what does a headphone amplifier do?

If you are a high-end headphone aficionado, you undoubtedly already know what a headphone amplifier is, and probably own several. But for most people, as popular as headphones have become, the whole idea of a headphone amplifier is a bit foreign.

What is a headphone amplifier?

Headphone amplifier, is a circuit built in or a separate box that amplifies the low level signal that comes from any device (computer, cd player, etc) just as speakers need a amplifier to amplify the low level signal from a source component so does headphones. That is why headphones are often called ear speakers. Higher quality amplifier you've attached will boost the signal, and produce more than enough clean power for any headphones you choose to listen to (which generally results in cleaner, stronger bass, less background noise, and overall better sound quality.

Why we need a headphone amplifier？

The fact also is that the built in headphone amps are likely going to be a significant compromise, given the size/space and power limitations they have to work with. A stand alone headphone amp has much more space to dedicate to better circuitry, and a more robust power supply, allowing both overall better controlled sound and, importantly for some headphones, the ability to provide considerably more output power to the headphone.