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Tube Tinker — Electron Tube Database
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Voltage - Dual Triode (similar high frequency) ·Triode-Triode

4BQ7A

Medium-mu twin triode for VHF television tuner cascode amplification and push-pull cathode-drive RF amplifier service, combining two closely matched high-frequency triode sections.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
2
Base
9AY
Socket code
B9A
Base pins
9
Nominal heater
4.2 V / 600 mA

Description

Medium-mu twin triode used as a cascode amplifier in VHF television tuners and in push-pull cathode-drive RF amplifiers.

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
9AY
Socket code
B9A
Base pins
9
Nominal heater voltage
4.2 V
Nominal heater current
600 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

9AY - Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

2 physical sections, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances
Plate resistance
5900 Ω
Transconductance
0.0064 S
Amplification factor
38
Max plate voltage
260 V
Max plate dissipation
2 W
Max cathode current
20 mA
Rectifier max heater-cathode voltage
200 V
Rectifier warm-up time
11 s

Published ratings and characteristics promoted where applicable.

Section 2

Triode

X-ray radiationInterelectrode capacitances
Plate resistance
5900 Ω
Transconductance
0.0064 S
Amplification factor
38
Max plate voltage
260 V
Max plate dissipation
2 W
Max cathode current
20 mA

Second physical triode section; electrically identical twin section.

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

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Triode

Capacitance

  • Input Capacitance

    2.85 pF

    EachUnit

  • Output Capacitance

    1.35 pF

    EachUnit

  • Grid-Plate Capacitance

    1.15 pF

    EachUnit

Other

  • Plate Voltage

    150 V

    ClassA;EachUnit

  • Cathode Bias Resistor

    220 ohm

    ClassA;EachUnit

  • Plate Current

    9 mA

    ClassA;EachUnit

Data set 02

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

  • Heater Warmup Time

    11 s

Data set 03

1965 Westinghouse Data Book

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristics

  • Heater Voltage

    4.2 V

  • Heater Current

    600 mA

  • Transconductance

    6400 uS

    RepresentativePublishedPoint

  • Plate Resistance

    6100 ohm

    RepresentativePublishedPoint

  • Amplification Factor

    39 ratio

    RepresentativePublishedPoint

  • Plate Voltage

    150 V

    ClassA; EachSection

  • Plate Current

    9 mA

    ClassA; EachSection

  • Cathode Bias Resistor

    220 ohm

    ClassA; EachSection

Other

  • Maximum Plate Voltage

    250 V

  • Maximum Plate Dissipation

    2 W

  • Plate Supply Voltage

    250 V

    GroundedGrid; DirectCoupled

Data set 04

1966 Tung Sol Electronic Tubes 1 of 4

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Plate voltage

    150 V

    EachSection

  • Plate current

    10 mA

    EachSection

  • Application

    VHF amplifier/cascode service

    Section1

Characteristic

  • Transconductance

    6400 µS

    EachSection

  • Plate resistance

    5900 Ω

    EachSection

  • Amplification factor

    38

    EachSection

Data set 05

1971 RCA HB3 Binder 4 of 7

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Heater Current

    560 mA to 640 mA

    Published nominal ± tolerance

  • Heater Voltage

    4.2 V

    At heater current 0.6 A

  • Warm-Up Time

    11 s

    Average

  • Plate Voltage

    150 V

    Inherited from explicitly referenced 6-volt parent type; heater variant

  • Cathode Bias Resistor

    220 Ω

    Inherited from explicitly referenced 6-volt parent type; heater variant

  • Plate Current

    9 mA

    Inherited from explicitly referenced 6-volt parent type; heater variant

Characteristics

  • Amplification Factor

    35

    Inherited from explicitly referenced 6-volt parent type; heater variant

  • Plate Resistance

    5800 Ω

    Inherited from explicitly referenced 6-volt parent type; heater variant

  • Transconductance

    6000 µS

    Inherited from explicitly referenced 6-volt parent type; heater variant

Data set 06

1975 RCA RC30

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Heater Voltage (ac/dc) 4.2 5.6

    6.3 V

    Published in approved 6BZ7 target datasheet entry; Section1

  • Heater Current 0.45

    400 mA

    Published in approved 6BZ7 target datasheet entry; Section1

  • Cathode Current

    20 mA

    Published in approved 6BZ7 target datasheet entry; Section1

  • Plate Dissipation

    2 W

    Published in approved 6BZ7 target datasheet entry; Section1

  • Plate Supply Voltage

    150 V

    Published in approved 6BZ7 target datasheet entry; Section1

  • Cathode-Bias Resistor

    220 Ω

    Published in approved 6BZ7 target datasheet entry; Section1

  • Plate Resistance (Approx.)

    5900 Ω

    Published in approved 6BZ7 target datasheet entry; Section1

  • Transconductance

    6400 µS

    Published in approved 6BZ7 target datasheet entry; Section1

  • Plate Current

    9 mA

    Published in approved 6BZ7 target datasheet entry; Section1

  • Grid-Circuit Resistance

    0.5 MΩ

    Published in approved 6BZ7 target datasheet entry; Section1

  • * Rating may be high as

    300 V

    Published in approved 6BZ7 target datasheet entry; Section1

Capacitance

  • Grid to Plate 1.2

    1.2 pF

    Published in approved 6BZ7 target datasheet entry; Section1

  • —

    -5 pF

    Published in approved 6BZ7 target datasheet entry; Section1

  • Plate to Grid, Heater, and Internal Shield

    2.2 pF

    Published in approved 6BZ7 target datasheet entry; Section1

  • Plate to Cathode 0.12

    0.12 pF

    Published in approved 6BZ7 target datasheet entry; Section1

  • Heater to Cathode 2.6

    2.6 pF

    Published in approved 6BZ7 target datasheet entry; Section1

  • * Rating: may be high as

    300 V

    Published in approved 6BZ7 target datasheet entry; Section1

Characteristic

  • For plate current of 100

    -6.5 V

    Published in approved 6BZ7 target datasheet entry; Section1