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

311B

Power pentode designed for both audio/output amplification and radio-frequency power-amplifier service.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
UX4
Base pins
4
Nominal heater
9 V / 600 mA

Description

Suppressor-grid power pentode for audio, carrier, and RF amplifier service.

Socket description

Medium-shell UX 4-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
UX4
Base pins
4
Nominal heater voltage
9 V
Nominal heater current
600 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

Pentode

X-ray radiationInterelectrode capacitances
Transconductance
0.0028 S
Max plate voltage
200 V
Max screen voltage
150 V
Max plate dissipation
9 W
Max screen dissipation
1.8 W
Max cathode current
60 mA

Promoted fields audited from printed ratings/characteristics; remaining published values preserved 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

2026 Western Electric 300s

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristic

  • Transconductance

    2800 micromhos

    Transconductance . . 2800 2900 micromhos

  • Power Output .... E^^ =

    -15 volts

    Power Output .... E^^ = -15 volts 2.5 2.5 watts

  • Heater Voltage, A-C or D-C (Note l)

    9 Volt

    Heater Voltage, A-C or D-C (Note l) 9«0 10.0 volts

  • Output

    8 puf

    Output 8.^ 10.4 puf

  • Plate Dissipation

    9 watts

    Plate Dissipation. . . 9.0 watts

  • Screen Grid Dissipation

    1.8 watts

    Screen Grid Dissipation 1.8 watts

  • Screen Grid Voltage

    135 Volt

    Screen Grid Voltage ... 135 135 135 volts

  • Transconductance

    2800 micromhos

    Transconductance 2800 2900 3000 micromhos

  • Load Resistance

    3500 ohms

    Load Resistance 3500 3500 4000 ohms

  • To t a l Harmonic Distortion

    1 per cent

    To t a l Harmonic Distortion 1 0 . 0 9.0 10.5 per cent

  • Note.l: For optimum tube life, a heater voltage of

    9 volt

    Note.l: For optimum tube life, a heater voltage of 9 volts is recommended.

Other

  • Maximum Signal Power Output

    2 watts

    Maximum Signal Power Output 2 . 0 2 . 0 2.8 watts