GUSTARD DAC-R26 Balanced Decoder R2R+1Bit Dual Native Decoding Music Bridge

Oct 18, 2023 at 6:19 AM Post #7,741 of 9,907
I don't agree that the R26 streamer is good at all! Many others here as well as me have found that it stutters when given high res files. No-one has come up with a solution and the problem seems to be it's limited memory so unable to be fixed with any firmware update. The DAC is wonderful - but along with others here I have to use an external streamer.
My experience points to the software feeding the data, not the LAN input circuit of the DAC:

I have no issues with 24-bit / 96kHz FLAC files when using Logitech Media Server via LAN. However, I did get short breaks when using Audirvana, but that happened with 16-bit FLAC files as well (sometimes even after a few minutes playing a song). Since it doesn't happen when using LMS (not even with 24-bit FLAC files), I have a hard time believing it's a buffer/memory issue.
 
Oct 18, 2023 at 6:45 AM Post #7,742 of 9,907
@LarsHP & @m-i-c-k-e-y - many thanks for you responses. Appreciated.

Yes, I realise that I can contact Gustard directly. Let me do that and see what the response is.

I was hoping that an R26 "guru" on this board might know the answer to my question.

Separate question - I have noticed that if I switch the R26 to use an external clock without connecting an external clock, the R26 displays the error "EXTERR" - which is expected. BUT, the R26 continues to play - what is going on there - how does it do that?


My experience points to the software feeding the data, not the LAN input circuit of the DAC

Definitely the same as my experience. I think it comes down to the "horsepower" and software of the "streamer" feeding the R26 Lan. I've had absolutely no issues with stuttering on the R26 even fed with PCM @768kHz via HQPlayer running on an Intel NUC (and HQPlayer is running on a VM).
 
Oct 18, 2023 at 7:01 AM Post #7,743 of 9,907
@LarsHP & @m-i-c-k-e-y - many thanks for you responses. Appreciated.

Yes, I realise that I can contact Gustard directly. Let me do that and see what the response is.

I was hoping that an R26 "guru" on this board might know the answer to my question.

Separate question - I have noticed that if I switch the R26 to use an external clock without connecting an external clock, the R26 displays the error "EXTERR" - which is expected. BUT, the R26 continues to play - what is going on there - how does it do that?




Definitely the same as my experience. I think it comes down to the "horsepower" and software of the "streamer" feeding the R26 Lan. I've had absolutely no issues with stuttering on the R26 even fed with PCM @768kHz via HQPlayer running on an Intel NUC (and HQPlayer is running on a VM).
You may find the discussion here (incl Gustard responses) of use around when an external clock may be referred by the K2 clock synthesiser, as logically in such instances if external clock is set to off then the internal clock is still referred by the K2 ie. Identifies scenarios where the embedded clock in the input signal is not the sole source of timing info referred by the R26.

https://www.head-fi.org/threads/gus...ve-decoding-music-bridge.963630/post-17493347
 
Oct 18, 2023 at 7:40 AM Post #7,744 of 9,907
@LarsHP & @m-i-c-k-e-y - many thanks for you responses. Appreciated.

Yes, I realise that I can contact Gustard directly. Let me do that and see what the response is.

I was hoping that an R26 "guru" on this board might know the answer to my question.

Separate question - I have noticed that if I switch the R26 to use an external clock without connecting an external clock, the R26 displays the error "EXTERR" - which is expected. BUT, the R26 continues to play - what is going on there - how does it do that?




Definitely the same as my experience. I think it comes down to the "horsepower" and software of the "streamer" feeding the R26 Lan. I've had absolutely no issues with stuttering on the R26 even fed with PCM @768kHz via HQPlayer running on an Intel NUC (and HQPlayer is running on a VM).
The laptop I mostly use is a passively cooled, quite modestly spec'ed Acer Swift 1 (Pentium Silver N6000 CPU, 8GB RAM). When playing 24-bit / 96kHz FLAC files it only uses a fraction of the processor capacity.

When running Audirvana with upsampling, it is still far from the limits of the hardware (according to both Audirvana and Windows). In other words, I don't think it requires a particularly fast computer to play music. To be honest, I don't understand why Audirvana makes these short pauses for no apparent reason, while LMS runs without issues.
 
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Oct 18, 2023 at 8:03 AM Post #7,745 of 9,907
Interestingly (and the driver for my original post), connecting the Pi2AES to the R26 using I2S does not sound as good as the AES/EBU connection. Which appears counter-intuitive since I had assumed I2S would be the better format.
[....]
Question: If I were to use the I2S input om the R26, will the R26 still use it's internal clock or does the R26 then ignore it's internal clock and become a "slave" to the clock information provided by the I2S input stream?
Based on your experience, short answer is that R26 do not reclock I2S port. Jitter introduced on the I2S connection is very small, it qualifies for a direct clocking, unlike S/PDIF where clock has to to be recovered from the data stream.

Whether it is good or wrong, it depends on quality of the source clock and a cable. If source clock is jittered, reclocking will remove high frequency noise, while passing low frequency noise and introduce its own. So design choice is difficult.

Bear in mind that ground loops can destroy sound (even if R26 does reclocking). S/PDIF source device usually use transformer that cut most of such noise. So a short answer is not definitive answer. We don't know what is really happening in your system.
 
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Oct 18, 2023 at 8:30 AM Post #7,746 of 9,907
Hello all

I'm a first-time poster here but have been "lurking" on this board for almost a year. Interesting, lively & helpful debate. Please be gentle ! :relaxed:

I've had my R26 for about 11 months now and am very pleased with it. But, like most here, I am addicted to the "upgrade" drug, looking for the next increment in sound quality.

I have a simple question - I think (although I expect I will get educated that nothing in audio is simple! ):

Question: If I were to use the I2S input om the R26, will the R26 still use it's internal clock or does the R26 then ignore it's internal clock and become a "slave" to the clock information provided by the I2S input stream?

Context here is that I am considering procuring a much better streamer than my current Pi2AES and I want to understand if a streamer with a good quality I2S output will yield benefits with the R26. I have read that some DACs (Denafrips as an example) re-clock every input including their I2S inputs and hence potential benefits of a really good streamer are limited.

Thank you in advance for your help !
Hello @camrector - Many thanks for your reply. Really appreciate you taking the time to respond. I am a keen follower of your posts ! :relaxed:



Up until a few weeks ago, I would have completely agreed with you regarding the quality of the internal streamer on the R26 and I have been using the R26's internal streamer quite happily.

Before going further, I know that everyone's system is different, room acoustics are different, mains supplies vary in quality etc. So what follows is in the context of my system.

I already had the Pi2AES before I acquired the R26 but had relegated it to storage when the R26 arrived and I realised how good the R26 internal streamer was. Once the R26 arrived, I also made a number of network upgrades:
  • Two fibre connections to my main network switch
  • FMC units - one for the R26, the other for my NUC running Roon, HQPlayer & LMS
  • High quality power supplies for both FMC units
A couple of weeks ago, I decided to "mess" about as I was getting a little restive for an "upgrade". I plugged the ethernet output from one FMC to the Pi2AES, gave the Pi2AES a high quality power supply and then connected the Pi2AES to the R26 using the AES/EBU connection. Imagine my surprise then, when there was a definite improvement to the sound quality compared to using the internal streamer on the R26 !! :relaxed:

Interestingly (and the driver for my original post), connecting the Pi2AES to the R26 using I2S does not sound as good as the AES/EBU connection. Which appears counter-intuitive since I had assumed I2S would be the better format.

Based on my experience, I have arrived at two conclusions:
  1. The internal streamer in the R26 is extremely good - but it can be bettered
  2. The DAC section of the R26 is simply outstanding and can make the most of a very high quality input stream
So, back to my original question please:

Question: If I were to use the I2S input om the R26, will the R26 still use it's internal clock or does the R26 then ignore it's internal clock and become a "slave" to the clock information provided by the I2S input stream?

Many thanks all
To answer your question the device upstream of the R26 will supply the clocking info when using I2S.
 
Oct 18, 2023 at 9:32 AM Post #7,748 of 9,907
I had had zero stutter issues or pops. I would say that if you are experiencing continued problems with this then it’s a setting in your playback software, not the R26.
Asking respectfully - what do mean by "playback software"? My R26 is connected directly to the internet via LAN - there's no computer or other appliance in the loop, just the mconnect control app. I've tried Roon which made no difference. My separate iFi Zen streamer works perfectly connected to the R26. There are plenty comments in this thread from others with the same issue when streaming HiRes or MQA files. I love the DAC function, playing mainly from CD which gives me the best quality via a glass optical cable, but have given up using the R26 as a streamer.
 
Oct 18, 2023 at 10:37 AM Post #7,749 of 9,907
Asking respectfully - what do mean by "playback software"? My R26 is connected directly to the internet via LAN - there's no computer or other appliance in the loop, just the mconnect control app. I've tried Roon which made no difference. My separate iFi Zen streamer works perfectly connected to the R26. There are plenty comments in this thread from others with the same issue when streaming HiRes or MQA files. I love the DAC function, playing mainly from CD which gives me the best quality via a glass optical cable, but have given up using the R26 as a streamer.
In your use case, streaming directly from the internet, I suggest that the iFi Zen Streamer may be working as a buffer, while going directly from the servers on the internet, that may be causing the issues. The "playback software" in this scenario is not in your house, but on the server at Tidal, Qobuz etc. At least I imagine that this could introduce delays in playback, for instance when (too) many users are accessing the server, and perhaps even the same track as you.
 
Oct 18, 2023 at 12:16 PM Post #7,750 of 9,907
You may find the discussion here (incl Gustard responses) of use around when an external clock may be referred by the K2 clock synthesiser, as logically in such instances if external clock is set to off then the internal clock is still referred by the K2 ie. Identifies scenarios where the embedded clock in the input signal is not the sole source of timing info referred by the R26
Thanks @Jake2 for the link. The response from Gustard seems to make it more complex than "I2S = not reclocked" and appears to depend on other settings on the R26 such as whether PCM NOS is on or off. Interesting.

I will try the I2S connection again and let my ears do the deciding - as always, it is the best criteria.

@sajunky - thank you for your feedback

Whether it is good or wrong, it depends on quality of the source clock and a cable. If source clock is jittered, reclocking will remove high frequency noise, while passing low frequency noise and introduce its own. So design choice is difficult.

Yes, and it is entirely possible that the AES/EBU output on the Pi2AES is better than its I2S output

Bear in mind that ground loops can destroy sound (even if R26 does reclocking). S/PDIF source device usually use transformer that cut most of such noise. So a short answer is not definitive answer. We don't know what is really happening in your system.

Yes, and incidentally, I seem to have got a good improvement in sound quality by grounding the RPi3 section of the Pi2AES streamer
 
Oct 18, 2023 at 1:21 PM Post #7,751 of 9,907
Asking respectfully - what do mean by "playback software"? My R26 is connected directly to the internet via LAN - there's no computer or other appliance in the loop, just the mconnect control app. I've tried Roon which made no difference. My separate iFi Zen streamer works perfectly connected to the R26. There are plenty comments in this thread from others with the same issue when streaming HiRes or MQA files. I love the DAC function, playing mainly from CD which gives me the best quality via a glass optical cable, but have given up using the R26 as a streamer.
Mconnect. Is a known source of drop outs. Jplay is better. Then Roon is best. I’d have to see your settings on the computer to trouble shoot.
 
Oct 18, 2023 at 7:23 PM Post #7,754 of 9,907
My experience with the streaming features of the R26 have been largely positive as well.
I use Renderer 1.4 and a few months ago lost NAA visibility to HQPlayer after a power flash, but when HQP was actually seeing the R26, the streaming through Roon into HQPlayer was flawless with both DSD and Hi-Res PCM.
Since I am slack and still haven't reflashed to 1.4 or the newer 1.42, I am using Foobar via UPnP and it also works perfectly with zero drop-outs [DSD/Hi-res PCM].
I am also using the FMC set-up as rec'd by @camrector .
I think I²S from the U18 and AES from my Pi2AES also sound great, but the LAN sounds best, in my set-up at least.
EDIT: I will also say that I am not using the DSD direct mode currently as I think it sounds better to my ears sent through the ladders and converted to PCM, but did extensive testing with DSD direct with no issues before eventually deciding to go the DSD>PCM route.
 
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Oct 18, 2023 at 9:24 PM Post #7,755 of 9,907
Mconnect. Is a known source of drop outs. Jplay is better. Then Roon is best. I’d have to see your settings on the computer to trouble shoot.
Same experience here, Mconnect was the worst with dropouts in the first 15-20 seconds of a song. Bubble wasn't much better, but Jplay was a lot better. Roon, no problem. I don't know too much about the subject, but I wonder if it's a combination of the software and the Gustard renderer, where most of the streaming software I tried isn't doing any or much buffering and the R26 just can't handle it. I think probably Roon is taking up the buffering and passing it on the the R26 after doing the heavy lifting.
 

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