GUSTARD H10 High-current Discrete Class A output Stage Headphone Amplifier

[BassDigger]

Reposted: post #403 

 

[GioF71]

  If your usb data channel has so much noise that packets are being dropped left and right, that indicates that a. you have a pretty rare problem, and b. you will experience issues with everything plugged into that bus at any data rate. On the other hand, if your noise is on the ground (like I have) then that noise can be audible at all sample rates but won't stop the dac operating at any speed up to & including 192khz. So I would say your issue most likely has nothing to do with noise, and is a problem with driver or bandwidth or implementation.

 
The problem with the SMSL has nothing to do with drivers, as it presents on the usb connection which is class 1 (no driver needed on any o.s.).
 
Also, these kind of issues always happen with laptops in my case; the same DAC works fine with any desktop PC i tried, regardless of the operating system.
Also, the same laptop computers have no issues with other dac/interfaces, for example the gustard x12/u12, the new audiophonics usb interface I bought or the Yulong D200.
 
My point is that the problem might still be in the dac itself (a poor usb implementation). After all we are talking of quite a low-end dac. I'm not trying to solve its problems, just to point out how many factors are in usb audio, apart from the 'bits' alone.

 

[GioF71]

  My actual understanding of the technicalities is probably no better than yours, but I think that you've got the right idea.
 
There are many different protocols for the transport, and use, of digital data. 'Bits are bits', in our field of interest, only really applies when we are copying, or moving a music file, e.g. from cd-rom to pc (using a craptastic cd drive), or even sending the file over the internet. This is all FTP and 'bits are bits' are bits; it doesn't matter, as long as the file is complete, the data is intact; it's the same data at the end of the process, as it was at the beginning. E.g. downloading a flac file doesn't lose any of its quality. And that data may have travelled around the world a few times!
 
But when you 'play' that flac file, using whatever hard and soft ware, it becomes music; it becomes real in the time dimension. So when you use a pc, as your source, the music begins to exist in your computer. The music, in digital form (not analogue), then has to be transmitted from inside your computer and through your connection chain, to your dac. This is when most of the damage and corruption of the signal occurs. Most of this corruption is known as jitter, or timing errors.
 
People tend to regard jitter as just a single phenomenon. But i think that it's more all-encompassing than that. Timing is what music is all about. Timing is what makes music musical. Timing is not only the beat, rhythm and tempo, it's the frequencies that create the notes themselves. So if something has a susceptibility to timing errors, aka jitter, i think that some emphasis should be placed on choosing components that are key to reducing the effects of this. This is why some people, myself included, prefer to use a dedicated transport.

 
Couldn't have explained it better... thanks!

About the transport, I agree. My 'dedicated transport' currently is the dedicated linux Atom PC with its linear PSU and the Schiit Wyrd.
Quite happy at the moment. Still, a better PSU, with dedicated 12v, 5v etc voltage rails, would be even nicer.

 

[spaech]

 
The problem with the SMSL has nothing to do with drivers, as it presents on the usb connection which is class 1 (no driver needed on any o.s.).

It's worth pointing out that it can still be a driver issue, since proprietary drivers can address the hardware in different ways to the inbuilt windows drivers. Often installing the proprietary driver solves problems like this. I'm not saying this is the issue, just that it can't be ruled out as a plausible cause. If you are curious, you could try installing the driver from smsl on the laptop and see if that helps.

 

[GioF71]

  It's worth pointing out that it can still be a driver issue, since proprietary drivers can address the hardware in different ways to the inbuilt windows drivers. Often installing the proprietary driver solves problems like this. I'm not saying this is the issue, just that it can't be ruled out as a plausible cause. If you are curious, you could try installing the driver from smsl on the laptop and see if that helps.

 
you're right, thought I wouldn't like much such a solution. The windows driver wouldn't fix problems (if any) on Linux.
Anyway I didn't even know a class 1 usb driver was provided by SMSL, can you privide a link?

 

[spaech]

   
you're right, thought I wouldn't like much such a solution. The windows driver wouldn't fix problems (if any) on Linux.
Anyway I didn't even know a class 1 usb driver was provided by SMSL, can you privide a link?

They host their drivers here (not sure which model your dac is): http://smsl-audio.com/index.php?c=list&cs=ziliaoxiazai

 

[GioF71]

  They host their drivers here (not sure which model your dac is): http://smsl-audio.com/index.php?c=list&cs=ziliaoxiazai

 
Thanks a lot, will try.
Just to clarify: when I use the SMSL Sanskrit on a windows 7 laptop, it's not that it does not work at all.
It works quite fine @44.1kHz and @48kHz.
@96kHz (and also @88.2kHz, fwiw) there is a lot of static noise and eventually dropouts.
As I mentioned, no issues on my other pcs apart from the two laptops I have at home and office.
More, I am not implying that ANY laptop will have the issue. Also, I didn't try different cables as I didn't have any at hand expect the standard usb cable provided by SMSL.

 

[spaech]

 
People tend to regard jitter as just a single phenomenon. But i think that it's more all-encompassing than that. Timing is what music is all about. Timing is what makes music musical. Timing is not only the beat, rhythm and tempo, it's the frequencies that create the notes themselves. So if something has a susceptibility to timing errors, aka jitter, i think that some emphasis should be placed on choosing components that are key to reducing the effects of this. This is why some people, myself included, prefer to use a dedicated transport.

It's interesting to break it down conceptually in order to figure out what's plausible and what kinds of perceptible artifacts we might experience from issues like usb timing errors. I think relating it to beat and tempo can be a little misleading because we can only perceive changes in time/tempo in the order of 10+ milliseconds. The entire waveform shifting in the order of 10+ms resulting in perceptible alteration to beat/temp is not a plausible manifestation of usb timing jitter -- the waveform is only going to be shifted temporally on very small time scales closer to the actual sample rate. So for the sake of clarity, when were talking about the audible manifestation of timing jitter, it's not of this kind where the entire waveform is being shifted perceptibly.
 
So what might timing jitter actually sound like? If it were purely random noise resulting in sampling points being shifted temporally relative to one another, that would only manifest as frequency changes in the 22khz+ range (assuming we're at 44.1 sample rate), i.e. outside the range of human hearing. So we're not going to hear that kind of jitter. What we might hear however is the cumulative effect of a consistent timing error over time, resulting in a fundamental frequency of minor variations in the waveform's amplitude. Which we would expect to manifest as a sort of "warble" on top of the sound. The question in my mind is how common this actually is in practice and whether it does manifest in a perceptible way, and that comes down to measurements and blind listening tests.
 
The idea here isn't to dismiss the possibility of jitter effects having a perceptible manifestation, but to narrow down plausible mechanisms and expected sonic colouring it might cause. If we understand what jitter can actually do in practice, then if we're experiencing artifacts, we can avoid attributing it to the wrong cause.

 

[spaech]

   
Thanks a lot, will try.
Just to clarify: when I use the SMSL Sanskrit on a windows 7 laptop, it's not that it does not work at all.
It works quite fine @44.1kHz and @48kHz.
@96kHz (and also @88.2kHz, fwiw) there is a lot of static noise and eventually dropouts.
As I mentioned, no issues on my other pcs apart from the two laptops I have at home and office.
More, I am not implying that ANY laptop will have the issue. Also, I didn't try different cables as I didn't have any at hand expect the standard usb cable provided by SMSL.

Interesting. I guess the laptop could be having trouble keeping up with resampling, but that seems unlikely and I'm not sure if it would explain the static noise. This is the sort of thing you might see when using ASIO for output. If you up the sampling rate with ASIO you can get artifacts and dropouts because your system can't keep up. But I'm not sure if the same principle applies for the windows audio engine. It'd be interesting to see whether a different cable helps. Also whether you get the same issues on battery power vs mains.

 

[GioF71]

Hello.
No, the tracks were nativelly @88.2 or @96kHz. No resampling dsp was active.
Still, the same issues were noted when artificially upsampling with sox or pphs on foobar2000.
ASIO did not make any relevant difference over wasapi.
I obviosly tried wasapi both event and push style, and also tried to increased the buffer length.
Nothing helped at all, leading me to think it's a matter of interference on the usb power/signal, while the pc was able to keep up.
 
 
I think probably battery power would help. Or the schiit wyrd.
But, at least basic functionality is desired with standard equipment. Such things should deliver improvements, not functionality. Do you agree?
 
That was the reason while I send my previous interface (not this SMSL Sanskrit DAC) back for refund. I sort of worked at last with the Wyrd (this had issues with every single system I use), but to me this was plain unacceptable.
As I mentioned earlier, the spdif interface I later bought from Audiophonics works perfectly with all the systems I work with as well as my other DACs (Yulong D200, Gustard X12 and U12) do.

 

[BassDigger]

Reposted: post #404

 

[spaech]

  Hello.
No, the tracks were nativelly @88.2 or @96kHz. No resampling dsp was active.
Still, the same issues were noted when artificially upsampling with sox or pphs on foobar2000.
ASIO did not make any relevant difference over wasapi.
I obviosly tried wasapi both event and push style, and also tried to increased the buffer length.
Nothing helped at all, leading me to think it's a matter of interference on the usb power/signal, while the pc was able to keep up.
 
 
I think probably battery power would help. Or the schiit wyrd.
But, at least basic functionality is desired with standard equipment. Such things should deliver improvements, not functionality. Do you agree?
 
That was the reason while I send my previous interface (not this SMSL Sanskrit DAC) back for refund. I sort of worked at last with the Wyrd (this had issues with every single system I use), but to me this was plain unacceptable.
As I mentioned earlier, the spdif interface I later bought from Audiophonics works perfectly with all the systems I work with as well as my other DACs (Yulong D200, Gustard X12 and U12) do.

It sounds as though you did a good amount of debugging. In terms of whether devices like the Wyrd should deliver improvements or functionality, I guess it depends how you define that. If noisy usb is causing audible static and failure at 96khz and the wyrd cleared that up, then I'd say the fault lies with the usb / motherboard. From the perspective of the DAC manufacturer, they can't be expected to engineer a product that will function on a usb interface that's not operating to spec. I think it's reasonable that you returned the DAC simply because it wasn't working to your satisfaction regardless of the cause. The fact that you didn't have any problems at 48khz is a little strange to me, and I don't fully understand why you'd get static/failure at 96khz but not 48khz if the problem is caused by noisy usb. In any case I'm glad other equipment resolved the issue.
 

   
I think that you've mentioned before that you're a scientist (maybe in a different field). Am I right? Anyway, your understanding seems to be deeper than mine, and your thought process is certainly more systematic!
 
I guess I was being intentionally generalistic; I just think that jitter is probably more of a culprit than can currently be explained. But, I wasn't suggesting that we can actually hear jitter; rather that its effects could have influences on any aspect of musical reproduction, through its effects on any process or equipment, or even its effects on how we perceive the music.
 
In the end, it's the sound that counts. The challenge is for science to prove where the correlations are genuine and discount the incorrect theories (and internet ramblings of bass loving posters). To define what are the exact effects and manifestations, of jitter, all the way through the chain, to the human brain. It's a long path (maybe not so long, in my case). But it seems to me that, as understanding improves, jitter has an ever growing list of misdemeanors!

Heh, I don't think I mentioned it but yeah I do work in academia. Not in audio though, and I'm by no means an expert so I wouldn't trust that I'm getting everything right with what I post here. I know that humans can only perceive timing & tempo changes in music in the order of 10+ ms because I do a bit of music production, and 10ms is about the lowest latency that a professional musician can detect when monitoring their own playing. It's even harder to detect if we don't have that physical feedback (like plucking a string) that tells us where the note should be. So for just listening to music, our ability to perceive whether a beat is slightly off-time is more like 30+ ms. So effectively, even the worst usb timing errors aren't going to manifest as noticeable timing/tempo changes in music.
 
You mention that we don't hear jitter directly but instead might hear its influences on any aspect of musical reproduction. We're totally on the same page there -- after all, the jitter itself is in the digital realm. There might be various ways it translates into perceptible differences in audio reproduction, and that's what I was trying to narrow down in the earlier post: what are the plausible manifestations that would be perceptible. My conclusion was that it would manifest as a "warble" overtone, sort of like a harmonic or subharmonic, but with a fixed frequency dependent on the timing error. There might be other ways that timing jitter could manifest but this is what makes sense to me. In any case it's all theoretical, and I'd be more interested in seeing measurements & blind tests that quantify the effect. Personally I have about zero trust in sighted listening tests.

 

[mandrake50]

  If your usb data channel has so much noise that packets are being dropped left and right, that indicates that a. you have a pretty rare problem, and b. you will experience issues with everything plugged into that bus at any data rate. On the other hand, if your noise is on the ground (like I have) then that noise can be audible at all sample rates but won't stop the dac operating at any speed up to & including 192khz. So I would say your issue most likely has nothing to do with noise, and is a problem with driver or bandwidth or implementation.

Or possibly simply with his laptop. I have several laptop machines from over the last 8 years. Other than the two most recent vintage machines,that were pretty high end, one about 6 months old with i7, 16 gig of Ram and SSD, will play anything I throw at it. The three year old machine also an i7  (about two generations older)16 gig of RAM and SSD struggles with DSD and DXD. This is using the same cables and other gear. I got a tool to measure latency..  link... the older machine was borderline at 500 to sometimes over 1000 ms (quite enough to wreck audio)
I wouldn't assign blame to cables or noise in the circumstances described. It is likely  hardware ... based on my experience.

 

[spaech]

  Or possibly simply with his laptop. I have several laptop machines from over the last 8 years. Other than the two most recent vintage machines,that were pretty high end, one about 6 months old with i7, 16 gig of Ram and SSD, will play anything I throw at it. The three year old machine also an i7  (about two generations older)16 gig of RAM and SSD struggles with DSD and DXD. This is using the same cables and other gear. I got a tool to measure latency..  link... the older machine was borderline at 500 to sometimes over 1000 ms (quite enough to wreck audio)
I wouldn't assign blame to cables or noise in the circumstances described. It is likely  hardware ... based on my experience.

Yeah you're right, cables causing that issue is a bit of a stretch.
 
For a bit of fun I just tried comparing sine sweeps between rca cables. Test 1 was the 6" schiit pyst interconnect, test 2 was 1.5m audioquest evergreen, test 3 was around 40 feet of rubbish generic rca daisy chained to another 5 foot one. Measured frequency response was identical for all cables, and the waveforms line up identically the whole way through. By ear, they seemed basically the same. The 6" interconnect seemed like it had slightly more resolution than the 40 feet cable, but if there was a difference then I'd judge it's a smaller effect than placebo. I couldn't do a proper comparison with a blind test. Anyway, this somewhat confirms what I already suspected, cables matter very little for line level signal.

 

[GioF71]

  It sounds as though you did a good amount of debugging. In terms of whether devices like the Wyrd should deliver improvements or functionality, I guess it depends how you define that. If noisy usb is causing audible static and failure at 96khz and the wyrd cleared that up, then I'd say the fault lies with the usb / motherboard. From the perspective of the DAC manufacturer, they can't be expected to engineer a product that will function on a usb interface that's not operating to spec. I think it's reasonable that you returned the DAC simply because it wasn't working to your satisfaction regardless of the cause. The fact that you didn't have any problems at 48khz is a little strange to me, and I don't fully understand why you'd get static/failure at 96khz but not 48khz if the problem is caused by noisy usb. In any case I'm glad other equipment resolved the issue.
 

 
In reality, it's not the SMSL Sanskrit the item I sent back. It was a spdif interface, chinese brand. I own a nice dac from the same brand, it is very good gear. Also the seller was kind enough, so I really have little to complain. Only, I lost a lot of time trying to make that interface work. It only worked when I bought the Schiit Wyrd.
 
The SMSL Sanskrit works well in coaxial mode when connected to the Audiophonics interface I bought to replace the previous interface.
No reason to send it back, considering also the low price.
The issues in usb mode are only with (my) laptops, so while this dac is not an excellent purchase, it works almost fine. So I am keeping it, even if I am not fully satisfied. As I told I am using it on vacation on a very old system, so the expectations are not that high