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Voltage - Dual Triode (similar) ·Triode-Triode

7729

High-reliability high-mu twin triode for 12AX7-class service, intended for dependable high-gain voltage amplification in professional and critical electronic equipment.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
2
Base
E9-1 / 9A
Socket code
B9A
Base pins
9
Nominal heater
6.3 V / 300 mA

Description

High-mu twin triode, high-reliability replacement for 12AX7; identical sections compressed to one section row.

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
E9-1 / 9A
Socket code
B9A
Base pins
9
Nominal heater voltage
6.3 V
Nominal heater current
300 mA
Parallel heater voltage
6.3 V
Parallel heater current
300 mA
Series capable
Yes

E9-1 / 9A - 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
62500 Ω
Transconductance
0.0016 S
Amplification factor
100
Max plate voltage
330 V
Max plate dissipation
1.1 W
Max cathode current
20 mA

Promoted from 250 V characteristic point; identical twin sections compressed.

Section 2

Triode

X-ray radiationInterelectrode capacitances
Plate resistance
62500 Ω
Transconductance
0.0016 S
Amplification factor
100
Max plate voltage
330 V
Max plate dissipation
1.1 W
Max cathode current
20 mA

Second identical physical triode section; added to align rows with SectionCount.

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 CBS Hytron

Published operating points and test conditions from this source.

SECTION 1

Triode

Capacitance

  • Grid-to-plate capacitance

    1.7 pF

    EachSection

Other

  • Plate voltage

    100 V

    ClassA

Characteristics

  • Plate current

    0.5 mA

    Va=100V

  • Transconductance

    1250 uS

    Va=100V

  • Plate resistance

    80000 Ohm

    Va=100V