Tube-number record
4BL8
0 archive entries
4BL8 is a tube type in the TubeDatabase archive (class: Triode Pentode). Recorded specifications: brand TUNG-SOL, year 1960, construction Multi-section, base Glass, socket Noval (B9A), maximum plate voltage 250 V, and maximum plate dissipation 1.7 W. The archive does not yet hold a photographed example of this type.
BrandTUNG-SOL
ClassTriode Pentode
BaseNoval (B9A)
Filament4.6 V @ 0.6 mA
Construction
Primary TypeMulti-section
EnvelopeGlass
Base MaterialGlass
Sections2
Filament / Heater
Heater NotesAC or DC
Absolute Maximum Ratings
Typical Operation
| Mode | Plate V | Gm (µmhos) | Rp (Ω) | µ | Plate mA |
|---|---|---|---|---|---|
| Pentode Section | 170 V | 6200 | 400000 | 47 | 10 mA |
| Triode Section | 100 V | 5000 | — | 20 | 14 mA |
| Mixer Service | 170 V | 2200 | 800000 | — | 5.2 mA |
Application Notes
Designed for use as a frequency changer in television receivers. It is recommended to employ the triode in a Colpitts type circuit rather than a Hartley type.
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