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

  1. #501
    VIP/Donor [VIP/Donor] microstrip's Avatar
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    Quote Originally Posted by amirm View Post
    Nope. The noise floor was plenty fine to show that addition of REGEN increased the spikes:



    The spikes rise up some 25 db above the noise floor with addition of Regen. And the spikes are narrowband and hence require no calibration for their levels to be correct.
    Even with this very low frequency resolution we can see visible differences in the audio band. Unless there is a calibration how can we ignore them? How can we be sure that the relevant data in this graph are the ultrasonic spikes?
    Under construction around the DCS Vivaldi 2.0 stack and a pair of Wilson XLF's : Forsell Air Force One, ARC Phono 2SE, cj GAT + Lamm M1.2 ref, TA OPUS MM2 +TA XL digital, TA XL gen V power cables and CenterStage footers ...

  2. #502
    Quote Originally Posted by amirm View Post
    The spikes rise up some 25 db above the noise floor with addition of Regen. And the spikes are narrowband and hence require no calibration for their levels to be correct.
    A while back, I showed that with some FFT software, a slight change in the parameters or the frequency could result in a change in level of a "spike" that was as much as 40 dB. This prompted me to question what were the FFT parameters that you used in your plots. I have yet to get a satisfactory answer. Consequently, I will continue to ignore all plots that you give me, since I do not know how to properly interpret them, nor do I have reason to believe that you do, either. If the problem is just my ignorance, please help me understand what you did and why you think it significant.

  3. #503
    Member Sponsor Addicted to Best! Elberoth's Avatar
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    amirm - why don't you just post the FFT parameters for everyone to see ? That seems much easier (and less time consuming) than constantly explaining why you can't post them.

    Just a thought.
    Adam

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  4. #504
    Quote Originally Posted by microstrip View Post
    Even with this very low frequency resolution we can see visible differences in the audio band. Unless there is a calibration how can we ignore them? How can we be sure that the relevant data in this graph are the ultrasonic spikes?
    I've got an idea - run your own measurements.

    Tim
    In high-end audio, you can't even fight an opinion with the facts.

  5. #505
    Quote Originally Posted by Tony Lauck View Post
    A while back, I showed that with some FFT software, a slight change in the parameters or the frequency could result in a change in level of a "spike" that was as much as 40 dB. This prompted me to question what were the FFT parameters that you used in your plots. I have yet to get a satisfactory answer. Consequently, I will continue to ignore all plots that you give me, since I do not know how to properly interpret them, nor do I have reason to believe that you do, either. If the problem is just my ignorance, please help me understand what you did and why you think it significant.
    Both Amir have been working with fft and signal processing for many years, myself in a professional test measurement environment. We are fully aware of fft processing characteristics, limitations and real world effects. If you don't believe anything that's being posted here then I am not sure why you are participating.

    Now if you don't understand fft processing then although we both are happy to help people understand, we are certainly not going to respond to the barrage of criticism direct or implied. It might also be helpful if you go and read some literature on the subject and even play with some free spectrum analyser on your PC at home.

  6. #506
    Quote Originally Posted by jkeny View Post
    What you consider argument after argument is what I see as correcting mistakes - mistakes in examples given (like BE's last two 8KHz plots)
    ?
    Jk, the fact that you think my last plots are mistakes betrays how little you know about the subject. You are clearly in no position to be making any analysis. You simply have no knowledge or experience of it.

    The fact that you persist in arguing about subjects you are ignorant of is strange but also somewhat fascinating.

    The irony of your signature is spectacular.

    You can continue to argue but I doubt you will get much response in future, it would be like banging ones head against a brick wall.
    Last edited by BE718; 10-07-2015 at 04:49 PM.

  7. #507
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    Quote Originally Posted by BE718 View Post
    Jk, the fact that you think my last plots are mistakes betrays how little you know about the subject. You are clearly in no position to be making any analysis. You simply have no knowledge or experience of it.

    The fact that you persist in arguing about subjects you are ignorant of is strange but also somewhat fascinating.

    The irony of your signature is spectacular.

    You can continue to argue but I doubt you will get much response in future.
    Mods, please exercise control over these personal attacks in an equitable way
    Manufacturer digital products www.Ciunas.biz
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  8. #508
    Quote Originally Posted by BE718 View Post
    Both Amir have been working with fft and signal processing for many years, myself in a professional test measurement environment. We are fully aware of fft processing characteristics, limitations and real world effects. If you don't believe anything that's being posted here then I am not sure why you are participating.

    Now if you don't understand fft processing then although we both are happy to help people understand, we are certainly not going to respond to the barrage of criticism direct or implied. It might also be helpful if you go and read some literature on the subject and even play with some free spectrum analyser on your PC at home.
    It might also be helpful for you to try being less disrespectful...

  9. #509
    Quote Originally Posted by amirm View Post
    My interest is in improvement of sound coming out of the DAC, your interest is improvement of pulses coming into the DAC. I have explained how the latter can be damaging to the former and at any rate, is not of interest to me since I don't listen to USB pulses.
    Amir:
    Correct me if I am wrong, but I believe that is an unproven new theory of yours that you came up with during your conversation with John Swenson and myself. On Monday you presented that in this thread by saying:

    "What matters here is an indirect connection between USB and DAC's analog output. Noise profile generated by the USB receiver in the DAC if not managed well, bleeds into the DAC. I explained that by making the USB signal cleaner with sharper edges, you are actually increasing the potential for this problem because the receiver must handle "more powerful" and hence more noise inducing signals."


    That strikes me as a pretty bold postulation, and one that is not proven by the very limited set of measurements you have taken. To prove that a cleaner, sharper, and higher amplitude USB signal (essentially the definition of higher signal integrity--and well illustrated by J. Westlake's eye-patterns and ones of Swenson's I have posted elsewhere) are detrimental to the DAC's functioning and to the analog output and fidelity, you are going to have to broaden your research beyond what you have presented to-date. You can measure water in the bucket outside, but that is not proof that it rained (sorry, I live in VERY dry California, not wet Washington ).

    As a computer chip, DAC and interface designer, John Swenson's methods reflect a bit of what JKeny was saying: Measuring things close in, step-by-step in the chain. Just as a engine designer models and tests each sub-system and then the final motor--long before it gets installed in the car and run on the track. So yes, I released the product before the final lap times could be clocked. But like a car, it is being driven by people in the real world, not just measured on the track or bench. So people who choose cars based solely on what the magazine's track timings say--and ignore the subjective driving impressions of the reviewers and all the buyers--are not going to try our product.


    At RMAF I had an interesting chat with the engineer at Aurender--one of the very few digital source components where people have consistently reported getting little or no benefit from a REGEN (though nobody ever said it made their Aurender sound worse AFAIK).
    I was asking him about their USB output port--the one assigned for audio--and he said they went to great lengths to drive it in such a way as to provide maximum signal integrity and obtain a really clean and open eye-pattern.

    Of course that is exactly what the REGEN does. Still nobody has yet shown exactly WHY that helps the sonics from the DAC. We and others have speculated (JS in an educated way about the PHY chips), and while we can measure reduction in ground-plane noise inside the DAC, other traditional tests have not shown much. John is developing a new test (for the analog outputs that can be done with even a cheap dual-channel scope) that we hope will make plain what we think is happening.

    BTW, ask any doctor why aspirin works in the many ways it does. As I recall, they still don't understand it fully. And if it was introduced as a drug today it would never make it past FDA approval.

    Regards,

    Alex Crespi
    UpTone Audio LLC

  10. #510
    Moderator Moderator treitz3's Avatar
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    Hello and good evening to you gentlemen. I'd like to take this opportunity to remind you that this is not a place where personal attacks, insults, mudslinging and what you see on many other forums is allowed. I'd like to also remind you of the forum's goal;

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    No editing has been done to this thread as of yet. If editing is necessary from here on out due to members violating the TOS, administrative action WILL be taken and those violating the rules may not like the outcome. Please think about that before you post again. With that said, lighten up a bit and be a little bit more polite to fellow members. This not only makes for a calmer atmosphere, it increases the pleasure that ALL members and visitors to this forum enjoy.

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