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Power - Pentode (NOT beam) ·Diode-Diode-Pentode

EBL21

Combination valve incorporating a power-output pentode with diode or triode sections for audio-frequency amplification, detection, or driver service.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
3
Base
LOCTAL 8-P
Socket code
B8G
Base pins
8
Nominal heater
6.3 V / 900 mA

Description

Double-diode output pentode for Class A audio power-amplifier service.

Socket description

Loctal 8-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
LOCTAL 8-P
Socket code
B8G
Base pins
8
Nominal heater voltage
6.3 V
Nominal heater current
900 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

LOCTAL 8-P - Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

3 physical sections, each with unique specifications.

Section 1

Pentode

X-ray radiationInterelectrode capacitances
Plate resistance
50000 Ω
Transconductance
0.009 S
Amplification factor
23
Max plate voltage
300 V
Max screen voltage
300 V
Max plate dissipation
11 W
Max screen dissipation
2.75 W
Max cathode current
60 mA

Output pentode section; published Class A and AB operating data.

Section 2

Diode

X-ray radiationInterelectrode capacitances
Rectifier peak inverse voltage
350 V
Rectifier nominal output current
0.8 mA
Rectifier peak forward current
0.8 mA

Detector diode I.

Section 3

Diode

X-ray radiationInterelectrode capacitances
Rectifier peak forward current
0.8 mA

Detector diode II.

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

1951 Mullard Valve and Service Manual

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Plate Voltage

    250 V

    ClassA

  • Plate Current

    36 mA

    ClassA

SECTION 2

Diode

Characteristic

  • Heater Voltage

    6.3 V

  • Heater Current

    800 mA

Data set 02

195X Tesla

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristics

  • Interelectrode capacitances

    Published

    See source sheet for electrode-specific capacitance values

SECTION 2

Diode

Characteristics

  • Interelectrode capacitances

    Published

    See source sheet for electrode-specific capacitance values

SECTION 3

Diode

Characteristics

  • Interelectrode capacitances

    Published

    See source sheet for electrode-specific capacitance values

Data set 03

1999 Philips E-Z

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristics

  • Heater voltage

    6.3 V

  • Heater current

    800 mA

  • Transconductance

    9000 uS

  • Plate resistance

    50000 ohm

Other

  • Plate voltage

    250 V

    ClassA

  • Screen voltage

    250 V

    ClassA

  • Plate current

    36 mA

    ClassA

  • Screen current

    4.5 mA

    ClassA

  • Load resistance

    7000 ohm

    ClassA

  • Output power

    4.5 W

    ClassA

  • Maximum plate dissipation

    11 W

  • Push-pull plate voltage

    300 V

    ClassAB;PushPull;TwoTubes

  • Push-pull output power

    13.2 W

    ClassAB;PushPull;TwoTubes

SECTION 2

Diode

Other

  • Maximum diode average current

    0.8 mA

  • Maximum diode inverse peak voltage

    350 V

  • Maximum diode peak current

    5 mA