DIY hifi source

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Hmmm ... I can see where part of this is leading - I've appear to be suffering from a misunderstanding, that a DAC is a hybrid device, a bridge between the digital and analogue world. Whereas, the truth is that it is a 100% digital device and therefore is only subject to the constraints and considerations relevant to "digital engineering".

My apologies for that confusion ...

Frank
 
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Originally Posted by marce
But however many times audiophiles (lost variety) say digital is analogue it will not change the fact that DIGITAL electronics is a discipline on its own with its own rules, and ways of working and especuialy PCB layout techniques.
Keep chasing the demons

The above quotation are what I simply call ********...
I am wondering what your motivations may be..
Raytech
Why is it bull, are you another audiofile who does not understand digital electronics...
My motivations aqre that for the last 27 years I have been involved with electronic design, often to mil aero medical level, and on some very interseting projects as well as numerous commercial ones, so I hva e some understanding of what goes on and lay out very complex digital, analogue and digital/analogue boards every day.
What dont you understand about digital and analogue/digital, and what dont you understand about the differences between the two.
Since you have been so dismisive explaqin yourself please.
 
I think we have now established that what started as an apparent claim that different digital storage methods can sound different has gradually morphed, under pressure of science, into a claim that different playback mechanisms can sound different. This is true and unsurprising. Of course different type of storage mechanism may generate different amounts of supply rail noise, ground bounce etc. so in weak equipment this may sound different if it can (for example) get into the master clock and create different patterns of jitter. As I said, this is a playback issue not a storage issue. Do we all agree now? Life would be much better if people said what they meant, rather than saying something different and even (at first) defending it before admitting that they actually mean something else.

Perhaps the reason for the fight is that there are people who claim, with a straight face, that audio data files somehow retain a memory of what storage devices they have been on. So a file copied from hard disc to a USB stick and back again will somehow retain some 'USBness' when you listen to it. Completely barmy, yet people believe it!

I apologise if we have been confusing complete idiots with people who merely don't mean quite what they say.
 
Fas 42m, stop being so stupidly childish, it is you lot that are moving the goalposts, it started of regarding this noise being part of the digital signal, now its noise in general. I even posted a link to another thread that I though may of been of interest in furthering your understanding regarding PC's, but no real facts and research dont come into it.
We were discusing the digital chain up to the DAC. There are numerous contributers who keep on equating digital design to analogue, you are one of them, which is a misunderstanding of electronic design, attributing analogue problems, etc to digital.
I have numerous documents on digital/analogue design and if you bothered looking and reading you may learn somthing, Ti ahave numerous ones as do other chip manufacturers, Henry Ott amonst others is a good source of info as well.
The basicss are covered in this document:
http://www.x2y.com/filters/TechDay09... _JohnWu.pdf

Grounding of Mixes Signal Systems
http://www.hottconsultants.com/pdf_files/june2001pcd_mixedsignal.pdf

http://www.ti.com/lit/ml/slyp167/slyp167.pdf
http://www.analog.com/static/imported-files/application_notes/AN-1142.pdf
 
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Of course different type of storage mechanism may generate different amounts of supply rail noise, ground bounce etc. so in weak equipment this may sound different if it can (for example) get into the master clock and create different patterns of jitter. As I said, this is a playback issue not a storage issue. Do we all agree now?
Yes, but most people would associate the storage with playback; in their mind there is a 1:1 relationship, they can't experience what that storage is, except via reproduction of the stored information. Hence the "confusion" ...

Frank
 
Fas 42m, stop being so stupidly childish, it is you lot that are moving the goalposts, it started of regarding this noise being part of the digital signal, now its noise in general. I even posted a link to another thread that I though may of been of interest in furthering your understanding regarding PC's, but no real facts and research dont come into it.
Well, had to change the tone of the conversation somehow, so at least now we have a bit more movement ...

Okay, any electrical signal can be considered to have digital properties, and analogue properties, if it has meaning in a digital context? It must have analogue properties, because I can do nasty things to it, by doing something as simple as applying an appropriately sized capacitor to a point in the circuitry where that signal is routed -- all of a sudden that precise, digital information degenerates into meaningless nonsense. So, looking back at the DAC now, all the "digital" inputs are also analogue ones from the point of view of the internal functioning of the chip: like the drawing of the vase that turns into 2 faces looking at each other nothing has actually changed, but our interpretation, understanding of what's going on has changed ...

Yes, there are all the techniques that minimise "problems", but we are still dealing with an analogue world, where nothing is ever really certain, we no longer have 0's and 1's, we have performances measured in "greater than", "less than", etc ...

Frank
 
******** Frank, you didnt change conversation topic to help it along, you tried to slide it over as if thats what you were talking about, while refusing to answer the very basic questions, because you dont have any data, you dont even have a theory, you just have a story.

while the decisions are digital, the voltages and noise are meaningless do you get that? meaningless, nothing, they mean nothing unless they force a change from a 0 to a 1, at which point it is not bit-perfect. little differences against the ideal do not collect somehow, waiting for the analogue electrons to have their backs turned, so they can attack when they are at their most vulnerable.

you are still trying to mix 2 things and talking as if its obvious, while utterly missing the point. digital is governed by a set of rules, or fence posts depending on the protocol the particular chip accepts and no matter how chaotic the voltages used to communicate the information, as long as it falls within the preset guidelines to discriminate between a 1 or 0 even a little bit, it is read as 100% 1, or 100% 0. it is not uncertain or confused if its close to, but not quite 1, it is 0, very definitely and instantly 0 and the action associated with being a 0 is instantly and completely carried out. this action, whether it means another digital stage, or a conversion to the analogue domain in a DAC, is then carried out with the same conviction and purity as if it was perfectly 0 to begin with.

thats the entire point and it works very well.
 
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The world I was referring to was that within the DAC, my apologies if that didn't come across clearly: everything before the inputs to the DAC can be considered always as purely digital entities, everything following normally is now considered analogue. It's what happens in that "black box" inbetween, the DAC itself, that's the troublesome area, that's what the last paragraph of my previous post was referring to.

Frank
 
27 years of high speed digital design and learning down the drain.
IT IS DIGITAL DESIGN AND DIGITAL LAYOUT, STOP ATTRIBUTING ANALOGUE TECHNIQUES TO IT.
What dont some understand, please at least learn the basics of how a digital signal travcels from a to b, transmission line theory comes into it as well. They are not analogue signals they are digital, the only analogue is the fact that a digital signal is made up of numerous summed sine waves, the spectral content of which is determined by the rise time of the digital signal.
beTheSignal.com
Signal Consulting, Inc. - Dr. Howard Johnson
 
It's what happens in that "black box" inbetween, the DAC itself, that's the troublesome area, that's what the last paragraph of my previous post was referring to
Its pretty well known how the various forms of digital to analogue work, it is not a black box unknown mystery.
How DACs Work
Look at some of the links I have put up regarding digital/analogue mixed systems, there are thousands of them out there, not just related to audio.
Many years ago you we had much more analogue elctronics, with 4-20mA loops for the analogue transducers, over the years that has changed due to improvements with digital signal processing and the fact that analogue signaling is prone to noise and other gremlins. Hence digital signal transfer became more popular and more and more analogue transducers had built in ADC's or were placed very near ADC and digital circuitry to convert the analogue signal to digital as soon as possible to allow for transmission of the information to the control electronics. As DSP became became more readily available, the amount of analoge elctronics on the end of this digital link has decreased greatly as more and more signal processing is done in the digital domain. it is not just in audio, nut medical equipement fly/drive by wire etc etc. So digital/analogue elctronics and the interface, noise etc is well understood and covered by numerous engineering practices etc.
 
Who knows, they may be right. When I left the office on Friday, the precision CNC machines were making 256 toothed gears. No-one changed the programming and the file is the same, but now the gears all have 255 or 257 teeth. The operators are telling me that this is normal, 256 is just an average value, this sort of thing happens all the time when they use disk drives instead of thumb drives.
 
Read Howard Johnson, or some of the others, they are a digital signals, RF is a different beast again, there is so much information on digital layout and signal integrity, so you dont need to lay them out as analogue RF, just as digital signals. If you was going to do that why not lay the DDR memory interface as analogue RF, its even faster than I2S or SPDIF.
Laying them out as normal digital signals is all that is required.
 
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Sy, that would worry me, though I have seen lots of problems with EMC and CNC machines, old ones though, had a red area marked on the floor, no one to enter when machine running. Problem could be the actual electronics in the machine and interpitation of the data once read in, common to read, if they find a solution please post it, though I would suspect some EMC event.
 
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He's already stated that he just waves his hands, which he considers more useful than data. Give it up.

You're right, I should. I guess I'll never know what he means when he says 'gets cosy' or 'black box'. Or maybe I already do. It means I want to believe.

I thought of something that might help his embattled cause, but on second thought, no. Did you know that eavesdroppers on wartime communications could tell who was keying the information? They didn't crack the enemy code, but interpolated troop movement because the key operator moved with the same army company. Though that wasn't just on and off since there were dots, dashes and spaces. Speed? Rhythm? Frequency of rest pauses? Length of dot, dash? Consistency? The eavesdroppers could just tell which operator it was. I find that fascinating. Will share the link if I can find it. Too far removed from the world of our believers, with machines talking to machines, though.

BTW Sy, your PM mailbox is full.
 
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