Science Thread: Review of Audioquest Jitterbug and Uptone Regen USB Conditioners

Apr 3, 2010
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The name of the forum is "science thread";
No, the name of the thread is: "Review of Audioquest Jitterbug and Uptone Regen USB Conditioners". "Science Thread" was a failed attempt by me to make sure every member coming here knows which forum the thread is in and not present arguments that are subjective in nature. Most members find threads by clicking on "new posts" and therefore are not aware of which forum they are in. That designation is meant to fix that. I have used it before and will continue to do so. I hope from here on it is clear what it means.

if you actually mean "engineering", or "measurements", then change the name to the appropriate one; your choice. As "site founder and administrator", you should have higher standards. As I posted before, engineering is not a science.
Again, you are mistaken about why those word are there. If you are bothered by the name of the forum, that is noted. Steve created the name and I am fine with it and I think everyone knows what it means.

As far as "peer review", read post #62 again.
No, I addressed that post. I know my peers in audio industry. That is all that matters. Not what other definitions you want to use from other places. And my peers would very much accept the work I have done although they would have told me that I am wasting my time confirming what they already know.

As far as reproducibility, I must have missed that. Who else has reproduced your results?
Reproducibility means ability to reproduce. It doesn't mean it has already been reproduced. I provided all the details for my work to be duplicated. I look to the manufacturer to do that and immediately so to see if I have done something wrong and set the record straight. They have not asked me any other questions about my work so I assume they have everything they need to repeat my work. Should they choose to not repeat them, or repeat and not publish, that is their call. I have done what I needed to do to create a fair situation where my work can be questioned with differing data.

So far, my measurements are consistent with that of AQ as tested by Paul Miller and JA at stereophile. That measurements do not show the kind of sonic improvements users are reporting. So confidence is being built and a picture emerging.
 

rbbert

Active Member
Dec 12, 2010
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...I am not responding to most of your posts because they are emotional rants with technical terms thrown around....
Unfortunately this describes most of this thread as well as most of the entire misnamed "Science of Audio" forum. When I have the cable TV repairman come out to my house he makes measurements not unlike those posted here; he also interprets them and makes equipment and firmware modifications based on them. I don't call that science and I don't think most posters here would either, so again I'm not sure why we are calling this forum the "Science of Audio" forum.
 
May 30, 2010
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(...) "Science Thread" was a failed attempt by me to make sure every member coming here knows which forum the thread is in and not present arguments that are subjective in nature. Most members find threads by clicking on "new posts" and therefore are not aware of which forum they are in. That designation is meant to fix that. I have used it before and will continue to do so. I hope from here on it is clear what it means. (...)
Amir,

Let us clarify with an example from the past : would your very participated thread Conclusive "Proof" that higher resolution audio sounds different fit in the Science Thread category?
 

Superdad

New Member
Apr 22, 2015
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Importantly, and I am repeating myself again, what we care about is what we hear.
But you don't seem to care about what close to 2,000 people (some with systems well into 6 figures) hear with our little $175 device. Rather you seem content to use a jitter pattern signal--designed decades ago specifically for exacerbating/showing issues with S/PDIF--and are content to see no difference with that and declare the REGEN does nothing (or that your test set up let a small amount of USB packet-rate 8Khz multiples noise in).
Does a doctor measure the efficacy of a drug by looking in a patient's throat and declaring he sees nothing but a few bumps?
Do you quantify the sonic differences between all DACs with just your J-test?

If I measure the clock pin to a DAC, how on earth would you correlate that what comes out of the DAC when you don't know what level of filtering is being done? Unless you are a DAC designer, it is never, ever important to look at the jitter at clock input.
Or unless one was designing a device meant to reduce the activity and ground-plane noise generated by the USB input PHY in a DAC. Which is what the REGEN does.

Look, we do not actually profess to have found the measured analog output correlation to what we and a couple thousand other people hear with the REGEN. An issue that exists with USB inputs was addressed close-in, and a number of measures (eye-pattern, GPN, etc.) show that the REGEN is effective for those.

It is a mystery to me why such energy is being exerted to "debunk" the product when there are hundreds, nay thousands, of other audio components, cables, AC power tweaks, etc. out there which do or don't affect SQ measurably or audibly. Have you found measurements in the analog domain to quantify the qualitative differences between many of those? Or do all "competently designed" DACs and amplifiers sound the same to you?

Alex C.
UpTone Audio LLC
 

jkeny

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Feb 10, 2012
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Yes, I looked at the datasheet. It says there is a PLL but doesn't go into details.
For the PCM5102 chip there is no internal PLL activated if it is fed MCLK via I2S - do you know what configuration the Meridien Explorer uses?

There are no performance characteristics in the datasheet for this PLL & as is well known, low frequency jitter passes through most PLLs because they have a corner frequency often up at 20KHz & very rarely below 1KHz where LF jitter would reside. Only jitter above the corner frequency is attenuated, below this frequency jitter sails on through.

This is far from the claim by Amir "The DAC has a PLL which filters jitter" - does this only apply to the PCM5102 DAC chip as implemented in the Meridien Explorer?
As I said lots of loose & imprecise talk on this thread.
 

jkeny

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Feb 10, 2012
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Sorry no, you are confused about the conversation. A generic comment was made that one is a fool to measure the jitter on the analog output of a DAC. There was no conversation about the specific DAC I am using. I commented that the DAC can have a loop filter in its PLL and no way can you throw that part out and pretend that you measuring the jitter that is coming out of the DAC. It would be unfair and improper to disadvantage DAC manufacturers that way. It would make a DAC with super jitter reduction on its clock input the same as one having little to none.

Importantly, and I am repeating myself again, what we care about is what we hear. If I measure the clock pin to a DAC, how on earth would you correlate that what comes out of the DAC when you don't know what level of filtering is being done? Unless you are a DAC designer, it is never, ever important to look at the jitter at clock input. This is why no one measures it that way in reviewing equipment and why every engineer would take you out back and shoot you if tried to represent the jitter in a DAC system as what goes into the clock pin.

As to your specific question, as noted the PCM5100 series DAC has internal PLL although it can be disabled. I have not looked at the schematic for the DAC I used so don't know which mode they are using. But again, it doesn't matter. I was addressing the generic comment that measuring jitter on the analog output of a DAC "is a joke." If you believe that is the case, please make your case clearly and we can address it.
Again, if you are making a generic claim about PLLs on DACs can you support your claim with some facts about the prevalence of usage of these PLLs in DACs to support your claim?

You don't know if the Explorer DAC uses a PLL or not as you don't know it's design so can you make this into a generic statement with any believability?
 

jkeny

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Feb 10, 2012
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MOD: this is the last warning. This is not a forum where we speak to each other this way. Continued argumentative rants will not be tolerated folks.

John, I am not responding to most of your posts because they are emotional rants with technical terms thrown around. The thread has a set of measurements. If you have questions about what they are, we can discuss them. If you don't, then that is that. You can present your own measurements or anyone else and I very much welcome that. If you don't have that, or ability to make such measurements, then you are not qualified to challenge them left and right with technical theories you have not confirmed.
You made a claim about PLLs which I have questioned - your claim is unfounded for even the Explorer DAC
You made a claim about isolated USB inputs which I questioned - there are no isolation devices within USB audio devices that isolate USB 2.0 high speed operation - the configuration that is found on 99% of modern USB audio devices.

Both claims were made by you in defense of your supposition that USB jitter or noise on USB lines is of little consequence,

It's your choice if you wish to ignore this
 
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Aug 20, 2014
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This is a wonderful thread and dialog. I found it valuable because I know nothing about digital technology, so I learned a considerable amount. Personally, I welcomed Amir's observations which I thought were accompanied by quite modest comments regarding the limitations and interpretation of his data.

I would add that the following comment left me gasping: "I would not have published your measurements, as it is too easy to interpret them as denigrating a well regarded product. Had they been positive, then I would have been inclined to publish the results..." One may certainly respect a scientist's decision as to when to publish, but as an Associate Editor of the most prestigious journal in my field, I think I can safely say with certainty such a publication policy by any modern medical or scientific journal would never see the light of day. Furthermore, while most high level medical journals consider material for publication that contains (to paraphrase from my own journal) "clinical and laboratory hypothesis-based research with statistically valid results that clearly advance the field" there is also ample opportunity in many journals to report observations and preliminary data that can serve as effective communication and stimulation to others in the field which might stimulate further work on a particular topic. Such observations are widely considered important in fostering collegiality among scientists. I view Amir's OP as serving a similar purpose.

Finally, I am curious however about his comment in the OP about putting a rock on his DAC to make it sound better. What kind of rock exactly? I hope you'll share that with us when you find it as I've tried a few and haven't found one yet that works. :)
It seems a safe assumption that your journal has a peer review and editorial process that selects serious scientific research and weeds out anecdotes. There is no such process in this forum, nor should there be one, as this is just for fun. However, anyone who invokes the name of Science had best measure up to scientific standards, lest there be blowback from their argument of authority.

Using anecdotal evidence to denigrate someone's product and business is not polite behavior. Making negative comments (or comments that a reasonable person might mistake as negative) requires a higher standard of evidence.
 
Aug 6, 2015
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Finally, I am curious however about his comment in the OP about putting a rock on his DAC to make it sound better. What kind of rock exactly? I hope you'll share that with us when you find it as I've tried a few and haven't found one yet that works. :)
Do a goggle on the VPI Magic Brick or the Shakti Electromagnetic Stabilizer Stone. Back 10 years or so they were all the rage and like the Regens and AQ Jitterbugs, had hoards of audiophiles claiming audible improvements. Very similar also to Synergistic Researches Magic Dots of today.
 
Jul 1, 2010
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I'm not sure what the "outcome" is here; perhaps you could state it again. As far as I can tell, you made some measurements; no meaningful correlations were made to their relation to potential audibility (or lack of). Nothing "scientific" about that, any more than someone else's subjective impression that there was (or wasn't) any audible change or improvement with the DUT's. It doesn't become science until you have used your data or observations to formulate a hypothesis, devise and perform an experiment to test that hypothesis, and then analyze those results. In today's world, that must also be followed by peer review and reproducibility, because while you may think that your experimental design and analysis of results (conclusion) is appropriate, your scientific peers may disagree.
Amir, we seem to be a bit stuck on the word "science." Perhaps you should change the name of subforum "tech talk" or "the engineering of audio," or "the rational forum?" ;) ...oh wait a minute! I just looked and saw that you did change the name! Good job! Of course the nature of pedanticism is to go on and on, but you've done what you can, and hope springs eternal.

Tim
 

Antoine

New Member
Jun 18, 2013
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So, who's having fun here?

I've taken a look at my internal, built in measuring system and my joy-o-meter indicates musical enjoyment did go up several notches after installing the Regen. It's the only proof I need so for me this matter's closed. Signing off, bye now! :D
 

Whatmore

New Member
Jun 3, 2011
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But you don't seem to care about what close to 2,000 people (some with systems well into 6 figures) hear with our little $175 device. Rather you seem content to use a jitter pattern signal--designed decades ago specifically for exacerbating/showing issues with S/PDIF--and are content to see no difference with that and declare the REGEN does nothing (or that your test set up let a small amount of USB packet-rate 8Khz multiples noise in).
Does a doctor measure the efficacy of a drug by looking in a patient's throat and declaring he sees nothing but a few bumps?
Do you quantify the sonic differences between all DACs with just your J-test?
A doctor measures drug efficacy via rigorous double blind testing.
Please share the results of yours with us...
 
Sep 30, 2015
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Well at just over 1700 sales, he's surpassed Jim Jones's 909 recruits with his religion so far. Quite impressive.
 

jkeny

Member Sponsor
Feb 10, 2012
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Looking at the posted graphs by Amir shows a reduction in noise floor when using the Regen of about 5dB throughout the audible range & beyond. It would be good to see a more expanded version of this reduction in the audio band. This signifies a cleaner 5V output from the Regen (even though it is powered by an SMPS) than the 5V output from his laptop

The Jitterbug shows no reduction in noise floor.

The Meridien Explorer is powered by the 5V power from the USB cable

But here's what I don't understand - in the following Jitter plots, taken on the output of the Meridien DAC, the noise floor is the same for both the Jitterbug & the Regen. Should the Regen not show a lower noise floor in these graphs?

I know the FFT grass is not the actual real noise floor & Amir has used different FFT settings between the broadband noise & Jitter plots which confuses matters (maybe he can tell us what the real noise floor is?). But on the two jitter plots he seems to have done these with the same FFT settings - so I would expect some difference between Jitterbug & Regen unless, of course the FFT grass in these plots is below the noise floor of the Regen.

Which I guess is the answer to my conundrum.

Still it might be useful to have an expanded view of the noise in the audio band frequency.
 
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Elberoth

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Dec 16, 2012
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Amir - just curious (and only slightly off topic) - do you believe cables can make an audible difference ?

If you do, can you show us a set of standard audio component measurements that would show any difference between different cables ? For example, can you show us, let's say preamp measurements, that would show any differencies in THD, HF intermodulation spectrum, etc with 2 sets of cables used while taking those measurements ? And I'm not talking about networked cables, which could limit FR for example, but regular ones like Siltech vs AQ for example.
 

steve williams

Site Founder, Site Owner, Administrator
Hi Adam et al

I have to step in here and suggest that your post is really not applicable here and serves a purpose other than to advance the topic of this thread.

You could certainly ask that question by way of PM or email or you can start a thread here as long as there are rules followed and no ad hominem attacks
 
Sep 30, 2015
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I find it mind boggling how people get so enchanted by products like these when everyone is free to choose products that have better interface options than USB anyways. Lack of education is the reason for the popularity of these trinkets. I'll take a DAC with an I2S or Ethernet interface over USB any day of the week.

Treat the cause not the symptom.
 

Elberoth

Member Sponsor
Dec 16, 2012
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My post was not meant as personal attack. Let me explain.

I think it is a valid question to ask in this discussion. If Amir can't show measured differencies in cables (and I do believe he can't), then he has to admit, that the measuring equipment we use, is still not accurate enough. There are still things we can hear, but cannot measure.

If so, then there is real possibility, that there are things that Regen does improve performance wise, which translate to SQ improvement many of us hear, even though we cannot show that on our set of measurements to prove it. Ergo, it is way too early to say Regen doesn't work, 'cos we can't show that on our set of measurements. And I think this is a position that many ppl posting in this thread had taken.
 

Whatmore

New Member
Jun 3, 2011
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My post was not meant as personal attack. Let me explain.

I think it is a valid question to ask in this discussion. If Amir can't show measured differencies in cables (and I do believe he can't), then he has to admit, that the measuring equipment we use, is still not accurate enough. There are still things we can hear, but cannot measure. Or do not know how to measure.

If so, then there is real possibility, that there are things that Regen does improve, which translate to SQ improvement many of us hear, even though we cannot show that on our set of measurements to prove it. Ergo, it is way too early to say Regen doesn't work, 'cos we can't show that on our set of measurements. And I think this is a position that many ppl posting in this thread had taken.
Or perhaps we can't measure them because we can't really hear them
 

Gregadd

WBF Founding Member
Apr 20, 2010
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It is unreasonable to demand members to respond to measurement based opinions with meaurement based opinions. Because those who are unable to provide them (measurements) may lack those measurements) because they lack the skill and equipment to perform them. Life is unfair that way.

How can a lay person respond to this with measurements?

For my money, I think a rock from the garden put on top of my DAC may do better than either one of these devices. For the price of Regen, you can buy 10 high-res downloads and I am confident that would bring more happiness to your music life than this device.
 

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