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Voltage - Dual Triode (similar high frequency) ·Triode-Triode

ECC81

Medium-mu twin triode for oscillator and AF/RF amplifier service, widely suited to high-frequency amplification, frequency generation, and general voltage-amplifier applications.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 2
Base: 9A
Socket code: B9A
Base pins: 9
Nominal heater: 12.6 V / 150 mA

Description

Twin triode for oscillator and AF/RF amplifier service; source also designates ECC81.

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: 9A
Socket code: B9A
Base pins: 9
Nominal heater voltage: 12.6 V
Nominal heater current: 150 mA
Parallel heater voltage: 6.3 V
Parallel heater current: 300 mA
Series capable: Yes

9A - Terminal pinout

Electrical assignments shared by every tube using this base designation.

Terminal	Section	Connection	Evidence
PIN12P	B	P — Plate (Anode) EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 130, 9A
PIN22G1	B	G1 — Control Grid EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 130, 9A
PIN32K	B	K — Cathode EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 130, 9A
PIN4H	—	H — Heater EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 130, 9A
PIN5H	—	H — Heater EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 130, 9A
PIN61P	A	P — Plate (Anode) EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 130, 9A
PIN71G1	A	G1 — Control Grid EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 130, 9A
PIN81K	A	K — Cathode EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 130, 9A
PIN9HCT	—	HCT — Heater Center Tap EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 130, 9A

Section ratings

2 physical sections, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 11000 Ω
Transconductance: 0.0055 S
Amplification factor: 60
Max plate voltage: 300 V
Max plate dissipation: 2.5 W
Max cathode current: 15 mA

A.F. double triode with 6.3/12.6 V series-parallel heater arrangement.

Section 2

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 11000 Ω
Transconductance: 0.0055 S
Amplification factor: 60
Max plate voltage: 300 V
Max plate dissipation: 2.5 W
Max cathode current: 15 mA

Second physical triode restored.

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

1951 Philips Receiving Tubes for Television

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristics

Anode Voltage
170 V
Each section
Anode Current
10 mA
Each section
Transconductance
6000 uS
AnodeVoltage=170V
Amplification Factor
62 ratio
AnodeVoltage=170V
Anode Voltage
250 V
Each section
Anode Current
10 mA
Each section
Transconductance
4900 uS
AnodeVoltage=250V
Amplification Factor
43 ratio
AnodeVoltage=250V

Other

Maximum Anode Voltage at Zero Current
550 V
Each section

Data set 02

1953 RFT Rundfunk Technik

Published operating points and test conditions from this source.

SECTION 1

Triode

Application

Application
VoltageAmplifier text

Data set 03

1958 Amperex Industrial

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Plate voltage
250 V
Published table
Plate current
10 mA
Published table
Control-grid bias
-2 V
VoltageAmplifier

Characteristic

Transconductance
5500 µS
Published table
Amplification factor
55
Published table
Heater/filament voltage
6.3 V
Published rating
Heater/filament current
300 mA
Published rating
Series heater voltage
12.6 V
SeriesHeater
Series heater current
150 mA
SeriesHeater

Data set 04

1961 Ferranti Technical Handbook

Published operating points and test conditions from this source.

SECTION 1

Triode

Application

Application
RF amplifier / frequency changer

Other

Maximum intended frequency
300 MHz

Data set 05

1963 Amperex Condensed

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

Heater voltage
6.3 V
Published heater rating
Heater current
300 mA
Published heater rating
Amplification factor
55
VoltageAmplifier
Transconductance
5500 µS
VoltageAmplifier
Series heater voltage
12.6 V
SeriesHeater
Series heater current
150 mA
SeriesHeater

Other

Plate voltage
250 V
VoltageAmplifier
Control-grid bias
-2 V
VoltageAmplifier
Plate current
10 mA
VoltageAmplifier

Data set 06

1963 Philips Electron Tubes Handbook V1a

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Plate voltage
170 V
Plate current
8.5 mA
Maximum plate voltage
300 V
Maximum plate dissipation
2.5 W

Characteristic

Transconductance
5900 uS
Amplification factor
66
Plate resistance
11 kohm

Capacitance

Grid capacitance
2.3 pF
Plate capacitance
0.45 pF
Grid-plate capacitance
1.6 pF

Data set 07

1967 Mullard Receiving and Amplifying Valves

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

Plate Current
3 mA
EachSection;Va=100V
Transconductance
3750 uS
EachSection;Va=100V
Amplification Factor
62
EachSection;Va=100V
Plate Resistance
16500 ohm
EachSection;Va=100V
Plate Current
8.5 mA
EachSection;Va=170V
Transconductance
5900 uS
EachSection;Va=170V
Amplification Factor
66
EachSection;Va=170V
Plate Resistance
11000 ohm
EachSection;Va=170V
Plate Current
11.5 mA
EachSection;Va=200V
Transconductance
6700 uS
EachSection;Va=200V
Amplification Factor
70
EachSection;Va=200V

Data set 08

1968 Mazda Belvu

Published operating points and test conditions from this source.

SECTION 1

Triode

Application

Application
Oscillator_RF_AF_Amplifier text

Data set 09

1972 Philips Receiving Tubes

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Anode current I
10 mA
Transconductance S
5.5 mA/V

Capacitance

Grid to all except anode Cgla)
2.3 pF
Cg'(a')
2.3 pF
Anode to all except grid Ca(g)
0.45 pF
Anode to grid Cag
1.6 pF
Ca'g’
1.6 pF
Anode to cathode Cak
0.2 pF
Ca'k’
0.2 pF
Cathode to heater Cxf
2.5 pF
Ck'f
2.5 pF

Data set 10

1973 Mazda Valves Binder 2

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

HeaterVoltageNominal
6.3 V
Nominal
HeaterCurrentNominal
300 mA
Nominal
Maximum Plate Voltage
300 V
Maximum Plate Dissipation
2.5 W
Maximum Cathode Current
20 mA

Characteristic

Transconductance
5500 µS
Typical
Amplification Factor
55
Typical
Plate Resistance
10000 ohm
Typical

Data set 11

1975 RCA RC30

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Heater Voltage (ac/dc) 12.6
6.3 V
Published in approved ECC81 target datasheet entry; Section1
Heater Current 0.15
300 mA
Published in approved ECC81 target datasheet entry; Section1
Plate Voltaire
300 V
Published in approved ECC81 target datasheet entry; Section1

Capacitance

Grid to Cathode and Heater (Each unit)
2.2 pF
Published in approved ECC81 target datasheet entry; Section1
Unit No.l
0.5 pF
Published in approved ECC81 target datasheet entry; Section1
Unit No.2
0.4 pF
Published in approved ECC81 target datasheet entry; Section1
Cathode to Plate (Each unit)
0.2 pF
Published in approved ECC81 target datasheet entry; Section1
Cathode to Grid and Heater (Each unit)
4.6 pF
Published in approved ECC81 target datasheet entry; Section1
Plate to Grid and Heater (Each unit)
1.8 pF
Published in approved ECC81 target datasheet entry; Section1
Heater to Cathode (Each Unit)
2.4 pF
Published in approved ECC81 target datasheet entry; Section1

Data set 12

1999 Philips E-Z

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

1) In case of series supply & current-limiting device
1 V
1) In case of series supply & current-limiting device

Data set 13

199X JJ

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Typical Plate Voltage
250 V
TypicalGridVoltage
-2 V
Typical Plate Current
10 mA

Data set 14

2026 Genalex Rebrand

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

Transconductance
4500 to 6500 µS
Plate 250 V; grid -2 V
Plate Current
9 to 12 mA
Plate 250 V; grid -2 V

Data set 15

2026 JJ Electronic

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristics

Ua
250 V
Published value
Ia
10 mA
Published value
Ug
-2 V
Published value
S
5500 µS
Published value
µ
60
Published value
Ri
11 kΩ
Published value

Other

Ua
300 V
Published value
Wa
2.5 W
Published value
Ik
15 mA
Published value
Ug
-50 V
Published value
Uk/f
90 V
Published value

Data set 16

2026 Mullard Rebrand

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristics

Heater current at 6.3 V
350 to 390 mA
Published min/max range
Heater current at 12.6 V
175 to 195 mA
Published min/max range