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1LA4

Low-drain directly heated battery power pentode providing roughly 115 mW Class-A audio output.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: 5AD
Socket code: B8G
Base pins: 8
Nominal heater: 1.4 V / 50 mA

Description

1LA4 is listed as a power-amplifier pentode in the supplied receiving-tube handbook. It uses a 1.4 V, 0.05 A directly heated filament. The handbook publishes maximum ratings and representative operating characteristics for its intended 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: 5AD
Socket code: B8G
Base pins: 8
Nominal heater voltage: 1.4 V
Nominal heater current: 50 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

5AD - 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: 300000 Ω
Transconductance: 0.00085 S
Max plate voltage: 110 V
Max screen voltage: 110 V

Pentode power amplifier.

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

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Maximum plate voltage
110 V
Published handbook rating
Maximum screen voltage
110 V
Published handbook rating
Plate voltage
90 V
ClassA
Screen voltage
90 V
ClassA
Control-grid voltage
-4.5 V
ClassA
Plate current
4 mA
ClassA
Screen current
0.8 mA
ClassA
Load resistance
125000 ohm
ClassA
Power output
0.115 W
ClassA

Characteristic

Plate resistance
300000 ohm
Published handbook characteristic
Transconductance
850 µS
Published handbook characteristic
Filament voltage
1.4 V
DirectlyHeated DC filament
Filament current
50 mA
DirectlyHeated DC filament

Data set 02

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristic

Maximum Signal Plate Current
4 mA
TypicalOperation
Maximum Signal Screen Current
1.1 mA
TypicalOperation