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Review and Measurements of Gustard DAC-X26

Shadrach

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It's not about being on paranoid level. But after what I have seen so far in this whole "audio world business" I will never trust anyone just "for word", and I can imagine every crazy scenario, especially when stakes are high, like having great measurements review by amir worldwide, which can boost sales significantly. Pricing is also high here per single unit, so all the effort may be worth it (hopefully it is not and this manufacturer can join great wall of defense against all bull$hit audio manufacturers available on the market).
I don't think the shill and marketing machine works by making one unit better than the production units; it's just too much trouble.
In my experience it goes more like this:
Design a unit that gives adequate performance, with audio products bear in mind that the vast majority of the DACs amirm has measured it's extremely unlikely that anyone will notice which measurement tier it lands in. Get the marketing dept to write up some wonderful bullshit about the product; in many cases it doesn't even need to be accurate. Very few people have the equipment or interest in measuring their latest purchase in order to prove they've been robbed.;)
Take a few units round to some reviewers and give them the units, plus a nice dinner and a promise of further products to review (no mention of returning such products) The reviewer waxes lyrical about the product. How many reviews have you red where a reviewer writes,'this is a pile of crap as current standards go. it's overpriced, under-performing and the only reason I'm doing this review is I got given the unit and the company has promised me exclusive access to their new models.
So far, from what I've seen of amirm's reviews, the designer vendor is taking a bit of a risk by offering their products for review here. Although amirm is rather more diplomatic than I would be, if the unit doesn't measure up it gets this fact published here for all to read.
 
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amirm

amirm

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I could not find in the specifications if the X26 USB input is compatible OTG.
How would I test that? Connect it to a phone and see if it gets recognized?
 

tpaxadpom

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Amir, is it possible to take measurements with volume control enabled? Curious how well volume control is enabled in this DAC. 1
 
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amirm

amirm

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Amir, is it possible to take measurements with volume control enabled? Curious how well volume control is enabled in this DAC. 1
I used the volume control in my testing to set -2 dB.
 

Music1969

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I used the volume control in my testing to set -2 dB.

Is this any different to setting DAC volume at max (0 dB) and setting software volume (like Roon headroom management) at -2 dB?

Just asking out of general interest, in understanding the effect on SINAD.
 
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amirm

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Is this any different to setting DAC volume at max (0 dB) and setting software volume (like Roon headroom management) at -2 dB?

Just asking out of general interest, in understanding the effect on SINAD.
This is something I intend to analyze in the future. I would say for now they are probably close enough.
 

Music1969

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This is something I intend to analyze in the future. I would say for now they are probably close enough.

Phew! I initially thought it was a stupid question on my part.

The fact that you want to take a look means it's not COMPLETELY a stupid question.
 

tpaxadpom

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This is something I intend to analyze in the future. I would say for now they are probably close enough.
The reason I asked the question perhaps is obvious to you but not some other readers. If you plan on purchasing doc and using it as a preamp you have to realize a few things. Power amps typically require 1V RMS to achieve full power on the output. Considering the typical amplifier gain and modern speaker sensitivity one would never use this thing with volume setting near 0dB (or -2dB). It would be great to see measurements in 10dB increments from -90dB up to 0db in 10dB steps. I realize it is your time and extra work. Though -90 and -45 (half way) would be sufficient to satisfy my curiousity. ;)
When I see AP measurements and that are interesting I always have some questions. I hope you don't treat them as me trying to criticize any work that you do. When you perform DAC measurements what load are you using? 100kOm? If so have you considered using 300 or 600 Ohm instead and plotting them side by side with 100kOhm? There are plenty of people that use passive amps and it would be interesting to see how DAC performs when you vary the load. In fact it would be very interesting to see comparison of DAC-X26 measurements with built in volume control vs using a passive pre-amp.
 

NTomokawa

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Regarding UL/ETL certifications: Right now I'm helping a certain lighting product manufacturer obtain an ETL certification for a product. The up-front cost is about $8 000 USD, in addition to a quarterly fee of nearly $2 000 USD (subject to increases) for as long as the manufacturer wants the certification to remain valid.

Of course that's a luminaire and not a DAC, but I can definitely see why a small-ish audio manufacturer wouldn't want to spend that kind of cash just to put a little mark on their products.

Doesn't change the fact that I'm a certification freak, though. :sensible chuckle:
 
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amirm

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What kind of volume control X26 DAC has, from ESS chip or something else?
I am not sure. Their marking material just says it goes from 0 to 90 and is digital in nature.
 
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amirm

amirm

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The reason I asked the question perhaps is obvious to you but not some other readers. If you plan on purchasing doc and using it as a preamp you have to realize a few things. Power amps typically require 1V RMS to achieve full power on the output. Considering the typical amplifier gain and modern speaker sensitivity one would never use this thing with volume setting near 0dB (or -2dB). It would be great to see measurements in 10dB increments from -90dB up to 0db in 10dB steps. I realize it is your time and extra work. Though -90 and -45 (half way) would be sufficient to satisfy my curiousity. ;)
The IMD measurements show those steps. A THD+N curve would be similar.
 
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amirm

amirm

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When I see AP measurements and that are interesting I always have some questions. I hope you don't treat them as me trying to criticize any work that you do. When you perform DAC measurements what load are you using? 100kOm? If so have you considered using 300 or 600 Ohm instead and plotting them side by side with 100kOhm?
If you look at the the bottom of the dashboard, you see the test conditions such as what you ask:

1552520921654.png


For unbalanced, it is 100 K ohm. For balanced it is naturally double that per above.

This is for DAC testing. The dashboard for headphone amps does use 600 ohm.

I don't think it makes much sense to test a DAC output at 300 or 600 ohm. I know stereophile does that but I don't see a common case where the target device has such a low input impedance.
 
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