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

EBL31

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
-
Socket code
IO
Base pins
8
Nominal heater
6.3 V / 1.2 A

Description

High-sensitivity output pentode combined with twin diodes for AC mains equipment.

Socket description

International Octal

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
IO
Base pins
8
Nominal heater voltage
6.3 V
Nominal heater current
1.2 A
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

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

Diode

X-ray radiationInterelectrode capacitances
Rectifier peak forward current
0.8 mA

Published ratings and characteristics promoted from the supplied Brimar source.

Section 2

Diode

X-ray radiationInterelectrode capacitances

No fixed ratings are recorded for this section.

Second physical diode section; added to align pentode plus twin-diode structure with SectionCount=3.

Section 3

Pentode

X-ray radiationInterelectrode capacitances
Plate resistance
55000 Ω
Transconductance
0.0095 S
Max plate voltage
250 V
Max screen voltage
250 V
Max screen dissipation
1.5 W

Published ratings and characteristics promoted from the supplied Brimar source.

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

Diode

Characteristic

  • Heater Voltage

    6.3 V

  • Heater Current

    1.2 A

SECTION 3

Pentode

Other

  • Plate Voltage

    250 V

    ClassA

  • Plate Current

    36 mA

    ClassA

Data set 02

1958 Mullard Receiving Tubes

Published operating points and test conditions from this source.

SECTION 1

Diode

Characteristic

  • Heater Voltage

    6.3 V

  • Heater Current

    1.2 A

SECTION 3

Pentode

Other

  • Plate Voltage

    250 V

    ClassA

  • Plate Current

    36 mA

    ClassA

Data set 03

1963 Mullard

Published operating points and test conditions from this source.

SECTION 3

Pentode

Other

  • Plate voltage

    250 V

    ClassA

  • Screen voltage

    250 V

    ClassA

  • Plate current

    36 mA

    ClassA

  • Cathode resistor

    146 ohm

    ClassA

  • Grid voltage

    -6 V

    ClassA

  • Screen current

    5 mA

    ClassA

  • Transconductance

    9.5 mA/V

    ClassA

  • Plate resistance

    50000 ohm

    ClassA

  • Load resistance

    7000 ohm

    ClassA

  • Power output

    4.3 W

    ClassA

  • Distortion

    10 %

    ClassA

  • Input voltage RMS

    3.6 V

    ClassA