Which DAC to get for my HD650

[bipolarsmile]

Hey guys,
Im new here,not sure if this is the right place to post this at.
Currently i have my Sennheiser HD650 with a Xonar Essence Stx which i tought about upgrading.
i heard good stuff about the Audioengine D1 and Fiio E17
So my questions are if either one of them is an improvement?
if not then which DAC or AMP would be an improvement for the STX?
Will i hear a difference with my Stereo Speakers?(i have Microlab Solo 7c stereo speakers)
And if i do upgrade should i just take the stx out or just plug the dac right into the Stx?

I know these are really newbie questions but,i Would greatly appreciate any help or comment.

 

[connieflyer]

The truth as Tom's Hardware sees it, read this thru, you may be surprised. What Does It Take To Turn The PC Into A Hi-Fi Audio Platform? - Turning The PC Into A True Hi-Fi Audio Platform .. I have the HD650's andXonar stx as well. I bought a dragonfly that had such great reviews the newest version 2.0. Glad I bought it from Amazon, it was back on the truck two days later. Tried all the usb ports and the music out of the pc was flat and ugly. Went back to the zonar dac and it was a world of difference. This card has an excellent dac. The headphone amp is alright but not the best, but the dac is stellar. I bought a Garage 1217 Project Ember hybrid amp, and now the headphones are head and shoulders over the card's amp. Rolled in several different tubes and finally settled on one after a few months that had the sound I wanted. The review is a little long but interesting . Asus is still selling the Essences and it is now version 2, and there stand alone dacs are being sold off. Good luck