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Tube Tinker — Electron Tube Database
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Power - Beam (NOT sweep) ·BeamPower

3LF4

Directly heated beam-power amplifier with series/parallel filament operation, designed for battery-operated receiver power-output applications.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
6BB
Socket code
B7G
Base pins
7
Nominal heater
2.8 V / 50 mA

Description

Directly heated beam-power amplifier with series/parallel filament operation.

Socket description

Miniature 7-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
6BB
Socket code
B7G
Base pins
7
Nominal heater voltage
2.8 V
Nominal heater current
50 mA
Parallel heater voltage
1.4 V
Parallel heater current
100 mA
Series capable
Yes

6BB - 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

Beam Power

X-ray radiationInterelectrode capacitances
Plate resistance
80000 Ω
Transconductance
0.002 S
Max plate voltage
110 V
Max screen voltage
110 V

Published promoted fields populated by semantic headings; identical repeated sections compressed.

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

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

  • Plate voltage

    110 V

    ClassA;ParallelFilaments

  • Screen-grid voltage

    110 V

    ClassA;ParallelFilaments

  • Grid No.1 bias

    6.6 V

    ClassA;ParallelFilaments

  • Plate current

    10 mA

    ClassA;ParallelFilaments

  • Screen-grid current

    1.4 mA

    ClassA;ParallelFilaments

  • Plate resistance

    100000 ohm

    ClassA;ParallelFilaments

  • Transconductance

    2200 uS

    ClassA;ParallelFilaments

  • Load resistance

    8000 ohm

    ClassA;ParallelFilaments

  • Power output

    0.4 W

    ClassA;ParallelFilaments

  • Plate voltage

    90 V

    ClassA;ParallelFilamentsLowVoltage

  • Screen-grid voltage

    90 V

    ClassA;ParallelFilamentsLowVoltage

  • Grid No.1 bias

    4.5 V

    ClassA;ParallelFilamentsLowVoltage

  • Plate current

    9.5 mA

    ClassA;ParallelFilamentsLowVoltage

  • Screen-grid current

    1.3 mA

    ClassA;ParallelFilamentsLowVoltage

  • Plate resistance

    90000 ohm

    ClassA;ParallelFilamentsLowVoltage

  • Transconductance

    2200 uS

    ClassA;ParallelFilamentsLowVoltage

  • Load resistance

    8000 ohm

    ClassA;ParallelFilamentsLowVoltage

  • Power output

    0.27 W

    ClassA;ParallelFilamentsLowVoltage

  • Plate voltage

    110 V

    ClassA;SeriesFilaments

  • Screen-grid voltage

    110 V

    ClassA;SeriesFilaments

  • Grid No.1 bias

    6.6 V

    ClassA;SeriesFilaments

  • Plate current

    8.5 mA

    ClassA;SeriesFilaments

  • Screen-grid current

    1.1 mA

    ClassA;SeriesFilaments

  • Plate resistance

    110000 ohm

    ClassA;SeriesFilaments

  • Transconductance

    2000 uS

    ClassA;SeriesFilaments

  • Load resistance

    8000 ohm

    ClassA;SeriesFilaments

  • Power output

    0.33 W

    ClassA;SeriesFilaments

  • Plate voltage

    90 V

    ClassA;SeriesFilamentsLowVoltage

  • Screen-grid voltage

    90 V

    ClassA;SeriesFilamentsLowVoltage

  • Grid No.1 bias

    4.5 V

    ClassA;SeriesFilamentsLowVoltage

  • Plate current

    8 mA

    ClassA;SeriesFilamentsLowVoltage

  • Screen-grid current

    1 mA

    ClassA;SeriesFilamentsLowVoltage

  • Plate resistance

    80000 ohm

    ClassA;SeriesFilamentsLowVoltage

  • Transconductance

    2000 uS

    ClassA;SeriesFilamentsLowVoltage

  • Load resistance

    8000 ohm

    ClassA;SeriesFilamentsLowVoltage

  • Power output

    0.23 W

    ClassA;SeriesFilamentsLowVoltage

Data set 02

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

  • Power Output

    0.33 W

    Typical

Characteristic

  • Transconductance

    2000 uS

    Typical