The Yamaha silent violin is an electric violin with a piezo pick-up and a pre-amp. The pre-amp is powered via a battery or adapter, which allows you to play the violin without an amp and still get a full electric sound. It also allows you to plug a pair of headphones into the output or headphone jack and listen to yourself play. This mutes the overall sound of the violin externally but allows you to hear the full sound in your headphones. It's perfect for when you are in a space where you need to practice but do so as quietly as possible. A passive electric violin requires that you have an amp to get the full sound from it; it only has a piezo pick-up and no pre-amp. You can play it without an amp, but it won't sound very good, and it will be difficult to truly enjoy the sound.