Wayne Parham Messages: 18787 Registered: January 2001
Illuminati (33rd Degree)
The field coil is separate from the output transformer and voice coil. The field coil usually conducts PS current through it, where it serves dual purpose, to energize the loudspeaker and to filter the power supply. The output transformer is about the same as it would be for a speaker with a fixed magnet, as it is matching high tube anode impedance to relatively low voice coil impedance.