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

3S4

Directly heated output pentode, co-designated DL92, designed for low-frequency power amplification. Its low-power filament makes it suitable for portable battery receiver output stages.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: 7BA
Socket code: B7G
Base pins: 7
Nominal heater: 2.8 V / 50 mA

Description

Directly heated output pentode for low-frequency power amplification; co-designated DL92.

Socket description

Miniature 7-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 7BA
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

7BA - Terminal pinout

Electrical assignments shared by every tube using this base designation.

Terminal	Section	Connection	Evidence
PIN1F	—	F — Filament Source EIA label F; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BA
PIN2P	A	P — Plate (Anode) Source EIA label P; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BA
PIN3G1	A	G1 — Control Grid EIA source designation G1; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BA
PIN4G2	A	G2 — Screen Grid EIA source designation G2; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BA
PIN5G3	A	G3 — Suppressor GridGroup 7BA5 EIA source designation G3; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BA
PIN5FCT	—	FCT — Filament Center TapGroup 7BA5 EIA source designation FCT; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BA
PIN6P	A	P — Plate (Anode) EIA source designation P; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BA
PIN7F	—	F — Filament EIA source designation F; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BA

Section ratings

1 physical section, each with unique specifications.

Section 1

Pentode

X-ray radiationInterelectrode capacitances

Plate resistance: 100000 Ω
Transconductance: 0.001575 S
Max plate voltage: 90 V
Max screen voltage: 67.5 V
Max plate dissipation: 1 W
Max cathode current: 5.5 mA

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

1948 Brimar Radio Valve Manual

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Maximum Cathode Current No Signal
9 mA
ParallelFilament
Maximum Cathode Current Maximum Signal
11 mA
ParallelFilament
Plate Voltage
67.5 V
ParallelFilament
Plate Voltage
90 V
ParallelFilament
Screen Voltage
67.5 V

Characteristic

Transconductance
1550 µS
67.5V plate, parallel filament
Transconductance
1575 µS
90V plate, parallel filament

Data set 02

1950 Sylvania

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristic

Plate Resistance
100000 ohm
Transconductance
1575 µS

Other

Maximum Plate Voltage
90 V
Maximum Screen Voltage
67.5 V
Maximum Cathode Current
12 mA
Plate Voltage
90 V
ClassA
Screen Voltage
67.5 V
ClassA
Maximum Signal Power Output
270 mW
ClassA; parallel filament

Data set 03

1955 Marconi

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Series filament voltage
2.8 V
Series filament current
50 mA
Parallel filament voltage
1.4 V
Parallel filament current
100 mA
Maximum plate voltage
90 V
Maximum screen voltage
67.5 V

Characteristic

Transconductance
5750 uS

Application

Primary application
Directly heated miniature output pentode with series/parallel filament.

Data set 04

1958 Brimar Radio Valve No 7

Published operating points and test conditions from this source.

SECTION 1

Pentode

Application

Application
Battery audio output

Data set 05

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Plate voltage
90 V
ClassA;ParallelFilaments
Screen-grid voltage
67.5 V
ClassA;ParallelFilaments
Grid No.1 bias
7 V
ClassA;ParallelFilaments
Plate current
7.4 mA
ClassA;ParallelFilaments
Screen-grid current
1.4 mA
ClassA;ParallelFilaments
Plate resistance
100000 ohm
ClassA;ParallelFilaments
Transconductance
1575 uS
ClassA;ParallelFilaments
Load resistance
8000 ohm
ClassA;ParallelFilaments
Power output
0.27 W
ClassA;ParallelFilaments
Plate voltage
67.5 V
ClassA;ParallelFilamentsLowVoltage
Screen-grid voltage
67.5 V
ClassA;ParallelFilamentsLowVoltage
Grid No.1 bias
7 V
ClassA;ParallelFilamentsLowVoltage
Plate current
7.2 mA
ClassA;ParallelFilamentsLowVoltage
Screen-grid current
1.1 mA
ClassA;ParallelFilamentsLowVoltage
Plate resistance
100000 ohm
ClassA;ParallelFilamentsLowVoltage
Transconductance
1550 uS
ClassA;ParallelFilamentsLowVoltage
Load resistance
5000 ohm
ClassA;ParallelFilamentsLowVoltage
Power output
0.18 W
ClassA;ParallelFilamentsLowVoltage
Plate voltage
90 V
ClassA;SeriesFilaments
Screen-grid voltage
67.5 V
ClassA;SeriesFilaments
Grid No.1 bias
7 V
ClassA;SeriesFilaments
Plate current
6.1 mA
ClassA;SeriesFilaments
Plate resistance
100000 ohm
ClassA;SeriesFilaments
Transconductance
1425 uS
ClassA;SeriesFilaments
Load resistance
8000 ohm
ClassA;SeriesFilaments
Power output
0.235 W
ClassA;SeriesFilaments
Plate voltage
67.5 V
ClassA;SeriesFilamentsLowVoltage
Screen-grid voltage
67.5 V
ClassA;SeriesFilamentsLowVoltage
Grid No.1 bias
7 V
ClassA;SeriesFilamentsLowVoltage
Plate current
6 mA
ClassA;SeriesFilamentsLowVoltage
Screen-grid current
1.2 mA
ClassA;SeriesFilamentsLowVoltage
Plate resistance
100000 ohm
ClassA;SeriesFilamentsLowVoltage
Transconductance
1400 uS
ClassA;SeriesFilamentsLowVoltage
Load resistance
5000 ohm
ClassA;SeriesFilamentsLowVoltage
Power output
0.16 W
ClassA;SeriesFilamentsLowVoltage

Data set 06

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristic

Transconductance
1550 uS
Typical

Other

Power Output
0.27 W
Typical

Data set 07

1966 Tung Sol Electronic Tubes 1 of 4

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Filament voltage series
2.8 V
Series
Filament current series
50 mA
Series
Filament voltage parallel
1.4 V
Parallel
Filament current parallel
100 mA
Parallel
Plate voltage
90 V
AudioOutput;ClassA
Screen voltage
90 V
AudioOutput;ClassA
Control-grid voltage
-7 V
AudioOutput;ClassA
Plate current
9.5 mA
AudioOutput;ClassA
Screen current
2 mA
AudioOutput;ClassA
Load resistance
8000 Ω
AudioOutput;ClassA
Power output
0.25 W
AudioOutput;ClassA

Data set 08

1968 Mazda Belvu

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Power Output
0.235 W
ClassA;OneTube;Plate 90 V