I found this schematic of a hearing aid on a newer website called Talking Electronics, and it looked familiar. I checked the one on RedCircuits.com, and found that they are identical, other than the copycat has gone to some lengths to pretty it up with color and graphics. I know that this particular schematic has been around since before the website was called Red Circuits, because years ago I built this circuit and put it into an Altoids tin and I still have it today. Either one or the other of these websites has stolen it from the other, and my bet is that Redcircuits had the original, because of what I just said. I think I built the circuit long before the Talking Electronics was around.