[Poston Drake]

Hi Scott,

Your Heathkit signal tracer has a PM speaker inside, and also a universal output transformer. The various jacks (such as the one labelled B+) serve to allow you to connect any combination of the following:

1) The internal PM speaker only
2) The PM speaker and the full primary winding of the output transformer for a push/pull audio output
3) The PM speaker and one-half of the primary winding of the output transformer for single-ended audio output.

There will also be a rotary selector switch to allow you to select proper impedance match for the output transformer.

Another switch allows you to use the output transformer in the Heathkit in combination with the speaker in the radio.

These signal tracers are handy to have on the workbench, since they permit easy substitution of a speaker, an output transformer, or both.

As has been mentioned, you must leave your electrodynamic speaker connected due to the field coil which is an integral part of the power supply circuit. But there is nothing to stop you from disconnecting the two leads to the voice coil and substituting a PM speaker, or if you don't want to hear any noise at all then substitute a resistor instead of the voice coil. Don't just disconnect the voice coil without substituting a temporary load (either a PM speaker or a resistor).

Poston