EVP quality, tele listening amp.



Hallo friends,
Please show me a schematic diagram of a highly sensative amplifier, or hearing aid that I can use as a telescopic remote spy hearing instrument.
Something as sensitive as the EVP paranormal audio recorder.

I tried this circuit but doesnt work :(
http://www.extremecircuits.net/2009/07/hearing-aid.html

Please guide me to a circuit that actually worked for you.
see you
thanks

The December 2008 issue of Nuts and Volts has a good article on how to build a parabolic microphone on pages 34-39. It includes the audio amplifier circuit with a gain of 200. You might also be able to find circuits by searching for "diy parabolic microphone" or some variation of that.
caitlinsdad7 years ago
You need to consider other factors in the design of such a device. The sound gathering is the other part to consider. Most likely a directional microphone or a parabolic dish reflector would help to concentrate and focus the sounds. You also want to filter out the noise or other sounds not from the source you want to hear. You also have to have a clean amplifier circuit that maybe filters out noise not in the voice range. Good luck.
ketan7s (author)  caitlinsdad7 years ago
oh hmm, yes I have seen those dish and cone designs, I can make it. But I was looking for a circuit that will work with it. like you said, noise cancelation and etc. thanks