1939 Sentinal farm radio model 80B 167-S |
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The tubes in this radio are
The radio uses three 45v dry cell battery blocks in series to provide the 'B' voltage. The filament 'A' supply can use 3v dry cells, a re-chargable storage cell, or an 'Aircell' battery. |
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As no rectifier tube or large filter capacitors are required the chassis is
very simple, a permanent magnet loudspeaker is used. The 5E1 ballast tube is used so that the 2v filaments can be supplied from two 1.5v dry cells in series. The ballast tube drops the socket voltage to 2v and therefore regulates the total filament current at 500mA as battery voltage changes. 1939 seems to be one of the last years that this older series of 2v tubes was used. Later radios are using the 1.4v filament tubes which do not require the ballast tube as they can be supplied directly from dry cells. |
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