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Tube Database (7,341 tube types · 1,270 archive entries)

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Tube-number record

N78

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BrandGEC
ClassOutput Pentode
BaseMiniature 7-pin (B7G)
Filament6.3 V @ 640 mA

Construction

Primary TypePentode
EnvelopeTubular
SectionsSingle

Filament / Heater

Heater NotesIndirectly heated

Absolute Maximum Ratings

Plate Voltage250 V
Plate Dissipation9 W
Grid 2 Voltage250 V
H-C Voltage150 V

Audio Performance

Typical THD9.2%
Power Output4 W
Key Features
  • Miniature
  • Low microphony
  • Any mounting position

Typical Operation

ModePlate VGm (µmhos)Rp (Ω)µPlate mA
Single Valve, Class A, Pentode Connection250 V1050040000—35 mA
Single Valve, Class A, Triode Connection250 V11400210024—

Application Notes

The maximum permissible D.C. resistance between control grid and cathode is limited to 0.27 MOhms with auto-bias and 0.1 MOhms with fixed bias. A retaining device should be used. Free air circulation is preferred.

Datasheets

Datasheet: N78.pdf

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Datasheets courtesy of Frank Philipse via Frank's Electron Tube Data Sheets.

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