[PurpleAngel]

Hmm that is interesting. I always thought my soundcard was enough. You have any amp suggestions?

The Essence STX II does a very decent job of driving headphones (but I did replace my Essence STX (w/upgraded op-amps) with a Audio-GD NFB-15.32 and now using the NFB-11.28).
You might consider getting a Darkvoice 336SE OTL tube headphone amplifier ($214-$250) and connecting it to the line-output (RCA) jack on the STX II.
(I own the Darkvoice 336SE, so I can plug headphones directly into my NFB-11.28, or use my NFB-11.28 as a DAC for my Darkvoice)
The STX II can not send it's headphone surround sound thru the line-output, but as music is usually stereo audio, headphone surround sound feature is not needed.