Data set 01
194X Miniwatt
Published operating points and test conditions from this source.
SECTION 1
Triode
Application
Application
Oscillator text
SECTION 2
Heptode
Application
Application
Mixer text
Voltage - Triode (with diode, heptode or hexode) ·Heptode-Triode
XCH81
Triode-heptode combination for radio mixer, oscillator, RF, and IF applications. Its sections support both frequency conversion and associated receiver amplification, giving broader front-end flexibility than a dedicated converter.
Directly heatedCold cathodeCommon cathodeDissimilar
- Sections
- 2
- Base
- -
- Socket code
- B9A
- Base pins
- 9
- Nominal heater
- 3.6 V / 600 mA
Description
Triode-heptode for mixer, oscillator, RF and IF applications.
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
- 3.6 V
- Nominal heater current
- 600 mA
- Parallel heater voltage
- -
- Parallel heater current
- -
- Series capable
- Yes
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
- 0.0037 S
- Amplification factor
- 22
- Max plate voltage
- 250 V
- Max plate dissipation
- 0.8 W
- Max cathode current
- 6.5 mA
Miniwatt XCH81/3AJ8 triode-heptode frequency changer for oscillator, mixer and RF/IF amplification. Oscillator triode typical static characteristics at Va 100 V, Vg 0 V: anode current 13.5 mA, gm 3.7 mA/V and amplification factor 22. The oscillator-mode effective conductance approximately 0.65 mA/V is not the static transconductance. Manufacturer per-triode maxima plate voltage 250 V, dissipation 0.8 W and cathode current 6.5 mA. Indirect series heater rating 3.6 V at 0.6 A.
Section 2
Heptode
X-ray radiationInterelectrode capacitances
- Max plate voltage
- 300 V
- Max screen voltage
- 125 V
- Max plate dissipation
- 1.7 W
- Max screen dissipation
- 1 W
- Max cathode current
- 12.5 mA
Miniwatt XCH81/3AJ8 heptode frequency-converter and optional RF/IF amplification section, common cathode shared with triode oscillator. Maximum plate 300 V, screen 125 V, plate dissipation 1.7 W, screen dissipation 1 W, cathode current 12.5 mA. Converter slope and RF/IF amplifier gm refer to different operating circuits and must not be conflated with static gm. Indirect heater supplied at 3.6 V, 0.6 A in series-heater designs.
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.