Measurements of Gustard X26 Pro Dual 9038 Pro By L7Audiolab

[Katji]

It is ridiculous that a DAC would need a cooling fan. I see that there are no vents on top but heat sink would probably be a better solution - for a problem caused by bad design in the first place.

 

[Krillin]

Had a quick look at that comment section, may I ask why you consider those temperatures to be too high? Assuming those measurements are accurate, 45 degrees surface and 66 inside are warm but seem totally reasonable to me?

Here are two capacitor life calculators. One of them is from the Nichicon corporation site itself. I selected Nichicon UFG 85°C 1000 hour rated caps on the Nichicon website.
https://eepower.com/tools/electrolytic-capacitor-life-calculator/#
https://www.nichicon.co.jp/english/products/lifetime/dc.html?sr=UFG

Below are three screenshots from Nichicon itself showing how bad the life expectancy is. And I was quite conservative on the ripple current. Notice how it gets worse and worse. And are we sure 66°C is the worst the temps inside can get if left on for a few days?

 

[Krillin]

Now lets see what happens if Gustard had used a 105°C rated capacitor for only 1000 hours.

This is why well engineered products that take thermals into account last around 40 to 50 years. A 1970's McIntosh MC2205 can last around 40-45 years before capacitor replacement becomes critical. On the other hand a 1970's competitor such as Sansui had many issues of their amplifiers "cooking" themselves to death. When temperatures get too high capacitors fail prematurely, transistors fail prematurely, and if too hot components can desolder themselves, the constant temperature swings can lead to pcb board traces cracking, and the solder holding the components to the board can suffer heat fatigue over time (cracks). Which is why many class A vintage amps need all components re-soldered.

 

[Krillin]

One last problem I had with this DAC is that my antivirus Malwarebytes did not like this product. Once installed I could not uninstall the Gustard 5.0 USB drivers. Malwarebytes was throwing everything into quarantine. As an administrator for 7 years in IT I can tell you that the major USA corporations use Malwarebytes for detecting malware. It's possible that this was a false positive but I wasn't too thrilled.

https://blog.malwarebytes.com/detections/malware-heuristic/

 

[TK750]

Interesting, I wonder how accurate that tool is? I'm not trying to say you are wrong or anything, it just seems surprising to me given that even at 33 degrees the estimated life is still only 2.3 years. I'm sure most if not all of us would not find it acceptable for a $1500 dac to fail after such a short period of time (or any electronic item at any price really).

I just checked using the nichicon tool for the 105 degree rated one at 33 degrees which gave 9.8 years. That seems a bit more like what I would expect and I imagine they probably under estimate a bit and that's assuming it's turned on 24/7 (does turning off/on increase wear or not have an effect?). I suppose the real test will be in 2/3 years if there are a lot of reports of failure!

 

[Krillin]

Well things like voltage matter too, if a capacitor voltage rating is uprated (but not too much) it will extend component life. There are other variables and how much the capacitor is stressed in the circuit. However, heat is a major problem affecting component life that should never be dismissed.

Here's a nice paper if you want to learn more about capacitor endurance.
https://ti.arc.nasa.gov/publications/5005/download/

 

[TK750]

Well things like voltage matter too, if a capacitor voltage rating is uprated (but not too much) it will extend component life. There are other variables and how much the capacitor is stressed in the circuit. However, heat is a major problem affecting component life that should never be dismissed.

Here's a nice paper if you want to learn more about capacitor endurance.
https://ti.arc.nasa.gov/publications/5005/download/

Thanks, I've got a long journey to do tomorrow so I'll have a look then. I was just surprised as I was thinking about pc and other components etc that can operate at pretty high temperatures. I suppose there are a large variety of different components designed for different operating temps and uses.

 

[FrankBRC2]

Good night,
Is this not the right place to post a problem with the product? If not, can you tell me where? I've already had considerable spending on two DACs. And I returned the first one to China, due to other problems, I paid the incredibly expensive shipping, after having already paid the incredibly expensive tax, and the Aliexpress seller after weeks returned me only 90% of the amount I paid at DAC.
I bought a much more expensive one, paid a much higher tax, thinking it would be free of problems, but a different problem comes, and every time it happens I feel a pain in my heart. I really like the sound of this Gustard x26pro. So if anyone can give me some direction I would be very grateful.

 

[nerekan]

Today I took an dac x16 from a friend.
sound problems disappeared!

maybe the problem is localized?
obviously a problem with my dac x26pro?
tell me, maybe this x26pro requires a more powerful computer than for the x16?
but I changed a hundred times NOS on/off

 

[Veri]

tell me, maybe this x26pro requires a more powerful computer than for the x16?

Definitely not the case.

 

[nerekan]

Definitely not the case.

Thank you.
I thought so.
I decided to make sure, otherwise they advised me in a personal to connect another amplifier by analogy ...
"wise" men advise and justify their delirium, allegedly:
"That’s the issue. You can only experiment/test if you have an extra amp/receiver with headphone jack hanging around. It appears you can bypass the oppo DAC via xlr or rca out to power amp, but does not appear you can bypass the built-in DAC for the headphone jack. See oppo manual link below "

 

[nerekan]

PROS:
* Sound. This dac changed my view on DACs because I started to listen recordings and experience the actual recording rather the device on the table. And I now understand better why serious listeners praise the old jazz recordings all the time. How can I tell.. those classic jazz recordings and vocals creates entirely different atmosphere in room. I can see that each artificial atmosphere differs by record to record, label to label, session to session. It is like putting another device on the table for each track. Vocals are my favorite part. They are so real and so attractive, this makes me pick the records with vocals in it. I begin to spend more time to listen to the music.

I'm pretty sure I know how to fix this!
today I have fixed all the problems with my x26pro.
you can congratulate me!
but even without that, I am immensely happy and enjoy the excellent sound.

 

[taner]

Did you have the same noise with other DACs in the same chain?

No such issue with other dacs of course. Otherwise why should I mention it ?

Btw, I see more clear when this noise appears. When I first power up x26pro and if it is on USB mode, it falsely put itself on DSD mode. If this is the case, noise appears. But when I power up x26pro after the source (PC or Pi device), x26pro opens in PCM mode accordance the source. This time noise doesn't appear. I don't mean its DSD mode is defective. I mean that x26pro puts itself falsely in DSD mode and this causes a HF noise at one of the RCA channels (I never used balanced outputs yet).

 

[taner]

Heat and longevity
I own the Gustard X26 Pro. My advice is to be cautious if you don't own a 3d printer to create an external fan (I did). The DAC gets way too hot and will not survive in the long-term. The inside temps get at least 66°C and the capacitors are rated 85°C for 1000 hours. Heat is the enemy of transistor and capacitor longevity ...

There is an important reason for not having air ventilation holes at top : DUST. All active parts those generate heat are SMD surface mount parts. If these parts begin to fall under the dust, their heat radiation factor will exponentially reduce in time. Dust will prevent the heat ventilation. Using an air ventilation fan will quicken the dust collecting process. It will collect floating dust around inside. Regular dust cleaning is an option but that would not be my first preference.

I don't take the heat as a big concern but it would be nice to provide a better air ventilation without a dust problem. I think that a custom top cover that provides gaps for hot air ventilation but prevents dust collection same time will be a better idea in my opinion.

 

[taner]

My take away

• Top tier speakers are more revealing than headphones.
• The Gustard is no worse than other DAC's at 44.1khz and 48khz. Sounds excellent when upsampled.
• Upsampling sounds better but requires SOTA speakers in regards to THD/IMD/crossover quality
• DAC quality is likely a result of filters and upsampling as opposed to THD/SINAD.
• Careful attention to 44.1khz upsampling might be good for future measurements on audiosciencereview, DAC's which upsample 44.1khz to a frequency divisible by 44.1khz might be better. I could hear the difference.
• NOS mode sounds horrible unless upsampled very high. Sounds excellent when upsampled.
• Upsampling to very high frequencies shifts the noise to higher frequencies. Upsampling very high likely moved this noise beyond 20khz, I assume my Revelator tweeters could pick this up.
• A computer does a better job than the upsampler built into the DAC. I wonder if this is Gustard thing or a ESS Sabre thing, maybe DAC's are not completely solved when it comes to CPU power. After all my laptop seemed to have struggled.
• Tube amplifiers are revealing of DAC's despite their inferior SN ratio and THD. However, I assume this is only if your tube amplifier is engineered to be objectively pure with TOTL output transformers and not subjectively "tubey"

@Krillin did you check that which firmware revision you were using when you had these opinions?

 

[Krillin]

I updated the Gustard with the firmware as soon as it was posted on the other thread. I didn't see what my X26 Pro's original firmware was before updating it, the post on how to see the current firmware was posted afterwards. After updating firmware I heard no difference so I assume my device was already running the latest.

My post about the Gustard USB drivers being flagged as malware is very likely a false positive. The same USB drivers are used by most Gustard products and nobody else with Windows Defender or Norton has complained on the forums.

 

[nerekan]

I updated the Gustard with the firmware as soon as it was posted on the other thread.

could not find, give a link please

 

[Krillin]

https://www.audiosciencereview.com/...pro-review-balanced-high-end-dac.24699/page-5

Post #81 - Link to new firmware.
Post #166 - Check this before updating firmare to see current version.

 

[yyzsb]

CONS:
* Some strange noise. When I directly connect the x26pro to the power amp or headphone amp, sometimes a noise appears on one channel. This noise sounds like a radio interference or a contact noise but not a hum. Noise disappears after recycling power. I admit that this issue is a bit discouraging which makes you check the setup at highest volume before each listening session. This issue may related with my setup and environment but I have to warn about this anyway.

I had the same issue and returned my unit, with shipping cost $116 by USPS to China. The replacement unit does not have this problem.

 

[taner]

I had the same issue and returned my unit, with shipping cost $116 by USPS to China. The replacement unit does not have this problem.

Can you share your experience on main thread please? Was it consistent or random? Where did you buy from? Did seller or Gustard @gustard confirmed the issue? We are discussing this issue there:

https://www.audiosciencereview.com/...rd-x26-pro-dual-9038-pro-by-l7audiolab.19921/