[RD777]

Hello everyone,
 
First of all, I'd like to apologize for starting yet another thread of soundcard vs external DAC, however, I didn't want to Necro-bump another thread, nor did I want to hijack another thread.
 
The Question:
I am looking to upgrade my current soundcard Xonar DX to either the Xonar STX or Xonar DX (SPDIF) - DAC. I was looking at the possibility of buying a Schiit Modi 2 Uber.
 
A little more info:
I use my computer as a media center and gaming pc. I enjoy listening to music and I rarely use the virtual surround on the Xonar DX, but if I do I normally use it on my gaming headset only when playing multi-player games.
I do own a Fiio headphone amp, which I mostly used paired to my DAP. 
 
The main question I want to know is about the SQ from the Xonar STX vs an external DAC. Regarding amps I currently own a Fiio E12 amp, when I plug in my headphones but I mainly use my Kanto Yumi's. In any case, I mostly use my ATH-M50s for listening to music because of the comfort. 
 
I do love the sound coming out of the PCM1792 DAC, which is the DAC in my Fiio X5 2nd gen and the DAC chip in the Xonar Essence STX (iirc). However, I would like to know how the Modi 2 Uber or another DAC in that price range would fair against the Xonar STX soundwise.
 
Thanks a lot for your help and if you have any questions ask them

!!! I'll add more pertinent information to this post if need be.

 

[pifidelity]

I currently have the Xonar Essence ST.. It's a great card but I am getting some computer noise leaking  into it when listening at high volumes, this is especially apparent when I hook up to an amp. 
 
I'm under the impression that external DACs have that inherit advantage over internal PC sound cards. Though, I can't comment much more on that... I haven't experimented much with external DACs. If you were to ask me to choose again however, I'd probably go for an external (one of schiit's DACs to match my amp ) over the soundcard. 
 
Aside from that, I can honestly say I cannot hear much difference in the various DACs, while some certainly measure better than others, I can honestly say I have trouble pinpointing the subtle audible differences.

 

[cel4145]

I upgraded from the STX to the ODAC/O2 and thought it a better sounding setup.

Note that the STX's low output impedance is 10 ohms. The general rule of thumb is that the low output impedance of the amp should be at least 1/8 of the impedance of the headphones. So your M50s with 38 ohm impedance would do a bit better with an amplifier with lower output impedance, such as in your E12. It should provide a bit more accurate frequency response and assist with proper electrical dampening of bass.

So sense you have the E12 and that is more optimal for the M50s than the amp in the STX, I would say go for the Modi 2, since, as pifidelity pointed out, external DACs can offer some isolation from low level EMI that a sound card might be subject to.