12-19-2018, 11:21 PM
I have finished working on my Philco Socket Power. I intend to use it for the B supplies to my Freed Eismann Model 50. Now I am working on a Magnavox Telemegaphone speaker to use with it. When I first checked it out it didn't seem to work at all, but, after taking it all apart, I found that both the voice coil and the magnetic field coil were reading approximately right after stripping back a little off the wires that go to them They each read 8 ohms. The speaker transformer reads correctly too. Must have just been corrosion between the old connectors that were screwed to the binding posts and the posts themselves. I knew right away what the voice coil wires were as soon as I saw them connected to the transformer. When I disconnected them from the transformer and very briefly touched them to a 1 1/2V AAA cell I could hear a feint crackle. Then I wondered if the other wires were to excite the magnetic field of the speaker, so I connected another 1 1/2V cell across them, and again briefly touched the wires to the field coil to another battery. The sound was much louder, so I knew they must go to the field coil, it is also 8 ohms. I looked online, and that is what it is supposed to be. If anyone here has more information on this kind of speaker, PLEASE let me know. I would like to know what the correct voltage is that I should be using for the field coil on this speaker. I am sure that 1 1/2 volts will allow me to listen to the radio, but I would like to get the full amount of sound from it that this speaker can produce. Thanks.