Yes, because the amplifier is an analog system that produces the actual electrical signals for the headphones. There are some systems on a chip (SOCs) that combine multiple pieces of the chain, but you basically have File handling (finding a file on the hard drive, an OS function, and queuing it to play which is a player software function) Digital signal processing (decoding the file into an audio stream, and optionally modifying it at the player software level) Digital-to-analog conversion (sound card or external DAC) Amplifier (sound card or external amplifier) Listening device (headphones or speakers) If you use Bluetooth headphones, the DAC/Amp parts are in the headphones, but the above list is the basic process of taking a FLAC/MP3 file and listening to it. In the analog days, we'd have three steps: source (LP or tape recorded with analog signals), amplifier, headphones/speakers. The definition of "source" in the digital audio world is less simple. I'm sure if I've missed something, the helpful folks here will point it out.