Speaker/OPT question

[David Roper]

If you opt to simply replace the speaker, you'll end up wondering what to do with all those extra wires. Your radio's speaker (like virtually all of that era) has an electro-magnet inside the bell which is called a field coil. The field coil serves the dual purpose of speaker magnet and power supply choke. Ideally it should be replaced by an outboard choke of similar characteristics--that is, inductance and maximum current ratings should be close to that of the field coil. A new choke which is close in such respects will probably be quite a bit lower in resistance, so you can add resistors in series with the choke to match the original resistance.

Or just forget a choke and replace the field with a (very large) power resistor, but if you do that you'll probably have to increase the values of C12 and C13 to avoid increased hum. I'd pop for a choke if it were me.