The answer differs, especially since all digital devices have a built-in amp and DAC. But the reason why you'd get a separate one is for one reason: better sound quality! If you want to improve your sound quality and have better control over your headphone volume, then a headphone amplifier is a great solution!

They mention that it's a great budget mobile DAC/AMP, with decent sound and features for the price. Some say that it performs very well for its price tag and with very little compromise. Customers like the build quality of the audio or video adapter. They say it has a solid build, is superior, and is well designed.

By the standards of today's music players, it's not picky about the sort of headphones you pair it with either (although 'better' is always better, of course). The FiiO M11S is definitely built to compete with the other portable music players in our best MP3 players guide, no matter how high-quality your files are.