TubeDatabase
  • Tubes
  • Testers
  • Companies
  • Submit
  • About

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

Pre (2,630 tube types), Other (2,603 tube types), Power (1,292 tube types), Rectifier (816 tube types)
DisclaimerA–Z indexSubmit a tube
404A vacuum tube outline illustration

Tube-number record

404A

0 archive entries

404A is a tube type in the TubeDatabase archive (class: RF AMPLIFIER PENTODE). Recorded specifications: construction Pentode, socket Noval (B9A), maximum plate voltage 200 V, and maximum plate dissipation 3.3 W. The archive does not yet hold a photographed example of this type.

ClassRF AMPLIFIER PENTODE
BaseNoval (B9A)
Filament6.3 V @ 300 mA

Construction

Primary TypePentode
EnvelopeT6-1/2
Sectionssingle

Filament / Heater

Absolute Maximum Ratings

Plate Voltage200 V
Plate Dissipation3.3 W

Typical Operation

ModePlate VGm (µmhos)Rp (Ω)µPlate mA
Class A1150 V130002000000—13.5 mA
Class A1 (Fixed + Cathode Bias)160 V130002000000—13.5 mA

Application Notes

Intended for use up to ultrahigh frequencies. The frame grid provides high broadband qualities and freedom from microphonics. Use of a 600 ohm cathode resistance in conjunction with a DC control grid return to a +8.5 volt supply is recommended to sensitivity to variations.

Filters

0 tubes found

Manufacturers

Brands

    0 results
    Grid 2 Voltage165 V
    Grid 1 Voltage-25 V
    Cathode Current40 mA
    H-C Voltage55 V

    Audio Performance

    Key Features
    • Frame grid
    • High transconductance
    • Low noise
    • Low inter-electrode capacitances
    • Broadband qualities
    • Freedom from microphonics