[PurpleAngel]

Quote:

Hey, I've got a question about Opamps
I'm a little confused why there are three. I'm guessing that the third one up front is for something specific to the white and red out.
Is it that one is for the left channel, and one is for the right? If so, that leaves me a little bit confused. I know that some Opamps are single channel and some are dual channel, and that this card requires dual channel opamps. Now, since there are two.. doesn't that mean single channels would suffice?
As you can probably tell, I'm a bit lost. If the Opamps are dual channel - why do you need two? Is there a difference between dual channel Opamps and stereo? If so, is that why there are two - for the stereo? If not - do they work together in a manner akin to SLI or something, alternating signal? (I literally have no idea how they work lol) Or, is it that the red/white out uses one, and the headphone out uses the other?
I'm also a bit curious about the third one - what exactly does it do? I know its something spesific to the White/Red out, but I don't know what exactly.
I'm willing to learn, but I'm finding conflicting sources and it's difficult to nail down an exact answer. I hope the question is phrased alright - It's mainly my confusion as to why there are two of the same Opamp, and the difference between single channel and dual channel opamps.
Currently I'm looking at getting myself two LME49720NA and a LM6172IN, and giving them a whirl to see if they suit my tastes.

The 2 matching op-amp sockets (JRC 2114 op-amp), referred to as "I/V" sockets and are used by the headphones
and the third socket is call the "buffer" socket.
And all three sockets are used for the line-out (RCAs).
Why they are all three dual channel? I have no idea, but you need to have two channels for each socket.
Technically it's better to use two single channel op-amps per socket (less crosstalk?).
I'm currently using 6 AD797BR (SOIC) single channel op-amps in my Essence STX, the AD797BRs are soldered to a dual SOIC to DIP-8 adapter.
DIP-8 is a socket (removable op-amp)
SOIC need to be soldered

 

[derbigpr]

Quote:

Thanks for the reply Elwappo!
 
I use these speakers: Harman Kardon Soundsticks III, and these headphones: Sennheiser HD 595 (should I use any gain for these, and what does gain really do - just increase the volume, or make the quality better?).
 
The question I still have in mind is, say that a movie has a 5.1 audio output (which I select in VLC), will HiFi mode playback 5.1? Do I need Dolby Headphone enabled for the surround 5.1 sound? In theory, it shouldn't, right? Since HiFi mode from what I've read is unprocessed signals only, which would equal to 5.1? Is this the same in games?
 
So all in all, HiFi and Dolby Headphone is 100% a matter of taste? If this is the case then the choice is simple for me, since HiFi is much better imo. But I want to make sure that I'm not missing out on some special "sound effect" feature that I'm not aware of such as surround sound or positioning?

 
 
 
No, you will not get full surround sound with dolby in movies. Its just a software illusion which changes the frequency responses of sounds and add various effect like echo/reverberation.  The only way for you to get surround sound with headphones is by listening to binaural recordings. Sadly, none of the movies and almost none of the music is recorded that way, and the music that is, sounds worse than normal stereo in some cases.
Listen to these binaural recordings (without dolby turned on) with your headphones, in HD and quite loud, so its at realistic volume levels as you'd hear it in reality.
http://www.youtube.com/watch?v=5R7zf30z_cg
http://www.youtube.com/watch?v=hjeN4iwDb14
http://www.youtube.com/watch?v=vVn4c0woig0
 
This gives you an idea of what headphones CAN sound like with properly recorded stuff, how great the sense of space and directionality can be, and also makes you realize how bad most music or movies actually sound on headphones.

 

[chewy4]

I think dolby headphone brings an immense improvement in games, haven't tried movies though. 

 

[derbigpr]

Quote:

I think dolby headphone brings an immense improvement in games, haven't tried movies though. 

 
 
Yea it does, but its still not as good as it could be.

 

[Jademalo]

Quote:

The 2 matching op-amp sockets (JRC 2114 op-amp), referred to as "I/V" sockets and are used by the headphones
and the third socket is call the "buffer" socket.
And all three sockets are used for the line-out (RCAs).
Why they are all three dual channel? I have no idea, but you need to have two channels for each socket.
Technically it's better to use two single channel op-amps per socket (less crosstalk?).
I'm currently using 6 AD797BR (SOIC) single channel op-amps in my Essence STX, the AD797BRs are soldered to a dual SOIC to DIP-8 adapter.
DIP-8 is a socket (removable op-amp)
SOIC need to be soldered

 
Could not have asked for a better answer. Thanks a ton!

 

[stv014]

Quote:

Originally Posted by PurpleAngel /img/forum/go_quote.gif
 
Why they are all three dual channel? I have no idea, but you need to have two channels for each socket.
Technically it's better to use two single channel op-amps per socket (less crosstalk?).

 
The reason why there are three dual op amps is that the I/V stage is balanced, and needs two amplifiers per channel (click on the picture below for simplified schematics of one channel). The buffers on both the line and headphone outputs are differential amplifiers, and convert the balanced signal to single ended. Therefore, each NJM2114D is used entirely for a single channel (left or right). However, even in the LM4562 buffer, crosstalk is far below a level anyone could hear. According to Stereophile, "channel separation (not shown) was superb, at 120dB at all frequencies" on the line output.
 

 

[Jademalo]

Hey guys, thanks a ton for those answers! =]
 
Anyway, I've got another question, and this one has to do with background hiss.
When I have the card set to 44.1KHz, there is a noticable background hiss when no sound is playing. However, with 48/96/192, there is none.
 
..And before I've even posted it, it's stopped. Bizzare.
EDIT: And now it's started again, but it's completely random if there will be hiss or not, it can change whenever I change the Channel settings or the KHz settings.
 
 
Also, I keep getting the error saying the extra power isn't plugged in, but it is, and the card seems to work perfectly.. I can't test the HPA since i've only got 38ohm headphones though.
 
Is it just required for the HPA?
 
Thanks again!

 

[ryssen]

Any one tried the LT1363 as I/V opamp?Is it any problem getting them stable?
I found out that LT1363 is a single opamp.. So that wont work.. sorry..

 

[stv014]

Quote:

Originally Posted by Jademalo /img/forum/go_quote.gif
 
Anyway, I've got another question, and this one has to do with background hiss.
When I have the card set to 44.1KHz, there is a noticable background hiss when no sound is playing. However, with 48/96/192, there is none.

 
It is a known issue on the Xonar family sound cards, 44.1, 88.2, and 176.4 kHz sample rates are noisier than others. This problem is the worst in the case of the headphone output of the STX, because the noise is further amplified, and the volume and gain controls are digital (i.e. the noise does not become quieter when you reduce the volume or the gain, it is always at the maximum level). With sensitive headphones, the noise can be audible. On the line output and using an external amplifier, it is less of an issue, because the analog volume control on the amplifier makes it possible to run the DAC at or near full digital volume, maximizing its dynamic range.
 

Quote:

Originally Posted by Jademalo /img/forum/go_quote.gif
 
Is it just required for the HPA?

 
If you mean the external power, then it is needed not only for the headphone amplifier, but also other analog components on the card.

 

[Jademalo]

Ok, thanks!
 
It seems that ASIO isn't working without the External power either, so I'm gonna have to dive back into my case to try and fix that. Also, is it worth just leaving the card on 48KHz to counter the background noise, or should I keep it at 44.1 for music?
I didn't notice the hiss when I had something playing at more than half volume, but if I've got it on quiet I can sort of hear it through my headphones.
 
It's still a 200% improvement to my onboard's noise, that thing in comparison sounded like a jet lol.

 

[PurpleAngel]

Quote:

Ok, thanks!
 
It seems that ASIO isn't working without the External power either, so I'm gonna have to dive back into my case to try and fix that. Also, is it worth just leaving the card on 48KHz to counter the background noise, or should I keep it at 44.1 for music?
I didn't notice the hiss when I had something playing at more than half volume, but if I've got it on quiet I can sort of hear it through my headphones.
 
It's still a 200% improvement to my onboard's noise, that thing in comparison sounded like a jet lol.

I just leave my sample rate at 96Khz

 

[WiR3D]

guys. for settings - check the wiki!!!! 
 
 
Quote:

Any one tried the LT1363 as I/V opamp?Is it any problem getting them stable?
I found out that LT1363 is a single opamp.. So that wont work.. sorry..

It was on my list, but it has some high DC offset, which is not so good. So decided not to use it. Some people really really enjoyed it.
 
Quote:

I just leave my sample rate at 96Khz

meh i use 48kHz. But then I dont have any 96kHz content/

 

[Jademalo]

Thanks, I'll just leave it on 48 =]
Right guys, last question - I promise!
 
I seem to be getting an ASIO crash when using 44.1KHz with ableton live 8.3
 
Using http://www.tropicalcoder.com/ASIOTestSigGen.htm seems to be fine, on 44.1 and 48. Ableton however, crashes after 2 seconds or so on 44.1, but is perfect on 48.
Is this a problem with ableton, or a problem with the card?
 
I also can't change any of the settings in the asio hardware config box, is that normal? It seems a bit pointless if you cant lol.

 

[e6600]

hey all
cool hearing about the 44100 white noise issue.  my cards now at 48000
 
but the problem im having is this clicking sound every time i change music on foobar.  it doesnt happen if i dont change songs myself
i can get rid of it using a dsp resampler (sox mod) but im likely losing quality using the software resampler over the xonar's hardware one
is there any other way of getting rid of it?

 

[stv014]

Quote:

Originally Posted by e6600 /img/forum/go_quote.gif
 
but im likely losing quality using the software resampler over the xonar's hardware one

 
If you set the sample rate to 48000 Hz to eliminate the noise, you are already using software sample rate conversion that is either in the C-Media/ASUS drivers, or Windows. However, software resampling can be (although it often is not) sufficiently well implemented on current PCs that it does not really lose quality compared to running the hardware at 44100 Hz.