esldude Posted July 14, 2016 Share Posted July 14, 2016 Why are you commenting in this thread? Because you haven't attributed these errors to jitter perhaps? Sent from my Nexus 6P using Computer Audiophile mobile app And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. Link to comment
NOMBEDES Posted July 14, 2016 Share Posted July 14, 2016 Pretty useless experiment.. USB normally transmits bits perfectly, so it takes a "horrible" USB cable to explore the limit of that ability. The problem of USB audio is not bit transmission, it is electrical noise and timing.. No. This is genius! This exercise proves we can build a bad cable. Therefore, we can build a good cable, and, someday a better cable.....the end result will be a $10K power cable to plug into your crappy home power source. In any dispute the intensity of feeling is inversely proportional to the value of the issues at stake ~ Sayre's Law Link to comment
Paul R Posted July 15, 2016 Share Posted July 15, 2016 No. This is genius! This exercise proves we can build a bad cable. Therefore, we can build a good cable, and, someday a better cable.....the end result will be a $10K power cable to plug into your crappy home power source. We need to get more defined meanings for "crappy." European power is - well - crappy. U.S. power - not so shabby... (grin) -Paul Anyone who considers protocol unimportant has never dealt with a cat DAC. Robert A. Heinlein Link to comment
sandyk Posted July 15, 2016 Share Posted July 15, 2016 I did some awful stuff to test USB but this put you straight in the hall of fame Hall of Fame, or Hall of Shame ? (grin) How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file. PROFILE UPDATED 13-11-2020 Link to comment
alfe Posted July 15, 2016 Share Posted July 15, 2016 To get a better picture of the errors, I used a test signal that simply increases by one with each sample. At 96 kHz this takes about 87 seconds. Dropped packets thus show up in the digital capture as a sample to sample difference greater than one. With the capacitor in the minimum setting, I got a total of 71 skips (the exact number is obviously random). Most of the skips were 12 samples long, some 60 samples, and a few were 13 or 61 samples. That look likes a baud mismatch. Link to comment
mansr Posted July 15, 2016 Author Share Posted July 15, 2016 That look likes a baud mismatch. The packet loss probably wreaks havoc with the rate feedback mechanism. A 96 kHz sample rate corresponds to 12 samples per microframe, so it's obvious where that came from, and if the DAC clock is slightly faster than the USB clock, a few frames would need 13 samples to keep up. Link to comment
alfe Posted July 15, 2016 Share Posted July 15, 2016 The packet loss probably wreaks havoc with the rate feedback mechanism. A 96 kHz sample rate corresponds to 12 samples per microframe, so it's obvious where that came from, and if the DAC clock is slightly faster than the USB clock, a few frames would need 13 samples to keep up. You should try a gizmo for fun:) Link to comment
Middy Posted July 15, 2016 Share Posted July 15, 2016 I hope it's not hijacking the thread to ask advice mansr. I want to make a y cable. Power from a HUB and data from my phone. I have an intona ipurifier in series from an otg to Brooklyn DAC. Sound great but I drain a full battery in less than 3 hours... Sorry to ask as Google has let me down searching for Y or splitter cables. I thought charger to hub.... > cable 1 USB2 D+ D- cut. 5v and Ground remain.. Cable attached to OTG D+ D- remain. Ground remain... cut 5V. Cable 2 Solder HUB 5v to pin cable from 1 to cable 2 Splice Ground from cable 1 to cable 2 In my none electrics brain that made sense. Wasn't sure if splicing of ground is required. To work or ground loops... Apologies for the question Mansr. A desperate man grabs at the nearest thing... I did think wall wart or a battery pack...but I have a hub no Walmart yet though.. waiting for advice.. The correct cable layout first I think from phone to dac. Power advice second Thanks for your or others time Kind regards Dave [emoji4] Sent from my SM-G900F using Computer Audiophile mobile app Link to comment
mansr Posted July 15, 2016 Author Share Posted July 15, 2016 You should try a gizmo for fun:) I would if I had one. Link to comment
Jud Posted July 15, 2016 Share Posted July 15, 2016 Note that the waveform is piecewise correct but riddled with skips and drop-outs. It sounds awful. In conclusion, if there are data errors on a USB connection, it will be obvious. The first few seconds of the recording are fine. When errors start showing up, it's as an occasional skip which is clearly audible. The thing is, as soon as a single bit is wrong, an entire packet is discarded, and this causes a huge error in the recovered data stream. Yup. To the extent there are relatively subtle qualitative differences in the sound of a system, they will not be caused by errors on the scale of "bit-flipping" or dropouts. 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
mansr Posted July 15, 2016 Author Share Posted July 15, 2016 I hope it's not hijacking the thread to ask advice mansr. I want to make a y cable. Power from a HUB and data from my phone. I have an intona ipurifier in series from an otg to Brooklyn DAC.Sound great but I drain a full battery in less than 3 hours... Sorry to ask as Google has let me down searching for Y or splitter cables. I thought charger to hub.... > cable 1 USB2 D+ D- cut. 5v and Ground remain.. Cable attached to OTG D+ D- remain. Ground remain... cut 5V. Cable 2 Solder HUB 5v to pin cable from 1 to cable 2 Splice Ground from cable 1 to cable 2 In my none electrics brain that made sense. Wasn't sure if splicing of ground is required. To work or ground loops... The ground needs to be connected for device detection to work. The host (phone in your case) detects device presence by one or both of the data lines being pulled high, the combination indicating the speed of the device. This means the ground is required as a reference. The 5V wire can be cut and spliced from another power source. Now if you're anyway using a hub, why don't you simply let it provide bus power the usual way? Link to comment
Middy Posted July 15, 2016 Share Posted July 15, 2016 Thanks for taking the time to respond Mansr. The hub came without a supply and I am still toying on a solution. I didn't want to destroy my AB supra I have. So thought to try a little mini male female B's. I did think of a phone battery pack or direct 5v Walmart. The ifi ipurifier and Intona do sound nice in series. But won't work post intona. I plug the IFI into the INTONA.... What ever I do as long as it doesn't sound worse I am ok. Don't forget I am Aerospace trained in soldering but teletubbie trained in electronics... I just got a multimeter for the continuity function...... I still have the OPPO HA1 under my Brooklyn. It has a USB port I can use to test the hub. When I get back from Spain /Lanzerote I will give it a try... Btw I hope everyone of our French friends are safe after another terrible day at the hands of a madman.. Sent from my SM-G900F using Computer Audiophile mobile app Link to comment
plissken Posted July 15, 2016 Share Posted July 15, 2016 Just need a reclocker. Which of course is the responsibility of the DAC. Link to comment
plissken Posted July 15, 2016 Share Posted July 15, 2016 Thanks for taking the time to respond Mansr. The hub came without a supply and I am still toying on a solution[/url] Get a well regulated supply for the hub then. Link to comment
Middy Posted July 15, 2016 Share Posted July 15, 2016 Cheers plissken, obvious but as soon as you invest in something on here. ... Have you tried this one..... I have the IFI AND THE INTONA (from advice here) but the intona is the power hog.... I'll look for a reasonable Wall Mart. . Just be gentle I am only a couple of years in... I am a cheap skate so if I can make one and have as a good as or better... Right off to the pool for a drink before the wife complains Sent from my SM-G900F using Computer Audiophile mobile app Link to comment
Archimago Posted July 19, 2016 Share Posted July 19, 2016 Nice test Mans! Wondering can you record a segment of music with these drop outs for us to hear? Maybe variations of the degradation? Does it sound something like this? Archimago's Musings: DEMO & MEASUREMENTS: What does a bad USB (or other digital audio) cable sound like? Archimago's Musings: A "more objective" take for the Rational Audiophile. Beyond mere fidelity, into immersion and realism. R.I.P. MQA 2014-2023: Hyped product thanks to uneducated, uncritical advocates & captured press. Link to comment
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