Originally Posted by RallyMaster
The Essence STX is a waste on the HD595 and HD598 in my opinion. The Xonar D1/DX would do just as good of a job with those two.
When it comes to amplification, the STX really isn't great. It's at that middle point where it's not really good enough for headphones that need the juice but it's not bad to the point where a Fiio E5 portable amplifier can beat it.
IMO the STX is more or less a Xonar DX with 6.3 mm headphone jacks, RCA outputs, an amplifying IC chip, some better components (that are barely distinguishable from the D1 I had, honestly) and a fancy looking tiger engraved metal cover.
The only reason Asus can get away with charging so much money for it is because it's top of the line when it comes to sound cards. Is it worth $200? Definitely not. I'd say it's more reasonable at $125 or so, as is the Creative X-Fi Titanium HD.
I tend to agree, I can hear a difference when I drive my 650s through an STX and through a beefier amp.
I would recommend going with a non-amplified card and some cans that don't require amplification..it just makes life simpler (and cheaper).
To make better recommendations we need a full budget and usage description (gaming, music, percentages).