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Voltage - Dual Triode (similar) ·Triode-Triode

12AU7A

Controlled-warm-up medium-mu twin triode documented for AF preamplifier service, combining moderate voltage gain with relatively low plate resistance and useful current-driving capability.

Directly heatedCold cathodeCommon cathodeDissimilar

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

Description

Twin triode with separate cathodes for AF preamplifier service; source also designates ECC82.

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: 7700 Ω
Transconductance: 0.0022 S
Amplification factor: 17
Max plate voltage: 300 V
Max plate dissipation: 2.75 W
Max cathode current: 22 mA

Each identical triode section.

Section 2

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 7700 Ω
Transconductance: 0.0022 S
Amplification factor: 17
Max plate voltage: 330 V
Max plate dissipation: 2.75 W
Max cathode current: 22 mA

Published promoted values applied where semantically applicable; additional table values retained in section parameters.

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

1960 RCA Industrial and Communications Types

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

HeaterOrFilamentVoltage
12.6 V
HeaterOrFilamentCurrent
150 mA

Data set 02

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

Plate Resistance
7700 ohm
AlternateOperatingPoint
Transconductance
2200 uS
AlternateOperatingPoint

Data set 03

1965 Westinghouse Data Book

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

Heater Voltage
12.6 V
Heater Current
150 mA
Plate Current
10.5 mA
Plate Resistance
7700 ohm
Transconductance
2200 uS
Amplification Factor
17
Grid To Plate Capacitance
2.4 pF
Input Capacitance
3.3 pF
Output Capacitance
0.5 pF

Other

Plate Voltage
250 V
EachUnit
Grid Voltage
-8.5 V
EachUnit

Data set 04

1966 Tung Sol Electronic Tubes 2 of 4

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Plate voltage
250 V
ClassA;EachSection
Plate current
10.5 mA
ClassA;EachSection
Grid voltage
-24 V
ClassA;EachSection
Heater warm-up time
11 s
BothSections

Characteristic

Plate resistance
7700 ohm
ClassA;EachSection
Transconductance
2200 uS
ClassA;EachSection
Amplification factor
17
ClassA;EachSection

Capacitance

Grid-to-plate capacitance
1.7 pF
EachSection
Input capacitance
1.8 pF
EachSection
Output capacitance
1.8 pF
EachSection

Data set 05

1968 General Electric Co

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

Plate Voltage
250 V
EachSection
Amplification Factor
17
EachSection
Plate Resistance
7700 ohm
EachSection
Transconductance
2200 uS
EachSection

Data set 06

1968 Mazda Belvu

Published operating points and test conditions from this source.

SECTION 1

Triode

Application

Application
AF_Preamplifier text

Data set 07

1971 RCA HB3 Binder 3 of 7

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Heater voltage
6.3 V
Nominal
Heater current
300 mA
Nominal
Heater voltage series
12.6 V
Series
Heater current series
150 mA
Series
Heater voltage parallel
6.3 V
Parallel
Heater current parallel
300 mA
Parallel
Maximum plate voltage
330 V
Promoted published value
Maximum plate dissipation
3 W
Promoted published value
PLATE VOLTAGE
330 V
Maximum RatingsE Design-Maximum Values:
PLATE DISSIPATION
3 W
Maximum RatingsE Design-Maximum Values:
to cathode
200 V
Maximum RatingsE Design-Maximum Values:
For cathode-bias operation
1 megohm
Maximum RatingsE Design-Maximum Values:

Characteristic

Plate resistance
7700 ohm
Promoted published value
Transconductance
2200 uS
Promoted published value
Amplification factor
17
Promoted published value
Voltage
20 V
Plate Voltage
250 V
Grid Voltage
8.5 V
Amplification Factor
17 A
Plate Resistance (Approx.)
7700 ohm
Transconductance
2200 uS
Plate Current
10.5 mA
Grid Voltage (Approx.) for plate µa =
24 V

Data set 08

1971 RCA HB3 Binder 5 of 7

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristics

Heater voltage series
12.6 V
SeriesHeater
Heater current series
150 mA
SeriesHeater
Heater voltage parallel
6.3 V
ParallelHeater
Heater current parallel
300 mA
ParallelHeater
Plate voltage
100 V
ClassA1;PublishedPoint1
Plate voltage
250 V
ClassA1;PublishedPoint2
Grid voltage
0 V
ClassA1;PublishedPoint1
Grid voltage
-8.5 V
ClassA1;PublishedPoint2
Amplification factor
19.5
ClassA1;PublishedPoint1
Amplification factor
17
ClassA1;PublishedPoint2
Plate resistance
6250 ohm
ClassA1;PublishedPoint1
Plate resistance
7700 ohm
ClassA1;PublishedPoint2
Transconductance
3100 µS
ClassA1;PublishedPoint1
Transconductance
2200 µS
ClassA1;PublishedPoint2
Plate current
11.8 mA
ClassA1;PublishedPoint1
Plate current
10.5 mA
ClassA1;PublishedPoint2

Other

Maximum plate voltage
330 V
ClassA1
Maximum cathode current
22 mA
ClassA1
Maximum plate dissipation
2.75 W
ClassA1
Peak heater-cathode voltage
200 V

Capacitance

Grid-to-plate capacitance
1.5 pF
Grid-to-cathode-and-heater capacitance
1.6 pF
Plate-to-cathode-and-heater capacitance
0.5 pF

SECTION 2

Triode

Characteristics

Heater voltage series
12.6 V
SeriesHeater
Heater current series
150 mA
SeriesHeater
Heater voltage parallel
6.3 V
ParallelHeater
Heater current parallel
300 mA
ParallelHeater
Plate voltage
100 V
ClassA1;PublishedPoint1
Plate voltage
250 V
ClassA1;PublishedPoint2
Grid voltage
0 V
ClassA1;PublishedPoint1
Grid voltage
-8.5 V
ClassA1;PublishedPoint2
Amplification factor
19.5
ClassA1;PublishedPoint1
Amplification factor
17
ClassA1;PublishedPoint2
Plate resistance
6250 ohm
ClassA1;PublishedPoint1
Plate resistance
7700 ohm
ClassA1;PublishedPoint2
Transconductance
3100 µS
ClassA1;PublishedPoint1
Transconductance
2200 µS
ClassA1;PublishedPoint2
Plate current
11.8 mA
ClassA1;PublishedPoint1
Plate current
10.5 mA
ClassA1;PublishedPoint2

Other

Maximum plate voltage
330 V
ClassA1
Maximum cathode current
22 mA
ClassA1
Maximum plate dissipation
2.75 W
ClassA1
Peak heater-cathode voltage
200 V
Peak negative-pulse grid voltage
660 V
HorizontalDeflectionOscillator
Peak cathode current
330 mA
HorizontalDeflectionOscillator
Peak negative-pulse grid voltage
440 V
VerticalDeflectionOscillator
Peak cathode current
66 mA
VerticalDeflectionOscillator
Peak positive-pulse plate voltage
1200 V
VerticalDeflectionAmplifier

Capacitance

Grid-to-plate capacitance
1.5 pF
Grid-to-cathode-and-heater capacitance
1.6 pF
Plate-to-cathode-and-heater capacitance
0.35 pF

Data set 09

1975 RCA RC30

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Plate Supply Voltage 100
250 V
Published in approved ECC82 target datasheet entry; Section1
Cathode-Bias Resistor 270
200 Ω
Published in approved ECC82 target datasheet entry; Section1
Plate Resistance (Approx.) 15000
10900 Ω
Published in approved ECC82 target datasheet entry; Section1
Transconductance 4000
5500 µS
Published in approved ECC82 target datasheet entry; Section1
Grid Voltage (Approx.) for plate current of 10 /iA —5
12 V
Published in approved ECC82 target datasheet entry; Section1
Plate Current 3.7
10 mA
Published in approved ECC82 target datasheet entry; Section1
Series 7 9.4
12.6 V
Published in approved ECC82 target datasheet entry; Section1
Parallel 3.5 4.7
6.3 V
Published in approved ECC82 target datasheet entry; Section1
Series 0.3 0.225
150 mA
Published in approved ECC82 target datasheet entry; Section1
Parallel 0.6 0.45
300 mA
Published in approved ECC82 target datasheet entry; Section1
Heater Warm-up Time (Parallel, Average) 11
11 seconds
Published in approved ECC82 target datasheet entry; Section1
Plate Voltage
330 V
Published in approved ECC82 target datasheet entry; Section1
Cathode Current
22 mA
Published in approved ECC82 target datasheet entry; Section1
Each Plate
2.75 W
Published in approved ECC82 target datasheet entry; Section1
Both Plates (Both units operating)
5.5 W
Published in approved ECC82 target datasheet entry; Section1
Plate Resistance (Approx.) 6250
7700 Ω
Published in approved ECC82 target datasheet entry; Section1
Transconductance 3100
2200 µS
Published in approved ECC82 target datasheet entry; Section1
For fixed-bias operation
0.25 MΩ
Published in approved ECC82 target datasheet entry; Section1
For cathode-bias operation
1 MΩ
Published in approved ECC82 target datasheet entry; Section1

Capacitance

Grid to Plate 1.5
1.5 pF
Published in approved ECC82 target datasheet entry; Section1
Grid to Cathode and Heater 1.6
1.6 pF
Published in approved ECC82 target datasheet entry; Section1
Plate to Cathode and Heater 0.5
0.35 pF
Published in approved ECC82 target datasheet entry; Section1

Characteristic

Plate Current 11.8
10.5 mA
Published in approved ECC82 target datasheet entry; Section1

Data set 10

2026 Electro Harmonix Gold

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

Plate Current
7.5 to 13.5 mA
Plate 250 V; Grid -8.5 V