A preamplifier is an electronic device that boosts weak audio signals before they are sent to a power amplifier. It is commonly used in audio systems to improve sound quality by increasing the signal strength from sources like microphones or musical instruments. Preamplifiers help ensure that the audio signal is strong enough for further processing without adding significant noise. These devices are essential in various applications, including home theater systems, recording studios, and musical instruments. By enhancing the signal, preamplifiers allow for clearer sound reproduction and better overall performance in audio equipment.