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

[LarsHP]

With respect, I wouldn't call these general statements using the terms picosecond and femtosecond as establishing any useful or specific specs differences between the two. Especially with use of the term 'sub' which generally means less than or below, what's less than/below pico? - that'd be femto!

In terms of establishing an R26 baseline of phase noise specs (for what they're worth) for comparison I've looked hard online without success on several occasions to find either the exact oscillator used in the R26 (e g Crystek model X) and/or it's claimed phase noise specs at 1hz and 10hz offsets from carrier. There was one suggestion I came across that the oscillator used in the R26 is not the same or as good as the low phase noise Accusilicon AS338 as used in the U18 (-108dBc/10hz offset, no claimed 1hz spec but this is normally around 30db more/worse).

Below picosecond isn't the same as femtosecond. There's a factor 1000 between the two. If it was femtosecond, it would be stated as such, not as "sub-picosecond". (It would be a gross marketing error if it in fact was a femtosecond clock.) I haven't searched for the actual components used, in part because I think it is supposed to be a secret. Gustard has covered them for this reason.

Here are the measurements from the R26. AFAIK, the "12K" measurements graphs are showing jitter.
https://www-l7audiolab-com.translat...l=auto&_x_tr_tl=en&_x_tr_hl=no&_x_tr_pto=wapp (via Google translate)

And here, from the A26, which uses the same clock
https://www-l7audiolab-com.translat...l=auto&_x_tr_tl=en&_x_tr_hl=no&_x_tr_pto=wapp (via Google translate)

A26 measurements from ASR:
https://www.audiosciencereview.com/forum/index.php?threads/gustard-a26-dac-streamer-review.43442/

Note that ASR marks the threshold of hearing is 115dB below zero and that the highest spikes are at around -135dB. This means that none of this will be audible. On the other hand, one can wonder why they added a master clock input if they thought jitter (audibly) can't get any better than it already is.

 

[Johnjc1]

I will bow out of this now
All I wanted to do was suggest a decent upgrade for not crazy money
I have done that

 

[Jake2]

Below picosecond isn't the same as femtosecond. There's a factor 1000 between the two. If it was femtosecond, it would be stated as such, not as "sub-picosecond". (It would be a gross marketing error if it in fact was a femtosecond clock.) I haven't searched for the actual components used, in part because I think it is supposed to be a secret. Gustard has covered them for this reason.

Here are the measurements from the R26. AFAIK, the "12K" measurements graphs are showing jitter.
https://www-l7audiolab-com.translat...l=auto&_x_tr_tl=en&_x_tr_hl=no&_x_tr_pto=wapp (via Google translate)

And here, from the A26, which uses the same clock
https://www-l7audiolab-com.translat...l=auto&_x_tr_tl=en&_x_tr_hl=no&_x_tr_pto=wapp (via Google translate)

A26 measurements from ASR:
https://www.audiosciencereview.com/forum/index.php?threads/gustard-a26-dac-streamer-review.43442/

Note that ASR marks the threshold of hearing is 115dB below zero and that the highest spikes are at around -135dB. This means that none of this will be audible. On the other hand, one can wonder why they added a master clock input if they thought jitter (audibly) can't get any better than it already is.

Thanks for sharing those graphs and coincidentally I was just looking at all three in a quick search again to see if I'd overlooked phase noise measurements of the R26.

What the jitter graphs lack in each case is a zoomed view to show the level of jitter at close offsets (1-10hz) from carrier signal of 12khz or whatever is used. I noted Amir's new 'below audibility threshold' line on the A26 graph with wry amusement as soaring straight through it is the carrier signal (of course) along with a level of low or close offset frequency noise the graph doesn't present with sufficient magnification to allow review. From what I have read close offset phase noise levels (ie jitter levels) are understood in many quarters - if not by ASR - to be more relevant to audibility than an overall/averaged jitter figure.

Good discussion here of audible significance of low offset phase noise.

https://www.head-fi.org/threads/master-clock-talk.228428/post-17330346

 

[rodthebod]

I will bow out of this now
All I wanted to do was suggest a decent upgrade for not crazy money
I have done that

Don't blame you..... me too I think
I'd much rather just enjoy how Leonard Cohen, enjoys his ten thousand kisses deep or has a secret life.........

 

[Jake2]

I will bow out of this now
All I wanted to do was suggest a decent upgrade for not crazy money
I have done that

You have John, thanks to you and others from TAS for doing so.

Don't blame you..... me too I think

Which would be a shame on both counts as the most valuable inputs in this thread by far have been first-hand personal experience. The experience of users on this and other threads continuously reinforce the conclusion that DACs - including how we power them, clock them, how they respond to noise and jitter on various inputs incl ethernet - are very complex systems and simple theoretical statements very rarely hold true.

 

[Dandoudou]

On the other hand, one can wonder why they added a master clock input if they thought jitter (audibly) can't get any better than it already is.

I don't think that there's such thing as jitter below audibility. An external clock improves the sound of DACs that are even superior to the A26.

 

[Jake2]

Thanks for sharing those graphs and coincidentally I was just looking at all three in a quick search again to see if I'd overlooked phase noise measurements of the R26.

What the jitter graphs lack in each case is a zoomed view to show the level of jitter at close offsets (1-10hz) from carrier signal of 12khz or whatever is used. I noted Amir's new 'below audibility threshold' line on the A26 graph with wry amusement as soaring straight through it is the carrier signal (of course) along with a level of low or close offset frequency noise the graph doesn't present with sufficient magnification to allow review. From what I have read close offset phase noise levels (ie jitter levels) are understood in many quarters - if not by ASR - to be more relevant to audibility than an overall/averaged jitter figure.

Good discussion here of audible significance of low offset phase noise.

https://www.head-fi.org/threads/master-clock-talk.228428/post-17330346

Further to this, here's an L7 Audiolab zoomed jitter graph of the X26 Pro + Gustard C18 external clock, to show the delta between a standard bnc cable and the Gustard C2. I've crudely marked up the differences in jitter level at A) 10hz offset and B) 1hz offset.

Different DAC and clock but two observations of relevance to the current discussion:
- the much higher level /audibility of jitter at closer offsets
- how much difference a clock cable can make ~15dB delta @ 1hz offset!!

Edit Added:
C) a theoretical 'threshold of hearing' line at -115dB. Not endorsing this theoretical threshold (it's from said forum), just overlaying it to show there's low offset jitter/phase noise above this theoretical level even with an expensive clock like the C18, depending on the cable; and
D) a more typical /illustrative phase noise plot for a DAC with a good but not superb internal Voltage Controlled Crystal Oscillator (VCXO) rather than a more expensive internal or external Oven Controlled Crystal Oscillator (OCXO) - with this there's quite a bit more jitter above the theoretical audibility line. As to where the R26's internal oscillator sits on this graph - in the absence of any specs or measurements your guess is as good as mine, though I'd hazard a guess that because many folk find appreciable improvements with even modestly priced clocks it is closer to my made-up green line than the C16 blue line.

 

[Stellabagpuss]

I will bow out of this now
All I wanted to do was suggest a decent upgrade for not crazy money
I have done that

You can lead a horse to water...
l think really the answer is try and buy,keep or return. Then you can comment on your experience, rather than graphs.
Point of interest, l have a Romania contact who tried the LB with his friends they loved it.
Placebo is a big word,as you could say everything we read is the placebo effect, sadly ASR,Hi Fi mags and indeed Head Fi could all be Placebo and we would never take a chance on purchasing anything...Which is a route to Madness

 

[Fluty]

This is exactly my viewpoint too. If someone hears an improvement, I feel quite confident it's placebo effect.

That said, I dislike that I now sound like the "objectivists" that go by measurements only and claim subjective differences are just placebo. If I had been in that camp, I would have bought a Topping D90 series DAC and called it the day.

However, claiming a device in the purely digital domain "sounding better" when it actually measures much, much, much worse, in fact measuring about 1000 times worse, then we can safely assume that it's confirmation bias / placebo.

The improvement made by the Leo Bodnar clock is no placebo effect. I've been a musician all my life as a professional orchestral woodwind soloist (I'm not allowed to post it here, but take my name - MichaelScott, add "flute" and find my website - I'm not trying to sell you anything). I know what live music sounds like after a lifetime of performing! I'm sure that if you were to take measurements in the middle of a 100 piece symphony orchestra, or any other live performance, you'd find all sorts of distortions and phase anomalies - but that is the reality of live music and it sounds wonderful.

 

[BShaw]

I’m gittin’ one.
EDIT: I've been trying to keep up with the thread on the fly these last couple of days, super busy, but the Leo Bodnar clocks aren't aimed for the audio market, but high-tech racing, is this correct? The reason I say this is that their tests and specs are most likely also geared to a different intended use. TBH the SNR numbers confused me a bit, but it seems like this may possibly be better for our purposes than first glance at those numbers would suggest?
A little side note: I was listening to the Soundstage Audiophile podcast yesterday while digging ditches around my house, and the guest was Diego Estan, who works for the Canadian National Labs, and is a tester's tester and an objectivist. They had a conversation about SNR and he (somewhat reluctantly maybe) admitted that in reality 70db is really adequate even for audiophiles and that he wouldn't probably hear the difference, although he still likes 120 just because he's a numbers guy. I live in a small quiet town and at 10pm when I measure my room in what I consider total silence, it's in the mid 30's.
This clock is probably doing something very right that has more of a positive impact than whatever is being considered the most important parameter. Just a thought. Isn't the fact that it's tethered to an atomic clock via GPS pretty significant regarding jitter?
With so many people freaking out about it, I just have to give it a shot.

 

[Jake2]

You can lead a horse to water...
l think really the answer is try and buy,keep or return. Then you can comment on your experience, rather than graphs.
Point of interest, l have a Romania contact who tried the LB with his friends they loved it.
Placebo is a big word,as you could say everything we read is the placebo effect, sadly ASR,Hi Fi mags and indeed Head Fi could all be Placebo and we would never take a chance on purchasing anything...Which is a route to Madness

Shipping to the Antipodes is a bit steep (half the LB’s price again) as I don’t really need it in 3-5 days via FedEx Express, but what the heck. In for a penny, in for a pound.

 

[Johnjc1]

I have been thinking about the suggestion to what I am hearing is just second harmonics.
So to be honest yes a bit, for instance the sound has more warmth and depth which coming from high end TT background this is not bad in my book but it is doing a bit more than just adding warmth. What I am hearing like Fluffy is a more real tone I also play and go to lots of live music. A few examples of what I hear include on Kate Bush Waking the Witch. For the first time in my system the church bells are fully ringing. This is more to do with really good timing rather than second harmonics. On Dream Theater Awaken the Master the mix is clearer I am hearing more instrument separation yet it makes more sense, guitars suddenly have more clout and body .keyboards are more real and have more detail. Listening to Visible Worlds by Jan Garbarek I am hearing a lot more natural sound with the collective whole its like a new level of detail.
I have heard the Rockna Wavelight quite a few times and it reminds me what I hear with that wonderful DAC I am not saying its as good as the Rockna but like the Rockna it has that kind of authority and gets me closer to hearing music.
I totally reject the idea of placebo I play guitar, used to hearing instruments regularly in a live setting and an experienced listener I have had the clock for 6 months in my system.
Fair enough if you do not believe me but can people stop presuming what I am hearing without any real experience themselves.
Last but not least everyone who has used this has had a positive experience with it,.
AS I said you need to measure from the DAC to understand what the clock is doing if someone can do this I would be interested in the results.

 

[Fluty]

I have been thinking about the suggested is what I am hearing just second harmonics.
So a bit for instance the sound has more warmth and depth which coming from high end TT is not bad in my book but this is not it. What I am hearing like Fluffy is a more real tone I also play and go to lots of live music. A few examples of what I hear include on Kate Bush Waking the Witch. For the first time in my system the church bells are fully ringing. This is more to do with really good timing rather than second harmonics. On Dream Theater Awaken the Master the mix is clearer I am hearing more instrument separation yet it makes more sense, guitars suddenly have more clout and body .keyboards are more real and have more detail. Listening to Visible Worlds by Jan Garbarek I am hearing a lot more natural sound such as percussion.
I have heard the Rockna Wavelight quite a few times and it reminds me what I hear with that wonderful DAC I am not saying its as good as the Rockna but like the Rockna it has that kind of authority and gets me closer to hearing real music.
I totally reject the idea of placebo I play guitar, used to hearing instruments regularly in a live setting and an experienced listener I have had the clock for 6 months in my system.
Fair enough if you do not believe me but can people stop presuming what I am hearing without any real experience themselves.
Last but not least everyone who has used this has had a positive experience with it,.
AS I said you need to measure from the DAC to understand what the clock is doing if someone can do this I would be interested in the results.

I totally agree - what I hear is more detail, sounds that I didn't notice previously but that I know should be present. For example, not simply a glockenspiel (bell like for those who are not familiar) - but hey, there's a celeste playing along in unison as well. Then the timpani - can now hear the shell of the instrument resonating - not there before. And so much more ambience - I can recognise the sound of concert halls I've played in. Countless more such examples of sounds that I hear every day but not noticed before on the recordings. By the way, call me Fluffy if you like, but because I'm a flute player I chose the nickname Fluty!

 

[Dandoudou]

How do you power this clock?

 

[Johnjc1]

A goof linear Power supply mine is at 9v or a IFi power supply would do a good job