It isn't, play with isolation between circuitry and interfaces all the time, true isolation requires very careful layout practices... been discussing this recently via PMs with another member which prompted me to look at some previous information from some designs I have worked on... Using such things as these:
Picor QuietPower DC-DC Filter ? Vicor | DigiKey
with good RF isolation techniques in the layout you can isolate and reduce noise. I have not seen any layouts or designs from the many that are proliferating the new Audio cash cow (USB/Ethernet Isolation, Hubs, noise reduction!). Regarding USB interface matching, it is a requirement of the USB standard (90ohm diff pairs for data lines) and I would imagine that most interfaces (especially in a PC, there are numerous controlled impedance interface requirements for a PC motherboard, USB is just one of these. I have read the entire thread linked, quite interesting, especially some views on what constitutes signal integrity. What does concern me is that none of the recent USB audio based devices actually have any actual measured data or minimal...
More on USB noise...
Archimago's Musings: MEASUREMENTS: Computer USB port noise, USB hubs and the 8kHz PHY Microframe Packet Noise
Done my own Jitterbug, downloaded some USB hub chip info (28 pin QFN's) might throw my own design (thank you evaluation designs) together with some Vicor/Picor power for the USB bus, and as much isolation as possible input to output to minimise any high frequency simultaneous switching noise (inherent to all digital servers be they PC or bespoke) creeping through as well as any lower frequency noise covered by the Picor devices (tens to hundred kHz, often the realm of switcher based noise run at 100kHzs switching frequencies).
Picor QuietPower DC-DC Filter ? Vicor | DigiKey
with good RF isolation techniques in the layout you can isolate and reduce noise. I have not seen any layouts or designs from the many that are proliferating the new Audio cash cow (USB/Ethernet Isolation, Hubs, noise reduction!). Regarding USB interface matching, it is a requirement of the USB standard (90ohm diff pairs for data lines) and I would imagine that most interfaces (especially in a PC, there are numerous controlled impedance interface requirements for a PC motherboard, USB is just one of these. I have read the entire thread linked, quite interesting, especially some views on what constitutes signal integrity. What does concern me is that none of the recent USB audio based devices actually have any actual measured data or minimal...
More on USB noise...
Archimago's Musings: MEASUREMENTS: Computer USB port noise, USB hubs and the 8kHz PHY Microframe Packet Noise
Done my own Jitterbug, downloaded some USB hub chip info (28 pin QFN's) might throw my own design (thank you evaluation designs) together with some Vicor/Picor power for the USB bus, and as much isolation as possible input to output to minimise any high frequency simultaneous switching noise (inherent to all digital servers be they PC or bespoke) creeping through as well as any lower frequency noise covered by the Picor devices (tens to hundred kHz, often the realm of switcher based noise run at 100kHzs switching frequencies).
Last edited:
True. I also find it funny that these issues are considered "new" or "edge of known science" in any way - we are talking about differential signalling and digital transmission links, bread and butter stuff in transmission (telecommunications) networks for the last 50 years or so. Jitter and jitter measurement is an extremely well understood topic (except in high end audio, it seems). We don't routinely transfer hundreds of gigabytes of data per second over thousands of miles of sea cable systems by randomly inserting capacitors and seeing if it improves the situation...
Hmmm... I think it's the other way around. The i2soverusb design is a commercial product, promoted here on the board. AFAIK it doesn't come with any measurements regarding jitter performance or isolation effectiveness. So actually the product is purchased on trusting the designer, which is fine by my standards, but it probably isn't by yours. The product does it's job, so in that way it proves it works when plugging it in. So I don't think measurements are needed either when a design is being criticized. On the contrary, (the wrong) measurements were used here trying to prove the design was just fine w.r.t. analog pin.
If someone wants to measure the effect of the capacitor, besides the subjective experience of listening, I can think of two methods. (1) to measure the voltage on the PLL_AVDD pin with an oscilloscope, to see if the noise on the pin is reduced (2) to measure the jitter of the XCore clock, by modifying XMOS software to output XCore clock on one pin. Then use a very good oscilloscope to produce an eye-diagram. Maybe somebody with plenty measuring experience can think of other methods.
As I explained before, we won't come any further by measuring frequency response of the entire setup, trying to 'prove' (in)audibility; that would be a dead end.
Hey guys, you are taking my words from the wrong side: i never said we should only trust my (or any other single person's) hearing ability.
I never said i think scientific approach is not of great importance and technical/engineering work is not needed.
Nor i said measures and spread blind tests are unnecessary and we only have to trust one person's subjective impressions.
Yes, tubes (for example) have been designed by technical experts after studies on theories and calculations, that's clear to anyone of us. But many tubes designed for other needs (think to Siemens CCAs) have been tested on audio equipment to check how they would sound and they resulted as good or better than tubes specifically designed for audio. This means that curiosity, experimentation and personal listening experience also played a strong role (that's why i said "as much as...", that doesn't mean "only") and can't be defined insignificant.
So if several other people have a positive experience about a mod, i think it's a very silly attitude to reject that mod without even testing deeply because it doesn't accord to the principles we actually know as confirmed.
We don't know everything about audio perception and electrical behaviour, surely much more has to be discovered and understood yet. So we can't deny that something could not be in accord to the principles we actually know and still be real, maybe there's something else we still didn't study enough that can play a role in good audio reproduction.
The theoretical field of atoms behaviour, electrical phenomenons and what really happens during digital reproduction is very vast and i don't think someone can say he knows everything, even between already made studies. So how can someone be absolutely sure about the inconsistence of another one's observation?
That's why i absolutely trust in Science, but in REAL Science, that never should deny an observed phenomenon before it has been deeply tested, just basing on existing theories. This doesn't mean that phenomenon objective effectiveness shouldn't be checked, i only want to say that it shouldn't be denied A PRIORI.
Current measurement methods are based on what we actually know, so they cannot be trusted 100%, as we could have measured a phenomenon the wrong way or in the wrong aspects.
First we have to find if the phenomenon is true and objective from the perception side, that's why i insist to test the mods using double blind tests. Until this will not be done, we can't say the phenomenon is an illusion. I agree that listening tests are only A PART of all the process. But this part surely has to be done and imho cannot be simplistically avoided if the phenomenon seems impossible upon our knowledge!
Maybe (and i emphasize maybe) even the common and mutual agreeing of all the people that tested the phenomenon could be enough to confirm it, as we always do for 99% of the phenomenons we face in our lives (if i see a wall ahead of me while driving a car, i don't have to wait that it is confirmed by technical measurements before i steer away!). Expecially if the phenomenon is about perception, as good audio surely is, and not entirely an objective and measurable phenomenon!
Anyway, when the phenomenon has been confirmed (and IF it has been confirmed), then we have to find how to measure it, if current measurements methods do not live up to the needs.
Finally, we will develop a new theory that explains the phenomenon using the measured datas. BUT if theory is incorrect and measurements lacking, this not necessarily means the phenomenon doesn't exist: imho this can be said only if the phenomenon has not been confirmed by perceptive (double blind, thus objective) methods.
I think REAL Science is the world of open minds and lives on continous subverting and expanding existing theories and knowledge: think about quantum physics...
Last edited:
Of course we can't be absolutely sure about anything. "Extraordinary claims require extraordinary evidence" is still a pretty good principle.
Any time somebody who isn't actually a quantum physicist mentions quantum physics, my pseudoscience radar goes "ding!"... 🙂
Do you mean my University Physics and mathematics professor, that works by Geneva's CERN and whom i took this phrase (and many other arguments i exposed) from, is a pseudoscientist? 😱
This actual statement you posted seems to me really very representative of a prejudice-filled point of view...
Last edited:
Good. So let's search for this evidence, or for the absolute evidence of it to be incorrect. I don't think we found none of the two yet.
This is what i'm tring to say from many days.
I do have a prejudice (based on years of experience) against people who are not quantum physicists but use "quantum physics" as an example. I have nothing as such against the phrase your professor used, if it used in the right context.
It's not my intention to talk any more about epistemology or quantum physics: i doubt the users of this thread would be interested.
All i wanted to explain is that any scientific theory, even if confirmed, has fields limits: of application, of observation, of magnitude, and so on.
Newtonian Mechanics are not incorrect, if we consider them in their own field limit of application. But if we think they're an absolute law that applies to everything at any field, we make a big error and many subatomic phenomenons could be considered false and impossible - even if they're absolutely real and demonstrable.
One doesn't have to be a Quantum Physicist to understand this...
Indeed.
Absolutely. But it takes more than someone just saying "I felt the earth move" to make me believe that person has detected a flaw in Newtonian Mechanics.
No, but in 99.9% of cases when a non-physicists evoke quantum physics, it is to support their argument that "science can't explain everything, so I might be right and scientists wrong". Yes, that is me being prejudiced, but it is at least based on statistics 🙂
I totally agree with this statement: it's not only a matter of science being correct or wrong, but anyone being trustable or not, too.
I know NinoSimona from a while here in Diyaudio and i think he's trustable enough. I don't think he has soldered a capacitor in a random place, so to experiment in a random manner.
But this doesn't mean his mod is surely good, i only wanted to say that he deserves some more tests before we can say his mod is not worth our attention. That's why i'm trying to convince some more users to implement the - quite simple - mod and perform some blind tests, even if the already carried out measurements seem to deny its effectiveness.
I can't know if after the tests the mod will be found worthy. But why not give it a try? We have 2 users that actually found an improvement and 1 that didn't find any improvement - unfortunately none of them made some double blind test, even the latter... It's a bit too little as a sample...
Not sure it is about trusting people - when somebody tells me they felt the earth move, I don't assume they are lying. I assume that they genuinely believe the earth moved. But unless they have verified it in some objective way, it really doesn't tell me much about the movement of earth.
Indeed. Hopefully somebody will make an effort to verify the effectiveness of the tweak objectively - but until then, it is just another unverified audiophile tweak, and there is unfortunately no shortage of those...
Bogus. It's not just an 'audiophile tweak', I think I documented it quite right. Until now I haven't heard anybody object to the fact that the analog pin should have been separated from VDD. You put that aside very easily.
But again: If you don't want to do the tweak, then don't. You make it very easy on yourself not to do the tweak and yet have an opinion about it. Talking about prejudice...
This is not true.. there is capacitor on that position, you just added bigger and slower..
Joro give only valid documents about your 'tweak'.. showing how bizarre it is..
Merriam-Webster gives this definition of "tweak":
What part of that definition do you disagree with (and in what way do you feel using that term constitutes prejudice?
😀
The funny thing about this era is that you can imagine the craziest thing and you'll ever find someone that agrees somewhere...
Eratostene from Cirene measured the Earth radium with a surprisingly low error in 3rd Century AC... he surely was not a rapper... 😉
Last edited:
This is true. Perhaps you didn't read the datasheet?
Sure, the capacitor I added doesn't make the analog pin separated from VDD, but that doesn't mean it doesn't compensate the mistake. Joro's measurements regarding this are not to be taken seriously, as I already explained in my post in response to his. Maybe you should read that one again and try to understand, together with the datasheet.
The definition has nothing to do with it, your prejudice lies in the fact you have an opinion on something you didn't do yourself, ignoring the arguments that came with it. That attitude gets annoying, you better try and contribute by, for example, investigating the setup using your ears or measurements, in your case to prove my wrong, and being on topic this way. Then your judgement will get some substance.Julf said:
Last edited:
I have to disagree. If you start using words in ways that differ from their commonly accepted definitions, you are creating your own language - and that makes communication difficult.
I can state 1 + 1 = 2 without having to have invented arithmetic myself. I can also have an opinion about the likely outcome of jumping off a 100 ft cliff without having tried it myself. If you call that prejudice, so be it...