A signal enhancer is a device that amplifies or boosts the strength of an audio or video signal. The term 'signal enhancer' can also refer to a preamp, which is a six-letter device used to increase the level of a weak signal before it is sent to an amplifier. Preamps are commonly used in audio systems to boost the signal from a microphone or other source before it is sent to the main amplifier. Preamps can also be used to adjust the tone of the signal, allowing for more control over the sound.