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Voltage Radio Detector Converter ·Heptode

6A7

Classic pentagrid oscillator-converter for superheterodyne radio receivers. It combines local oscillation and mixing in one multi-grid tube, providing conventional frequency-changing performance for early AC receiving equipment.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: 7C
Socket code: UX7
Base pins: 7
Nominal heater: 6.3 V / 300 mA

Description

Pentagrid frequency converter recommended to perform detector and local-oscillator functions simultaneously in superheterodyne receivers.

Socket description

Small 7-contact (0.75-inch pin circle)

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 7C
Socket code: UX7
Base pins: 7
Nominal heater voltage: 6.3 V
Nominal heater current: 300 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

7C - Terminal pinout

Electrical assignments shared by every tube using this base designation.

Terminal	Section	Connection	Evidence
PIN1H	—	H — Heater EIA transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7C
PIN2P	A	P — Plate (Anode) EIA transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7C
PIN3G3	A	G3 — Suppressor GridGroup 7C3 EIA transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7C
PIN3G5	A	G5 — Fifth GridGroup 7C3 EIA transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7C
PIN4G2	A	G2 — Screen Grid EIA transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7C
PIN5G1	A	G1 — Control Grid EIA transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7C
PIN6K	A	K — Cathode EIA transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7C
PIN7H	—	H — Heater EIA transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7C
CAP1G4	A	G4 — Fourth Grid EIA transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7C

Section ratings

1 physical section, each with unique specifications.

Section 1

Heptode

X-ray radiationInterelectrode capacitances

Plate resistance: 360000 Ω
Transconductance: 0.00055 S
Max plate voltage: 300 V
Max screen voltage: 100 V
Max plate dissipation: 1 W
Max screen dissipation: 0.3 W
Max grid dissipation: 0.75 W
Max cathode current: 18 mA

Published promoted fields populated from the datasheet; identical repeated sections compressed where applicable.

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

1937 Raytheon Radio Receiving Tubes

Published operating points and test conditions from this source.

SECTION 1

Heptode

Other

Plate voltage
100 V
Converter
Screen voltage
50 V
Converter
Control-grid voltage
-1.5 V
Converter
Plate current
1.1 mA
Converter
Screen current
1.3 mA
Converter
Plate voltage
250 V
Converter
Screen voltage
100 V
Converter
Control-grid voltage
-3 V
Converter
Plate current
3.5 mA
Converter
Screen current
2.7 mA
Converter
Oscillator-grid resistor
50000 Ω
Converter
Oscillator-grid current
0.4 mA
Converter

Characteristic

Conversion transconductance
360 µS
Converter
Plate resistance
300000 Ω
Converter
Conversion transconductance
580 µS
Converter

Data set 02

1940 RCA

Published operating points and test conditions from this source.

SECTION 1

Heptode

Other

HeaterVoltageNominal
6.3 V
Nominal
HeaterCurrentNominal
300 mA
Nominal
Maximum Plate Voltage
250 V
Maximum Screen Voltage
100 V
Maximum Cathode Current
18 mA

Characteristic

Transconductance
550 µS
Typical
Plate Resistance
360000 ohm
Typical

Data set 03

1948 Brimar Radio Valve Manual

Published operating points and test conditions from this source.

SECTION 1

Heptode

Characteristics

RF Input Capacitance
8.5 pF
IF Output Capacitance
9 pF
Oscillator Input Capacitance
7 pF
Oscillator Output Capacitance
5.5 pF
Control Grid to Oscillator Grid Capacitance
0.15 pF
Control Grid to Anode Capacitance
0.3 pF
Control Grid to Oscillator Anode Capacitance
0.15 pF
Oscillator Grid to Oscillator Anode Capacitance
1 pF

Data set 04

1950 Sylvania

Published operating points and test conditions from this source.

SECTION 1

Heptode

Other

Maximum Plate Voltage
300 V
Maximum Screen Voltage
100 V
Maximum Plate Dissipation
1 W
Maximum Screen Dissipation
0.3 W
Maximum Grid Dissipation
0.75 W
Maximum Cathode Current
14 mA

Data set 05

1958 Brimar Radio Valve No 7

Published operating points and test conditions from this source.

SECTION 1

Heptode

Other

Heater Voltage
6.3 V
Heater Current
300 mA

Characteristic

Application
Heptode frequency changer

Data set 06

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Heptode

Other

Maximum plate voltage
300 V
Published handbook rating
Maximum screen voltage
100 V
Published handbook rating
Plate voltage
250 V
ClassA
Screen voltage
100 V
ClassA
Control-grid bias
3 V
ClassA
Plate current
3.5 mA
ClassA
Screen current
2.7 mA
ClassA

Characteristic

Plate resistance
360000 ohm
Published handbook characteristic
Transconductance
550 µS
Published handbook characteristic
Heater/filament voltage
6.3 V
Published heater/filament rating
Heater/filament current
300 mA
Published heater/filament rating

Data set 07

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Heptode

Characteristic

Conversion Transconductance
550 uS
Typical

Other

Screen Voltage
100 V
Typical