equivalent?

Direct equivalents to the WE437A include 6S45P-E, 6C45Pi. 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 WE437A?

Amplification factor μ ≈ 40, transconductance gm ≈ 46 mA/V, plate resistance rp ≈ 870 Ω, max plate voltage 160 V, max plate dissipation 7 W, heater 6.3 V / 0.4 A.

Is the WE437A still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the WE437A 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 WE437A sound like?

Holy grail small triode. ~2W SE. Legendary.. 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.

WE437A Triode Vacuum Tube

Also known as 6S45P-E · 6C45Pi

Medium-gain triode for driver and line stage applications

TriodeHeater 6.3 V · 0.4 A9-pin MagnovalWestern Electric 1956

Plate dissipation: 7W
Max plate voltage: 160V
Transconductance: 46mA/V

WE437A

Characteristics

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

HeaterIndirectly heated

Specifications of WE437A — Heater
Heater voltageVh	6.3 V
Heater currentIh	0.4 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of WE437A — Limiting values
Plate voltageVa max	160 V
Plate dissipationPa max	7 W

Mechanical

Specifications of WE437A — Mechanical
Base	9-pin Magnoval
Rarity	Collector
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of WE437A — Small signal
Transconductance	46 mA/V
Plate resistance	870 Ω
Amplification factor	40

Capacitances

Specifications of WE437A — Capacitances
Grid–cathode	4.5 pF
Grid–plate	0.07 pF
Plate–cathode	2.8 pF

Charactereditorial reading, not a measurement

Specifications of WE437A — Character
Gain	40%
Power	18%
Drive	99%
Linearity	80%

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

Push-pull output
Headphone output

Generic triode power (se) stage

Hi-Fi stereoHeadphone amp

Replace or compare

Sources

By Jean-Michel Falligan Devergne

Manufacturer datasheets

WE437A DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: Western Electric
Reviewed: —
Status: DataModelCalc
Model: under review

Context

The WE437A is a indirectly-heated triode from Western Electric, introduced around 1956. It provides a gain factor (μ) of 40 with 870Ω plate resistance. Commonly used in power (se) applications. Holy grail small triode. ~2W SE. Legendary.

History

Introduced: 1956
Manufacturer: Western Electric
Era: Golden Age

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