[Ron Ramirez]

Hi

The original speaker used in your Philco was an electrodynamic type, which used a field coil (electromagnet) instead of a permanent magnet, to produce a magnetic field which makes the speaker work. Of course, permanent magnets now perform that job which do not require electrical energy to produce the magnetic field.

This field coil is, often, part of the radio's power supply; specifically, it is used as a filter choke in many applications. This is the case with your 37-61.

Yes, it can be replaced with a permanent magnet speaker...but then, you also need an audio output transformer to match the audio output of the receiver to the voice coil of your replacement speaker...which will be a different value than original. In addition, you have to replace the resistance of that original field coil with something. A power resistor, 1000 ohms @ 25 watts will work as a substitute for the field coil, but you may have to increase the value of the set's electrolytic (filter) capacitors to make up for the increased hum due to the loss of the field coil.