Gustard X16 Balanced MQA DAC Review

[ABall]

Hi,

I stumbled on to this thread while about streaming MQA files from Tidal via the I2S output of a Pi2AES Raspberry Pi HAT (see link) to the Gustard X16.

PI2AES - PRO AUDIO SHIELD - Pi2 Design

Is there some specific software (Moode, Max2Play) required to decode/unfold MQA (from the Raspberry Pi/Pi2AES) or will the Gustard X16 accept any stream of bits from the Pi2AES I2S output and decode and render the MQA files?

Thanks.

I am sure someone will comment on what software works but this answers your questions on bit rate support and which input...

 

[navin]

I am sure someone will comment on what software works but this answers your questions on bit rate support and which input...

Thank you so much. This helps a lot. I guess I would have to use the USB input if I want full decoding of MQA.

I guess only if USBridge Signature can decode MQA can I use the Pi2AES HAT to send the signal to the IIS port of the Gustard X16. Is this assumption right?

I am hoping to use the USBridge Signature instead of an RPi 4B with the Pi2AES HAT as my streamer.

 

[Dannemand]

Thank you so much. This helps a lot. I guess I would have to use the USB input if I want full decoding of MQA.

I guess only if USBridge Signature can decode MQA can I use the Pi2AES HAT to send the signal to the IIS port of the Gustard X16. Is this assumption right?

I am hoping to use the USBridge Signature instead of an RPi 4B with the Pi2AES HAT as my streamer.

Is there a reason you want to use USBridge instead of RPi 4B's own USB? The USB problems of earlier Pi versions are gone in 4B. Really!

I've used RPi 4B USB with moOde for a couple months now, and it works perfectly, including full MQA decoding by the DAC (A18, but works the same).

I can understand using Pi2AES HAT if you've already used the DAC's USB for something else. But then you need software on the RPi to perform MQA decoding (1st unfold). MoOde's dev hates MQA like the plague, and swears moOde will never support it. But it doesn't have to when feeding into USB on the DAC.

I don't know which software will decode MQA directly on the RPi. Maybe Volumio, which does support Tidal in their paid version.

 

[navin]

Is there a reason you want to use USBridge instead of RPi 4B's own USB? The USB problems of earlier Pi versions are gone in 4B. Really!

I've used RPi 4B USB with moOde for a couple months now, and it works perfectly, including full MQA decoding by the DAC (A18, but works the same).

I can understand using Pi2AES HAT if you've already used the DAC's USB for something else. But then you need software on the RPi to perform MQA decoding (1st unfold). MoOde's dev hates MQA like the plague, and swears moOde will never support it. But it doesn't have to when feeding into USB on the DAC.

I don't know which software will decode MQA directly on the RPi. Maybe Volumio, which does support Tidal in their paid version.

Thank you!

I assumed that since the USBridge was purpose-built for Audio it would be better than the RPi4B for this application.

I was hoping to keep the USB input on the DAC for my laptop should I need to connect it later for whatever reason.

A lot of people do not like MQA (I don't have an opinion on this). The only reason to has products that support it, is so as not to miss out on any music that becomes available only on MQA.

 

[prerich]

You will be very happy I'm sure, except for the display which is completely useless if it's going to sit more than 2 feet away from your face, never satisfied me, happy, but never satisfied. I turn mine off because I couldn't read it if it was on anyway!

My rack is off to the side where I can't see my components so I'm good

 

[ABall]

Thank you!

I assumed that since the USBridge was purpose-built for Audio it would be better than the RPi4B for this application.

I was hoping to keep the USB input on the DAC for my laptop should I need to connect it later for whatever reason.

A lot of people do not like MQA (I don't have an opinion on this). The only reason to has products that support it, is so as not to miss out on any music that becomes available only on MQA.

I would give it a try but it's not included in the free trial so they can swivel..

 

[MiLi]

Thank you!

I assumed that since the USBridge was purpose-built for Audio it would be better than the RPi4B for this application.

I was hoping to keep the USB input on the DAC for my laptop should I need to connect it later for whatever reason.

A lot of people do not like MQA (I don't have an opinion on this). The only reason to has products that support it, is so as not to miss out on any music that becomes available only on MQA.

Hi, I have NAS with 1TB of music in different quality, some of files ate DSD, some flac and others MQA. I'm running Moode Audio on Raspberry PI4B, connected by blue USB connector to X16. Working great as Moode is bitperfect streamer feeting X16 bu USB. MQA files are decoded well. There is no limit in data stream speed for DSD or FLAC.

 

[Dannemand]

Thank you!

I assumed that since the USBridge was purpose-built for Audio it would be better than the RPi4B for this application.

I was hoping to keep the USB input on the DAC for my laptop should I need to connect it later for whatever reason.

A lot of people do not like MQA (I don't have an opinion on this). The only reason to has products that support it, is so as not to miss out on any music that becomes available only on MQA.

That is understandable!

I never used the earlier RPi models (prior to 4B) but I do believe their USB issues were real (although Archimago wasn't able to reproduce them in his tests). This led to a large ecosystem of expensive (dare I say overpriced) USB purifiers, power cleaners, and I2S HATS for audiophile users -- undermining the idea of RPi as a low cost DIY streamer.

Famously, in earlier RPi models, USB and Ethernet shared the same bus, which would have been a bottleneck, and might have introduced jitter. Again, I believe that.

But reading the official RPi USB documentation I see that those earlier models implemented USB partially in software. I started my professional life as an assembly language programmer (~40 years ago) writing hardware drivers and other system level code. And my immediate reaction when I read that was "whoa, major ISR storms", i.e. lots of Interrupt Service Request calls for the OS to keep USB data flowing. Maybe Ethernet too. This can easily cause latencies, particularly if upsampling, EQ and other processes compete for CPU cycles.

RPi 4B has a proper hardware USB implementation, so all software has to do is keep output and audio buffers full, and hardware takes care of the rest. (I am oversimplifying, but you get the idea.)

This, combined with solid asynchronous USB implementations in recent DACs, means there really isn't a USB issue in RPi 4B with those DACs.

And that has indeed been my experience: CPU load rarely exceeds a few percent on my RPi 4B with moOde. And I can play all day long (including streaming) with no USB glitches.

I don't want to get into the MQA debate here either, but one benefit of MQA is that the stream has to arrive bit-perfect at the DAC in order to authenticate. So if the DAC displays "MQA" (with or without the "Dot") you know that the stream is arriving intact (with a few unique exceptions). And I have streamed Tidal MQA for hours without MQA dropping out.

(Since moOde doesn't support Tidal, I use mConnect or BubbleUPnP on my phone, which then plays through the UPnP renderer in moOde. BubbleUPnP uses the OpenHome protocol, where the entire playlist is sent to the renderer, including Tidal links. So audio doesn't have to pass through the phone.)

Edit: @MiLi beat me to it, and managed to say the same thing in way fewer words

 

[navin]

That is understandable!
I never used the earlier RPi models (prior to 4B) but I do believe their USB issues were real.

Famously, in earlier RPi models, USB and Ethernet shared the same bus, which would have been a bottleneck, and might have introduced jitter.

I started my professional life as an assembly language programmer (~40 years ago) writing hardware drivers and other system level code. And my immediate reaction when I read that was "whoa, major ISR storms", i.e. lots of Interrupt Service Request calls for the OS to keep USB data flowing. Maybe Ethernet too. This can easily cause latencies, particularly if upsampling, EQ and other processes compete for CPU cycles.

RPi 4B has a proper hardware USB implementation, so all software has to do is keep output and audio buffers full, and hardware takes care of the rest. (I am oversimplifying, but you get the idea.)
This, combined with solid asynchronous USB implementations in recent DACs, means there really isn't a USB issue in RPi 4B with those DACs.

And that has indeed been my experience: CPU load rarely exceeds a few percent on my RPi 4B with moOde. And I can play all day long (including streaming) with no USB glitches.

And I have streamed Tidal MQA for hours without MQA dropping out.

(Since moOde doesn't support Tidal, I use mConnect or BubbleUPnP on my phone, which then plays through the UPnP renderer in moOde. BubbleUPnP uses the OpenHome protocol, where the entire playlist is sent to the renderer, including Tidal links. So audio doesn't have to pass through the phone.)

@Dannemand Since you have programmed for 40+ years I suspect you might be somewhere close to my generation. When I graduated the "IBM PC" was barely created. The Apple II was; we mostly used the PDP 8 (which we nicknamed Big Bertha) and later the PDP 11/70. I haven't touched a computer program since 1987 (they shunted me into "engineering management", besides software was never my strong suit).

I believe that 4 USB ports on the RPi 4 share the same hardware resources (chips), or maybe the 2 3.0 share one chipset and the 2.0 ports share another. The USBridge, however, has one USB port (which they call CLEAN) that they claim is isolated from all other USB ports and hence should have a much lower noise floor.

I did not expect the RPi (either 3 or 4) to be overwhelmed by processing audio data (even DSD512). Audio streaming requires very little in terms of processor horsepower. The trick is to find some way to decode MQA on the RPi (or USBridge Signature which is in effect an RPi3 break out board) so that the Gustard X16 can render it via I2S.

So MoOde does not support MQA. From what I hear, they never will. I believe BubbleUPnP isn't available for iOS. Will Airplay work?

 

[ABall]

@Dannemand Since you have programmed for 40+ years I suspect you might be somewhere close to my generation. When I graduated the "IBM PC" was barely created. The Apple II was; we mostly used the PDP 8 (which we nicknamed Big Bertha) and later the PDP 11/70. I haven't touched a computer program since 1987 (they shunted me into "engineering management", besides software was never my strong suit).

I believe that 4 USB ports on the RPi 4 share the same hardware resources (chips), or maybe the 2 3.0 share one chipset and the 2.0 ports share another. The USBridge, however, has one USB port (which they call CLEAN) that they claim is isolated from all other USB ports and hence should have a much lower noise floor.

I did not expect the RPi (either 3 or 4) to be overwhelmed by processing audio data (even DSD512). Audio streaming requires very little in terms of processor horsepower. The trick is to find some way to decode MQA on the RPi (or USBridge Signature which is in effect an RPi3 break out board) so that the Gustard X16 can render it via I2S.

So MoOde does not support MQA. From what I hear, they never will. I believe BubbleUPnP isn't available for iOS. Will Airplay work?

From another forum "MQA can work over AirPlay when files are created 16-bit/44.1 kHz as they are on MQA CDs" so pretty pointless really, Airplay is restricted to 16/44. I bought a RPi4 to test against my Squeezebox touch so I was looking to test some MQA for myself but I haven't found any software for the Pi that does MQA without truncating it which defeats the object. Maybe a new thread is required that will bring out the Pi experts?

Just for the record I didnt detect any improvement from the Pi vs the Touch even though other scream about how much better it is, I think my cognitive Bias system is broken or ive gone deaf.....

 

[curiouspeter]

@Dannemand Since you have programmed for 40+ years I suspect you might be somewhere close to my generation. When I graduated the "IBM PC" was barely created. The Apple II was; we mostly used the PDP 8 (which we nicknamed Big Bertha) and later the PDP 11/70. I haven't touched a computer program since 1987 (they shunted me into "engineering management", besides software was never my strong suit).

I believe that 4 USB ports on the RPi 4 share the same hardware resources (chips), or maybe the 2 3.0 share one chipset and the 2.0 ports share another. The USBridge, however, has one USB port (which they call CLEAN) that they claim is isolated from all other USB ports and hence should have a much lower noise floor.

I did not expect the RPi (either 3 or 4) to be overwhelmed by processing audio data (even DSD512). Audio streaming requires very little in terms of processor horsepower. The trick is to find some way to decode MQA on the RPi (or USBridge Signature which is in effect an RPi3 break out board) so that the Gustard X16 can render it via I2S.

So MoOde does not support MQA. From what I hear, they never will. I believe BubbleUPnP isn't available for iOS. Will Airplay work?

Using i2s to avoid USB on a Pi 4B is overthinking it.

Just use USB and be happy.

 

[galanakop]

Dream Team
View attachment 117837

Could you put a photo from the back to see the links between these two ???
are combined well together ???

 

[navin]

From another forum "MQA can work over AirPlay when files are created 16-bit/44.1 kHz as they are on MQA CDs" so pretty pointless really.

Maybe a new thread is required that will bring out the Pi experts?

Bummer! Yeah we need to create a new thread for this to draw in more experts on this topic. I thought I was the only one with this question.

Using i2s to avoid USB on a Pi 4B is overthinking it.
Just use USB and be happy.

Agreed. Normally it makes sense. I was keeping the USB input on the DAC for the occasions when I needed to connect my laptop to the DAC. I did not want to go behind the DAC and switch connections each time I needed to connect or disconnect my laptop.

 

[pbarata]

I’m getting some USB glitches with TIDAL streaming using a Raspberry Pi 4 & Volumio, wired directly to an Internet router. In every 10 music’s, one is interrupted for 1 second or less, some just jump to the next track.

This is more notorious using Pi USB 2.0 outputs. After changed to the USB 3.0 outputs there is a clear improvement.

Anyone having the same issues?

 

[curiouspeter]

Bummer! Yeah we need to create a new thread for this to draw in more experts on this topic. I thought I was the only one with this question.



Agreed. Normally it makes sense. I was keeping the USB input on the DAC for the occasions when I needed to connect my laptop to the DAC. I did not want to go behind the DAC and switch connections each time I needed to connect or disconnect my laptop.

I just use Airplay for that. Streaming and music files are streamed to the Pi. At least for me, anything else does not need good quality.

 

[MiLi]

@Dannemand Since you have programmed for 40+ years I suspect you might be somewhere close to my generation. When I graduated the "IBM PC" was barely created. The Apple II was; we mostly used the PDP 8 (which we nicknamed Big Bertha) and later the PDP 11/70. I haven't touched a computer program since 1987 (they shunted me into "engineering management", besides software was never my strong suit).

I believe that 4 USB ports on the RPi 4 share the same hardware resources (chips), or maybe the 2 3.0 share one chipset and the 2.0 ports share another. The USBridge, however, has one USB port (which they call CLEAN) that they claim is isolated from all other USB ports and hence should have a much lower noise floor.

I did not expect the RPi (either 3 or 4) to be overwhelmed by processing audio data (even DSD512). Audio streaming requires very little in terms of processor horsepower. The trick is to find some way to decode MQA on the RPi (or USBridge Signature which is in effect an RPi3 break out board) so that the Gustard X16 can render it via I2S.

So MoOde does not support MQA. From what I hear, they never will. I believe BubbleUPnP isn't available for iOS. Will Airplay work?

OK, I agree with your statement about MoOde and MQA.
But, X16 is capable to play MQA files directly. MoOde on RPI4 is only bit perfect transport between my NAS and x16.
The test files are from L2 free database.

 

[Gradius]

Why people talks so much about mqa?

If you trully likes/loves music, you should NEVER use it in first place.

All mqa managed to do was to killing music.

 

[Dannemand]

@Dannemand Since you have programmed for 40+ years I suspect you might be somewhere close to my generation. When I graduated the "IBM PC" was barely created. The Apple II was; we mostly used the PDP 8 (which we nicknamed Big Bertha) and later the PDP 11/70. I haven't touched a computer program since 1987 (they shunted me into "engineering management", besides software was never my strong suit).

I believe that 4 USB ports on the RPi 4 share the same hardware resources (chips), or maybe the 2 3.0 share one chipset and the 2.0 ports share another. The USBridge, however, has one USB port (which they call CLEAN) that they claim is isolated from all other USB ports and hence should have a much lower noise floor.

I did not expect the RPi (either 3 or 4) to be overwhelmed by processing audio data (even DSD512). Audio streaming requires very little in terms of processor horsepower. The trick is to find some way to decode MQA on the RPi (or USBridge Signature which is in effect an RPi3 break out board) so that the Gustard X16 can render it via I2S.

So MoOde does not support MQA. From what I hear, they never will. I believe BubbleUPnP isn't available for iOS. Will Airplay work?

I've been out all day, lots of catching up and lots of posts to respond to.

I started out on HP professional micro-computers, then IBM PC in 1982. Never did the PDP11. I kept programming into late 80s, but mostly led development departments after that -- except when some low-level work required my background. All my programming later in life is on a proprietary platform (EasyLanguage).

You are right that RPi4 and even 3 are mostly cruising when handling audio data, except if performing heavy DSP work (such as moOde's new CamillaDSP). Even then, if RPi 3 and earlier needed frequent ISR calls to keep USB data flowing, that could be very sensitive to latencies and thus cause USB jitter.

For full MQA passthrough with moOde to the X16, mConnect is the only option I know (available for Android and iOS). But it requires all audio data flow through the control point (the Android/iOS device). BubbleUPnP supports MQA, but only has access to the Tidal HiFi tier (16/44). That's OK for all the 16/44 MQA tracks on Tidal (mostly from Warner), but other MQA tracks will either be truncated to 16-bit (but still authenticate on the DAC if they're 44KHz base rate) or resampled AND truncated (from 24/48 to 16/44 -- which of course won't authenticate).

 

[Dannemand]

From another forum "MQA can work over AirPlay when files are created 16-bit/44.1 kHz as they are on MQA CDs" so pretty pointless really, Airplay is restricted to 16/44. I bought a RPi4 to test against my Squeezebox touch so I was looking to test some MQA for myself but I haven't found any software for the Pi that does MQA without truncating it which defeats the object. Maybe a new thread is required that will bring out the Pi experts?

Just for the record I didnt detect any improvement from the Pi vs the Touch even though other scream about how much better it is, I think my cognitive Bias system is broken or ive gone deaf.....

See above: mConnect will pass any MQA file intact through RPi, no truncation. I've seen it work both with moOde and Volumio. But I am not aware of any software that decodes directly on the RPi -- which would be needed to play via a I2S HAT on to the X16. The MQA decoder must be licensed, which is antithetical to the open-source nature of many RPi based solutions.

I haven't used AirPlay since I don't have any iOS devices.

 

[Dannemand]

Using i2s to avoid USB on a Pi 4B is overthinking it.

Just use USB and be happy.

That's what I am thinking too. But most of the current DACs (at least the Chi-Fi measuremaster DACs) only have a single USB input, so that can be a bottleneck. As @navin mentioned.