Analogue and digital sound amplification

A sound amplifier can be analogue or digital. Let's take a look at the differences:

• an analogue amplifier is a device that takes a low-power analogue signal as input and outputs a more powerful version of the same signal;
• a digital amplifier, also known as a class D amplifier, has circuitry that can take a purely digital signal and amplify it, generating an analogue output at speaker level.