401A

Seven-pin miniature professional pentode for Class-A voltage amplification, providing high plate resistance and flexible small-signal operation.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: E7-1
Socket code: B7G
Base pins: 7
Nominal heater: 6.3 V / 150 mA

Description

Seven-pin miniature pentode with 200 V plate and 155 V screen maximum ratings.

Socket description

Miniature 7-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: E7-1
Socket code: B7G
Base pins: 7
Nominal heater voltage: 6.3 V
Nominal heater current: 150 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

E7-1 - 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: 450000 Ω
Transconductance: 0.002 S
Max plate voltage: 180 V
Max screen voltage: 140 V
Max plate dissipation: 1.7 W
Max screen dissipation: 0.5 W
Max cathode current: 18 mA

Promoted fields mapped from printed maximum-rating and characteristic headings; additional published values preserved in parameter rows.

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

1956 Western Electric Tubes

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristic

HeaterOrFilamentVoltage
6.3 V
HeaterOrFilamentCurrent
150 mA

Data set 02

1965 Ericsson Longlife

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Plate supply voltage
45 V
ClassA
Screen-grid supply voltage
45 V
ClassA
Cathode bias resistor
390 Ohm
ClassA
Plate current
2.7 mA
ClassA
Screen-grid current
0.8 mA
ClassA
Plate supply voltage
90 V
ClassA
Screen-grid supply voltage
90 V
ClassA
Cathode bias resistor
820 Ohm
ClassA
Plate current
3.9 mA
ClassA
Screen-grid current
1.2 mA
ClassA
Plate supply voltage
120 V
ClassA
Screen-grid supply voltage
120 V
ClassA
Plate current
5 mA
ClassA
Transconductance minimum
1500 uS
Va=90V;Vg2=90V
Transconductance maximum
2500 uS
Va=90V;Vg2=90V

Characteristics

Transconductance
1900 uS
ClassA;Va=45V;Vg2=45V
Plate resistance
0.3 MOhm
ClassA;Va=45V;Vg2=45V
Transconductance
2000 uS
ClassA;Va=90V;Vg2=90V
Plate resistance
0.45 MOhm
ClassA;Va=90V;Vg2=90V
Transconductance
2200 uS
ClassA;Va=120V;Vg2=120V
Plate resistance
0.5 MOhm
ClassA;Va=120V;Vg2=120V

Data set 03

2026 Western Electric Other

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Heater Voltage
6.3 V
General characteristics
Heater Current
150 mA
General characteristics
Plate Voltage Maximum
180 V
Design-center value
Screen Voltage Maximum
140 V
Design-center value
Plate Dissipation Maximum
1.7 W
Design-center value
Screen Dissipation Maximum
0.5 W
Design-center value
Cathode Current Maximum
18 mA
Design-center value
Heater-Cathode Voltage Maximum
90 V
Design-center value
Bulb Temperature Maximum
120 degC
Design-center value
Plate Voltage
45 V
ClassA; operating column 1
Screen Grid Voltage
45 V
ClassA; operating column 1
Control Grid Voltage
-1.5 V
ClassA; operating column 1
Plate Voltage
90 V
ClassA; operating column 2
Screen Grid Voltage
90 V
ClassA; operating column 2
Control Grid Voltage
-5 V
ClassA; operating column 2
Plate Voltage
90 V
ClassA; cathode-bias operating column
Screen Grid Voltage
90 V
ClassA; cathode-bias operating column
Cathode Bias Resistor
820 ohm
ClassA; cathode-bias operating column
Plate Voltage
120 V
ClassA; operating column 4
Screen Grid Voltage
120 V
ClassA; operating column 4
Control Grid Voltage
-7 V
ClassA; operating column 4

Capacitance

Grid-to-Plate Capacitance Maximum
0.01 pF
With external shield RMA #316
Input Capacitance
3.4 pF
With external shield RMA #316
Output Capacitance
2.9 pF
With external shield RMA #316

Characteristic

Plate Current
3 mA
ClassA; operating column 1
Screen Grid Current
1.1 mA
ClassA; operating column 1
Plate Resistance
0.29 megohm
ClassA; operating column 1
Transconductance
2000 uS
ClassA; operating column 1
Plate Current
3.9 mA
ClassA; operating column 2
Screen Grid Current
1.3 mA
ClassA; operating column 2
Plate Resistance
0.45 megohm
ClassA; operating column 2
Transconductance
2000 uS
ClassA; operating column 2
Plate Current
4.3 mA
ClassA; cathode-bias operating column
Screen Grid Current
1.4 mA
ClassA; cathode-bias operating column
Plate Resistance
0.41 megohm
ClassA; cathode-bias operating column
Transconductance
2100 uS
ClassA; cathode-bias operating column
Plate Current
5.1 mA
ClassA; operating column 4
Screen Grid Current
1.8 mA
ClassA; operating column 4
Plate Resistance
0.41 megohm
ClassA; operating column 4
Transconductance
2200 uS
ClassA; operating column 4