An amplifier is an electronic device that has a very simple job: to make a tiny electrical signal bigger.

In audio, an amplifier takes the tiny electrical signals generated by whatever you’re listening to (eg. turntable, CD player/DAC, or whatever else… your signal source, in other words) and increases their power, to drive a pair of speakers.

An amplifier is a vital part of listening to music, whether through headphones or speakers (be they large house speakers or portable bluetooth ones). No matter how you’re listening, the signal has gone through an amplifier.

This is because these source signals are too tiny to drive a speaker. The signal needs to have power added to it before it will be able to drive a speaker, or even a headphone.