Good news, you don't need a field coil in this radio. Since it was an option they connected it between B+ and ground..
If you connect to plates of the 45's a high impedance speaker is needed. A PM speaker with output transformer would also work.
A PM speaker should work connected directly to dynamic terminals. Just leave field terminals open.
Norm
:I have a series 1929 Stewart Warner 950AC series set. It has two 45's in push pull for an output stage. This set has provisions for two types of speakers. It has a built in dynamic speaker that is fed from an output transformer from the 45's. Unfortunately the field coil is open on the dynamic speaker. A magnetic speaker connection is provided which is connected to the plates of the 45's (which are also connected to the primary of the output transformer...I have two questions:
:1. Is a magnetic speaker the same as a PM speaker and if so what type of matching output transformer do I need to connect a pm speaker to the magnetic speaker connection?
:2. What is the DC resistance of the field coil (speaker is a 445-A SW dynamic speaker)
:Any assistance would be greatly appreciated...