70A7GT

Combined beam-power amplifier and half-wave rectifier with a tapped heater, designed for series-heater receiving equipment.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 2
Base: 8AB
Socket code: IO
Base pins: 8
Nominal heater: 70 V / 150 mA

Description

Combined beam-power amplifier and half-wave rectifier with a tapped heater, intended for series-heater receiver applications.

Socket description

International Octal

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 8AB
Socket code: IO
Base pins: 8
Nominal heater voltage: 70 V
Nominal heater current: 150 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

8AB - 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

Beam Power

X-ray radiationInterelectrode capacitances

Transconductance: 0.0048 S
Amplification factor: 80
Max plate voltage: 110 V
Max screen voltage: 110 V

Section 2

Rectifier

X-ray radiationInterelectrode capacitances

Max plate voltage: 110 V
Rectifier nominal output current: 60 mA
Rectifier forward voltage drop: 14 V

Published handbook ratings and representative operating characteristics reviewed.

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 2

Rectifier

Other

Maximum plate voltage
110 V
Published handbook rating
Plate voltage
110 V
ClassA
Control-grid bias
7.5 V
ClassA
Load resistance
2600 ohm
ClassA
Power output
1.5 W
ClassA

Characteristic

Transconductance
5800 µS
Published handbook characteristic
Heater voltage
70 V
Published heater rating
Heater current
150 mA
Published heater rating

Data set 02

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

Heater voltage
70 V
Nominal
Heater current
150 mA
Nominal
Plate voltage
110 V
ClassA
Screen voltage
110 V
ClassA
Control-grid voltage
-7.5 V
ClassA
Load resistance
2500 ohm
ClassA
Total harmonic distortion
6.5 %
ClassA
Power output
1.5 W
ClassA

Characteristic

Plate current
40 mA
ClassA
Screen current
3 mA
ClassA
Transconductance
4800 uS
ClassA
Amplification factor
80
ClassA

SECTION 2

Rectifier

Other

Heater voltage
70 V
Nominal
Heater current
150 mA
Nominal
Maximum AC plate voltage RMS
125 V
HalfWaveRectifier
DC output current
60 mA
CapacitorInputFilter