437A

Directly heated transmitting power triode intended for RF amplifier, oscillator, or modulator service. Manufacturer operating data emphasize radio-frequency power generation, substantial plate loading, and professional transmitter applications.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: -
Base pins: 9
Nominal heater: 6.3 V / 450 mA

Description

Western Electric 437A is a high figure-of-merit triode with an indirectly heated cathode designed primarily for the output amplifier of the L-3 tandem two-stage amplifier.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: -
Base pins: 9
Nominal heater voltage: 6.3 V
Nominal heater current: 450 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

1 physical section, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 900 Ω
Transconductance: 0.046 S
Amplification factor: 41
Max plate voltage: 250 V
Max plate dissipation: 7 W
Max cathode current: 45 mA

Promoted from design-center maximum ratings and representative published characteristics.

Source-dependent data

Operating conditions by source

Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.

Data set 01

2026 Western Electric 400s

Published operating points and test conditions from this source.

SECTION 1

Triode

Capacitance

Grid to plate maximum
3.8 pF
Input without external shield
11.1 pF
Output without external shield
1 pF

Other

Maximum heater-cathode voltage
50 V