DAC and amp or Xonar STX
May 13, 2012 at 1:15 PM Post #16 of 63
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I was reading some of the threads about this problem in the STX/ST series, and after this I am totaly sure I don't want to spend 160 bucks in a defective product
I'm thinking about an Xonar DX + desktop Amp
Is it a good combo? i own a Xonar DG right now, is it a good upgrade?

I like the idea of the Xonar DX used with an external headphone amplifier.
I've also hooked up an external headphone amplifier to the DG, fairly decent.
The Xonar DX (& D1, DS, DSX) use the same audio processor (C-Media CMI8788) as the Essence STX (& ST).
So the DX has the same surround sound features as the STX.
 
I do not myself consider the STX to be a defective product, I would say it's as good as it can be, for price it is selling for.
Works great with the 8 different headphones that I have used with it.
 
May 13, 2012 at 1:18 PM Post #17 of 63
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It might be helpful to know what you use your computer audio for?
Music?
Movies?
Gaming?
Also what headphones your currently using or planning on buying in the future?
(I am biased toward the STX myself).

music, games and movies 
i am using right now an AD700, but i plan to upgrade them soon, probably DT990 250ohms
 
May 13, 2012 at 1:20 PM Post #18 of 63
Quote:
I like the idea of the Xonar DX used with an external headphone amplifier.
I've also hooked up an external headphone amplifier to the DG, fairly decent.
The Xonar DX (& D1, DS, DSX) use the same audio processor (C-Media CMI8788) as the Essence STX (& ST).
So the DX has the same surround sound features as the STX.
 
I do not myself consider the STX to be a defective product, I would say it's as good as it can be, for price it is selling for.
Works great with the 8 different headphones that I have used with it.

 
do you know the diference between the DAC of the DX and STX? is it much better?
 
May 13, 2012 at 2:06 PM Post #19 of 63
Quote:
music, games and movies 
I am using right now an AD700, but i plan to upgrade them soon, probably DT990 250ohms

The Fiio E11 ($65) can decently power the DT990 Pro 250-ohm
and it can plug into the Xonar DG, thus is just one option.
 
Also for $65 you can get a decent single tube headphone amplifier off eBay, ships from China and takes ten days.
Lots for voltage for powering up to 600-Ohm headphones.
 
May 13, 2012 at 2:12 PM Post #20 of 63
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Do you know the difference between the DAC of the DX and STX? is it much better?

Off hand I do not remember,
but I'm guessing the STX uses the PCM1794
and the DX might be the CS4398?
But I have to run off now, be back in a few hours.
Spending the extra $110? for buying the STX over the DX just for the DAC?
Where as you could spend just $65 for a simple tubes amplifier that do the job with the DX.
 
May 13, 2012 at 4:24 PM Post #21 of 63
thanks everybody for the infos and help

@stv014
i was reading some of the threads about this problem in the STX/ST series, and after this i am totaly sure i dont want to spend 160 bucks in a defective product


It's not perfect, but it is hardly defective. There are outboard DACs costing many times the price of the STX which will perform worse than it does.
 
May 13, 2012 at 8:15 PM Post #22 of 63
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It's not perfect, but it is hardly defective. There are outboard DACs costing many times the price of the STX which will perform worse than it does.

 
Thats what I'm worried about. I'm purely interested in audio, not gaming. So if it wasn't for this hiss problem for the STX, I would've gone for it. Still waiting for the measurements of the ODAC, for the cost its pretty good if it can perform well.
 
May 13, 2012 at 8:24 PM Post #23 of 63
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Thats what I'm worried about. I'm purely interested in audio, not gaming. So if it wasn't for this hiss problem for the STX, I would've gone for it. Still waiting for the measurements of the ODAC, for the cost its pretty good if it can perform well.

I would guess the O2 is a better amp. then the STX's.
 
May 13, 2012 at 8:34 PM Post #24 of 63
Thats what I'm worried about. I'm purely interested in audio, not gaming. So if it wasn't for this hiss problem for the STX, I would've gone for it. Still waiting for the measurements of the ODAC, for the cost its pretty good if it can perform well.


I've never heard any hiss out of the STX through a variety of headphones and one pair of speakers, even at 44.1khz. It may be that the STX is being fed cleaner power/isn't running into interference, or that I'm not listening loud enough on the headphones (though I've cranked the speakers with the line out at 100).

Given the testing and feedback the ODAC's going through, its performance is a safe bet.
 
May 13, 2012 at 8:49 PM Post #25 of 63
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I would guess the O2 is a better amp. then the STX's.

The ODAC, not the O2. The O2 is of course better than the STX's amp.
 
Quote:
I've never heard any hiss out of the STX through a variety of headphones and one pair of speakers, even at 44.1khz. It may be that the STX is being fed cleaner power/isn't running into interference, or that I'm not listening loud enough on the headphones (though I've cranked the speakers with the line out at 100).
Given the testing and feedback the ODAC's going through, its performance is a safe bet.

 
From what I've heard from others here, it affects when using low impedance headphones/IEMs, because the amp impedance is ~10 Ohms. With >250 Ohms, not much (as stv014 reported). 
And some users on other forums have reported no change in this noise by using on other PCs. Also, the noise disappears if you resample to 48kHz, so its probably the DAC that has the problem.
Anyways, I'm mostly interested in the DAC section and line outs for using speakers, for the headphones I can just use the line out with an amp.
I just think a soundcard should have lesser latency compared to USB, but I'm not sure about that. But, an external DAC has the usefulness of being external, so can be used with any PC/laptop.
So I'm thinking that I can use the soundcard for using with speakers as most audio is PC based nowadays, and use the external DAC with my amp/headphones.
 
May 13, 2012 at 8:56 PM Post #26 of 63
From what I've heard from others here, it affects when using low impedance headphones/IEMs, because the amp impedance is ~10 Ohms. With >250 Ohms, not much (as stv014 reported). 
And some users on other forums have reported no change in this noise by using on other PCs. Also, the noise disappears if you resample to 48kHz, so its probably the DAC that has the problem.
Anyways, I'm mostly interested in the DAC section, for the headphones I can just use the line out with an amp. I just think it should have lesser latency compared to USB, but I'm not sure about that.


The output impedance would alter the frequency response of low z phones, but the hiss would be brought out by high sensitivity. I've used high sensitivity phones with the STX without hearing any hiss, though this is just my experience and I'm not aware of the details of the sorts of problems others have been having.

Unless there's some glaring bug in the implementation, latency shouldn't be noticeable in USB v. soundcard output. Humans are slow bunches of neurons.
 
May 14, 2012 at 7:34 AM Post #27 of 63
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It may be that the STX is being fed cleaner power/isn't running into interference

 
I do not think I have interference, as the noise is very low at 48, 96, or 192 kHz. Although maybe the DAC clocking at only the other sample rates is very sensitive to interference ? But that would not necessarily be a good thing, since the problem could be worse then on some other machines.
 
Quote:
or that I'm not listening loud enough on the headphones (though I've cranked the speakers with the line out at 100).

 
The absolute noise level of the headphone output does not depend on the volume or gain setting at all, since both are digital. When using the line output, the volume is controlled downstream of the DAC, and then the reduced ~110 dB dynamic range (roughly comparable to the ODAC) is still plenty low enough to be inaudible, especially on speakers. With speakers that have 90 dB/W sensitivity, and 1000 W amplifier power at 0 dBFS, the A-weighted DAC noise SPL would be only 10 dB. Only with sensitive (and isolating) headphones is there some slight hiss. Using my high impedance headphones, I hear no noise at all.
Note also that depending on the configuration, 44.1 kHz audio may be resampled to e.g. 96 kHz by Windows.
 
May 14, 2012 at 7:58 AM Post #28 of 63
I have now reproduced the same noise issue with the Xonar D1 (CS4398 DAC)
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It is of less significance, however, since this card does not have a built-in headphone amplifier anyway. The line out noise level at 44.1 kHz is basically the same as that of the STX.
 
May 14, 2012 at 8:16 AM Post #29 of 63
Quote:
So if it wasn't for this hiss problem for the STX, I would've gone for it.

 
It is only relevant if you are using the built-in amplifier of the STX with sensitive headphones, which would likely also be affected by the 10 Ohm output impedance. Even then, it can be worked around to some extent (software sample rate conversion, external voltage dividers that could also be used to reduce the output impedance).
 
Quote:
Still waiting for the measurements of the ODAC, for the cost its pretty good if it can perform well.

 
ODAC measurements are already available (link not allowed), not all of them, but enough to give a decent picture of what it is capable of.
 
May 14, 2012 at 8:16 AM Post #30 of 63
If you need Dolby Headphone or other virtual surround (THX Surround or SRS TruSurround HD like many motherboards uses now days), then you could use optical out and external DAC/AMP..
 
I´m using DG optical --> X-fi USB HD and dont have any hissing + Dolby Headphone works. Easiest would be STX "all in one" 
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.. My dream setup, Xonar phoebus (Xear 3D surround, dolby v4) optical --> Xonar One 
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