[raoultrifan]

  [...] Like i said, you don't have the equipement to back it up but you engaged your soul by saying it is the true. But sadly i heard the complete opposite from people looking "internetably" (lol) honest too".
 
So, the best way is just to basicaly try it out and see by yourself. Better? not better? placebo or not? matter of tast or measurement to back it up? it's a mic mac
[...]
 
Have a good day wherever you leave

Hi pocahontas, 
 
I only trust 2 things in audio world:
- 1'st would be measurements done carefully with dedicated equipment that should proves that DAC+AMP are not oscillating and are within acceptable "audiophile" parameters;
- 2'nd would be A/B and blind A/B tests done by at least 2 persons with decent hearing (A/B tests done either between 2 identical DACs/AMPs, either by using a "reference" system to compare with and write down all noticed differences).
 
What you need right now is to find someone having both ODAC+O2 and ALC1155 motherboard to do this A/B test I was speaking above (though I believe in one of my links provided in an earlier post there was someone on another forum that already compared that).
 
Also, just by looking at ALC1155 specs from the datasheet and comparing with ODAC doesn't really proves anything because ODAC and O2 measurements were done at RCA/outputs plugs with scopes and AP Precision equipment, but "some motherboard manufacturer" will only tell you the spces provided by the ALC1155 itself in the datasheet and not the actual measurements done at RCA/outputs or headphone plugs. It's hard for me to believe that a manufacturer will perfectly implement a great audiophile DAC & headamp inside a "usually very noisy" computer case and powered from a "usually very noisy" switching power supply (try searching over Internet about computer PSU noisy and ripple). So, yes your computer PSU is going to influence a lot your motherboard DAC's sound, unless you're spending a lot of money on a high-end PSU with decent ripple & noise figures...and usually most people is swapping computers at every 3-5 years to get most of price/performance ratio, so perhaps would be wiser to invest in external DAC/amps.
 
Have a great day yourself, 
Raul.

 

[pocahontas]

 

 
Hello. Well i think we will never really know for sure. "The truth is out there" my friend
 
Have a great day too.
 
ps: if some one have a solid reponse to provide, just quote one of my post so i know

 

[jseaber]

  Hi Raul,
I did my best to capture the area of interest, as well of the whole unit itself for reference. I'll be sure to take your advice and head to diyaudio later to ask that community if we can't sort it out here. Also, note this unit was modded for a 1/4 '' plug, with the plug squeezed over the bottom right area of the board. This is why I suspect it is taped there, to make sure the plug doesn't accidentally short anything.
 
Top view:
 

 
 
Bottom view:
 

 
 
Potentially damaged areas:
 

 
-Ryan

 
FWIW - That type of flux residue requires cleaning. Its presence often interferes with circuit behavior.

 

[raoultrifan]

  Hi Raul,
I did my best to capture the area of interest, as well of the whole unit itself for reference. I'll be sure to take your advice and head to diyaudio later to ask that community if we can't sort it out here. Also, note this unit was modded for a 1/4 '' plug, with the plug squeezed over the bottom right area of the board. This is why I suspect it is taped there, to make sure the plug doesn't accidentally short anything.
 
Top view:
 

 
-Ryan

Do I see something wrong with R16 & R22 resistors? I believe someone tried to modify the low-pass filter or something. I would recommend you change R16 & R22 with original values from BOM and also to double check values for C19 & C20 caps.
 
Also, I suggest using a magnifier glass to check for cold-soldering around affected area (the big resistor from the other picture).

 

[MrMateoHead]

 
ps: if some one have a solid reponse to provide, just quote one of my post so i know

I just gave you one on pg 334.
 
In short, and "in theory" (because the specs are largely incomplete so only Realtek's incomplete specs are in use here), the 1150 should adequately power your AKG 550s. That would be true of any headphone with similarly flat impedance fixed at about 32-35 Ohms, and with low power requirements (under 1/10th of 1 mW). I would not stray far from those "specs", but then again you can't know what the real impedance curve looks like without independent testers so you have to trust their measurements - even if you don't want to.
 
As to whether the 1150 chipset actually provides 115 dB of SNR, a -75 THD (0.02% distortion) and 96 dB of dynamic range AT the headphone jack is unknown without professional testing of the actual computer / motherboard. IF those are the "best case" specifications, than poor implementation can only make them worse from there. Where the audio section is largely an "afterthought", there are too many variables and not enough specs to guess whether, even if perfectly implemented, the chipset will deliver its theoretical best-case performance.
 
My present chipset, as implemented inside my existing computer (the 892), is close to being relatively indistinguishable, but it has audible hiss and bass/treble roll-off / softness and low power which is the surest way I know it is not as good as my O2. I need to use more demanding headphones to make that assertion (easy - I own some). "Any amp played within its limits" will sound the same. Maybe. But different headphones have different efficiency and impedance curves, and will respond not only objectively but subjectively different to low power (e.g. one sounds "louder"/"better" the other "hisses" more/less / lacks bass). Sorry to disagree with your Internet, but you have a lot more to learn.
 
My PSB's are very similar to the AKG's in terms of impedance and efficiency, and can play loud with my phone, tablet, and computer, so that is a "proxy" for guessing that a setup such as yours will work just fine. In fact, in the past I've argued quite clearly that, unlike my other headphones, I'd likely be claiming that amps are a "waste of money" were the PSBs my only headphones. Not true anymore - I've seen where having dedicated equipment is a big plus. Again, sorry about your Internet.
 
As others point out, the "noisiness" of your audio environment will relate to other parts in use, and the power supply, shielding etc. may or may not matter. It also dawned on me that all integrated onboard audio is probably limited to around 3.3V peak-to-peak to power I think, which will never be enough for the most demanding headphones. Dedicated cards and/or external solutions will continue to have more ideal operating conditions and can potentially supply more power IF they are designed to do so.
 
So to provide a more solid (educated) response, "Yes".

 

[WilliamLeonhart]

Can anyone here that has tried the ODAC revB please give me an A-B comparison? I've already got the revA but currently has a deal for the revB, and I don't know if the difference (if any) will be worth it.

 

[214324]

  Can anyone here that has tried the ODAC revB please give me an A-B comparison? I've already got the revA but currently has a deal for the revB, and I don't know if the difference (if any) will be worth it.

There really shouldn't be any audible difference.
 
If the numbers difference really makes you feel that uncomfortable go ahead and buy it.
 
I'd say get a Rev B ONLY if you switch sources very often and don't want to run into the distortion issue over certain USB connections found on the Rev A. Details here:
 
http://blog.jdslabs.com/?p=1003
 
Also straight from JDSLabs themselves:
 

 Minor performance improvements (audibly equivalent)

 

[deaconblues]

Can anyone here that has tried the ODAC revB please give me an A-B comparison? I've already got the revA but currently has a deal for the revB, and I don't know if the difference (if any) will be worth it.

RevA had compatibility problems with a very small percentage of motherboards. Its power regulation would become unstable and cause severe distortion. RevB was made to fix this problem. If you don't have this problem, there is no reason to replace your odac. Even if you have the problem, it can be fixed by connecting the odac to a USB hub instead of directly to the computer.

 

[serman005]

RevA had compatibility problems with a very small percentage of motherboards. Its power regulation would become unstable and cause severe distortion. RevB was made to fix this problem. If you don't have this problem, there is no reason to replace your odac. Even if you have the problem, it can be fixed by connecting the odac to a USB hub instead of directly to the computer.

Good to know.

 

[WilliamLeonhart]

This is great. I'd stay with my trusted revA then. 

 

[adydula]

Absolutely no sonic difference...I have several and if you have a Rev A there is no need for a B.
 
A.

 

[riverlethe]

Can anyone here that has tried the ODAC revB please give me an A-B comparison? I've already got the revA but currently has a deal for the revB, and I don't know if the difference (if any) will be worth it.

RevB does have the advantage of being able to run straight from, eg., an iPhone battery without the use of a powered hub.

 

[WilliamLeonhart]

RevB does have the advantage of being able to run straight from, eg., an iPhone battery without the use of a powered hub.

Thanks for the info.

 

[gab840]

Guys my o2 amp power supply just got blown away with huge sound and after that my o2 amp is not working
I was not present in the room when it blowed up and the upper cover of power supply was blown away
I used mY ifi ican power supply , with it is getting power on but are not able to produce any sound. What can i do to check whats wrong ?

 

[deaconblues]

Does your ican power supply output DC voltage?
The O2 need an AC power supply.