This is basically how the first transistorized hearing aids in the 60s worked. Zero innovation, and an implementation that wastes lots of power. Why would you

This is basically how the first transistorized hearing aids in the 60s worked. Zero innovation, and an implementation that wastes lots of power. Why would you use a volume potentiometer at the OUTPUT of the amplifier? It turns most of the output power into heat. And why would you use a stereo amplifier and short the two channels together to get a mono amplifier? You can already buy (in ear) hearing aids for less than $3 from China. A little bit more money even gets you rechargeable ones. Also: Even in developing countries, more and more people have smartphones. In fact it might be easier to get a smartphone there than a professional hearing aid. There are apps that act as a hearing aid, taking the sound from the microphone, amplifying and filtering it, and sending it to the headphone output. Unlike with this project, the use can individually adjust the frequency response to his hearing.