[Bill Kinghorn]

The dc resistance in a choke is deliberately minimized, so a close equivalent to the speaker field would be a choke and resistor in series. 8 or 10 Henrys, 75 or 100 mA, and a resistor chosen so the total dc resistance is 1140 Ohms should work. The 1140 figure does sound about right for the old field. Without the resistor, voltages would be higher but probably tolerable. When a maximum capacitor value to be used with a rectifier is specified, the source impedance due to the transformer is usually taken to be zero, and the derived dc voltage taken to be the maximum for which the tube is rated. Neither of those conditions is typical in a radio receiver, and I just use the biggest cap handy.