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
EFF 50 vacuum tube outline illustration

Tube-number record

EFF 50

0 archive entries

EFF 50 is a tube type in the TubeDatabase archive (class: Twin H.F. Pentode). Recorded specifications: brand Philips Miniwatt, year 1940, construction Pentode, maximum plate voltage 300 V, and maximum plate dissipation 3 W. The archive does not yet hold a photographed example of this type.

BrandPhilips Miniwatt
ClassTwin H.F. Pentode
Filament6.3 V @ 0.6 mA

Construction

Primary TypePentode
EnvelopeGlass
SectionsTwin

Filament / Heater

Heater NotesIndirect heating, parallel supply

Absolute Maximum Ratings

Plate Voltage300 V

Typical Operation

ModePlate VGm (µmhos)Rp (Ω)µPlate mA
Single section operation (Case 1)250 V8000350000—6 mA
Single section operation (Case 2)300 V10000250000—10 mA

Application Notes

With push-pull operation, a separate dropping resistance should be used for each screen-grid to compensate for inequalities between systems. Grid damping is improved by inserting a 0.1 µH induction in each screen-grid lead.

Filters

0 tubes found

Manufacturers

Brands

    0 results
    Plate Dissipation3 W
    Grid 2 Voltage225 V
    Grid 1 Voltage-1.3 V
    Cathode Current15 mA
    H-C Voltage50 V

    Audio Performance

    Key Features
    • Ultra shortwave amplification
    • Push-pull connection capability
    • Wideband amplification capability
    • Parallel connection capability