10-30-2016, 11:19 AM
Unlike Ron, I am an electrical engineer. Here are my thoughts on the heat question. Resistors have a smaller surface area and typically do not have an inherent heat sink, but are rated at as high as 175C (347F) ambient. They will run hotter, but can tolerate the heat. Typical modern magnet wire is rated at 155C (311C), but this is the wire temperature. (Magnet wire from the late 1930s might be lower.) The surface of the field piece would run much cooler. The field coil and speaker frame provide a LOT more surface area so the field coil will run much cooler. On the other hand, it needs to run much cooler.
To get the same filtering from a resistor, you will need to have a higher capacitance on the load end of the field coil, but not on the rectifier end or you may get too high of a voltage on the rectifier end cap and damage the rectifier or capacitor.
TerryMSU
To get the same filtering from a resistor, you will need to have a higher capacitance on the load end of the field coil, but not on the rectifier end or you may get too high of a voltage on the rectifier end cap and damage the rectifier or capacitor.
TerryMSU
