Until now, just about every amplified harmonica has involved some kind of microphone. Little Walter invented a great sound and we love it, but that was 70 years ago in the last century. We took a different approach, just as Leo Fender and Les Paul did to the guitar. If you wrap a magnet, or magnetized metal, with a coil of electrically conductive wire, and move something ferrous near it, the ferrous metal will get magnetized and when it moves it will cause an electrical current to be induced in the coil. It’s an alternating current (AC) with the same frequency as the frequency of the moving element (including some harmonics and partials). In an electric guitar that’s a vibrating string. In the HarmonicasterTM it’s vibrating stainless steel reeds. The current can then be supplied to an amplifier which makes it loud enough to be heard as a musical tone.