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Gustard X16 Balanced MQA DAC Review

Jimbob54

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"Clarifications" Yes because they are very clear in their advice aren't they........
At least its another channel of dialogue.
 

Matias

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Regarding "degrading" by attentuation: Can I see from the graphs at which level I degraded SINAD to less than 115 or less than 95?

Sorry if that question "sounds" silly. I'm willing to get burned while learning a thing or two
If using a digital volume, you just subtract the attenuation used from the maximum SINAD. If someone is using -30 dB digital attenuation, DAC goes from about 120 dB to only 90 dB SINAD.

That is why I always advocate to use an in line XLR analog attenuator from -10 up to -20 dB and only attenuate the minimum necessary with digital volume.

https://www.parts-express.com/Inline-XLR-Attenuator-Pad-10dB-240-412

https://www.parts-express.com/Inline-XLR-Attenuator-Pad-15dB-240-414

https://www.parts-express.com/Inline-XLR-Attenuator-Pad-20dB-240-416
 

Atanasi

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If using a digital volume, you just subtract the attenuation used from the maximum SINAD. If someone is using -30 dB digital attenuation, DAC goes from about 120 dB to only 90 dB SINAD.
Not exactly. SINAD consists of noise and distortion. A simple approximation is that the noise floor is constant, while the distortion is linear with respect to the signal.
Therefore, let's suppose SINAD is 120 dB, where the noise part is 127 dB and the distortion part 125 dB. If the signal is -30 dB, the noise part is still -127 dB FS and the distortion -155 dB FS. The resulting SINAD is about 97 dB. You can also get a good approximation from subtracting 30 dB from the SNR (127 dB). This means that SINAD becomes dominated by noise.
 

JohnYang1997

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Not exactly. SINAD consists of noise and distortion. A simple approximation is that the noise floor is constant, while the distortion is linear with respect to the signal.
Therefore, let's suppose SINAD is 120 dB, where the noise part is 127 dB and the distortion part 125 dB. If the signal is -30 dB, the noise part is still -127 dB FS and the distortion -155 dB FS. The resulting SINAD is about 97 dB. You can also get a good approximation from subtracting 30 dB from the SNR (127 dB). This means that SINAD becomes dominated by noise.
Not exactly true in this case.
 

gustard

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I bought my X16 on @SHENZHENAUDIO november 26, and the unit is not ship. Very long time to wait .........

Orders placed before December were delivered yesterday and were delivered by express delivery yesterday. Your order should be included in this delivery note (please subject to Shenzhen audio response). MQA certification took a lot of time. Now, as the Chinese New Year approaches, we are very busy and keep you waiting. I'm very sorry!
 

trl

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No because in your previous post you said float pin 3, now it should be basically shorted to ground via the return path, as I originally had my XLRs terminated.
The DAC's output buffers will get stressed if you short-circuit one of the outputs by grounding V- or V+ of an XLR plug. Instead, you should do that on the XLR plugs that will get connected to an ADC (to minimize the incoming noise), but not for an output of a DAC.
 

lizhuoyin

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If using a digital volume, you just subtract the attenuation used from the maximum SINAD. If someone is using -30 dB digital attenuation, DAC goes from about 120 dB to only 90 dB SINAD.

That is why I always advocate to use an in line XLR analog attenuator from -10 up to -20 dB and only attenuate the minimum necessary with digital volume.

https://www.parts-express.com/Inline-XLR-Attenuator-Pad-10dB-240-412

https://www.parts-express.com/Inline-XLR-Attenuator-Pad-15dB-240-414

https://www.parts-express.com/Inline-XLR-Attenuator-Pad-20dB-240-416
Does that mean I should only use x16 volume control (which is digital volume control) for fine adjustment and use line XLR analog attenuator for main reduction if I connect DAC to an pair of active speakers?
For example, if I want to get -30 dB, I should use 20dB attenuator and use digital volume control -10dB?
 

JohnYang1997

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Does that mean I should only use x16 volume control (which is digital volume control) for fine adjustment and use line XLR analog attenuator for main reduction if I connect DAC to an pair of active speakers?
For example, if I want to get -30 dB, I should use 20dB attenuator and use digital volume control -10dB?
There's no difference if you cannot hear any noise in the first place.
 

ABall

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The DAC's output buffers will get stressed if you short-circuit one of the outputs by grounding V- or V+ of an XLR plug. Instead, you should do that on the XLR plugs that will get connected to an ADC (to minimize the incoming noise), but not for an output of a DAC.
So you advocate float pin 3? Gustard have given me 2 answers which in my view are completely different.
1 Grounding 2 Positive pole 3 No connection (open circuit)
How do you connect? It is recommended to connect xlr 1 to the rca shell, 2 to the rca center, and 3 to the rca shell.
The last post is grounding V- even though its at the amp end, its no different than bridging 1 to 3 at the XLR end, the only difference as I have since been reading is noise, this is how March Audio recommend RCA to XLR and I think he may have got this from Ghent. My cable has 2 conductors plus shield.



rca-xlr.png
 

lizhuoyin

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There's no difference if you cannot hear any noise in the first place.
Yeah, I know that's the best way for me to judge the sound quality. Just want to understand the technical parts. I read a lot recently in asr. There are software, digital and analog attenuation. So for dac, it works best at 0dB. Then we can adjust volume in software and/or analog.
 

ABall

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Yeah, I know that's the best way for me to judge the sound quality. Just want to understand the technical parts. I read a lot recently in asr. There are software, digital and analog attenuation. So for dac, it works best at 0dB. Then we can adjust volume in software and/or analog.
Fundamentally yes you are correct a DAC will produce its highest SINAD at 0dB, "works best" if you like, software volume will be digital and again you are in effect reducing performance.
 

trl

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So you advocate float pin 3? Gustard have given me 2 answers which in my view are completely different.
[...]
I think Gustard told you to follow post# 1290, which leads you to the below pic:
index.php

The pinout for the XLR 3-pin plug can be found here as well: http://www.clarkwire.com/pinoutxlrbalanced.htm. As long as you route V+ and GND to the RCA plug, leaving V- not connected, you should be fine.

You will short V- to GND only with non-balanced microphones or sources, to connect them to an ADC. You don't want to do that for a DAC output.
 

lizhuoyin

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Fundamentally yes you are correct a DAC will produce its highest SINAD at 0dB, "works best" if you like, software volume will be digital and again you are in effect reducing performance.
I guess the goal is to let DAC output at highest Vrms. This will require software playing music at highest volume before clipping. And analog attenuation later. It reminds me of ettr in photography.
 

ABall

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I think Gustard told you to follow post# 1290, which leads you to the below pic:
index.php

The pinout for the XLR 3-pin plug can be found here as well: http://www.clarkwire.com/pinoutxlrbalanced.htm. As long as you route V+ and GND to the RCA plug, leaving V- not connected, you should be fine.

You will short V- to GND only with non-balanced microphones or sources, to connect them to an ADC. You don't want to do that for a DAC output.
They did indeed tell me to do it as that picture, at the same time they also say pin 3 to RCA shell, I cant do both. Anyway the picture is how they told me to connect it in the first post, float pin 3, which is what I did and it is still not good for my DC coupled amp contrary to what they have said. I have since contacted Benchmark to see if there DAC3 is designed differently, IE doesn't spit out DC during power up or down. I will not say better as I will get told all I have to do if follow a turn on off sequence which I personally feel is ridiculous. Unless Benchmark tell me theirs will do exactly the same in which case I will have a rethink.... Thanks for the post.
 

ABall

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I guess the goal is to let DAC output at highest Vrms. This will require software playing music at highest volume before clipping. And analog attenuation later. It reminds me of ettr in photography.
Yes if you want the x16 to perform at its max SINAD but that is above and beyond what you would be able to distinguish as worse performance, you have leeway to use the DACs volume control, maybe a lot which will depend on both your ears and your system so as others have pointed out it may not matter, I just sleep better knowing im not reducing that SINAD but I am a bit anal.... ok a lot anal! Dont worry about software clipping the DAC input, music is typically recorded at -10 to -15dB in real life. The important goal if your anal like me is to bypass windows mixer, so you should be using something like WASAPI or ASIO, Im not an expert here so perhaps others will help out.
 

gustard

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Yes if you want the x16 to perform at its max SINAD but that is above and beyond what you would be able to distinguish as worse performance, you have leeway to use the DACs volume control, maybe a lot which will depend on both your ears and your system so as others have pointed out it may not matter, I just sleep better knowing im not reducing that SINAD but I am a bit anal.... ok a lot anal! Dont worry about software clipping the DAC input, music is typically recorded at -10 to -15dB in real life. The important goal if your anal like me is to bypass windows mixer, so you should be using something like WASAPI or ASIO, Im not an expert here so perhaps others will help out.

I did not tell you two wiring methods, only one from start to finish. I don’t know if I am doing it wrong or you understand it wrong?
1 Ground 2 Positive pole 3 Floating (not connected). Floating=not connected=no.
After knowing that your connection is incorrect, I made a picture and pasted it on 1290# as a reference to avoid other errors.
If my expression is not clear and causes your confusion, I apologize to you!
To reiterate: Please press 1290# picture to connect, thank you!
 

ABall

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I did not tell you two wiring methods, only one from start to finish. I don’t know if I am doing it wrong or you understand it wrong?
1 Ground 2 Positive pole 3 Floating (not connected). Floating=not connected=no.
After knowing that your connection is incorrect, I made a picture and pasted it on 1290# as a reference to avoid other errors.
If my expression is not clear and causes your confusion, I apologize to you!
To reiterate: Please press 1290# picture to connect, thank you!
I really appreciate your help, Im not sure which one of us is confused, probably me because I am not very clever so I am sorry but it remains that you have said connect pin 3 to RCA shell and float pin 3 in 2 different posts to me. I have linked both versions a few times now so I wont repeat myself. Thanks for posting though. Also as I have posted that did not solve the problem.
 
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