Voltage - Triode (single) ·Triode
99UX
The 99UX is a directly heated, low-current receiving triode used for radio detection and audio amplification in battery-operated sets. It offers modest amplification with economical filament consumption and uses the later UX-style four-pin base, distinguishing it mechanically from the earlier 99UV.
- Sections
- 1
- Base
- -
- Socket code
- -
- Base pins
- 4
- Nominal heater
- 3.3 V / 63 mA
General specifications
Tube and section characteristics
Properties common to every published source and operating point.
Heater and base
- Base
- -
- Socket code
- -
- Base pins
- 4
- Nominal heater voltage
- 3.3 V
- Nominal heater current
- 63 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
1 physical section, each with unique specifications.
Section 1
Triode
- Plate resistance
- 15500 Ω
- Transconductance
- 0.000425 S
- Amplification factor
- 6.6
- Max plate voltage
- 90 V
Arcturus 99UX directly heated receiving triode for battery-operated radio detector and amplifier service. Published 99-series amplifier operating point: plate 90 V, grid bias approximately -4.5 V, plate current approximately 2.5 mA. Lower plate voltage may be used for detector operation; UX-style four-pin base.
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.