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Voltage Pentode - Sharp Cutoff (single) ·Pentode-Triode

6CH8

General-purpose medium-mu triode plus sharp-cutoff pentode for television IF, video, AGC, oscillator, and phase-splitter circuits.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 2
Base: 9FT
Socket code: B9A
Base pins: 9
Nominal heater: 6.3 V / 450 mA

Description

General-purpose medium-mu triode and sharp-cutoff pentode for television IF, video, AGC, oscillator and phase-splitter circuits.

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: 9FT
Socket code: B9A
Base pins: 9
Nominal heater voltage: 6.3 V
Nominal heater current: 450 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

9FT - Terminal pinout

Electrical assignments shared by every tube using this base designation.

Terminal	Section	Connection	Evidence
PIN1Base Pin	A	K — Cathode Literal label 1K; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FT
PIN2Base Pin	B	P — Plate (Anode) Literal label 2P; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FT
PIN3Base Pin	B	G2 — Screen Grid Literal label 2G2; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FT
PIN4Base Pin	—	H — Heater Literal label H; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FT
PIN5Base Pin	B	G3 — Suppressor GridGroup 9FT5 Literal label 2G3; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FT
PIN5Base Pin	—	H — HeaterGroup 9FT5 Literal label H; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FT
PIN5Base Pin	—	IS — Internal ScreenGroup 9FT5 Literal label IS; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FT
PIN6Base Pin	B	K — Cathode Literal label 2K; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FT
PIN7Base Pin	B	G1 — Control Grid Literal label 2G1; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FT
PIN8Base Pin	A	G1 — Control Grid Literal label 1G1; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FT
PIN9Base Pin	A	P — Plate (Anode) Literal label 1P; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FT

Section ratings

2 physical sections, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 5750 Ω
Transconductance: 0.0033 S
Amplification factor: 19
Max plate voltage: 300 V
Max plate dissipation: 2.6 W

Published source values promoted where applicable.

Section 2

Pentode

X-ray radiationInterelectrode capacitances

Plate resistance: 300000 Ω
Transconductance: 0.0062 S
Max plate voltage: 300 V
Max screen voltage: 300 V
Max plate dissipation: 2 W
Max screen dissipation: 0.5 W

Published source values promoted 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

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Heater voltage
6.3 V
Heater current
450 mA
Plate voltage
300200 V
Typical operating conditions
Plate current
139.5 mA
Typical operating conditions

SECTION 2

Pentode

Other

Heater voltage
6.3 V
Heater current
450 mA
Plate voltage
300200 V
Typical operating conditions
Plate current
139.5 mA
Typical operating conditions

Data set 02

1966 Tung Sol Electronic Tubes 2 of 4

Published operating points and test conditions from this source.

SECTION 1

Triode

Capacitance

Grid-to-plate capacitance
1.6 pF
Triode input capacitance
1.9 pF
Triode output capacitance
1.6 pF

Other

Plate supply voltage
200 V
ClassA
Grid #1 voltage
-6 V
ClassA
Plate current
13 mA
ClassA

SECTION 2

Pentode

Capacitance

Pentode grid-to-plate capacitance
0.025 pF
Pentode input capacitance
7 pF
Pentode output capacitance
2.25 pF

Other

Plate supply voltage
200 V
ClassA
Grid #2 supply voltage
150 V
ClassA
Cathode bias resistor
180 ohm
ClassA
Plate current
9.3 mA
ClassA
Grid #2 current
2.8 mA
ClassA