Make A Crystal Headphone
SC2-300 sound powered earpiece
SC2-300 is the most famous sound powered earpieces in China. It's a decent earpiece with venerable
sensitivity. It's used to be phone earpieces back into old days.
I had several of them. Recently decades built these earpices might be less sensitive. On it's peak perfermance, SC2-300 could do everything like USI/Dynalec earpieces. It's gonna received power line noise with 1 or 2 meters long wire in room, It's a remarkable sensitivity.
SC2-300 earpices
SC2-300 earpices internal
Install SC2-300 to A modern Headphone
It's definetely need a Headphone to hold the earpieces. Most easy way is modify a modern Headphone. 3D printer help a lot to fit the earpices to headphone support.
Teardown a new headphone
3D print help fit the earpieces very well
Soundproof Equals Sensitivity
Even though the headphone feels tight a little bit, but gains sensitivity. Keep quiet as possible, it's rule number one for sensitivity.