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Gustard X26Pro Review (Balanced High-end DAC)

taner

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This has nothing to do with JVC K2, the function is completely different. There are many things in the same model in the world, but it does not mean that they are all related. South Korea has a car called K2, which does not mean that Gustard has a relationship with Kia Motors.

I hope your engineers who design and build your DACs aren't based on same logic as yours. @Sonil Mone is legitimate with his/her question. Because he/she doesn't talk about a hair dryer or a car model named K2. Question is legit because you somehow "concidentally" choose the same branding that used for a digital audio product from other company for similar purpose.
 

anagorny

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Hi everyone, happy owner of X26Pro here, driving it via AES input and then to studio monitors via XLR out. Got a weird issue though - whenever I cycle through the inputs (AES, USB, BT etc), I get a pop coming out of the RIGHT channel only. The pops are pretty loud and are not affected by the DAC volume control. Pretty annoying, plus I'm a bit worried the pops may damage (or put unnecessary strain) on the monitors.

Does anyone else have the same behaviour or do I have a bad unit? Seems weird it's only one channel... @gustard, any comments on this?
 

Doodski

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Hi everyone, happy owner of X26Pro here, driving it via AES input and then to studio monitors via XLR out. Got a weird issue though - whenever I cycle through the inputs (AES, USB, BT etc), I get a pop coming out of the RIGHT channel only. The pops are pretty loud and are not affected by the DAC volume control. Pretty annoying, plus I'm a bit worried the pops may damage (or put unnecessary strain) on the monitors.

Does anyone else have the same behaviour or do I have a bad unit? Seems weird it's only one channel... @gustard, any comments on this?
It sounds as if the mute circuitry is noisy or not muting properly. Just a guess.
 

gustard

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Hi everyone, happy owner of X26Pro here, driving it via AES input and then to studio monitors via XLR out. Got a weird issue though - whenever I cycle through the inputs (AES, USB, BT etc), I get a pop coming out of the RIGHT channel only. The pops are pretty loud and are not affected by the DAC volume control. Pretty annoying, plus I'm a bit worried the pops may damage (or put unnecessary strain) on the monitors.

Does anyone else have the same behaviour or do I have a bad unit? Seems weird it's only one channel... @gustard, any comments on this?
It is recommended to add a preamplifier, adjust the volume of the decoder to the maximum, and then control the volume on the preamplifier. This can effectively reduce popping noise.
 

gustard

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I hope your engineers who design and build your DACs aren't based on same logic as yours. @Sonil Mone is legitimate with his/her question. Because he/she doesn't talk about a hair dryer or a car model named K2. Question is legit because you somehow "concidentally" choose the same branding that used for a digital audio product from other company for similar purpose.
The origin of the name K2, clock takes the last letter K, which is the second generation technology, so take 2 to form K2. If there is a third-generation technology in the future, it will naturally be K3 or even K4 K5. ..
This is just a sign, it is recommended to stop the argument.
 
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Sonil Mone

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The origin of the name K2, clock takes the last letter K, which is the second generation technology, so take 2 to form K2. If there is a third-generation technology in the future, it will naturally be K3 or even K4 K5. ..
This is just a sign, it is recommended to stop the argument.
Really, nothing against the X26. If I was looking for a new dac this would be the one.
I’m just a JVC “fanboy” and the K2 logo coincidence or not is another reason for wanting this..
Does this get very hot during operation? What is the warranty?
 

gustard

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Do not stack, pay attention to ventilation, turn off the power when not in use, and use it with confidence.
The manufacturer's warranty is 2 years, but it needs to be returned to the factory for repair.
 

taner

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It is recommended to add a preamplifier, adjust the volume of the decoder to the maximum, and then control the volume on the preamplifier. This can effectively reduce popping noise.

There are relays at outputs. If you think just a bit deeper, you may realize that you can use these relays for pop-free operation. Your software can be updated in order to momentary disconnect the relays during mode switch. It is just simple as this. Suggesting a preamp for this purpose is not a good move.
 

anagorny

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It is recommended to add a preamplifier, adjust the volume of the decoder to the maximum, and then control the volume on the preamplifier. This can effectively reduce popping noise.
Thank you for your fast reply. So do I understand correctly that popping in the right channel only is by design and is present in all units? Just strange that only one channel is affected. By the way, popping is still there even when output is muted altogether.

Is there a chance of firmware fix like @taner suggested above?
 

taner

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Thank you for your fast reply. So do I understand correctly that popping in the right channel only is by design and is present in all units? Just strange that only one channel is affected. By the way, popping is still there even when output is muted altogether.

Is there a chance of firmware fix like @taner suggested above?
I just realized that when the noise problem appears, a serious POP problem also appears during mode switch. Recycling power fixes the POP as well as the noise. At least for me. This might be another problem relating the noise @gustard ...

You may check-out if noise is apparent when pop problem occurs.
 
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anagorny

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I just realized that when the noise problem appears, a serious POP problem also appears during mode switch. Recycling power fixes the POP as well as the noise. At least for me. This might be another problem relating the noise @gustard ...

You may check-out if noise is apparent when pop problem appears.
The noise problem only occurs with USB, right? I’ve only ever connected my unit by AES and not by USB so I guess I wouldn’t have noticed if there was a noise issue with my unit?
 

taner

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The noise problem only occurs with USB, right? I’ve only ever connected my unit by AES and not by USB so I guess I wouldn’t have noticed if there was a noise issue with my unit?

Ok, I understand. Maybe the problem related with input section is more complicated and maybe the actual problem shows its signs on different conditions. Your situation is probably one of them.

You can try this sequence:
1. Switch to IIS input (unused input)
2. Power off
3. Power on
4. Make sure your AES source is powered up
5. Switch to AES and cycle other inputs. And observe the pop problem.

Btw, magnitude of pop noise is very serious and can damage the speakers when it occurs.
 

anagorny

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Ok, I understand. Maybe the problem related with input section is more complicated and maybe the actual problem shows its signs on different conditions. Your situation is probably one of them.

You can try this sequence:
1. Switch to IIS input (unused input)
2. Power off
3. Power on
4. Make sure your AES source is powered up
5. Switch to AES and cycle other inputs. And observe the pop problem.

Btw, magnitude of pop noise is very serious and can damage the speakers when it occurs.
Yes I agree the magnitude is big and that's what makes me worried, given my speakers are about 30x the price of of the DAC.
@gustard - any comments please?
 

JohnYang1997

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Some strange measurements over here
The measurements are ok. Just don't look at people talking about what's what people hear.
There are some design choices that can lead to the unevenness in the THD vs Amplitude. They will not cause any issue in audibility.
 

andyxx

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Hi all,
I own a nice X-26 Pro too, I don't know which firmware version, driven via USB with a sMS-200 ultra Neo + tX-USBUltra and sps-500, but I can confirm that also mine has three major issues (as reported by other users):

1) pop/very loud sound changing inputs
2) pop/very loud sound when it changes sampling rate/format (for example from 44.1 16 bit PCM to DSD or to MQA)
3) background rustle (not always, in particular from right channel but sometimes from both channels)


This is a really well sounding DAC in my chain but those bad sounds are terrible.
gustard said:
It is recommended to add a preamplifier, adjust the volume of the decoder to the maximum, and then control the volume on the preamplifier. This can effectively reduce popping noise.

I have a full analogic preamp BAT VK5I and dac has volume set to 100 (fixed to the max), problem(s) are still current.
Please Gustard update firmware/fix the issue, otherwise a lot of users will replace it (only my mono poweramps are 5x times the value of the DAC)
 

linger63

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Hi all,
I own a nice X-26 Pro too, I don't know which firmware version, driven via USB with a sMS-200 ultra Neo + tX-USBUltra and sps-500, but I can confirm that also mine has three major issues (as reported by other users):

1) pop/very loud sound changing inputs
2) pop/very loud sound when it changes sampling rate/format (for example from 44.1 16 bit PCM to DSD or to MQA)
3) background rustle (not always, in particular from right channel but sometimes from both channels)


This is a really well sounding DAC in my chain but those bad sounds are terrible.


I have a full analogic preamp BAT VK5I and dac has volume set to 100 (fixed to the max), problem(s) are still current.
Please Gustard update firmware/fix the issue, otherwise a lot of users will replace it (only my mono poweramps are 5x times the value of the DAC)

I have had my X26Pro for a quite while now and have experienced ZERO issues.
Maybe you just have a bad one.
 

andyxx

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I have had my X26Pro for a quite while now and have experienced ZERO issues.
Maybe you just have a bad one.

Hi Linger63, thanks for you reply.
It can be a faulty device but, indeed, also reading on the forum, it seems that clicks/pops changing inputs are not limited to my experience (check the posts of "taner" user), and also Gustard (https://www.audiosciencereview.com/...eview-balanced-high-end-dac.24699/post-885549) proposed to add a preamp in order to limit the pop/click issue...
I'm not an electronic engineer, but I work in IT and, as Taner was suggesting, since the issue regards only the change input "feature", DSD not correctly implemented (background noise, not in playback!) and when a song starts...maybe it could be easily fixed with a firmware update (for example, adding a xx ms delay when a song starts).
This is my humble opinion, of course related only to my personal experience and without any claim to "universality".
I hope it can be fixed via firmware because it would be much easier than sending a well built, fragile and heavy product, in an international round trip shipping.
Thanks
 
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taner

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I have had my X26Pro for a quite while now and have experienced ZERO issues.

Maybe you just have a bad one.

You are lucky because your setup doesn't trigger the issue. This doesn't mean that your DAC isn't a faulty one.

Gustard X26 Pro is a faulty device from right at the start. No excuse. If we don't repeat this more often and loud, @gustard may falsely consider that we are in peace with this issue..but not. It is months since @gustard told us that they are doing something for this issue...but no avail.

Hi Linger63, thanks for you reply.

It can be a faulty device but, indeed, also reading on the forum, it seems that clicks/pops changing inputs are not limited to my experience (check the posts of "taner" user), and also Gustard (https://www.audiosciencereview.com/...eview-balanced-high-end-dac.24699/post-885549) proposed to add a preamp in order to limit the pop/click issue...

I'm not an electronic engineer, but I work in IT and, as Taner was suggesting, since the issue regards only the change input "feature", DSD not correctly implemented (background noise, not in playback!) and when a song starts...maybe it could be easily fixed with a firmware update (for example, adding a xx ms delay when a song starts).

This is my humble opinion, of course related only to my personal experience and without any claim to "universality".

I hope it can be fixed via firmware because it would be much easier than sending a well built, fragile and heavy product, in an international round trip shipping.

Thanks

The problem occurs mostly on Linux based PC's or embedded devices like streamers, media players etc.

I tested it and I confirmed that x26 Pro isn't happy with Linux snd_usb_usbaudio kernel module. This kernel module is the driver that recognizes USB based DACs on Linux systems (may include Android OS). The kernel module is automatically loading to the PC's, streamer's memory when an USB DAC connected or powered on. This module is not part of the DAC's firmware. It is an operating system driver.

If the x26Pro's input is not on the USB (eg. IIS) input during connecting the cable or first power-on, snd_usb_usbaudio kernel module is loading anyway but noise and input switch pop noise don't appear. Noise mostly appears when X26Pro is on the USB input during the first power-on or connection.

I'm an experienced Linux user and I can easily trigger the noise by loading and unloading the kernel module manually. I have no doubt about the issue.
 
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andyxx

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You are lucky because your setup doesn't trigger the issue. This doesn't mean that your DAC isn't a faulty one.

Gustard X26 Pro is a faulty device from right at the start. No excuse. If we don't repeat this more often and loud, @gustard may falsely consider that we are in peace with this issue..but not. It is months since @gustard told us that they are doing something for this issue...but no avail.



The problem occurs mostly on Linux based PC's or embedded devices like streamers, media players etc.

I tested it and I confirmed that x26 Pro isn't happy with Linux snd_usb_usbaudio kernel module. This kernel module is the driver that recognizes USB based DACs on Linux systems (may include Android OS). The kernel module is automatically loading to the PC's, streamer's memory when an USB DAC connected or powered on. This module is not part of the DAC's firmware. It is an operating system driver.

If the x26Pro's input is not on the USB (eg. IIS) input during connecting the cable or first power-on, snd_usb_usbaudio kernel module is loading anyway but noise and input switch pop noise don't appear. Noise mostly appears when X26Pro is on the USB input during the first power-on or connection.

I'm an experienced Linux user and I can easily trigger the noise manually with loading and unloading the kernel module manually. I have no doubt about the issue.


Hi,
I can confirm that if I boot up using (i.e.) the I2S input, and then switch to USB, the "background noise" seems completely surpassed (currently I tested this with two power off - power on cycles).
Thanks, from my side, for the general information and, in particular, about the USB driver's module involved.
I will test with a windows pc.
IMHO it's a little bit frustrating that such an evident fact hasn't been detected earlier (maybe Windows only testing?) but I'm very confident that a quick reaction and a fix will arrive asap.
In case, I'm available for testing any firmware :)
 
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