Tube-number record
TWIN PENTODE
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BrandTung-Sol
ClassCombined Sync-AGC Tube
BaseNoval (B9A)
Filament4.2 V @ 450 mA
Construction
Primary TypePentode
EnvelopeGlass
Base MaterialGlass Button
Sections2
Filament / Heater
Warm-up Time11s
Heater NotesAC or DC, Controlled warm-up
Absolute Maximum Ratings
Plate Voltage300 V
Plate Dissipation1.1 W
Grid 2 Voltage150 V
Grid 1 Voltage50 V
Cathode Current12 mA
H-C Voltage200 V
Audio Performance
Key Features
- Miniature multisection tube
- Separate plates and grid 3s
- Common screen grid (G2)
- Common cathode
- Common G1 (G4)
- Thermal characteristics controlled for series strings
Typical Operation
| Mode | Plate V | Gm (µmhos) | Rp (Ω) | µ | Plate mA |
|---|---|---|---|---|---|
| Both Sections Operating | 100 V | 180 | — | — | 2.2 mA |
| Each Section Separately | 100 V | 500 | — | — | 2.2 mA |
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