[Unclewall]

You dont need high Ohm head phones mine are 32 Ohm and work fine,
I have a STX II and changing the op amps can have a big improvement in sound over the amps that come with the card
If you want to improve Bass, sound stage and details you might want to try op amps in the TI Burr Brown line such as OPA 2134
If you can solder you can use Burr Brown OPA1612 which Is one I like best so far but they need to be soldered in to adapters 
If you you use the headphone amp you only need 2, But make sure you put the chips in the right direction other wise you will burn out the chip or your STX this also will happen if the wrong type of chip is used so stick with chips that are known to be compatible

 

[Voxata]

Well, the V5 added a lot of bass and power with realistic heft for me compared to the LME

 

[bluex]

So, the V5 will add more bass / power ? I hope i could notice a difference, with the V5 vs the default ones
As I said, i use only the headphones Sennheiser HD600.
One more question : would you recommend the UNi XONAR driver, for STX II ?

 

[CVLover]

it will increase the quality alot, the bass will be deeper and with more impact, also the soundstage is amazing on these. you will find yourself beeing able to play music at a louder volume because of the clearness. with the stock op amps its very sharp sounding at high volumes.

 

[bluex]

Okay, i will order the V5. Would you give me a link, please ?
As I said, i use only the headphones Sennheiser HD600
What exactly do i have to order ? And how many ? 1 or 2 ??
Thank you very much

 

[Unclewall]

Burson Audio v5's are being recalled because they melt and I have heard  of a few STX line of cards damaged, Last I heard they werent for sale

 

[bluex]

where did you read this ?

 

[Unclewall]

  where did you read this ?

http://www.head-fi.org/t/735828/gustard-h10-high-current-discrete-class-a-output-stage-headphone-amplifier/5010#post_12610516
 
http://www.head-fi.org/t/735828/gustard-h10-high-current-discrete-class-a-output-stage-headphone-amplifier/4275#post_12277319
 
And on other forums 
 
Last I heard Burson stopped selling V5's because they were melting and was giving a credit or credit and V5i's (V5i's don't sound as good ) don't know if they resumed sales
Thanks I will pass

 

[bluex]

So, what else should i go for ? Any ideas ?
Thank you

 

[Unclewall]

There is not a best op amp just like there is no best headphone, Everyone has different hearing and what they like and don't like
Your previous post said that you have a STX II and wanted to get more bass and warmer sound like I said TEXAS INSTRUMENTS Burr Brown OPA2134
http://www.newark.com/texas-instruments/opa2134pa/audio-operational-amplifier-8mhz/dp/74K3897
is a good op amp to start with which comes in 2 channel dip8 which drops right in and costs $4 us each from TI authorized distributor dont buy on Ebay (Burson V5 are $70 each)  you need 2 if you use the headphone amp 
If you know how to solder, the newer burr brown op amps are soic8 and need to be soldered to a adapter they are small about 1/10 the size of a dip8 chip but they are great sounding maybe I could help you with this
I highly recomend the  UNi XONAR drivers in ASIO mode
If you just bought the card it need 40 -50 hours at least to burn in 

 

[bluex]

Thank you very much, Unclewall
I will take a deeper look at this link
Excuse me, but what do you mean with 
" If you just bought the card it need 40 -50 hours at least to burn in "
I tried many times to install the UNi XONAR drivers but i couldn't. Even in test mode, not a chance
I did like here, as well
https://www.raymond.cc/blog/loading-unsigned-drivers-in-windows-7-and-vista-64-bit-x64/

 

[Unclewall]

I the card is brand new you need to use it for 40 - 50 hours of use for it to break in and get the best sound out of it. 
You could not get it to install did you uninstall other driver, disable on board sound if you have it, You get unsigned driver error? the FAQ on that site talks about that 
Are you using STX II version not reg
More power, what headphone are you using and how many ohm? what gain setting are you using 

 

[bluex]

I uninstalled the ASUS drivers first, the onboard sound is disabled, and as I said, the same error, i can't install the UNi Xonar driver
Yes, i'm using the STX II version
My headphones are Sennheiser HD600, 300 ohm, gain settings - extra high gain 300- 600 ohm headsets
I tried as well with SPDIF Out - PCM and without PCM, i couldnt notice a difference
Underneath of PCM i have Dolby Digital Live, but when i try / test / this, there is no sound , only mute ...
Whats the advantage with UNi Xonar driver vs the official one ?
Thank you

 

[Unclewall]

Uni drivers have slightly better sound and work a little better if you can't get them working I wouldn't worry too much. Spdif out is a different type of output you don't need to use it. A good way of playing music is using ASIO to use it you need a music player that supports it such as musicbee which I use, it by passes windows and send sound directly to the sound card it has the best sound, Google ASIO and your music player

 

[bluex]

I installed UNi driver and played with the setting a bit, but i can't find the option for gain headsets ohm and Smart Volume
Is there, any ?
 
LE : what's the best setting for LFE crossover frequency ? I tried there everything, but i couldn't notice a difference