N77

Marconi miniature output pentode designed for audio power service. Its compact construction provides conventional low-frequency load drive in receiver and amplifier output stages.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: B7G
Base pins: 7
Nominal heater: 6.3 V / 200 mA

Description

The Marconi N77 is a miniature output pentode for audio power service.

Socket description

Miniature 7-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: B7G
Base pins: 7
Nominal heater voltage: 6.3 V
Nominal heater current: 200 mA
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

1 physical section, each with unique specifications.

Section 1

Pentode

X-ray radiationInterelectrode capacitances

Plate resistance: 130000 Ω
Transconductance: 0.0026 S
Max plate voltage: 250 V
Max screen voltage: 250 V
Max plate dissipation: 4 W
Max screen dissipation: 0.6 W

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

1955 Marconi

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Heater voltage
6.3 V
Heater current
200 mA
Maximum plate voltage
250 V
Maximum screen voltage
250 V
Maximum plate dissipation
4 W
Maximum screen dissipation
0.6 W

Characteristic

Transconductance
2600 uS
Plate resistance
130000 ohm

Application

Primary application
Miniature output pentode for audio power service.