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Measurements of Gustard X26 Pro Dual 9038 Pro By L7Audiolab

ti33er

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Blankets do this... not DAC's.



JSmith
I’m not so sure that is strictly true ...I’ve heard varying DACs over the years with varying differing sonic signatures (and I’m not talking about the pen to paper variety) ;-)
 
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I’m not so sure that is strictly true ...I’ve heard varying DACs over the years with varying differing sonic signatures (and I’m not talking about the pen to paper variety) ;-)
He's certainty joking.
As I said before, pick a glary (bad IMD) dac with bad linearity in the treble region, and you'll give yourself an unforgivingly bright dac
 

ti33er

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I don't know how it could become a passthrough, as a dac job is to convert digital information into an analog signal that your amp can read.
A passthrough dac would mean that your amp would recieive the digital signal; it wouldn't know how to interpret it.
John Westlake’s infamous MDAC2/FDAC will feature an AVBypass - Phono or XLR inputs so one can put the DAC inbetween AV Processor and Power Amp; a significant number of us have AV equipment and would love to have the best of both worlds, high end Stereo integrated into Cinema setups :)
 

ti33er

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...when the DAC is off, there is a relay that allows the AV signal to pass through the DAC passively! Nifty feature for us that desire this
 

taner

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I'm a DIY guy actually but when I see most of things that I try to implement already done in this design, I decided to get one and ordered during Aliexpress 11th anniversary sales.

Most handy features in this design in my opinion:

1. Separate power rails
Digital and analog rails are independent starting right at the mains plug. Also, analog and digital power stages and grounds separated for each channel afterwards.

2. Using a current-output dac (ESS) and discrete (hybrid actually) current-to-voltage conversion (IV)
Current-output (I_out) dacs' sound signature highly depends on their output stage which makes each particular design different from each other. If you want an unique design, pick a current output dac chip.

3. Bypassed internal filter
Instead of using internal hardcoded "silicone" digital reconstruction filter, Gustard had implemented a software based filter by using a dedicated DSP processor. In this way, Gustard choose a very distinc path comparing other ESS designs.

4. NOS mode
Since on-chip digital filter already bypassed via DSP solution, you can bypass DSP too. So, you can freely adjust your custom digital filters by using SoX like high quality filters on your source (PC in my situation). Allowing 768kHz pcm data is a big advantage in this regard.

5. Non trendy case design
Instead of following trends, Gustard choose a simple but serious looking case design which I liked.

6. Measurements
@WolfX-700 did a very useful job to put measurements online before Aliexpress sales. Otherwise I will be in confusion despite existence of all other features that I wanted.

7. Price
Gustard could easily put a higher price tag on this model. Price is within my "affordable" range (as a DIY person) so I was able to order one and delayed my PCM1792 NOS dac project.
 
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I'm a DIY guy actually but when I see most of things that I try to implement already done in this design, I decided to get one and ordered during Aliexpress 11th anniversary sales.

Most handy features in this design in my opinion:

1. Separate power rails
Digital and analog rails are independent starting right at the mains plug. Also, analog and digital power stages and grounds separated for each channel afterwards.

2. Using a current-output dac (ESS) and discrete (hybrid actually) current-to-voltage conversion (IV)
Current output dacs' sound signature highly depends on their output stage which makes each particular design different from each other. If you want an unique design, pick a current output dac chip.

3. Bypassed internal filter
Instead of using internal hardcoded "silicone" digital reconstruction filter, Gustard had implemented a software based filter by using a dedicated DSP processor. In this way, Gustard choose a very distinc path comparing other ESS designs.

4. NOS mode
Since on-chip digital filter already bypassed via DSP solution, you can bypass DSP too. So, you can freely adjust your custom digital filters by using SoX like high quality filters on your source (PC in my situation). Allowing 768kHz pcm data is a big advantage in this regard.

5. Non trendy case design
Instead of following trends, Gustard choose a simple but serious looking case design which I liked.

6. Measurements
@WolfX-700 did a very useful job to put measurements online before Aliexpress sales. Otherwise I will be in confusion despite existence of all other features that I wanted.

7. Price
Gustard could easily put a higher price tag on this model. Price is within my "affordable" range (as a DIY person) so I was able to order one and delayed my PCM1792 NOS dac project.
Can you elaborate more on the NOS component please ?
 

taner

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Can you elaborate more on the NOS component please ?

Of course.

When you play 16bit 48kHz content, the actual data must have to be upsampled to the much higher rates. Dac chips have hard-coded internal filters in order to reconstruct the actual analog sound wave. Otherwise (if you send the 48kHz data directly to the dac chip) sound waves look like stair steps and bandwidth will be highly limited.

As I mentioned on previous post, the X26pro implemented a software based digital reconstruction filter by using a DSP chip. You can utilize similar concept on your own BUT the device must allow you to use your own filters, we call this mode as NOS (Non Over Sampling, all-filters bypass) mode. In NOS mode, when you play 44.1/48kHz raw data, you will see stair steps like wave forms on oscilloscope which is expected. So, you have to feed the DAC with much higher sample rates. I don't mean you have to download 32bit/768kHz FLAC files. You have to "re-construct" the 44.1/48kHz data on-the-fly by using a software algorithm (filter). Since x26pro allows 768kHz pcm data, you can upsample all your files to this rate using popular filters like SoX. The MPD (Music Player Daemon) supports SoX custom settings natively as well as foobar2000 SoX plugin.

You can find lots of info on internet about SoX and customization settings.

There is a filter comparison site for this purpose:
https://src.infinitewave.ca/
 
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Of course.

When you play 16bit 48kHz content, the actual data must have to be upsampled to the much higher rates. Dac chips have hard-coded internal filters in order to reconstruct the actual analog sound wave. Otherwise (if you send the 48kHz data directly to the dac chip) sound waves look like stair steps and bandwidth will be highly limited.

As I mentioned on previous post, the X26pro implemented a software based digital reconstruction filter by using a DSP chip. You can utilize similar concept on your own BUT the device must allow you to use your own filters, we call this mode as NOS (Non Over Sampling, all-filters bypass) mode. In NOS mode, when you play 44.1/48kHz raw data, you will see stair steps like wave forms on oscilloscope which is expected. So, you have to feed the DAC with much higher sample rates. I don't mean you have to download 32bit/768kHz FLAC files. You have to "re-construct" the 44.1/48kHz data on-the-fly by using a software algorithm (filter). Since x26pro allows 768kHz pcm data, you can upsample all your files to this rate using popular filters like SoX. The MPD (Music Player Daemon) supports SoX custom settings natively as well as foobar2000 SoX plugin.

You can find lots of info on internet about SoX and customization settings.

There is a filter comparison site for this purpose:
https://src.infinitewave.ca/
is there an audible difference between a "staircase" steps wave form, and upsampled more natural wave form for the same 48khz file ?
 

taner

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is there an audible difference between a "staircase" steps wave form, and upsampled more natural wave form for the same 48khz file ?

Entirely different thing than what it is look like in nature. Only exist in electronics. So you guess it.
 
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Entirely different thing than what it is look like in nature. Only exist in electronics. So you guess it.
Then I suppose you recommand that I change NOS mode to ON in my gustard x26 pro ? (Since I don't use a pc for music listening)
 
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taner

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Then I suppise you recommand that I cha'ge NOS mode to ON in my gustard x26 pro ? (Since I don't use a laptop for music listening)

Of course not!

But it is a nice thing if you are curious on these kind of customizations. Just to satisfy curiosity. I guess custom DSP filter of Gustard would be highly sophisticated already. You will not need to turn on NOS mode most of times, neither myself.
 

Stoutblock

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Just picked up this X26pro DAC and can confirm it is one very fine audio instrument. I always thought my Oppo UDP-205 DAC sound good but this little guy is a clear step up. Absolutely no digital edge that I can hear. I have not spent much time with the new R2R DACs but somehow I thing this new Gustard DSP solution with dual ESS9038PRO chips will give them a run for the money?
 

Veri

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I have not spent much time with the new R2R DACs but somehow I thing this new Gustard DSP solution with dual ESS9038PRO chips will give them a run for the money?
Don't buy into the R2R hype. So many reviewers will claim it sounds orgasmic/organic whatever, in the end it's just a DAC. I liked Zeos' review on the Holo MAY DAC. He said it's nothing special lol. brutally honest. Not that I'd otherwise follow his advice, but pretty nice conclusion there ;)
 

Stoutblock

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Don't buy into the R2R hype. So many reviewers will claim it sounds orgasmic/organic whatever, in the end it's just a DAC. I liked Zeos' review on the Holo MAY DAC. He said it's nothing special lol. brutally honest. Not that I'd otherwise follow his advice, but pretty nice conclusion there ;)
.

I’m sure the May and the Terminator are fine sounding DACs. Truly Engineering marvels. I think the X26pro is also a masterpiece, but with much more restraint and without any compromise. Certainly a much better value.
 

Veri

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I’m sure the May and the Terminator are fine sounding DACs.
Oh yeah I'm sure they sound fine indeed. But it's pretty obvious they are stuffed to the brim with capacitors to look "impressive". They essentially bait the unsuspecting customer into buying something fancy-looking :D

This really makes no sense other than to look special:
O8KAeAF.jpg
 
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Oh yeah I'm sure they sound fine indeed. But it's pretty obvious they are stuffed to the brim with capacitors to look "impressive". They essentially bait the unsuspecting customer into buying something fancy-looking :D

This really makes no sense other than to look special:
O8KAeAF.jpg
Agreed
 
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