Antique radios, Old Time Radios
257A
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Country:
United States of America (USA)
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| Identical to |
257A
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| Similar
Tubes |
Other base:
231D
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| Base |
UX-Base (4 Pins (2 thick, USA 1924, UX)
Top contact with a cap.
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| Filament |
Vf 3 Volts / If 0.06 Ampere / Direct / Battery = |
| Description |
Receiving triode, T8 bulb on four pin base plus grid cap. Mu = 8.5, Gm 0.38 to 0.56mS. 4000 hours life expectancy; controlled microphonics. Grid and filament spring supported by glass bead from top of plate. Developed for Northern Electric as variant of 231D.
Not to be confused with HK-257A/4E27 or with other transmitting tubes.
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| Information source |
Tube Lore (I)
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257A: From my schematic collection.
Pier Antonio Aluffi
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Just Qvigstad
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257A: Manufacturer's Literature
Emilio Ciardiello
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