[NJARC] speakers

[David Sica]

Victor,

I'm assuming that you're aware that a four wire speaker means that it's an
electrodynamic unit rather than a permanent magnet type. But to begin at
the beginning, are you sure you had the field coil connections and the
voice coil connections identified correctly and connected correctly? If one
wire was out of place, you'd get little or nothing from the speaker.

An ohmmeter test should reveal two wires with continuity and a modest
amount of DC resistance. These would be going to the field coil. Since the
set played, however slightly, that would indicate that you had the field
coil in the circuit and it was working. The voice coil wires would show
continuity and a very low DC resistance (significantly lower than the
typically 8 or 16 ohm impedance rating of the speaker.) If both sets of
leads were identified and connected correctly, this would seem to indicate
either a fault in the speaker or in the radio.

Again, you may already know this, but you can substitute a permanent magnet
speaker for an electrodynamic one by either leaving the field coil in the
circuit, or replacing it with a suitable choke or resistor ("suitable"
being determined by a bit of calculation or some educated guesswork.) The
PM speaker will work just fine and can even be hidden between the cone of
the original speaker and the grillecloth to maintain the original
appearance, like restuffing a cap. If substituting a PM speaker doesn't
give you good performance, the trouble is likely in the radio, not the
speaker. A short in the field coil would reduce or cripple the performance
of the original speaker, but mostly just cause an increase in the hum level
if a PM speaker were subbed in.

Have I interpreted your situation correctly or might something else be
going on?

Good luck!
-- Dave