Over the last two days I have been playing with a shortwave crystal set I built years ago as a shack tool. I can use it as a monitor or use it to check if a newly built transmitter is actually on freq or is pumping in through an if or image (the crystal set only hears where it is tuned). Yesterday in a moment of thought i wondered what would happen if I took the diode and phones off the tank circuit, wound a multi turn coil on the end of the coil form and reconnected them there. Sort of a built in audio transformer. It works and I can yesterday and today here the station on 3215 (last night was stronger then tonight) and can just hear the CHU time signal. The station on 3215 is 750 miles away as the crow flies so I am calling this experiment success. Your post audio transformer, crystal set hit the subject dead on so I stuck it here. Hope that is OK.
don