Hello. First let me apologize if I shouldn't be posting this here, but this is the only circle that I've ever participated in. Everybody in the GR circle has proven to be friendly and helpful in the past.
I have had a true "aha" moment. At work we have a MOTU 828 mkII that we use to help test out some of our software. Recently I started using it as the audio output device on my workstation (Mac Pro). I'm using a set of Grado SR 80s and the difference between the MOTU and everything else I have available (built-in audio, iMic, Presonus Firebox) is startling. There is so much more separation between instruments and vocals. I can listen much louder without fatigue (perhaps I shouldn't be, but I can).
It's left me wondering, how much better does it get? What accounts for the difference? DAC, preamp? How much better can it get with different headphones?

I'm not really concerned with including budget in this discussion...yet. There will probably be some new equipment in my future though.
-- jaydillyo