This is probably very obvious to some but I don't get it.
I've seen people with proper sound cards using an extra amp between their headphones and the soundcard.
I'm not exactly sure why someone would do this, especially considering that most sound cards only have 1 analog output instead of a separate left and right output.
On a Pc you can use equalisation software to change the sound so it confuses me a bit.
Why would someone want to use an expensive amp if they already have a high-quality sound card?