Tube-number record
UBL71
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ClassDuodiode-Endpentode
BaseRimlock
Filament55 V @ 100 mA
Construction
Primary TypePentode
EnvelopeGlass
Base MaterialGlass
Sections3
Filament / Heater
Heater NotesIndirekt geheizt
Absolute Maximum Ratings
Plate Voltage250 V
Plate Dissipation11 W
Grid 2 Voltage250 V
Grid 1 Voltage-1.3 V
Cathode Current75 mA
H-C Voltage150 V
Audio Performance
Typical THD10%
Power Output4.8 W
Key Features
- Indirekt geheizt
- Demodulator system
- Power output pentode
Typical Operation
| Mode | Plate V | Gm (µmhos) | Rp (Ω) | µ | Plate mA |
|---|---|---|---|---|---|
| Pentode Section | 200 V | 8000 | 25000 | — | 55 mA |
| Pentode Section | 180 V | 9000 | 22000 | — | 61 mA |
| Pentode Section | 100 V | 7500 | 25000 | — | 32.5 mA |
Application Notes
Negative grid bias should be generated via cathode resistor. A non-bypassed damping resistor of approx 1 kOhm should be placed in the grid lead to suppress VHF oscillations.
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