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Power - Pentode (NOT beam) ·Pentode

59

Versatile audio power pentode for Class A operation, also usable in triode-connected Class A or Class B service.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
7A
Socket code
U7B
Base pins
7
Nominal heater
2.5 V / 2 A

Description

Power-amplifier pentode that may also be operated in triode connection for Class A or Class B service.

Socket description

Medium 7-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
7A
Socket code
U7B
Base pins
7
Nominal heater voltage
2.5 V
Nominal heater current
2 A
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

7A - 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
40000 Ω
Transconductance
0.0025 S
Amplification factor
100
Max plate voltage
250 V
Max screen voltage
250 V
Max plate dissipation
10 W
Max screen dissipation
1.5 W

Promoted from clearly identified printed ratings/characteristics; additional published operating points, capacitances, and specialized ratings retained in TUBE_SECTION_PARAMETER.

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

1937 Raytheon Radio Receiving Tubes

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Maximum plate voltage

    250 V

    ClassA

  • Maximum plate voltage

    400 V

    ClassB

  • Maximum screen voltage

    250 V

  • Plate voltage

    250 V

    ClassA; TriodeConnection

  • Grid 1 bias

    -28 V

    ClassA; TriodeConnection

  • Plate current

    26 mA

    ClassA; TriodeConnection

  • Load resistance

    5000 ohm

    ClassA; TriodeConnection

  • Power output

    1.25 W

    ClassA; TriodeConnection

  • Plate voltage

    250 V

    ClassA; PentodeConnection

  • Screen voltage

    250 V

    ClassA; PentodeConnection

  • Grid 1 bias

    -18 V

    ClassA; PentodeConnection

  • Plate current

    35 mA

    ClassA; PentodeConnection

  • Screen current

    9 mA

    ClassA; PentodeConnection

  • Load resistance

    6000 ohm

    ClassA; PentodeConnection

  • Power output

    3 W

    ClassA; PentodeConnection

  • Maximum peak plate current

    200 mA

    ClassB; PerTube

  • Maximum average plate dissipation

    10 W

    ClassB; PerTube

  • Maximum average grid 1 and 2 dissipation

    1.5 W

    ClassB; PerTube

  • Plate voltage

    300 V

    ClassB; PushPull; TwoTubes

  • Grid 1 and 2 bias

    0 V

    ClassB; PushPull; TwoTubes; PlateVoltage=300V

  • No-signal plate current

    10 mA

    ClassB; PerTube; PlateVoltage=300V

  • Load resistance plate-to-plate

    4600 ohm

    ClassB; PushPull; PlateVoltage=300V

  • Power output

    15 W

    ClassB; PushPull; PlateVoltage=300V

  • Plate voltage

    400 V

    ClassB; PushPull; TwoTubes

  • Grid 1 and 2 bias

    0 V

    ClassB; PushPull; TwoTubes; PlateVoltage=400V

  • No-signal plate current

    13 mA

    ClassB; PerTube; PlateVoltage=400V

  • Load resistance plate-to-plate

    6000 ohm

    ClassB; PushPull; PlateVoltage=400V

  • Power output

    20 W

    ClassB; PushPull; PlateVoltage=400V

Characteristic

  • Amplification factor

    6

    ClassA; TriodeConnection

  • Plate resistance

    2300 ohm

    ClassA; TriodeConnection

  • Transconductance

    2600 uS

    ClassA; TriodeConnection

  • Amplification factor

    100

    ClassA; PentodeConnection

  • Plate resistance

    40000 ohm

    ClassA; PentodeConnection

  • Transconductance

    2500 uS

    ClassA; PentodeConnection

Data set 02

1940 RCA

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Power Output

    20 W

    ClassB;PushPull;TwoTubes

Data set 03

1950 Sylvania

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Class B plate voltage

    400 V

    ClassB;TriodeConnection

  • Class B peak dynamic plate current

    200 mA

    ClassB;TriodeConnection

  • Class A screen voltage

    250 V

    ClassA;Pentode

Data set 04

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Plate voltage

    250 V

    ClassA

  • Screen voltage

    250 V

    ClassA

  • Control-grid voltage

    -18 V

    ClassA

  • Plate current

    35 mA

    ClassA

  • Screen current

    9 mA

    ClassA

  • Load resistance

    6000 Ω

    ClassA

  • Power output

    3 W

    ClassA

Characteristic

  • Plate resistance

    40000 Ω

    ClassA

  • Transconductance

    2500 µS

    ClassA