5755

Special-quality high-mu twin triode intended for reliable voltage-amplifier service, providing two similar sections for low-level amplification and related professional electronic applications.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 2
Base: -
Socket code: B9A
Base pins: 9
Nominal heater: 6.3 V / 360 mA

Description

Double triode for computer, regulated-power-supply and precision amplifier applications.

Socket description

Small-button Noval 9-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: B9A
Base pins: 9
Nominal heater voltage: 6.3 V
Nominal heater current: 360 mA
Parallel heater voltage: 6.3 V
Parallel heater current: 360 mA
Series capable: Yes

Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

2 physical sections, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 140000 Ω
Transconductance: 0.0005 S
Amplification factor: 70
Max plate voltage: 225 V
Max plate dissipation: 0.9 W

Promoted fields mapped from printed maximum-rating and characteristic headings; additional published values preserved in parameter rows. Representative row for repeated identical physical sections.

Section 2

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 140000 Ω
Transconductance: 0.0005 S
Amplification factor: 70
Max plate voltage: 225 V
Max plate dissipation: 0.9 W

Second identical physical triode section; added to align rows with SectionCount.

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

2026 Western Electric 400s

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

Plate Current (each section) \ Eh =
110 volts
Plate Current (each section) \ Eh = 110 volts; Ep - -0.6 volt 10.15 milliampere
Transconductance (each section)/ I
500 micromhos
Transconductance (each section)/ I 500 micromhos
Heater-Cathode Voltage
70 volts
Heater-Cathode Voltage 70 volts
Cathode Bias Resistor (Cathodes tied together)
150000 ohms
Cathode Bias Resistor (Cathodes tied together) 150,000 ohms
Plate- Current
0.15 milliampere
Plate- Current 0.15 milliampere
Load Resistance
0.9 megohm
Load Resistance 0.9 megohm
Transconductance
500 micromhos
Transconductance 500 micromhos
equivalent to a
0.26 volt
equivalent to a 0.26 volt change in the output voltmge.)

Other

Plate Dissipation
0.9 watt
Plate Dissipation 0.9 watt