Tube-number record
3B/505E
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BrandSTC
ClassR.F. Triode
BaseSpecial / none
Construction
Primary TypeTriode
EnvelopeGlass
SectionsSingle
Filament / Heater
MaterialThoriated tungsten
Absolute Maximum Ratings
Plate Voltage1500 V
Plate Dissipation50 W
Cathode Current120 mA
Audio Performance
Key Features
- Thoriated tungsten filament
- High frequency operation up to 250 Mc/s
- Natural cooling
Typical Operation
| Mode | Plate V | Gm (µmhos) | Rp (Ω) | µ | Plate mA |
|---|---|---|---|---|---|
| Static Characteristics | 500 V | 3750 | 12000 | 45 | 100 mA |
| Class B Telephony (Modulated Carrier) | 1500 V | — | — | — | 50 mA |
| Class C Power Amplifier (Anode Modulated) | 1250 V | — | — | — |
Application Notes
The valve should be operated in a vertical position and a free circulation of air must be provided to ensure adequate cooling of the bulb.
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