Tube-number record
U709
0 archive entries
U709 is a tube type in the TubeDatabase archive (class: Rectifier). Recorded specifications: brand Marconi, year 1953, construction Other / special, socket Noval (B9A), and maximum plate voltage 350 V. The archive does not yet hold a photographed example of this type.
BrandMarconi
ClassRectifier
BaseNoval (B9A)
Filament6.3 V @ 950 mA
Construction
Primary TypeOther / special
Rectifier TypeBi-phase half-wave
EnvelopeTubular
Filament / Heater
Heater NotesIndirectly heated
Absolute Maximum Ratings
Plate Voltage350 V
Cathode Current150 mA
H-C Voltage450 V
Audio Performance
Key Features
- Indirectly heated
- Miniature construction
- Mounting in any position
Typical Operation
| Mode | Plate V | Gm (µmhos) | Rp (Ω) | µ | Plate mA |
|---|---|---|---|---|---|
| Single valve, Bi-phase half-wave, Capacitor input | 350 V | — | — | — | 150 mA |
Application Notes
Free air circulation is preferable for cooling. A retaining device should be used.
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