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Gustard X26Pro Review (Balanced High-end DAC)

amirm

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#1
This is a review and detailed measurements of the Gustard X26Pro USB balanced DAC. It was sent to me by SHENZHENAUDIO which sells it for US $1,499.

I must say, this is one of the heaviest and largest desktop DACs I have tested:

Gustard X26Pro Review Balanced USB DAC.jpg


This is an unusual DAC in that it goes to extremes to implement everything on its own including digital filters for the DAC using a combo of ARM and Analog devices DSP. Many circuits are discrete and overbuilt. It is worth a read just to geek out on its design!

The back panel is the usual bits but an extra item in the form of external clock:

Gustard X26Pro Review Balanced back panel USB DAC.jpg


External clocks are used for synchronization in pro environment. Its application in home audio is dubious and my previous tests show it to have slightly worse performance, not better. I don't have anything to test the X26Pro on it though. It certainly appeals to high-end audiophiles who equate such things as being better.

Gustard X26Pro Measurements
As usual we start with our dashboard with XLR output adjusted to 4 volts out:

Gustard X26Pro Measurements Balanced USB DAC.png


What a relief that all that reimplementation did not degrade performance as it often does.

best balanced dac.png


The X26Pro lands in our top 10 DACs ever reviewed:

top 10 balanced stereo dac review.png


Performance improves some if you allow full output:

Gustard X26Pro THD vs Level Measurements Balanced USB DAC.png


Using RCA output costs you a couple of dBs as it typically does:

Gustard X26Pro Measurements RCA USB DAC.png


Dynamic range is excellent but not top of the class:

Gustard X26Pro DNR Measurements RCA USB DAC.png


I was a bit surprised that jitter was higher with Toslink and Coax given the internal clock circuits:
Gustard X26Pro Jitter Measurements Balanced USB DAC.png


Of course nothing of significance otherwise but worth a note.

Linearity is nailed:

Gustard X26Pro Linearity Measurements Balanced USB DAC.png


Gustard implements three custom filters of their own. While I could easily switch between them in the menu, the response does not change:

Gustard X26Pro filter Measurements RCA USB DAC.png


I tried everything I could but could not figure out why it did not change. The menu would reflect the new setting but the output would not change. I have seen measurements from member Wolf which shows the difference so it is puzzling that this production version doesn't reflect that. I looked for a firmware upgrade but could not find one. Seems like something the company needs to fix. Or maybe it is a blind test for audiophiles who think they can hear such differences! :D

EDIT: the problem was incorrect firmware in my early sample. See the new results here: https://www.audiosciencereview.com/...eview-balanced-high-end-dac.24699/post-835479

The slow filter really hurts THD+N vs frequency due to wideband measurements which includes the mirror images from the DAC:
Gustard X26Pro THD+N vs Frequency Measurements Balanced USB DAC.png


Edit: forgot the IMD graph:
Gustard X26Pro IMD Measurements Balanced USB DAC.png

And Multitone:

Gustard X26Pro Multitone Measurements RCA USB DAC.png

Conclusions
Gustard flexes its design muscle by implementing a highly unconventional DAC around the venerable ESS DAC. Most of the time such efforts result in disasters performance wise. Not so here. State of the art performance is achieved albeit at high cost. If you are a fan of unconventional, this is the DAC for you. You can tell stories forever to your audiophile friends on what makes this DAC "better." :)

Edit: recommendation changed due to bug fix.

I am happy to recommend the Gustard X26Pro. It shows that you can build a DAC (almost) from scratch and get superb performance -- something almost all high-end companies get wrong.

-----------
As always, questions, comments, recommendations, etc. are welcome.

Harvested a bunch of basil to make pesto pasta tonight. Grabbed a bunch of greens as well for a nice salad. Nice to see the garden paying us back for all the work we have put into it!


Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 
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gvl

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#2
One peculiarity is that the ESS chip always runs in sync mode on this one. Would be interesting to see how well jitter rejection works on SPDIF inputs.
 

Matias

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#4
And multitone!
 
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#9
XLR output ‘adjusted’ to 4 volts?
5 volts is XLR default on the x26p
crosstalk?
nvm
 
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amirm

amirm

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Thread Starter #10
OP
amirm

amirm

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Thread Starter #11
XLR output ‘adjusted’ to 4 volts?
5 volts is XLR default on the x26p
Correct. This is all noted in the review. Level for XLR out was set to -2 dB for almost all the tests. However, I also showed the full output performance in the THD+N vs Level:


I have to keep a level playing field by equalizing the outputs. Small offsets are fine but not to this extent.
 
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amirm

amirm

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Thread Starter #12
Amir looks like he is trying to cross a bunch of these off his list right now. Thanks for all of the recent reviews.
I am just so tired of being behind on these reviews, hoping to catch up and create some breathing room.
 

jasonq997

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#14
Might be challenging at the rate our Chinese friends are releasing new products.
We might not always get along with them as a nation, but as individuals and small companies they are certainly working hard to produce a certain genre of audiophile products for us and I appreciate it.
 

jtwrace

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#15
We might not always get along with them as a nation, but as individuals and small companies they are certainly working hard to produce a certain genre of audiophile products for us and I appreciate it.
Yeah, it's troubling to me that nobody in North America can design/produce them. I know for a fact it can be manufactured in NA, why people seem to steer clear is beyond me. I simply just don't get it.
 

restorer-john

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#16
So, is this another product where the sampling rate is in huge letters and the volume in tiny letters (like the photo), or does it default to a large volume indicator when you adjust it? Does it have a remote?
 

PeteL

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#17
External clocks are used for synchronization in pro environment. Its application in home audio is dubious and my previous tests show it to have slightly worse performance, not better. I don't have anything to test the X26Pro on it though. It certainly appeals to high-end audiophiles who equate such things as being better.

/
Maybe one of the very very few devices where the moniker "Pro" in the name actually mean something?
 

sam_adams

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#19
The external clock in could be used with an ADC so that the two devices would be in sync. The thing that still gets me is the inclusion of the IIS-LVDS HDMI connector. Now I don't know of any computer—laptop or desktop—that includes an IIS-LVDS connector as a standard output. There is this Pink Faun I2S Bridge card which would allow a desktop to connect to these DACs with this port, but, from my understanding this signaling protocol usually works only works at the chip/board level, I2C, or through very short cables. So where is the value in adding this connector?
 

PeteL

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#20
If you use spdif everything is already synced. The clock input is for more exotic external clock.
I do know that, but it’s not what I am talking about, I’m talking pro environment, where you need to know where is the master clock, when you have 48 channels of ADC, many of DACS, over sometimes many pieces of equipments and often many rooms, multi channel mixers, etc. Pros don’t use word clock to be « exotic » , not because you get better performance, but because they need to have one clock that is the reference and that all streams walk to the same beat.
 
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