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Review and Measurements of Gustard DAC-X26

amirm

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#1
This is a review and detailed measurements of the Gustard DAC-X26 stereo audio dac. It is was kindly sent to me by Shenzhen Audio for testing. The DAC-X26 normally costs USD $1,299 but seems to be on sale at Shenzhen Audio for $1,169 as of this writing. Note that I have no relationship with either Shenzhen Audio or Gustard. And nothing was communicated other than wanting to send the unit in for testing.

The Gustard DAC-X26 is one heavy box. You can't tell it from the picture but it I promise you, it is:

Gustard DAC-X26 Audio DAC Review.jpg

I like the super clear display showing everything you need to know at a glance. There is a remote which I did not use for this testing.

The back panel has the inputs you expect including I²S input:

Gustard DAC-X26 Audio DAC Back Panel Review.jpg

There are two independent linear power supplies with their own transformers and hence the two voltage switches and hefty weight of the unit.

Gustard has gone quite far in building their own digital filters using an Analog Devices Sharc DSP, discrete output low pass filter, etc. I let you read them in the Shenzhen Audio link. Truth to be told, when I hear companies doing their own custom implementations of such things, I worry that they are catering to audiophile addiction to technical terms than pure performance.

Another "worrisome" technical note is use of two ESS9038 Pro DAC chips in Gustard DAC-X26. The 9038 is the flagship DAC from ESS but testing of other DACs using it showed less, not more performance than products using lower tier DACs from their line.

Let's get into measurements and see if my worries are merited or not.

Measurements
As always, I start with our dashboard view. The output from the DAC-X26 was a bit high so I lowered it by 2 dB using the front panel control to get 4 volt in balanced and 2 volts in unbalanced. Here is what I got:

Gustard DAC-X26 DAC Balanced measurements.png


Wow. This is exceptional performance and lands the DAC-X216 the top of all DACs tested:
Gustard DAC-X26 DAC Balanced SINAD measurements.png


No other DAC regardless of price has produced better performance.

Unbalanced RCA performance was 2 dB lower as noted on the dashboard.

Also noted is the level of highest harmonic which is around -118 dB. The absolute best case dynamic range of our hearing assuming 120 dB SPL max playback level is -116 dB. By that definition, the harmonic distortion of Gustard DAC-X26 is provably inaudible!

As some of you know, the THD+N is the sum of harmonic distortion (THD) plus noise. Classical audio measurement tools couldn't separate these two but using signal processing, we can do that. So here is that break down for the DAC-X26:

Gustard DAC-X26 DAC Balanced Aduio THD and Noise Percentage measurements.png


In other words, performance is limited more by distortion than noise.

Speaking of noise, here is the dynamic range:
Gustard DAC-X26 DAC Balanced Audio Dynamic Range measurements.png


These are very low noise figures.

The incredibly low noise floor shows more jitter and spike distortions that would normally be visible:
Gustard DAC-X26 DAC Balanced Jitter measurements.png


Given all the talk in Gustard DAC-X26 I would have expected a cleaner display to please the eye. The ear though, would be super happy given the exceptionally low level of these spikes.

Multitone shows the low impact of harmonic distortion:
Gustard DAC-X26 DAC Balanced Audio Multitone measurements.png


Linearity is nailed, absolutely nailed:

Gustard DAC-X26 DAC Balanced Linearity measurements.png


This is as perfect as it gets folks.

THD+N versus frequency shows very well behaved performance:

Gustard DAC-X26 DAC Balanced Audio THD versus Frequency measurements.png


As an aside, I realized this test is run without the high-performance (dual ADC) feature of my analyzer. It used to not matter because the measurements were higher than what that feature is for. Not here. While I have left the above as I have always run it, selecting the high-performance analyzer lowered the distortion graphs further (not shown).

Frequency response was boring meaning as good as we want to see it:
Gustard DAC-X26 DAC Balanced Audio Frequency Response measurements.png


Now the big question: do we have what I have coined the "ESS IMD hump" where distortion rises mid-level in intermodulation test? Let's see:

Gustard DAC-X26 DAC Balanced Audio Intermodulation distortion measurements.png


We do not! Some engineer at Gustard knows exactly what he is doing. There is no hint of rise in distortion at mid-levels or max for that matter. It has been a while since I have seen any DAC outperform our modestly priced Topping DX3 Pro. The DAC-X26 does that with both of its balanced and unbalanced outputs.

I will do more testing of the different filters later. For now, here are the default results starting with square wave:
Gustard DAC-X26 DAC Balanced Audio Square Wave measurements.png


And white noise response of the filter transition band:
Gustard DAC-X26 DAC Balanced Audio Filter Response measurements.png


As if fashionable these days, it is a very gentle filter, allowing fair bit of response above nyquist frequency 22.05 kHz.

Conclusions
What a pleasure it is to see a company talk about building a super high performance DAC in their marketing material and then proceed to deliver it! The Gustard DAC-X26 delivers state-of-the-art performance in every sense of the word. It is clearly designed by experienced engineers who have made sure the actual implementation matches the fancy specifications.

Needless to say, I am happy to give my strongest recommendation for Gustard DAC-X26. If you want a DAC that produces guaranteed transparency to your source content, you are there.

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

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folzag

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#4
Also very interesting that the other DAC tied for first place with this one uses the ESS9038 PRO. Clearly somebody has figured out how to wring out the performance from those chips. I wonder if the same guy designed both of these units?
 

amirm

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#7
Wow, how did they fix the hump!
I don't know but they definitely have. Otherwise with the very low level of noise here, it would show up easily.
 

graz_lag

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#10
@amirm
The $1,169 ($1,299 regular) is for the version with no USB ...
$1,269 ($1,399 regular) for the "with USB" version instead ...
Super-solid performance, indeed, very nice design as well, the section around the Power push button is really beautiful !
 

Patrick1958

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#11
These excellent results make me wonder how the predecessor Gustard X22 (only one ES9038 dac) would measure and for that its predecessor the X20 Pro (2x ES9028 dac)?
 

graz_lag

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#13
Volume control ?
From the manufacturer's web site :

... Supports 0dB ~ -90dB total 90-speed digital volume, and is convenient to adjust the volume with the supplied high-quality remote control ...
 
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#14
From the manufacturer's web site :

... Supports 0dB ~ -90dB total 90-speed digital volume, and is convenient to adjust the volume with the supplied high-quality remote control ...
wondering this too, how is the remote control since I cant see any pictures of it anywhere...
 

maty

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#15
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March Audio

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#17
Now, the dilemma is Gustard DAC-X26 ($ 1,289) vs RME ADI-2 DAC (€ 989 at home -> $ 1,112, in EU).

https://www.thomann.de/es/rme_adi_2_dac.htm
https://www.thomann.de/gb/rme_adi_2_dac.htm

I LOVE the ADC from RME (to make very good vinyl rips). And it is made in Germany (EU) and technical service is very good. If there were problems like with Topping DX3 and if you are European... And it is a very valued brand in European recording studios. Well, I keep my choice.
Not sure its a dilema. The ADI has a superb ADC, is cheaper and has performance that is very close on its DAC.

Cant knock the Gustard though as I think its the first implementation of a 38pro that I have seen that hasnt been completely ballsed up :)

1552212096965.png
 
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maty

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#18
And besides, I am very cautious. I followed the development of the ODAC by NwAvGuy from the beginning and it took months to buy it while waiting for others to report problems and / or weaknesses. Those that I detected I reduced them.

In Spanish there is a saying: "los primeros suelen pagar el pato" - "the former usually pay for the duck". The last example is the Topping DX3. Waiting for an MKII version?
 

JJB70

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#20
Now, the dilemma is Gustard DAC-X26 ($ 1,289) vs RME ADI-2 DAC (€ 989 at home -> $ 1,112, in EU).

https://www.thomann.de/es/rme_adi_2_dac.htm
https://www.thomann.de/gb/rme_adi_2_dac.htm

I LOVE the ADC from RME (to make very good vinyl rips). And it is made in Germany (EU) and technical service is very good. If there were problems like with Topping DX3 and if you are European... And it is a very valued brand in European recording studios. Well, I keep my choice.
I think it is a fair point that the RME is cheaper, but it is also true that you can get a transparent DAC for much less than the RME too. As expensive hifi goes this Gustard is not over the top (the high end enthusiasts would probably deride it as mid-fi). My own view is I see no reason to spend so much on a DAC but I also think that the measurements at least show a genuine depth of engineering and it does perform extremely well. I think once you reach audible transparency that further improvement is slightly moot but I also understand the attractiveness of seeking ultimate performance even if it is not necessary in audible terms. However, I really don't see why being made by a Chinese company is a reason to judge a product. Good performance and engineering is good performance and engineering regardless of the point of origin.
 
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