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Power - Triode ·Triode

D404

Power triode for audio-output, amplifier, or oscillator service with manufacturer operating data supporting substantial power delivery.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
A35
Socket code
-
Base pins
-
Nominal heater
4 V / 650 mA

Description

Philips D404 is a directly heated output triode intended as an audio power amplifier. It operates with a 4 V, 0.65 A filament and published 150–200 V anode operating conditions.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
A35
Socket code
-
Base pins
-
Nominal heater voltage
4 V
Nominal heater current
650 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

A35 - 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
1000 Ω
Transconductance
0.0035 S
Amplification factor
3.5

Published ratings and characteristics promoted where a locked-schema field is semantically applicable; additional values retained as parameters.

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

1999 Philips 0-D

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Anode voltage range

    150 to 200 V

    Published datasheet value

  • Negative grid bias at 200 V anode

    30 V

    Published datasheet value

  • Normal anode current at 200 V

    30 mA

    Published datasheet value

  • Negative grid bias at 150 V anode

    20 V

    Published datasheet value