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Power - Pentode (NOT beam) ·Pentode

6A4LA

Directly heated power pentode for Class A and push-pull Class AB audio-output service.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
5
Socket code
UX5
Base pins
5
Nominal heater
6.3 V / 300 mA

Description

Directly heated pentode power amplifier for Class-A and push-pull Class-AB output service.

Socket description

Small 5-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
5
Socket code
UX5
Base pins
5
Nominal heater voltage
6.3 V
Nominal heater current
300 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

5 - 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
45500 Ω
Transconductance
0.0022 S
Amplification factor
100
Max plate voltage
180 V
Max screen voltage
180 V

Published promoted fields populated from the datasheet; identical repeated sections compressed where 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

1937 Raytheon Radio Receiving Tubes

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Plate voltage

    100 V

    ClassA

  • Screen voltage

    100 V

    ClassA

  • Control-grid voltage

    -6.5 V

    ClassA

  • Plate current

    9 mA

    ClassA

  • Screen current

    1.6 mA

    ClassA

  • Load resistance

    11000 Ω

    ClassA

  • Power output

    0.31 W

    ClassA

  • Plate voltage

    180 V

    ClassA

  • Screen voltage

    180 V

    ClassA

  • Control-grid voltage

    -12 V

    ClassA

  • Plate current

    22 mA

    ClassA

  • Screen current

    3.9 mA

    ClassA

  • Load resistance

    8000 Ω

    ClassA

  • Power output

    1.4 W

    ClassA

  • Plate and screen supply voltage

    230 V

    ClassAB;PushPull;TwoTubes;SelfBias

  • Load resistance plate-to-plate

    16000 Ω

    ClassAB;PushPull;TwoTubes;SelfBias

  • Power output

    4.2 W

    ClassAB;PushPull;TwoTubes;SelfBias

Characteristic

  • Plate resistance

    83250 Ω

    100V

  • Transconductance

    1200 µS

    100V

  • Plate resistance

    45500 Ω

    180V

  • Transconductance

    2200 µS

    180V

Data set 02

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Power Output

    1.4 W

    ClassA1;PlateVoltage=180V

  • Total Harmonic Distortion

    9 %

    ClassA1