Just like a good room speaker can improve when partnered with a great power amp, a headphone is a miniature speaker system that can benefit from a headphone amp to sound its best.
With top headphones, an uncompressed music source and a great headphone amp, you'll be astonished at the level of pure clarity, huge dynamic range and deep musical detail you'll be able to hear.
In fact, while big speaker systems may out-perform headphones in terms of visceral sonic impact, great headphones can deliver much superior audio resolution and access to nuanced low-level information obscured in the recording. The most common reaction folks have with their first experience listening to high-end audiophile headphone systems is, “I heard stuff I’ve never heard before. I need to listen to my music collection over again.”