Add up the tube heater voltages and subtract from 120 to see how much voltage you need to drop. There are several ways to drop the voltage but the one I like the best is to use non polarized capacitors. They make no heat like a resistor would. Also they give the tubes a soft start, coming up to full voltage across the string after about 20 seconds. The way to calculate the size is below. Scroll down to the capacitive dropper section. Sometimes you can find them on places like Electronic Goldmine, but they can also be ordered from Mouser, etc.
http://www.vintage-radio.com/repair-...per-calcs.html
05-31-2011, 06:10 AM
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