What is the WE350B vacuum tube?

The WE350B is a tetrode vacuum tube designed for power (pp/se) applications. Ultimate 6L6. Cinema systems. 3D midrange..

What is a WE350B substitute or equivalent?

Direct equivalents to the WE350B include 367A. 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 WE350B?

Amplification factor μ ≈ 400, transconductance gm ≈ 6.4 mA/V, max plate voltage 500 V, max plate dissipation 25 W, heater 6.3 V / 1.6 A.

Is the WE350B still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the WE350B 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 WE350B sound like?

Ultimate 6L6. Cinema systems. 3D midrange.. 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.

WE350B Tetrode Vacuum Tube

Also known as 367A

Beam power tetrode rated at 25W for high-power output stages

TetrodeHeater 6.3 V · 1.6 AOctalWestern Electric 1940

Plate dissipation: 25W
Max plate voltage: 500V
Transconductance: 6.4mA/V

WE350B

Characteristics

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

HeaterIndirectly heated

Specifications of WE350B — Heater
Heater voltageVh	6.3 V
Heater currentIh	1.6 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of WE350B — Limiting values
Plate voltageVa max	500 V
Plate dissipationPa max	25 W

Mechanical

Specifications of WE350B — Mechanical
Base	Octal
Rarity	Collector
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of WE350B — Small signal
Transconductance	6.4 mA/V
Amplification factor	400

Capacitances

Specifications of WE350B — Capacitances
Input	10 pF
Grid–plate	0.7 pF
Output	8.5 pF

Charactereditorial reading, not a measurement

Specifications of WE350B — Character
Gain	100%
Power	63%
Drive	50%
Linearity	10%

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

High-power output

Generic tetrode power (pp/se) stage

Replace or compare

Sources

By Jean-Michel Falligan Devergne

Manufacturer datasheets

WE350B DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

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

Context

The WE350B is a indirectly-heated beam tetrode from Western Electric, introduced around 1940. Commonly used in power (pp/se) applications. Ultimate 6L6. Cinema systems. 3D midrange.

History

Introduced: 1940
Manufacturer: Western Electric
Era: Pre-War

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