So first of all, for people who are saying that they are hearing noise from outputs. The only noise I hear from the card is from HP out, when sample rate is set to 44.1 Khz.
What can be the reason of the noise and how to prevent it:
1. Don't use video cards. Use only integrated video.
2. Before buying a PSU read some reviews about ripple and noise tests, voltage regulator circuit ... (I even use ferrite filter on the molex end).
3. Don't use many fans in the case. The fan motor generates noise. Or if you want to use many fans then you should buy fan filters (I'm using only 4 fans: CPU, PSU, intake and outtake)
4. Try to avoid using many HDDs, instead try SSD or HDD filters.
If you do these simple steps, than you'll have a black background, like in graveyard.
SQ is very good for its price, it's worthy of buying. After using the card for a certain period of time I changed op-amps in the I/V section and I put LME49990 instead of JRC2114 which added some bass extension and added some smoothness in highs, plus I didn't lose the energetic stream of music that JRC2114 had. The RCA output quality is much better than the HP output. I'm using iFi's iCAN micro amp, which is my favorite HP amp at the moment. The iCAN runs Class A, so you get a nice sense of its sonic flavor. The RCA out is also using the third op-amp, which is called buffer op-amp. I didn't change it, because the LM4562 has great tonal balance, air and
What can be the reason of the noise and how to prevent it:
1. Don't use video cards. Use only integrated video.
2. Before buying a PSU read some reviews about ripple and noise tests, voltage regulator circuit ... (I even use ferrite filter on the molex end).
3. Don't use many fans in the case. The fan motor generates noise. Or if you want to use many fans then you should buy fan filters (I'm using only 4 fans: CPU, PSU, intake and outtake)
4. Try to avoid using many HDDs, instead try SSD or HDD filters.
If you do these simple steps, than you'll have a black background, like in graveyard.
SQ is very good for its price, it's worthy of buying. After using the card for a certain period of time I changed op-amps in the I/V section and I put LME49990 instead of JRC2114 which added some bass extension and added some smoothness in highs, plus I didn't lose the energetic stream of music that JRC2114 had. The RCA output quality is much better than the HP output. I'm using iFi's iCAN micro amp, which is my favorite HP amp at the moment. The iCAN runs Class A, so you get a nice sense of its sonic flavor. The RCA out is also using the third op-amp, which is called buffer op-amp. I didn't change it, because the LM4562 has great tonal balance, air and
soundstage which are similar to MUSES01. This was actually a great choice for the final buffer stage. 2xLME9990+LM4562=LOVE 
The official driver is crap, I'm using the UNi Xonar driver. After using the UNi driver I'm never gonna use the official driver. never. ever.
ASIO is working well, but it starts glitching (pops and clicks) when you use PC.
Solution: use Fidelizer http://www.windowsxlive.net/fidelizer-6-0-released-big-release-that-comes-with-even-better-upgrade/
Fidelizer not only solves the problem, but it also improves the SQ. However, if you don't wanna use Fidelizer use this http://www.hydrogenaud.io/forums/index.php?showtopic=97127&st=0&p=814345&#entry814345
There is no way out if you wanna use ASIO. Otherwise you must open task manager and set the ASIO host's priority to real-time every time you change the song.
P.S. don't forget to use good quality unbalanced cable with card and amp.
✔Asus xonar essence ST may be the best internal sound card in the market!
Bonus stuff from me!
I got bored from the Asus stock xonar ST center skin and I decided to make some custom/mix skins. Don't judge too harsh, I'm not a professional at this
Preview:
Who it’s work?
You just need to find the folder where the Skin folder is.
Go to C:\Program Files\UNi Xonar Audio\Customapp or C:\Program Files\ASUS Xonar Essence ST Audio\CustomApp\Program
it depends what driver you are using
Then you will see the Skin folder. Delete it and then move downloaded the Skin folder there.
Before deleting make a copy of old Skin folder! So you can change it back to original skin.
Download link:
http://www.mediafire.com/download/iobtjeup7mtp5wg/Skin.zip
mirror
https://mega.co.nz/#!5B4UXYIb!JJu9jxso8pQglZ2jyiQL_8Cvg0gX7FyQ4Apg9aoSGtA
That’s all folks!.
UPDATE: Windows 7 is the only windows that makes this card shine SQ wise!!! (I have tried win 10 and win 8.1).
ASIO is working well, but it starts glitching (pops and clicks) when you use PC.
Solution: use Fidelizer http://www.windowsxlive.net/fidelizer-6-0-released-big-release-that-comes-with-even-better-upgrade/
Fidelizer not only solves the problem, but it also improves the SQ. However, if you don't wanna use Fidelizer use this http://www.hydrogenaud.io/forums/index.php?showtopic=97127&st=0&p=814345&#entry814345
There is no way out if you wanna use ASIO. Otherwise you must open task manager and set the ASIO host's priority to real-time every time you change the song.
P.S. don't forget to use good quality unbalanced cable with card and amp.
✔Asus xonar essence ST may be the best internal sound card in the market!
Bonus stuff from me!
I got bored from the Asus stock xonar ST center skin and I decided to make some custom/mix skins. Don't judge too harsh, I'm not a professional at this
Preview:
Who it’s work?
You just need to find the folder where the Skin folder is.
Go to C:\Program Files\UNi Xonar Audio\Customapp or C:\Program Files\ASUS Xonar Essence ST Audio\CustomApp\Program
it depends what driver you are using
Then you will see the Skin folder. Delete it and then move downloaded the Skin folder there.
Before deleting make a copy of old Skin folder! So you can change it back to original skin.
Download link:
http://www.mediafire.com/download/iobtjeup7mtp5wg/Skin.zip
mirror
https://mega.co.nz/#!5B4UXYIb!JJu9jxso8pQglZ2jyiQL_8Cvg0gX7FyQ4Apg9aoSGtA
That’s all folks!.
UPDATE: Windows 7 is the only windows that makes this card shine SQ wise!!! (I have tried win 10 and win 8.1).
kungmarten
Sometimes you can just put another big card between your video card and the soundcard to reduce the interference. I know there are some overpriced dedicated interference reducing cards out there.
bcschmerker4
This is one of the few PCI audio cards out there that (1) can function, and function well, adjacent to some models of video cards (as I can attest from experience with Vendor's CM1630-06 packing, among other upgrades, both a XONAR STX and an EAH6850 DirectCU in adjacent slots); and (2) are fully supported by the Advanced LinUX Sound Architecture Project with their own driver (in this case, snd-virtuoso, re-written from snd-oxygen to control the on-board output relays). I have the ST short-listed as new hardware for my Hot Rod gPC upon dist-upgrade to Ubuntu 15.12a1.
NOOOOOOOOOO!!!!!1