12SA7

Heptode oscillator-converter for superheterodyne radio receivers. It combines local oscillation and mixing in one multi-grid tube, translating incoming RF signals to the receiver intermediate frequency.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: 8RV
Socket code: IO
Base pins: 8
Nominal heater: 12.6 V / 150 mA

Description

Pentagrid-converter/heptode tube; 12.6-volt heater version of 6SA7.

Socket description

International Octal

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 8RV
Socket code: IO
Base pins: 8
Nominal heater voltage: 12.6 V
Nominal heater current: 150 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

8RV - 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

Heptode

X-ray radiationInterelectrode capacitances

Plate resistance: 800000 Ω
Transconductance: 0.00035 S
Max plate voltage: 300 V
Max screen voltage: 100 V
Max plate dissipation: 1 W
Max screen dissipation: 0.35 W
Max cathode current: 6 mA

Promoted from printed maximum/characteristic columns; additional published values retained in TUBE_SECTION_PARAMETER.

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

Heptode

Other

Oscillator-grid current
0.5 mA
Converter
Oscillator-grid resistor
20000 Ω
Converter
Plate voltage
250 V
Converter
Screen voltage
100 V
Converter
Control-grid voltage
-2 V
Converter
Plate current
3.5 mA
Converter
Screen current
8.5 mA
Converter

Characteristic

Plate resistance
1000000 Ω
Converter
Conversion transconductance
450 µS
Converter

Data set 02

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Heptode

Other

Heater voltage
12.6 V
Nominal

Data set 03

1971 RCA HB3 Binder 5 of 7

Published operating points and test conditions from this source.

SECTION 1

Heptode

Other

Heater voltage
12.6 V
Heater current
150 mA
Plate voltage
250 V
Converter
Screen supply voltage
100 V
Converter
Oscillator anode voltage
100 V
Converter
Cathode resistor
200 ohm
Converter
Plate current
3 mA
Converter
Screen current
1 mA
Converter
Oscillator-anode current
4 mA
Converter
Maximum plate voltage
300 V
Maximum screen voltage
100 V

Characteristic

Conversion transconductance
450 uS
Converter