Crystal Radio germanium diode smackdown

[haversin]

To evaluate different diodes, impedance transformers, headphones and configurations of my crystal set I made an electret microphone test stand to record the sound coming out of the headphones. The microphone signal is first amplified and sent to the audio line-in input on my PC. The software Audacity then can record, edit and analyze the audio signal. A 50 uA moving coil meter was also added to the crystal radio circuit to measure diode current. The video shows a comparison between two different germanium diodes. Turn sound on.

[klugesmith]

Thank you for making and posting a well-annotated video.
And using modern electronics to record the sound.
Extra applause for measuring the diode current!

You found the Beatles song playing on your "strong" AM radio station.

Did you try using an old-style crystal earphone instead of the moving-coil headphone set?

Now that you are set up to pick up and record the small sounds from high impedance headphones,
how about sharing the sounds from putting an auto-ranging digital multimeter on the headphones, in resistance or capacitance mode?

[haversin]

I don't have the old style crystal earphone but I tried to made one using a piezo speaker from a singing card.

It worked with out an impedance matching transformer but sounded a little tinny.