Paul R Posted March 14, 2012 Share Posted March 14, 2012 Do you realize that this thread along is nearly 4 years old? Yep - started in 2008! Have you read back through it or through the 10's of other threads on the system regarding USB cables? You will find all your graphs and testing there, as well as every single argument you have brought up. All you have to do to find your answers is read... -Paul Anyone who considers protocol unimportant has never dealt with a cat DAC. Robert A. Heinlein Link to comment
Mark Powell Posted March 14, 2012 Share Posted March 14, 2012 I put that in about converters in the (false) hope you would not bring that up again. Let me repeat. I did NOT NOT NOT NOT NOT do anything to the DAC. That was linked with a Toslink to the S/PDIF converter. I did NOT NOT NOT NOT NOT effectively 'improve' or 'alter' the cable. I powered the S/PDIF converter from a separate (battery) supply rather than the USB supply. It was simply convenient to cut the USB cable two inches from the converter and insert my power connection there rather than inside the converter. In fact you can now buy socket to plug USB adapters that do just this, so you don't have to touch the cable. The converter was USB powered. So not only are you persisting in misreading what I originally did, it is completely irrelevant to my comment here, even had you not misinterpreted it. Tomorrow, just for you, I am going back to an uncut cable of precisely the same sort, open up the converter and do it there. Will that satisfy you? ALL THAT SAID: Yes, of course the cable behaves the same as all other cables. It is the way that the signal is interpreted that is different. In an 'analogue' signal there are an effectively infinite number of values and any noise becomes part of the signal. In a 'digital' signal there are only TWO values, an electrical representation of zero and one. As long as the voltage (including noise) of those values fall between a certain range, let us say, as an example, between plus 2 volts and plus 4 volts for a zero and between minus 2 volts and minus 4 volts for a one, they are correctly interpreted. So, for example, a voltage jiggling about between minus 2.5 volts and minus 3.5 volts will be correctly interpreted as a one. So noise is allowed for, and does NOT become part of the interpreted signal. If it was not, computers could not operate at all. Link to comment
pilgrum Posted March 14, 2012 Share Posted March 14, 2012 i gave up looking for attachments after 2 pages of posts. Win7pro64>JRiver17>ESI JULI@PCIE>Custom AQ DCoax>AdcomGDA700Mod >GTP450ModAUDIO>AudioquestYIQ3>AdcomGFA5500Mod>12gRomex/MC M1.2s/AQ DB14.2>KEF Q Towers>KEF Reference SBox>ESS AMT1C Mod Link to comment
pilgrum Posted March 14, 2012 Share Posted March 14, 2012 I would like to know how you can have error correction with out a memory buffer and whats the delay involved when using a dac with bi directional talk and error correction? I was wondering because several dac's state they do this but by looking at the boards i don't see any memory modules that would hold the data and analyse it. I am not an computer or electrical engineer but it struck me as odd. Win7pro64>JRiver17>ESI JULI@PCIE>Custom AQ DCoax>AdcomGDA700Mod >GTP450ModAUDIO>AudioquestYIQ3>AdcomGFA5500Mod>12gRomex/MC M1.2s/AQ DB14.2>KEF Q Towers>KEF Reference SBox>ESS AMT1C Mod Link to comment
pilgrum Posted March 14, 2012 Share Posted March 14, 2012 it's very common for complete designs (computer, program ROM, data RAM, and interface logic) to be inside one chip. often these are FPGAs (field-programmable gate arrays), essentially hardware that can become whatever you want it to be. the designer works as if he's drawing a normal schematic (or uses a logic language like verilog), and the design tool spits out data that goes into a little PROM, which is loaded into the FPGA at power up. Error detection is embedded in the data stream and corrections applied one block at a time. The format of the data stream determines how robust the detection and correction can be. Data file transfers can be guaranteed error free. Media streaming assumes that the transfer will continue even if there are uncorrectable errors. They are filled in fro the before and after parts of the stream. Then there's the business of jitter. A great DAC will have it's own clock and will reconstruct the waveform before converting it to analog. you MUST have a memory buffer to stream anything from USB. it has nothing to do with error correction. USB is bursty (sends small packets at high speed, with pauses in between), and the DAC wants one sample per sample clock tick. Win7pro64>JRiver17>ESI JULI@PCIE>Custom AQ DCoax>AdcomGDA700Mod >GTP450ModAUDIO>AudioquestYIQ3>AdcomGFA5500Mod>12gRomex/MC M1.2s/AQ DB14.2>KEF Q Towers>KEF Reference SBox>ESS AMT1C Mod Link to comment
wdw Posted March 15, 2012 Share Posted March 15, 2012 a question if I may... I'm assembling the various cables needed for the Berkeley Alpha USB.. (all Nordost Norse 2 if the budget allows) but if following the dictum from M. Ritter the cables should be, when possible, 1.5 metres in length. I note that the Blue Heaven isn't offered in this length and these guys are "nuts" about appropriate cable lengths...the humour isn't lost on me when this group is selling cables by the metre and strongly suggest the optimum length to be, at least for analogue cables, four metres! ;-) Link to comment
wdomeika Posted March 15, 2012 Share Posted March 15, 2012 BTW, color graphs sound far better than black and white graphs. More colors = better sounding graph. This is indisputable. Cheers, Bill Mac Mini 2011, 60 gb SSD, 8gb ram; PureMusic & BitPerfect; Wavelength Audio Cosecant V3 DAC; Wireworld Silver Starlight usb interconnect; McIntosh C2200 preamp; pair of McIntosh MC252 SS amps run as monoblocks; vintage MC240 Tube amp and 50th Anniversary MC275 tube amps; Krell LAT-2\'s on Sound Anchors; JL Audio F112 subwoofer; Nirvana SX ltd interconnects and speaker cables and power cords; PS Audio P5 Link to comment
tarquineous Posted March 15, 2012 Share Posted March 15, 2012 Please keep the garbage out, goldsdad. In response to Barrows issue with Nordost: I don't trust Nordost Corp. in general. They can make a cable to any length with little problem. Their reluctance is an example of their dishonesty. They make good cables, but are certainly not the best, even if you fall for their false notion that all cables in a system have to be the same brand. Also, no cable is exactly 1.5 meters. And as soon as you plug it in, the length in the circuit changes. So what part of the cable or circuit are they referring to ? Tarq Link to comment
pilgrum Posted March 15, 2012 Share Posted March 15, 2012 Can you post pics of that dac? Win7pro64>JRiver17>ESI JULI@PCIE>Custom AQ DCoax>AdcomGDA700Mod >GTP450ModAUDIO>AudioquestYIQ3>AdcomGFA5500Mod>12gRomex/MC M1.2s/AQ DB14.2>KEF Q Towers>KEF Reference SBox>ESS AMT1C Mod Link to comment
Julf Posted March 15, 2012 Share Posted March 15, 2012 "You are correct about frequency response. Unless 'we' as a group, stop talking about a particular USB cable sounding 'dull', 'bright', or similar we are fixed in an irrelevant paradigm and will get absolutely nowhere." Agree 100%. Approaching possible audible effects of digital cables with the thinking and terminology of the traditional analog world is a bit like the way some military planners went into World War I thinking in cavalry terms... Link to comment
Mark Powell Posted March 15, 2012 Share Posted March 15, 2012 Whoever he might be, is talking out of his a**h*le. A cable is a passive device. It can never add to the sound, it can only detract from it. The shorter the cable is the less the detraction will be. The optimum length is zero. Link to comment
Julf Posted March 15, 2012 Share Posted March 15, 2012 "The optimum length is zero." Not always. When we go to high enough frequencies (and USB / Ethernet is getting there) reflections and wavelength issues start becoming a factor (but aren't usually serious unless there is a real system design flaw). I would be curious to hear what reasons Mr Ritter gives for his recommendations. Link to comment
Mark Powell Posted March 15, 2012 Share Posted March 15, 2012 The same frequencies are used inside the computer and I don't see great lengths of wire hanging out to 'optimise' the length. Also, though it is not used for USB, coax was originally designed for frequencies much much greater than used in our stuff. And now with 'digital' TV we have the signal being better as you shorten the cable between aerial and TV. I was mad enough to try this, with the TV on the roof and the aerial cable shortened, and signal quantity and quality improved slightly, as measured by the TV itself. If one was being totally lunatic, one would solder the cable to the pc boards at either end, thus removing the connectors, where reflections, if any, will occur. But again as always, with 'digital' signals, no matter who is right, we have to ask "Do reflections change the bits?" Link to comment
Artmindes Posted March 15, 2012 Share Posted March 15, 2012 I haven't done any test on USB cables yet, but to me different SPDIF cables sound differently. The differences are not as big as in analog cables for sure, but they still exist. I have 3 different digital cables and each one of them sounds a bit different - one sounds more grainy (Blue Jeans Cable), one is smoother and has more 'air'(DIY silver cable), one has tighter bass (Black Cat SilverStar 75). As for USB cables, I don't know yet, but quite a lot of people report differences, too. This is why I asked for recommendations on the forum as I want to audition a few in my system and see for myself. If I hear the differences then I don't care for any scientific reasons. For me audio is mostly about the experience and what I can hear. Still it is very interesting to read more scientific explanations. Although they are not something I would solely base my decisions on, (not in audio world), but they give a fuller picture of the audio reality. For me my personal experience is more valuable as this is what this hobby is about for me. However I think it's good not to fall into any of the extremes - neither experience alone or measurements only, as both of them are prone to many traps and different errors. Link to comment
Mark Powell Posted March 15, 2012 Share Posted March 15, 2012 But the inconvenient fact remains that if a cable carrying 'digital' signals does not change the bits it cannot change the sound. At least, not with an async USB port on the DAC. That's not an 'extreme', it is merely a fact. Link to comment
Julf Posted March 15, 2012 Share Posted March 15, 2012 "we have to ask "Do reflections change the bits?" Exactly. And my answer was/is "not unless there is a real system design flaw". Link to comment
Mark Powell Posted March 15, 2012 Share Posted March 15, 2012 Does one bit perfect player sound better than another? Does a Mac playing bit perfect sound better/worse that a Windows machine playing bit perfect? Does a purpose built dedicated audio computer sound better than an off-the-shelf laptop? (Not too sure about this, noise from the machine may, just may, get into the DAC. That's the only reason I can think of.) Etc. Etc. Etc. I am slowly coming to the conclusion that it's all nonsense. But I am not totally there yet. Have you noticed that the objectivists seem to be leaving, or only contributing to 'best DAC', or 'music of the evening' and similar? Link to comment
Iberian Posted March 15, 2012 Share Posted March 15, 2012 I really wanted to be able to hear a difference over USB so I joined two 5 meter cables And compared it with the bundled one that came With my DAC Young...... Unfortunately i could hear no discernible difference... Link to comment
Julf Posted March 15, 2012 Share Posted March 15, 2012 "Have you noticed that the objectivists seem to be leaving, or only contributing to 'best DAC', or 'music of the evening' and similar?" Not only that, but there is a very clear pattern of people with actual training, experience and expertise in digital audio, who join CA, start battling the windmills of misinformation, and quickly leave in utter frustration. Link to comment
Mark Powell Posted March 15, 2012 Share Posted March 15, 2012 But my wife still insists on reading 'the stars' astrology column to me out of the paper every morning. All I have observed is that what they say is so broad it could apply to absolutely anything that happens Link to comment
Jud Posted March 15, 2012 Share Posted March 15, 2012 there is a very clear pattern of people with actual training, experience and expertise in digital audio, who join CA, start battling the windmills of misinformation, and quickly leave in utter frustration. Leaving only utter newbies with no actual training or experience, like Demian Martin, Gordon Rankin, Miska, and PeterSt. One never knows, do one? - Fats Waller The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature. Link to comment
Mark Powell Posted March 15, 2012 Share Posted March 15, 2012 I agree with you too It is only a few, and there are more here to learn from than disagree with. I could add quite a lot more names to your list. But there is a whole lot of basically wrong information, and anecdotal stuff, more so on 'digital' cables than anything else. All this 'I hear a difference, you only measure' stuff gets to me. How do they know what others do? Link to comment
Julf Posted March 15, 2012 Share Posted March 15, 2012 "Leaving only utter newbies with no actual training or experience, like Demian Martin, Gordon Rankin, Miska, and PeterSt." I didn't say *all* of them had left. Link to comment
Jud Posted March 15, 2012 Share Posted March 15, 2012 All this 'I hear a difference, you only measure' stuff gets to me. There have been measurements and graphs posted in various threads. There have also been experienced designers such as Gordon Rankin with tens of thousands of dollars worth of test equipment who say they are certain they do hear additional differences (beyond the measurable ones) that aren't accounted for by their measurements so far. So either Gordon is crazy, or there are things in the system of source/cable/DAC that cause audible differences that at least some knowledgeable, experienced people don't know how to measure yet. I'm very happy to have measurements when they're available, but also tend to allow some validity to people's experiences even if they don't happen to own the very expensive test apparatus or have the spare time necessary to do repeated, careful, robust measurements. I also don't think Gordon's crazy. :-) (Gosh, I'm sure Gordon is breathing a sigh of relief about that, right?) One never knows, do one? - Fats Waller The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature. Link to comment
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