One thing that is common between a preamplifiers and an amplifier is that they both amplify sound signals. However, how they do it, and at what stage they do it is way different from one another. Just like the name suggests, preamps come before the amplifier in an audio setup. Unlike an amplifier, a preamp will not be directly connected to speakers. Instead of boosting the line signal like an amplifier, a preamp boosts the weak part of an audio signal to the line level. After that, the amplifier boosts this signal with all the other audio signals and sends it to the speaker.