DAC and amp or Xonar STX - Page 3

Quote:

Originally Posted by stv014 

I have now reproduced the same noise issue with the Xonar D1 (CS4398 DAC) 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.

This is intriguing, Could it be the that the sound cards are very close to the PSU? Is your STX still shielded? What PSU do you have and how old is your Mobo.

i have never had a hiss issue, and have never heard of anyone having anything except for a minute hiss with ultra sensitive IEMs.

Quote:

Originally Posted by Migi06 

If you need Dolby Headphone or other virtual surround (THX surround like many motherboards uses now days), then you could use optical out and use external DAC/AMP..

An external DAC is not needed, unless a "noisy" computer makes it necessary. As already noted, the SNR of even a cheap Xonar D1 or DX in the "buggy" 44.1 kHz mode is still high enough not to be an issue if the volume is controlled at the amplifier. Getting an ODAC (no S/PDIF input) for about a dB reduction in already inaudible noise, but higher inaudible distortion is not necessarily worth the money. External DACs that are a safe choice over the sound cards for better measured performance (that may exclude many small "audiophile" brands) and have S/PDIF input are not cheap.

Quote:

Originally Posted by WiR3D 

This is intriguing, Could it be the that the sound cards are very close to the PSU? Is your STX still shielded? What PSU do you have and how old is your Mobo.

The Xonar D1 is as far away from the PSU and any other EMI sources as it is physically possible, it is at the bottom of the machine. The STX does have the shield, and I have never removed it. I have a motherboard that is less than 1 year old. Most importantly, the noise is as low as it can get, as long as I use a DAC sample rate that is an integer multiple of 48 kHz, rather than 44.1.

Quote:

Originally Posted by WiR3D 

i have never had a hiss issue

The AH-D2000 is not very sensitive, even without an impedance adapter. It also does not isolate well, so the most important source of noise is probably the fans in your machine.

Quote:

Originally Posted by WiR3D 

and have never heard of anyone having anything

Some did, according to the link posted earlier in the thread. It is also mentioned in this review. I also suspect (although have no evidence) that the Stereophile review may have measured significantly worse noise for the ST than the STX because of this issue (i.e. perhaps they tested the ST at 44.1 kHz).

Quote:

Originally Posted by stv014 

 

The Xonar D1 is as far away from the PSU and any other EMI sources as it is physically possible, it is at the bottom of the machine. The STX does have the shield, and I have never removed it. I have a motherboard that is less than 1 year old. Most importantly, the noise is as low as it can get, as long as I use a DAC sample rate that is an integer multiple of 48 kHz, rather than 44.1.

 

 

The AH-D2000 is not very sensitive, even without an impedance adapter. It also does not isolate well, so the most important source of noise is probably the fans in your machine.

 

 

Some did, according to the link posted earlier in the thread. It is also mentioned in this review. I also suspect (although have no evidence) that the Stereophile review may have measured significantly worse noise for the ST than the STX because of this issue (i.e. perhaps they tested the ST at 44.1 kHz).

I always like reading your posts, I always learn something. 

just for reference my card is directly above my HD4890 which is hot and consumes a continental amount of power for a single GPU it is also under my CoolerMaster V8 CPU cooler, with a 2000rpm fan (mounted horizontally), also I have 8 fans, most of which are 2000rpm, but my saving grace will be my single rail 750w Corsair PSU, and still no noise on max max max, but you are correct, the D2k are not sensitive.

I suspect you may be correct with the Stereophile review, because theoretically the ST should perform better.

Quote:

Originally Posted by stv014 

 

The Xonar D1 is as far away from the PSU and any other EMI sources as it is physically possible, it is at the bottom of the machine. The STX does have the shield, and I have never removed it. I have a motherboard that is less than 1 year old. Most importantly, the noise is as low as it can get, as long as I use a DAC sample rate that is an integer multiple of 48 kHz, rather than 44.1.

 

 

The AH-D2000 is not very sensitive, even without an impedance adapter. It also does not isolate well, so the most important source of noise is probably the fans in your machine.

 

 

Some did, according to the link posted earlier in the thread. It is also mentioned in this review. I also suspect (although have no evidence) that the Stereophile review may have measured significantly worse noise for the ST than the STX because of this issue (i.e. perhaps they tested the ST at 44.1 kHz).

Something tells me this may have something to do with our setups. It's kinda hard to digest that a problem that has existed for more than 3 years has been ignored by Asus.

On the other hand, someone told me today its maybe because of the filter design Asus uses.

Originally Posted by proton007 

It's kinda hard to digest that a problem that has existed for more than 3 years has been ignored by Asus.

Well, it is not a major issue in practice, it does not occur if the audio is resampled by Windows to 48 or 96 kHz, and even those people who hear some noise with sensitive headphones most likely think it is caused by EMI or other computer interference.

Another test: can the DAC play this without distortion at 100% digital volume ? When reconstructed, this waveform has peaks above 0 dBFS:

Xonar D1 (left) vs. STX (right):

Interestingly, only the cheaper card with the CS4398 DAC passes this test. Although it is probably not of great relevance with actual music, and obviously not with any digital attenuation (not 100% volume).

Quote:

Originally Posted by WiR3D 

I actually more or less understand that graph, at which bit/sample rates?

44.1 kHz / 24 bit, but it seems to be the same at 48 kHz. On the headphone output of the STX, it is not relevant at all, since normally no one uses 100% volume and high gain with loud music.

Quote:

Originally Posted by stv014 

 

The Xonar D1 is as far away from the PSU and any other EMI sources as it is physically possible, it is at the bottom of the machine. The STX does have the shield, and I have never removed it. I have a motherboard that is less than 1 year old. Most importantly, the noise is as low as it can get, as long as I use a DAC sample rate that is an integer multiple of 48 kHz, rather than 44.1.

 

 

The AH-D2000 is not very sensitive, even without an impedance adapter. It also does not isolate well, so the most important source of noise is probably the fans in your machine.

 

 

Some did, according to the link posted earlier in the thread. It is also mentioned in this review. I also suspect (although have no evidence) that the Stereophile review may have measured significantly worse noise for the ST than the STX because of this issue (i.e. perhaps they tested the ST at 44.1 kHz).

I notice that on all "flagship" cheaper DACs, Xonar STX and X-Fi HD, they have problems with 44.1khz, all give terrible performance with 44.1khz( for X-fi HD IMD@10Khz shoots up to 0.044% compared to 0.005% ). THD+N for X-Fi HD also shoots up in my 24/44.1khz vs 24/96khz test but that is partially because X-fi HD resamples all in coming inputs before D/A conversion. These problems tend to be ignored by the companies if its relatively minor to sales... 

Oh well, compromises have to come from somewhere and for the record, both devices still measure better than a certain 24/96 DAC released a few months back and definitely sound better than a certain subpar US$369 dac/amp....

Quote:

Originally Posted by firev1 

I notice that on all "flagship" cheaper DACs, Xonar STX and X-Fi HD, they have problems with 44.1khz, all give terrible performance with 44.1khz( for X-fi HD IMD@10Khz shoots up to 0.044% compared to 0.005% ).

44.1 kHz issues are likely to be related to using a fixed clock frequency that is an integer multiple of 192 kHz, typically 24.576 Mhz. The FiiO E10 may also have problems with 44.1/24 input. I think the X-Fi HD does not have hardware support for 44.1 kHz, so the high IMD is probably aliasing in low quality software sample rate conversion. The Xonars are not quite "terrible" at 44.1 kHz, the 109-110 dB SNR is still decent (especially for the ~$70 Xonar D1/DX), and other than the increased noise floor, there do not seem to be other significant problems. But when referenced to the 7 Vrms maximum output of the TPA6120, the noise level is not that good. I wonder if the "improved clocking circuit" on the ST actually fixes this ?

Quote:

Originally Posted by stv014 

 

44.1 kHz issues are likely to be related to using a fixed clock frequency that is an integer multiple of 192 kHz, typically 24.576 Mhz. The FiiO E10 may also have problems with 44.1/24 input. I think the X-Fi HD does not have hardware support for 44.1 kHz, so the high IMD is probably aliasing in low quality software sample rate conversion. The Xonars are not quite "terrible" at 44.1 kHz, the 109-110 dB SNR is still decent (especially for the ~$70 Xonar D1/DX), and other than the increased noise floor, there do not seem to be other significant problems. But when referenced to the 7 Vrms maximum output of the TPA6120, the noise level is not that good. I wonder if the "improved clocking circuit" on the ST actually fixes this ?

You are right on the problem of the X-Fi HD which is why for the moment I always resample to 24/96 till I change DACs, its a pretty decent dac with good I/O options otherwise, though I noticed that Creative decided to act stupid and use the same output buffers for both line and headphone outs(resulting in harsh sound and decreased noise performance with headphones).

It is amazing though that the Asus managed to come up with a good series of soundcards(pity the D1/DX does no come with EMI shields though it be easier to come up with one) I highly doubt that the "improved clocking circuit" would actually improve things given that by itself STX is pretty amazing and overall outperforms the ST.

If there is only one thing to dislike on both Asus and Creative, it is their subpar after sales support.

I'm enjoying this read

How would the STX's DAC compare with the E17's?