6CM8

High-mu triode plus sharp-cutoff pentode; the pentode is designed for television IF, AGC, and reactance-tube service.

Directly heatedCold cathodeCommon cathodeDissimilar

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

Description

High-mu triode plus sharp-cutoff pentode; pentode is intended for IF, AGC and reactance-tube 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: 9FZ
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

9FZ - Terminal pinout

Electrical assignments shared by every tube using this base designation.

Terminal	Section	Connection	Evidence
PIN1Base Pin	A	P — Plate (Anode) Literal label 1P; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FZ
PIN2Base Pin	B	G1 — Control Grid Literal label 2G1; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FZ
PIN3Base Pin	B	G3 — Suppressor GridGroup 9FZ3 Literal label 2G3; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FZ
PIN3Base Pin	B	K — CathodeGroup 9FZ3 Literal label 2K; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FZ
PIN3Base Pin	—	IS — Internal ScreenGroup 9FZ3 Literal label IS; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FZ
PIN4Base Pin	—	H — Heater Literal label H; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FZ
PIN5Base Pin	—	H — Heater Literal label H; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FZ
PIN6Base Pin	B	P — Plate (Anode) Literal label 2P; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FZ
PIN7Base Pin	B	G2 — Screen Grid Literal label 2G2; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FZ
PIN8Base Pin	A	K — Cathode Literal label 1K; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FZ
PIN9Base Pin	A	G1 — Control Grid Literal label 1G1; manufacturer confirmation pending	Unverified EIA Base Connections printed p132, 9FZ

Section ratings

2 physical sections, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 50000 Ω
Transconductance: 0.002 S
Amplification factor: 100
Max plate voltage: 300 V
Max plate dissipation: 1 W

Published promoted fields populated from printed headings.

Section 2

Pentode

X-ray radiationInterelectrode capacitances

Plate resistance: 600000 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 promoted fields populated from printed headings.

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

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
1.9 pF
Input capacitance
1.6 pF
Output capacitance
0.22 pF

Other

Heater warm-up time
11 s
BothSections
Plate supply voltage
250 V
ClassA
Grid #1 voltage
-2 V
ClassA
Plate current
1.8 mA
ClassA

SECTION 2

Pentode

Capacitance

Grid #1-to-plate capacitance
0.04 pF
Input capacitance
6 pF
Output capacitance
2.6 pF
Pentode plate to triode grid capacitance
0.01 pF
Coupling
Pentode grid #1 to triode plate capacitance
0.15 pF
Coupling
Pentode plate to triode plate capacitance
0.1 pF
Coupling

Other

Plate supply voltage
200 V
ClassA
Grid #2 voltage
150 V
ClassA
Grid #1 voltage
0 V
ClassA
Cathode bias resistor
180 ohm
ClassA
Plate current
9.5 mA
ClassA
Grid #2 current
2.8 mA
ClassA

Characteristic

Grid #1 voltage at 10 uA plate current
-8 V