Hello,
A long time ago I saw a schematic for a crystal radio that had an audio amplifier that was powered by another crystal radio. I wasn't able to copy the schematic and have found nothing online about it. The radio-powered audio amplifier was used so high-impedance headphones would not be needed. Standard 8-ohm headphones were supposed to work. I've tried using 8-ohm 'phones with a 1000-ohm to 8-ohm transformer, but the audio level was very weak. Anyone have any helpful thoughts? Thanks. <ckd>