ITC Bridge Forum: USB based and digital recorder based Raudive Entity Mic

[Vparanormal]: Vparanormal designs a Raudive diode microphone (Raudive Entity Mic TM) to help capture EVP's. There are 2 versions, a USB based one and a digital recorder based one. This digital recorder one has a circuit that is placed in a metal box along with a small condenser microphone. The USB based one is put inside the inside of a USB mic (in place of the original condenser mic).The original Raudive germanium diode circuit operated in the middle of the AM frequency band. After some experimentation and testing using a frequency sweep generator, an oscilloscope and a RF coil, I determined the changes to the original circuit to allow operating out of the AM band. This video shows these changes in a schematic form and shows the internal circuitry used. Vparanormal will use this device on future investigations along with Adobe Audition software to try and capture higher quality EVP's. https://www.youtube.com/watch?v=dogVxdm2iSI https://www.youtube.com/watch?v=NX4ov6ggMLA