Data set 01
1958 Brimar Radio Valve No 7
Published operating points and test conditions from this source.
SECTION 1
Triode
Application
Application
Oscillator
SECTION 2
Heptode
Application
Application
Frequency changer / mixer
Voltage - Triode (with diode, heptode or hexode) ·Heptode-Triode
20D4
High-conversion-conductance triode-heptode frequency changer for superheterodyne receivers. The triode supplies local oscillation while the heptode performs mixing with comparatively strong conversion performance.
Directly heatedCold cathodeCommon cathodeDissimilar
- Sections
- 2
- Base
- -
- Socket code
- B9A
- Base pins
- 9
- Nominal heater
- 6.3 V / 300 mA
Description
Triode-heptode frequency changer with high conversion conductance.
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
- 6.3 V
- Nominal heater current
- 300 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
- Transconductance
- 0.0035 S
- Max plate voltage
- 150 V
Published Brimar ratings and characteristics promoted where applicable; additional data retained as parameters.
Section 2
Heptode
X-ray radiationInterelectrode capacitances
- Transconductance
- 0.0028 S
- Max plate voltage
- 300 V
- Max screen voltage
- 125 V
Published Brimar ratings and characteristics promoted where applicable; additional data retained as 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.