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Power - Triode ·Triode

P425

Power-output triode designed for audio-frequency output stages and loudspeaker drive.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
B4
Base pins
-
Nominal heater
4 V / -

Description

Super-power output triode for moving-coil and similar loudspeakers.

Socket description

European 4-pin base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
B4
Base pins
-
Nominal heater voltage
4 V
Nominal heater current
-
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
5000 Ω
Transconductance
0.00195 S
Max plate voltage
150 V

Published ratings/characteristics promoted from the approved datasheet where legible.

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

1955 Marconi

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Filament/heater voltage

    4 V

Characteristic

  • Transconductance

    1950 uS

  • Plate resistance

    5000 ohm

Application

  • Primary application

    Audio power output