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Power - Pentode Single (NOT beam) (under 10W) ·Pentode

AL4

Power pentode designed for audio-output amplification. Manufacturer documentation identifies it as a dedicated low-frequency output tube for driving receiver loads.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
P35
Socket code
P8A
Base pins
8
Nominal heater
4 V / 1.75 A

Description

Power pentode for audio output amplification.

Socket description

European 8-pin side-contact base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
P35
Socket code
P8A
Base pins
8
Nominal heater voltage
4 V
Nominal heater current
1.75 A
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

P35 - 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

Pentode

X-ray radiationInterelectrode capacitances
Plate resistance
25000 Ω
Transconductance
0.0095 S
Max plate voltage
250 V
Max screen voltage
250 V
Max plate dissipation
9 W
Max screen dissipation
1.5 W

Published ratings and characteristics promoted where clearly stated; identical repeated sections compressed when applicable.

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

1938 Philips Miniwatt Vacuum Tube Catalog

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Plate voltage

    250 V

  • Plate current

    36 mA

  • Screen voltage

    250 V

  • Screen current

    5 mA

  • Optimum load resistance

    7000 ohm

  • Power output

    4.3 W

  • Grid AC input voltage

    3.6 V RMS

  • Maximum anode dissipation

    9 W

Characteristics

  • Transconductance

    9500 µS

  • Plate resistance

    50000 ohm

Data set 02

1953 RFT Rundfunk Technik

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristics

  • Heater or filament voltage

    4 V

    Published nominal value

  • Heater or filament current

    1.75 A

    Published nominal value

  • Transconductance

    9000 µS

    Published operating characteristic

Other

  • Output power

    4 W

    Single-ended audio output

Data set 03

1999 Philips 0-D

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristics

  • Heater voltage

    4 V

  • Heater current

    1.75 A

Other

  • Electrical data reference

    EL3N

    SourceCrossReference