plissken Posted June 7, 2017 Share Posted June 7, 2017 Instead of guessing the S.I. (signal integrity) of your computer is buggered, would people here want to chip in on a USB analyzer to see if their USB output is even compromised? Link to comment
pkane2001 Posted June 7, 2017 Share Posted June 7, 2017 28 minutes ago, plissken said: Instead of guessing the S.I. (signal integrity) of your computer is buggered, would people here want to chip in on a USB analyzer to see if their USB output is even compromised? What would be a good one to get? -Paul DeltaWave, DISTORT, Earful, PKHarmonic, new: Multitone Analyzer Link to comment
plissken Posted June 7, 2017 Author Share Posted June 7, 2017 3 minutes ago, pkane2001 said: What would be a good one to get? Teledyne-LeCroy and they make a few models. Link to comment
The Computer Audiophile Posted June 7, 2017 Share Posted June 7, 2017 If such a tool would be useful, I'd be happy to help obtain one. Founder of Audiophile Style | My Audio Systems Link to comment
Popular Post wgscott Posted June 7, 2017 Popular Post Share Posted June 7, 2017 If the product isn't all smoke and mirrors, they would have a 30 day return policy emblazoned on their web page. ;-) The Computer Audiophile and semente 2 Link to comment
jabbr Posted June 7, 2017 Share Posted June 7, 2017 1 hour ago, plissken said: Teledyne-LeCroy and they make a few models. I guess it depends on what you are looking to test. What general test equipment do you have? Custom room treatments for headphone users. Link to comment
Popular Post The Computer Audiophile Posted June 7, 2017 Popular Post Share Posted June 7, 2017 3 minutes ago, jabbr said: I guess it depends on what you are looking to test. What general test equipment do you have? This is where things get a bit sticky. Ask @Wavelength about all his USB testing gear and all the analysis it takes to figure out what's happening and if it matters or how much it matters etc... This isn't an easy thing where we get a scope and a red or green light illuminates to say things are good or bad. 4est and Albrecht 2 Founder of Audiophile Style | My Audio Systems Link to comment
plissken Posted June 7, 2017 Author Share Posted June 7, 2017 6 minutes ago, jabbr said: I guess it depends on what you are looking to test. What general test equipment do you have? Since Alex posited via the images he posted, and so many here are backing him, ergo it stands to reason that we would be concerned with Eye Pattern tests. Link to comment
Popular Post jabbr Posted June 7, 2017 Popular Post Share Posted June 7, 2017 Right @The Computer Audiophile. Let's assume for the sake of argument, that the devices that claim to "clean up" the USB signal, do just that. Ok, so what effect does this really have on the DAC is the question that interests me more. This then raises the question: how is the DAC measurably affected such that an "improvement" is measurable? crenca and semente 2 Custom room treatments for headphone users. Link to comment
jabbr Posted June 7, 2017 Share Posted June 7, 2017 2 minutes ago, plissken said: Since Alex posited via the images he posted, and so many here are backing him, ergo it stands to reason that we would be concerned with Eye Pattern tests. Heck, let's just grant that the eye pattern test is "improved". So what? How does that actually, measurably, help the DAC? Custom room treatments for headphone users. Link to comment
Popular Post Miska Posted June 7, 2017 Popular Post Share Posted June 7, 2017 2 minutes ago, jabbr said: Right @The Computer Audiophile. Let's assume for the sake of argument, that the devices that claim to "clean up" the USB signal, do just that. Ok, so what effect does this really have on the DAC is the question that interests me more. This then raises the question: how is the DAC measurably affected such that an "improvement" is measurable? ...that's why I always prefer sticking to measure the DAC output instead of any intermediate step... I can replace things from DAC upstream and see how it affects (or not) things that come out from the DAC. That's in the end what matters. And quite many of the interactions actually happen inside the DAC, even though some upstream equipment's involvement is needed for that thing. crenca and esldude 2 Signalyst - Developer of HQPlayer Pulse & Fidelity - Software Defined Amplifiers Link to comment
pkane2001 Posted June 7, 2017 Share Posted June 7, 2017 3 minutes ago, plissken said: Since Alex posited via the images he posted, and so many here are backing him, ergo it stands to reason that we would be concerned with Eye Pattern tests. In addition, I'd think it should measure error rates and latency. It would be very useful if there was a way to quantify their effect on the (various) DAC outputs. -Paul DeltaWave, DISTORT, Earful, PKHarmonic, new: Multitone Analyzer Link to comment
lucretius Posted June 7, 2017 Share Posted June 7, 2017 2 hours ago, plissken said: Instead of guessing the S.I. (signal integrity) of your computer is buggered, would people here want to chip in on a USB analyzer to see if their USB output is even compromised? I would chip in a token amount if there was a paypal account. mQa is dead! Link to comment
plissken Posted June 7, 2017 Author Share Posted June 7, 2017 24 minutes ago, jabbr said: Heck, let's just grant that the eye pattern test is "improved". So what? How does that actually, measurably, help the DAC? I don't care because, as the title of the thread suggests, we are testing the native eye pattern of someones computer. If it's clean like in the Tekronix image I posted then there is no need for a regen type device in the confines of S.I. of the Eye Pattern. Link to comment
Popular Post Wavelength Posted June 7, 2017 Popular Post Share Posted June 7, 2017 Guys, There are 3 types of USB testing equipment available. The most basic of test is the protocol analyzer. These are available from TotalPhase, ITIC and others (I have those 2) $500-$1500. The second is a USB compliance analyzer. This is what companies use to determine the basics of USB. These go between a computer and a device. My Tektronix version of this cost about $18K. It's not really good for testing how well things are working. But you can set this up and see more information than a protocol analyzer can. You can go a step further with Tektronix and I have been working with them on this so that you can test real time between devices. Look at EYE patterns and stuff and calculate USB jitter (not to be confused with digital audio jitter). The big problem here is on HS/FS devices you really have to sit down and take note of who's talking. Remember it's a bi-directional bus system. Anyway this adds another $10K on top of the compliance testing for HS and don't ask category for USB3 stuff. But really what's it going to tell you? You bought the wrong product? Why not spend the money wisely on something else? Thanks, Gordon AudGuy, The Computer Audiophile, plissken and 5 others 8 J. Gordon Rankin Wavelength Audio http://www.usbdacs.com/ http://www.wavelengthaudio.com/ http://www.guitar-engines.com/ Link to comment
Popular Post plissken Posted June 7, 2017 Author Popular Post Share Posted June 7, 2017 10 minutes ago, Wavelength said: You bought the wrong product? Why not spend the money wisely on something else? Thanks, Gordon 1: Thanks 2: Enjoy arguing with a sub group here about 'wrong product' and 'wisely on something else?' (I.E. correctly designed product) Because when you call a manufacturer like I did with Chord, and they state they don't need a regeneration device, all I hear here is: WTF does Chord know about USB. They make DACs. STC, daverich4 and esldude 3 Link to comment
plissken Posted June 7, 2017 Author Share Posted June 7, 2017 To do S.I. Eye measurements we are talking about ~$800 for a scope, probes, and break out board. *never mind :)* EEVBlog #340 Link to comment
mansr Posted June 7, 2017 Share Posted June 7, 2017 2 minutes ago, plissken said: To do S.I. Eye measurements we are talking about ~$800 for a scope, probes, and break out board. That doesn't sound right. Such products cost in excess of $10k. What device are you looking at? Link to comment
plissken Posted June 7, 2017 Author Share Posted June 7, 2017 5 minutes ago, mansr said: That doesn't sound right. Such products cost in excess of $10k. What device are you looking at? You're correct. Just looking for a way to just get clear data. I'm assuming that a protocol analyzer isn't going to do anything for anyone. Link to comment
wgscott Posted June 7, 2017 Share Posted June 7, 2017 OK, each of us can scrape $1K to $2K out of the car seat cushions... plissken 1 Link to comment
mansr Posted June 7, 2017 Share Posted June 7, 2017 8 minutes ago, plissken said: You're correct. Just looking for a way to just get clear data. I'm assuming that a protocol analyzer isn't going to do anything for anyone. A protocol analyser will tell you if there are transmission errors or higher level protocol violations. They are useful mainly when developing hardware. If we trust the host and device to be well-behaved and use reasonable cables, an analyser isn't of much use. Granted, there are many USB devices out there that don't quite follow spec, but DACs from reputable vendors are usually fine. Besides, if the DAC is misbehaving, it won't be fixed by inserting some gizmo in the chain anyhow. plissken 1 Link to comment
mav52 Posted June 7, 2017 Share Posted June 7, 2017 A few questions : This USB analyzer. Is this a group buy ?, aka more than one. What "deal" is being made for more than one unit / Whom decides on the unit to purchase ? Where would the device be kept ?, which country or countries Who pays for shipping from one user to the next ? Whom handles the unit or units should they need repair ? Whom is going to react when someone fails to return the unit ? The Truth Is Out There Link to comment
Speed Racer Posted June 7, 2017 Share Posted June 7, 2017 Why would we want to invest in this? If we were smart, we would be looking for ways to get away from USB. That's the future anyway. Teresa 1 Link to comment
jabbr Posted June 8, 2017 Share Posted June 8, 2017 Instead of a protocol analyzer I'd invest in: 1: (generally) a good high speed oscilloscope (can do eye patterns) 2: high resolution spectrum analyzer 3: vector signal analyzer Custom room treatments for headphone users. Link to comment
Teresa Posted June 8, 2017 Share Posted June 8, 2017 I agree with Speed Racer perhaps new DACs should move away from USB. Maybe something like Thunderbolt. I have dementia. I save all my posts in a text file I call Forums. I do a search in that file to find out what I said or did in the past. I still love music. Teresa Link to comment
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