Ok, fine, this comment is on topic, thank you. Apologies in return.
I respect your views regarding digital power supply, it's an interesting world indeed, you seem quite involved in this. Perhaps you didn't understand my first post regarding the issue, but this capacitor isn't about digital power supply and isn't about (extra) digital decoupling either.
Digital supply seems to be fine with this design. Joro made the decision of not to supply the analog PLL_AVDD pin with separate psu and connected it with the RC-filter to VDD. As I explained in my posts, the clock the XMOS device is running is VCO based, which is powered by this pin. By adding the capacitor I improved the noise rejection of the filter, as to compensate for the mistakenly shared psu. The analog pin will rise to the correct voltage somewhat slower at startup, but that's still tolerated.
I don't feel any need myself to prove this by measurements, of whatever kind, but if someone else does, it's their challenge to do so the correct way. I kindly reserve the right to disagree on the effectiveness of measurements in general and of joro's in particular.
The mod is easy, and fully reversible. If you don't appreciate it, don't do it. By doing this audio hobby for years, I'm very well aware of the subjectivity involved and made mistakes as well. That's why I didn't try to describe what exactly the differences in SQ in my setup are, because that could make judgement for others more difficult. Still I'm convinced I did the right thing, don't blame me for my enthusiasm in sharing what I found.
As in response to Baka: If you don't agree with him, all right, but with such a response, not taking him seriously, in the end nobody, regardless of what origin, will ever contribute to whatever thread, other than to confirm each others shared views; you'll never hear something that tickles imagination. In my opinion that is not the atmosphere to aim for.
Nino
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Yes, that is a perfect parody/spoof of all the typical audiophile tweaks. Very funny! Thanks for sharing!
Observing a phenomenon, trying to replicate it and adjust theory to explain it if it's confirmed = SCIENCE
Accepting a phenomenon only if it conforms with own (understanding of) theory, without even verifying if it is real = BLIND FAITH (that's what Christian Church was doing in the Medieval age, do you remember? With a bit more ferocity, to be honest...)
IMHO, attacking or trying to ridicule other's findings, refusing to test them directly even if it's so easy to do, is the exact opposite of a scientific approach.
We have not come to know EVERYTHING about electricity, or about atoms, or about anything at all. Theories have to evolve every day, enriched by observation of new phenomenons: this would be real science.
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I did comment to say that if anything the capacitor is acting as a reservoir cap, myself I would be inclined to use another MLCC SMD say around 100uF/150uF. Looking at some designs I have worked on there is a variety of solutions from exactly as the data sheet, to extra caps, pi filters with MLCC ferrite MLCC up to the extreme cases a separate LDO for each power section of a device (this is over a range of devices and designs). All these designs have been through EMC testing etc. and all work.... Does the extra care on PLL make a difference, in the majority of cases they were not tested for such fine detail, the schemes were what was the engineers view/pet decoupling scheme (they often have their own views often misguided). Where testing was done down to very low level detail was on a frequency hopping communications system, the best results were from using a low value COG as well as a 0.1uF X7R for local decoupling (the value of the COG choses to give a small package size) small package size (0402) and minimum inductive parasitic of the layout. The larger reservoir caps didn't have any noticeable effect, unless removed, but could be placed some distance from the pin (mm's). The problem is these things are best done at layout as extra parasitic inductance can negate any benefits, though with reservoir caps the parasitic inductance and resistance is required to damp down any chance of oscillations. It is a complex subject, we have a simulation tool for power integrity, that is not often used (unfortunately) mainly due to the time and resources required to do the simulations. I would like to play with it more but never have the time these days as it is interesting to see how bad even common practice decoupling schemes are.... Distributed planar capacitance and HDI layouts are the way to go....
I spend my days herding signals round PCBs I know how signals travel I know how fast electrons move...
I spend a lot of time and 30 years of my life doing this so I am speaking from knowledge and experience, hence I can ridicule this daft idea. We have understood signal propagation for many years, Oliver Heaviside gave us the initial equations and did the initial research based on Maxwell's principles, many others have followed and furthered our knowledge. Look up electron drift velocity then come back and argue from understanding rather than blind faith and accusing me of commenting without understanding....
In fact your starter...
https://en.wikipedia.org/wiki/Drift_velocity
then if you want we can move onto how signals propagate and return current flow (very critical) because if you understand return current flow then you will understand ground loops and other aspects of audio better. The electrons do not travel rounds a wire or trace, they jiggle in place under the influence of the EM wave the signal creates... so electron pools are total HUMBUG.....
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IMHO, being so sure about anything is hazardous and does not allow further development of knowledge unless in a specific direction.
Nothing personal, but i don't think this is a correct approach.
The electrons theory around battery ground tweak is only an attempt to explain many users observations, but even the authors say they're not sure about that theory.
So focusing on it you're diverting from the real point: do that tweak produce any SQ enhancement? If it does, then someone will find a more correct theory to explain this enhancement, that could be totally different from the suggested theory. If it does not, there's surely no need to spend time about it. But this common observation has to be made FIRST.
The same for NinoSimona mod.
Exactly. And the scientific way to proceed is to verify if there really is a difference in sound - by independent observations, and by trying to remove other factors that might be causing the effect (such as confirmation bias).
When we are sure there is something to explain we can come up with theories that can explain the effect - but those theories have to be falsifiable (there has to be a test that can disprove the theory), and they have to be tested - until then they are just speculation.
So let's verify if there is a difference in sound by applying NinoSimona mod: the more of us will do so, the more precise observation we will have.
If possible, it would be better to do double blind tests, obviously.
Then, if something positive is found, we will discuss on the right way to make measurements to show what originates that enhancement.
Don't you agree?
Absolutely. Looking forward to the results. But I am willing to make a prediction (and happy to be proven wrong) - if people try, many will report an improvement, some will not, but all will be either sighted or single-blind tests.
I agree, this kind of tests is always confused by many factors, not only subjective tastes or emotivity, but also differences in each one's systems.
Anyway, we will have something to start from and to discuss, based on effective tests.
Making double blind tests is very important, so who has the necessary hardware and time please try to perform them...
so what, it still does not change the laws of physics or reality... If you bother to read up the Battery Ground Tweak it was based on Bud Purvines Ground tails again the theory being it acted as an electron pool.
As I said before just some basic knowledge of signal flow will show that this is ridiculous concept, and in fact more likely to act as a dipole and introduce airborne EMI into the circuitry.
Someone's background does not mean they can still be party to audiophile add-ons designed to remove the money from the gullible pockets there are many of them out there, often designed (according to the marketing)
by moonlighting aerospace engineers or similar... The operation of these devices is dubious and often relies on the suspension of the rules of physics, BGT, BQPs and earthing boxes are prime examples of what is effectively a scam...
Jack Bybee! the purveyor of one of Audio biggest jokes, the Quantum purifier, LOL not the best recommendation.......
Of course the usual insults and pull downs will now be thrown in my direction...
Anyway two excellent guides, with information that is relevant to this thread, and to help your understanding of how signals propagate...
http://www.x2y.com/filters/TechDay0...log_Designs_Demand_GoodPCBLayouts _JohnWu.pdf
A bit about clocks halfway down in these notes...
Analog Devices: Analog Dialogue: Ask The Applications Engineer - 12
Also do a search on google for “Tackling EMI and RFI at the Board and System Level” open the power point 2, all the lecture notes are included.
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Without empirical testing and data, hearsay does not count sorry, be it 1 person or 1 million.
What do you mean you have made your choice, what choice!
Ah you use the battery ground tweak... your choice, personally I would not be hanging anything from my system that could act as an antenna... I am also more open minded and don't just do random things but try and get some knowledge and understanding of what I am going to do and whether there is any science or sense behind it, especially when it comes to audio tweaks, one has to separate the BS from reality and also realise that our perceptions are easily fooled, we are subject to strong expectation bias and there are numerous cons out there and many myths with no basis in science or engineering.... none of which do the audio hobby any good and in fact are often detrimental to the hobby... You may disagree as many do, but getting back to reality in audio and getting rid of many of the myths and scams would help us move forward....
Interesting that you wont even look at the documentation posted though or revue the reality of the product you are using"!
Ah you use the battery ground tweak... your choice, personally I would not be hanging anything from my system that could act as an antenna... I am also more open minded and don't just do random things but try and get some knowledge and understanding of what I am going to do and whether there is any science or sense behind it, especially when it comes to audio tweaks, one has to separate the BS from reality and also realise that our perceptions are easily fooled, we are subject to strong expectation bias and there are numerous cons out there and many myths with no basis in science or engineering.... none of which do the audio hobby any good and in fact are often detrimental to the hobby... You may disagree as many do, but getting back to reality in audio and getting rid of many of the myths and scams would help us move forward....
Interesting that you wont even look at the documentation posted though or revue the reality of the product you are using"!
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What do you mean you have made your choice, what choice!
I am not an EE nor a person with particular technical knowledge so I am not designing anything.
I am an audiophile, ready to by some modules and build something straight, try some proven tweaks and that's my field of interest.
That is my choice so thank you for your opinions and links that you've attached.
BGT will hapilly stay in both my cd player and amp together with some other applied tweaks.
I am out of this thread from now on.
Regards to all.
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