Dampfradioforum

Hallo Georg,

die Spannung lag bei 110V, aber es gab Lampen mit 55V, da mussten dann logischerweise 2 in Reihe geschaltet werden.
Unsere Radios können auch nur auf 110 Volt gestellt werden und nicht etwa auf 55V. Oder hast Du schonmal eins gesehen mit Umschaltung auf 55V?
Edison war ja bekanntlich ein Verfechter des Gleichstroms, seine Glühlampen waren damals schon für 100V ausgelegt.


Freundliche Grüße Otto

Farm radio

A "farm radio" modification (usually done at the point of sale) allowed an AA5 to run off 32 volt DC, commonly generated by farm windmills. With a relatively simple rewiring, the tube heaters could be put in series-parallel to run off 32 volts, with the three twelve-volt heaters in series and a 25L6, 35L6 or 43 in parallel; the tubes would still function with the heater voltage somewhat out of specification. If run from a 32-volt supply the radio had a substantially reduced performance because the B+ voltage would only be 32 volts compared with 160-170 volts when operated from AC. With 32 volts on the plate, the radio tended to be insensitive.[8] Sometimes only the tube heater power was derived from a windmill, and dry batteries were retained for the plate voltage supply. The advantage was that the heaters were a high and continuous load on the battery, whereas the plate voltage battery drain was smaller and intermittent. Often a wet-cell rechargeable battery was used for tube heaters, recharged by a local garage or by exchanging with a vehicle battery.

Many 32-volt farm radios were factory-built for the purpose. They usually had two type 48 power tetrodes that could operate with B+ voltages as low as 28 volts. The type 48 pairs were parallel connected, or connected in push-pull as shown in this schematic of a 1936 farm radio from Sears Roebuck. Some factory 32-volt radios used an electromechanical vibrator power supply to provide increased voltage. Vibrator power supplies could also be made to work from a 6 volt supply from a dedicated wind-charger or from a car battery borrowed from a farm vehicle.