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Voltage Triode Pentode ·Pentode-Triode

6JT8

Triode-pentode combination designed for television receiver signal-processing service.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 2
Base: 9DX
Socket code: B9A
Base pins: 9
Nominal heater: 6.3 V / 725 mA

Description

The Westinghouse 6JT8 combines a high-mu triode with a sharp-cutoff pentode for sync/phase and video-amplifier service.

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: 9DX
Socket code: B9A
Base pins: 9
Nominal heater voltage: 6.3 V
Nominal heater current: 725 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

9DX - Terminal pinout

Electrical assignments shared by every tube using this base designation.

Terminal	Section	Connection	Evidence
PIN12K	B	K — Cathode EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 131, 9DX
PIN22G1	B	G1 — Control Grid EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 131, 9DX
PIN32P	B	P — Plate (Anode) EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 131, 9DX
PIN4H	—	H — Heater EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 131, 9DX
PIN5H	—	H — Heater EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 131, 9DX
PIN61G3	A	G3 — Suppressor GridGroup 9DX6 EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 131, 9DX
PIN6IS	A	IS — Internal ScreenGroup 9DX6 EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 131, 9DX
PIN61K	A	K — CathodeGroup 9DX6 EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 131, 9DX
PIN71G1	A	G1 — Control Grid EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 131, 9DX
PIN81G2	A	G2 — Screen Grid EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 131, 9DX
PIN91P	A	P — Plate (Anode) EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 131, 9DX

Section ratings

2 physical sections, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 37000 Ω
Transconductance: 0.0027 S
Amplification factor: 100
Max plate voltage: 330 V
Max plate dissipation: 1 W

Published ratings and characteristics promoted where clearly stated; identical repeated diode/triode sections compressed where applicable.

Section 2

Pentode

X-ray radiationInterelectrode capacitances

Plate resistance: 50000 Ω
Transconductance: 0.02 S
Max plate voltage: 330 V
Max screen voltage: 330 V
Max plate dissipation: 4 W
Max screen dissipation: 1.1 W

Published ratings and characteristics promoted where clearly stated; identical repeated diode/triode 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

1940 RCA

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristics

Heater voltage
6.3 V
Published nominal value
Heater current
725 mA
Published nominal value
Transconductance
2700 µS
Published operating characteristic
Amplification factor
100
Published operating characteristic

Other

Application
Sync separator; voltage amplifier; video amplifier
Printed source application

SECTION 2

Pentode

Characteristics

Heater voltage
6.3 V
Published nominal value
Heater current
725 mA
Published nominal value
Transconductance
20000 µS
Published operating characteristic

Other

Maximum plate dissipation
17.6 W
Published maximum or stated design maximum

Data set 02

1965 Westinghouse Data Book

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristics

Heater Voltage
6.3 V
Heater Current
725 mA
Amplification Factor
100 ratio
Grid-Plate Capacitance
3.2 pF

Other

Maximum Plate Voltage
330 V
Maximum Plate Dissipation
1 W

SECTION 2

Pentode

Other

Maximum Plate Voltage
330 V
Maximum Plate Dissipation
4 W
Maximum Screen Supply Voltage
330 V

Characteristics

Grid-Plate Capacitance
0.075 pF
ShieldedOrMaximum
Input Capacitance
13 pF
Output Capacitance
3 pF

Data set 03

1975 RCA RC30

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Heater-Cathode Voltage :
200 V
Other;PublishedValue1
Heater-Cathode Voltage :
200 V
Other;PublishedValue2
Peak value
100 V
Other;PublishedValue1
Peak value
100 V
Other;PublishedValue2
Plate Voltage
330 V
MaximumRating
Grid-No.l (Control-Grid) Voltage, Positive-bias value
0 V
MaximumRating
Plate Dissipation
4 W
MaximumRating
For grid-No.2 voltages up to 165 volts
1.1 V
MaximumRating
For fixed-bias operation
0.5 megohm
MaximumCircuitValue;PublishedValue1
For fixed-bias operation
0.25 megohm
MaximumCircuitValue;PublishedValue2
For cathode-bias operation
1 megohm
MaximumCircuitValue;PublishedValue1
For cathode-bias operation
1 megohm
MaximumCircuitValue;PublishedValue2
Maximum Plate Voltage
330 V
Section1

Characteristic

Plate Supply Voltage
250 V
Characteristic;PublishedValue1
Plate Supply Voltage
50 V
Characteristic;PublishedValue2
Plate Supply Voltage
200 V
Characteristic;PublishedValue3
Grid-No.2 Supply Voltage
100 V
Characteristic;PublishedValue1
Grid-No.2 Supply Voltage
100 V
Characteristic;PublishedValue2
Grid-No.l Voltage
-2 V
Characteristic;PublishedValue1
Grid-No.l Voltage
0 V
Characteristic;PublishedValue2
Cathode-Bias Resistor
82 ohm
Characteristic
Plate Resistance (Approx.)
37000 ohm
Characteristic;PublishedValue1
Plate Resistance (Approx.)
50000 ohm
Characteristic;PublishedValue2
Plate Current
1.5 mA
Characteristic;PublishedValue1
Plate Current
65 mA
Characteristic;PublishedValue2
Plate Current
17 mA
Characteristic;PublishedValue3
Grid-No.2 Current
18 mA
Characteristic;PublishedValue1
Grid-No.2 Current
3.5 mA
Characteristic;PublishedValue2
100 iiA.
-6 V
Characteristic
20 juA
-5.3 V
Characteristic
Plate Resistance
37000 ohm
Section1
Transconductance
2700 uS
Section1
Amplification Factor
100
Section1

SECTION 2

Pentode

Other

Maximum Plate Voltage
330 V
Section2
Maximum Screen Voltage
330 V
Section2
Maximum Plate Dissipation
4 W
Section2
Maximum Screen Dissipation
1.1 W
Section2

Characteristic

Plate Resistance
50000 ohm
Section2
Transconductance
20000 uS
Section2