I have a waveform! I did a bunch of testing of various parts and such, discovering that the carbon transmitter (microphone) I had was indeed fully functional, and really, it came down to “not enough voltage.” 1.5v is pretty borderline for carbon microphone power, so that’s fine.

The waveform is kind of lopsided, but that’s because this test harness doesn’t have the balanced output yet; I’ve ordered the balanced transformer, and that should help. It’s also a bit noisy – here’s a sample – which is partly related to SHIELDING WHAT IS SHIELDING because it’s a test harness.

Talking of, here’s what version one looked like:

This is a direct implementation of the first half of the circuit described in this instructable, which runs off a 9V battery. Once the rest of the circuit is added, it’ll have balanced output, which is pretty snazzy.

This is a closer view, and also after I added an LED, because hey, LEDs!

After that, I tried a smaller capacitor, and that’s working fine – mostly, I’m just picking from what I’ve got, which goes along with what the circuit designer described.

I’m going to play more with the circuit a bit, pending getting the matching transformer. And some shielding.

And, of course, the can. 😀

ps: this harmonica “bullet mic” looks pretty cool too.