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Review and Measurements of Gustard DAC-X26

solderdude

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These are separate questions.

I still don't get this reclocking thing. How does the dac recover the clock, it receives the 0 and 1 and it guess the timing, just by some algoritme?

You would have to understand how this signal is made.
Basically you have data and clock.

The clock is a continuous changing signal always in the same frequency and it basically tells the receiver at which moment it should look in the data signal to decide the data is 1 and 0.

The data can have consequtive 0's and '1's in a row. For instance 0000110001010011111010.
The only way to tell whether in a row of consequtive 0's or 1's there was a 0 or 1 is by usage of the clock.
That clock signal tells you WHEN to look for the signal level is representing a 0 or a 1.
This is when the signal is stabile so not near the rising or falling edges but in the center of the bit.

So you need a clock and data stream so 2 cables.
The clock is easy to retrieve as the signal changes constantly and in a fixed manner.
The data not so.
Technically it is easier to receive a constantly varying signal than one that flips at different times and lengths (data)

Folks wanted 1 cable. Would have been easier to design a 'stereo' cable with 2 different plugs but it was decided to do this in one cable as that could be a standard 50 or 75 Ohm shielded cable and easy to convert to optics and or modulate a single signal instead of 2 (or more as left and R signals and extra data is also in the data).

So technical solution is to 'combine' the clock and data signals in a nifty way.
In the receiver the signal thus changes constantly but differently for a 0 or a 1.
This way it is easy to retreive the clock, by just synchronising a clock on the receiver end on the rising and/or falling edges of a signal.
clock is thus easily 'recovered' using simple electronics.
Also when a clock is recovered and due to the way the 0's and 1's are embedded (encoded) in the combined signal it is easy to retrieve what was a 0 and 1.
Data thus also recovered.
There are different types of en/decoding these types (there are severall ways to do this) of signals SPDIF is one of them.

so no guessing, no algorithms, just simple electronics that can unravel a re-conditioned datastream.

In reality there are quite a few technically different ways to recover and synchronise the clock each with stronger and less strong benefits.
Clocks on the receiving end differ with those on the transmitting end and here too many different technical solutions exist. One better than the other in some areas.

The old Sony dac or the Linn Karik/Numerik used a separate cable for the clock, why? Because the reclocking was not invented at the time? Sony was making some cost no object at the time, they could have found a better solution..

Has been answered above. A decision was made and everyone now has to comply or come up with other formats (HDMI, USB, I2S etc)

Why in the studio they still use a word clock?

This is so all digital processing, DAC's, ADC's all sample at exactly the same time and all data words (so 16 or 24 bits) are generated/read at the exact same time.
When this was not done the drift in each clock of every 'device' would make them all different in frequency (very slightly) and timing.
So the clock here is only needed for this task.
 
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sonci

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This way it is easy to retreive the clock, by just synchronising a clock on the receiver end on the rising and/or falling edges of a signal.
clock is thus easily 'recovered' using simple electronics.
Also when a clock is recovered and due to the way the 0's and 1's are embedded (encoded) in the combined signal it is easy to retrieve what was a 0 and 1.
Data thus also recovered.
There are different types of en/decoding these types (there are severall ways to do this) of signals SPDIF is one of them.

so no guessing, no algorithms, just simple electronics that can unravel a re-conditioned datastream.
Thank you for the explanation, I still don't get it , but it's not your fault.
You say the clock is easy to retreive it, but then why they had to build 2 box cd players?
 

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amirm

amirm

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I still don't get this reclocking thing. How does the dac recover the clock, it receives the 0 and 1 and it guess the timing, just by some algoritme?
By some algorithm. :) This is called embedded clock when it is mixed with data. Edges in the digital transmission determine the clock rate. This edge is subject to noise and variation. Here is the S/PDIF jitter over a very long cable:

dunn CableJitterEye.png


Depending on what comes before or after any edge, the signal transition time may be different and hence, induce variations in clock. And this is induced entirely by the cable itself in S/PDIF!

In addition to such sources of jitter, the source clock may vary by itself and the extracted clock may be corrupted in the receiver.
 

andymok

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apart from word clock, SMPTE timecode can also be embedded, which basically is a must whenever working with pictures/transport

a world clock is needed because many things work hand in hand throughout the whole capturing/playback process, like a clock work.
 

terlino

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Hello, I have receved the Gustard X26U just yesterday
I use Daphile and I have same problem.
For 16/44 all good, but for dff or dsf at start O.K. but after few seconds an hard shsssssssss for few seconds
After not problem and not problem if I put another dsf
On Daphile It Is possible only DSD to PCM DoP
I have some other problem, with file 96/24 or 192/24 same time of Is impossible reproduce It, the sound Is distorced totaly
Excuse for my english
Regards
Lino
 

graz_lag

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Hello, I have receved the Gustard X26U just yesterday
I use Daphile and I have same problem.
For 16/44 all good, but for dff or dsf at start O.K. but after few seconds an hard shsssssssss for few seconds
After not problem and not problem if I put another dsf
On Daphile It Is possible only DSD to PCM DoP
I have some other problem, with file 96/24 or 192/24 same time of Is impossible reproduce It, the sound Is distorced totaly
Excuse for my english
Regards
Lino

Hi Lino :
From which vendor did you buy it ?
Pls. verify how long is the time frame to return it, I would return it with no hesitation, I would not lose time searching here and there what the possible causes for the problems are ... :rolleyes:
 

mickeyd123

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Question if I am using a cd player purely as a transport going into my RME ADI-2 DAC am I better off using coaxial compared to an optical toslink cable as far as any degradation? or is that on a case by case basis according to the player itself?
 

solderdude

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Question if I am using a cd player purely as a transport going into my RME ADI-2 DAC am I better off using coaxial compared to an optical toslink cable as far as any degradation? or is that on a case by case basis according to the player itself?

Both inputs are excellent with the RME. optical has the benefit of galvanic separation but most likely the coax in is also separated (small transformer)
 

Veri

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Question if I am using a cd player purely as a transport going into my RME ADI-2 DAC am I better off using coaxial compared to an optical toslink cable as far as any degradation? or is that on a case by case basis according to the player itself?
Both should be completely fine, since the RME has truly world-class jitter rejection and reclocking.
I think you might be posting in the wrong thread though ;)
 

mickeyd123

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Thanks a bunch, when I saw the pictures above of jitter and SPDIF I got worried.. lol.
 

GPx86

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I just received mine. If anyone is looking for the USB driver for the Gustard DAC X26 with the ESS USB input module, it seems that the driver is the same one as used for the Gustard U16 USB digital to digital converter. I found no mention from the Gustard distributors that this was the case. But, I looked at the manual for the DAC X26 which references the same driver file as shown below.

I was able to download the file from this link https://download.shenzhenaudio.com/Gustard/GSD U16 V1.4 0dB/

Download the file GUSTARD_U16_USB_Driver.zip and look for GUSTARD U16 USB DRIVER ---> Gustard_USBAudio_v1A_2018-10-15_setup
 

Oukkidoukki

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Question if I am using a cd player purely as a transport going into my RME ADI-2 DAC am I better off using coaxial compared to an optical toslink cable as far as any degradation? or is that on a case by case basis according to the player itself?
There has been depate about this couple years ago and some experts chose coax over optical when it comes to ” quality” (whatever that means). I did some comparison while ago and I was able to hear differences. Even with two coax cables. Other one had more low end. I end up liking coax over optical. There was a bit more sense of separation between the instruments, it was more real, at least in my mind. However, i guess there are lots of variables and new rme might handle things better and you might not hear the difference.
 

Gizmoh

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I just received mine. If anyone is looking for the USB driver for the Gustard DAC X26 with the ESS USB input module, it seems that the driver is the same one as used for the Gustard U16 USB digital to digital converter. I found no mention from the Gustard distributors that this was the case. But, I looked at the manual for the DAC X26 which references the same driver file as shown below.

I was able to download the file from this link https://download.shenzhenaudio.com/Gustard/GSD U16 V1.4 0dB/

Download the file GUSTARD_U16_USB_Driver.zip and look for GUSTARD U16 USB DRIVER ---> Gustard_USBAudio_v1A_2018-10-15_setup

Owner of X26 and new to Gustard; Two issues so far:

Power button on Remote doesn't work.. StandBy mode doesn't exist supposedly. Can other owners confirm?

Since ESS usb module is new, i'm unable to play native DSD through linux streamers & Roon.
 
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Oukkidoukki

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I understand the excitement generated by new gear, and the utility that Youtube brings to enable people to check it out, but this serves absolutely no purpose.
Okeyy, I just keep watching cat videos then........
 

mickeyd123

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There has been depate about this couple years ago and some experts chose coax over optical when it comes to ” quality” (whatever that means). I did some comparison while ago and I was able to hear differences. Even with two coax cables. Other one had more low end. I end up liking coax over optical. There was a bit more sense of separation between the instruments, it was more real, at least in my mind. However, i guess there are lots of variables and new rme might handle things better and you might not hear the difference.
Thanks, and is there anything measurable in the idea that a better cd transport gives more error free transmission of the bits from the disc compared to less expensive cd players used as transports?
 

Killingbeans

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Okeyy, I just keep watching cat videos then........

He might be a bit condescending, but he does have a point.

Capturing the output from the X26 via an ADC -> uploading it to YouTube and letting it be compressed to 126 kbps AAC -> decompressing it at your end and playing it back via a totally different DAC. That can't really be classified as an audio "demo", can it?

If you scratch the "hear" and replace it with "see the features of", then it makes sense :)
 

GPx86

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Two issues so far:
Power button on Remote doesn't work.. StandBy mode doesn't exist supposedly.
Since ESS usb module is new, i'm unable to play native DSD through linux streamers & Roon.

I can confirm that the power button on the remote does nothing. I'm OK with this, though. I will leave mine powered on all the time. My Linux streamer is not finished yet but I will definitely take it home and run it there ASAP once I finish my Debian setup.
 
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