Data set 01
1950 Sylvania
Published operating points and test conditions from this source.
SECTION 1
Triode
Characteristic
Heater Voltage
13.5 V
Heater Current
155 mA
Voltage - Dual Triode (similar) ·Triode-Triode
7058
Mobile-service high-mu twin triode, similar electrically to the 12AX7 apart from heater characteristics, intended for phase inversion, resistance-coupled amplification, and low-frequency oscillator service.
Directly heatedCold cathodeCommon cathodeDissimilar
- Sections
- 2
- Base
- -
- Socket code
- B9A
- Base pins
- 9
- Nominal heater
- 13.5 V / 155 mA
Description
Mobile-service high-mu twin triode with separate cathodes, similar to 12AX7 except heater characteristics.
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
- -
- Socket code
- B9A
- Base pins
- 9
- Nominal heater voltage
- 13.5 V
- Nominal heater current
- 155 mA
- Parallel heater voltage
- -
- Parallel heater current
- -
- Series capable
- No
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
- 61000 Ω
- Transconductance
- 0.00165 S
- Amplification factor
- 100
- Max plate voltage
- 330 V
- Max plate dissipation
- 1 W
- Max cathode current
- 10 mA
Representative row for two identical high-mu triodes.
Section 2
Triode
X-ray radiationInterelectrode capacitances
- Plate resistance
- 61000 Ω
- Transconductance
- 0.00165 S
- Amplification factor
- 100
- Max plate voltage
- 330 V
- Max plate dissipation
- 1 W
- Max cathode current
- 10 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 02
1960 RCA Industrial and Communications Types
Published operating points and test conditions from this source.
SECTION 1
Triode
CrossReference
Prototype / equivalent family
12AX7
Application
Application
Phase inverter / resistance-coupled amplifier / LF oscillator
Data set 03
1965 Sylvania Electronic Tubes Vol3
Published operating points and test conditions from this source.
SECTION 1
Triode
Other
Heater voltage range
12 to 15 V
Plate voltage maximum
330 V
Plate dissipation maximum
1 W
Typical plate voltage
250 V
ClassA
Characteristics
Heater current at 13.5 V
155 mA
Transconductance
1650 uS
CrossReference
Equivalent type
12AX7
Application
Application
High-mu voltage amplifier
Data set 04
1971 RCA HB3 Binder 3 of 7
Published operating points and test conditions from this source.
SECTION 1
Triode
Other
Heater voltage
13.5 V
Heater current
155 mA
Plate voltage
250 V
ClassA;EachSection
Plate current
1.25 mA
ClassA;EachSection
Maximum plate voltage
330 V
EachSection
Maximum plate dissipation
1 W
EachSection
Characteristic
Plate resistance
61000 ohm
EachSection
Transconductance
1650 uS
EachSection
Amplification factor
100
EachSection