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

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Tube-number record

20D4

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20D4 is a tube type in the TubeDatabase archive (class: Triode-Heptode Frequency Changer). Recorded specifications: brand Brimar, construction Multi-section, socket Noval (B9A), and maximum plate voltage 300 V. The archive does not yet hold a photographed example of this type.

BrandBrimar
ClassTriode-Heptode Frequency Changer
BaseNoval (B9A)
Filament6.3 V @ 300 mA

Construction

Primary TypeMulti-section
EnvelopeGlass
Sections2

Filament / Heater

Absolute Maximum Ratings

Plate Voltage300 V
Grid 2 Voltage125 V

Typical Operation

ModePlate VGm (µmhos)Rp (Ω)µPlate mA
Heptode Characteristics250 V2800900000—7 mA
Triode Characteristics100 V3500—1615 mA
Frequency Changer250 V850——3 mA

Application Notes

The BRIMAR 20D4 is a triode-heptode frequency changer on the Noval (B9A) base, featuring very high conversion conductance.

Datasheets

Datasheet: 20D4.pdf

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

Filters

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Manufacturers

Brands

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    Cathode Current
    17.5 mA

    Audio Performance

    Key Features
    • High conversion conductance
    • Noval (B9A) base