Musical instrument amplifiers are devices that increase the volume of sound produced by instruments, such as electric guitars and keyboards. They work by taking the weak electrical signal from the instrument and boosting it, allowing the sound to be heard more clearly in larger spaces. Amplifiers can also shape the tone of the sound, adding effects like distortion or reverb. There are different types of amplifiers, including tube amplifiers, which use vacuum tubes for a warm sound, and solid-state amplifiers, which use transistors for a cleaner sound. Musicians often choose amplifiers based on their specific needs and the style of music they play.