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Power - Pentode (NOT beam) ·Pentode

DL72

Subminiature output pentode with a 1.25 V, 25 mA filament for low-voltage Class-A audio amplification. Designed for compact portable equipment requiring minimal heater power.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
Subminiature
Socket code
WIRE8
Base pins
8
Nominal heater
1.25 V / 25 mA

Description

Subminiature output pentode with a 1.25 V, 25 mA filament for low-voltage Class-A audio amplifier service.

Socket description

Subminiature all-glass 8-wire lead family

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
Subminiature
Socket code
WIRE8
Base pins
8
Nominal heater voltage
1.25 V
Nominal heater current
25 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

Subminiature - 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
170000 Ω
Transconductance
0.0005 S
Max plate voltage
45 V
Max screen voltage
45 V
Max cathode current
2 mA

Published ratings and characteristics promoted semantically from the approved source; repeated identical physical 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

1951 Mullard Valve and Service Manual

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Plate Voltage

    45 V

    ClassA

  • Screen Voltage

    45 V

    ClassA

  • Plate Current

    1.25 mA

  • Screen Current

    0.4 mA

Characteristic

  • Transconductance

    500 µS

  • Plate Resistance

    170000 ohm

Data set 02

1999 Philips 0-D

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Anode voltage

    45 V

    ClassA

  • Anode current

    1.25 mA

    ClassA

  • Screen-grid current

    0.4 mA

    ClassA

  • Load resistance

    30 kOhm

    ClassA