[BarbecueGamer]

Specifically, the motherboard with the on-board audio being the GIGABYTE GA-78LMT-USB3 http://www.newegg.com/Product/Product.aspx?Item=N82E16813128565
The Amp/DAC  being JDS Labs Odac O2 Combo, and the headphones being the Sennheiser Momentum. 
 
Will there be an obvious improvement with the ODAC O2 Combo? And how so? I'm thinking about getting the ODAC used off Ebay. But that means I'm unable to return it if I don't think there's a big enough difference in sound over my motherboard. So I'm just a bit worried. I'd love to get everyone's opinion on this and see what you think. 

 

[PurpleAngel]

  Specifically, the motherboard with the on-board audio being the GIGABYTE GA-78LMT-USB3 http://www.newegg.com/Product/Product.aspx?Item=N82E16813128565
The Amp/DAC  being JDS Labs Odac O2 Combo, and the headphones being the Sennheiser Momentum. 
 
Will there be an obvious improvement with the ODAC O2 Combo? And how so? I'm thinking about getting the ODAC used off Ebay. But that means I'm unable to return it if I don't think there's a big enough difference in sound over my motherboard. So I'm just a bit worried. I'd love to get everyone's opinion on this and see what you think. 

 
ODAC/O2 combo, current bid $102 (shipping with in the USA about $15).
http://www.ebay.com/itm/171713756568?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
If you can get a good price ($150?) on the ODAC/O2, I say go for it.
 
Your motherboard use the DAC feature that comes with the on-board Realtek ALC887 audio processor
To me it would be worth getting the ODAC/O2 (but only for a good price).
 
An Asus Xonar DX or D1 sound card (used $40-$50) and a FiiO E11K headphone amplifier ($60) would be a good bang for the buck.

 

[BarbecueGamer]

   
ODAC/O2 combo, current bid $102 (shipping with in the USA about $15).
http://www.ebay.com/itm/171713756568?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
If you can get a good price ($150?) on the ODAC/O2, I say go for it.
 
Your motherboard use the DAC feature that comes with the on-board Realtek ALC887 audio processor
To me it would be worth getting the ODAC/O2 (but only for a good price).
 
An Asus Xonar DX or D1 sound card (used $40-$50) and a FiiO E11K headphone amplifier ($60) would be a good bang for the buck.

That's exactly the one I was looking at. So, do you think I'd easily hear the difference in sound? 

 

[PurpleAngel]

  That's exactly the one I was looking at. So, do you think I'd easily hear the difference in sound? 

 
You should at least get better detail in the audio.
Also the ODAC being external means you will not pick up electrical noise, that would effect DACs and amps that would be inside the computer case (mounted on the motherboard)

 

[cel4145]

Will there be an obvious improvement with the ODAC O2 Combo? And how so?

That's extremely difficult to answer. The ODAC/O2 is undoubtedly better hardware than the Realtek ALC887 audio in your motherboard. But the implementation of the audio chipset in the motherboard, as well as other components and how they influence the sound (e.g. noise, as PurpleAngel pointed out), may make the Realtek sound worse. And so one person's experience with that Realtek chipset in their computer could be different from yours. Then "obvious improvement" is such a subjective evaluation in itself. Maybe you won't find the extra difference worthwhile. The only way to know is try it and find out

 

[billybob_jcv]

Some people hear differences that aren't even there...

 

[BarbecueGamer]

That's extremely difficult to answer. The ODAC/O2 is undoubtedly better hardware than the Realtek ALC887 audio in your motherboard. But the implementation of the audio chipset in the motherboard, as well as other components and how they influence the sound (e.g. noise, as PurpleAngel pointed out), may make the Realtek sound worse. And so one person's experience with that Realtek chipset in their computer could be different from yours. Then "obvious improvement" is such a subjective evaluation in itself. Maybe you won't find the extra difference worthwhile. The only way to know is try it and find out

Yea, I think it's best to just buy something brand new that way I can simply return it if I can't justify the purchase. 

 

[cel4145]

Yea, I think it's best to just buy something brand new that way I can simply return it if I can't justify the purchase. 

If you don't, you will always wonder if it could sound better. IMO, it's worth the demo fee of returning it if you don't like it, unless the cost of the O2/ODAC would be burden to you.