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#1
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A/D converter- replace crystal unit?
OK, I'd like to get some input on this one, as there may be some
"unknown unknowns" to consider: (opens can of worms) I have several M Audio Delta 1010LT souncards that I have been using successfully for multitracking in a DAW of my own assemblage. Recently, a friend of mine mentioned that Black Lion Audio is offering an upgrade package for the 1010. I was intrigued, and did some comparative listening to recordings I've made through the 1010's and recordings I made a few years back on a Roland VSR-880. I noticed a difference in the sound quality- I perceived less clarity in the newer recordings. I will mention that everything has been tracked through the same mics and preamps, the only difference is the Roland vs. the PC with the Delta setup. It seems to make sense to me that there may be some benefits to upgrading the 1010's, and in fact the PC itself. I have replaced capacitors in ATX PSU's and motherboards before, (for different reasons) and noticed improved stability and increased performance. (In this case, I was replacing poorly designed capacitors with better-quality parts). Due to the low cost of DIY, I figured I could do better than G Luxon caps on the PSU rails of the 1010's, and bumped them up from 470uF to Nichicon 1000uF low-ESR types, complete with film bypass caps. OK, that should feed the flames enough, right? But there's more- BLA will also upgrade the "clock" on your 1010. I've stared at a few datasheets, and it seems that there are tighter tolerance parts available than that of the stock card. So here's my question for those who have experience with A/D clock design: Is there more to it than just swapping out the crystal with a better spec'd part? Due to the low cost of both the soundcards and the crystals, it would be pretty easy to set up a comparative test. If you have more than one card, you normally sync them up via SPDIF and choose one as the "master clock". You could install the new crystal in one card, then run a parallel A/D and/or D/A test, specifying a different card as the master clock for each run. Sound good? Great! But how do I analyze the results? Arny, I know you're familiar with these cards- any recommendations on how I can test for jitter? (sorry to single you out, but I've read your posts on the 1010LT, and I figured you'd sympathize with a fellow user). Thanks in advance for your replies- this should be interesting! (and hopefully useful!) -dave M. |
#2
Posted to rec.audio.pro
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A/D converter- replace crystal unit?
On Mar 25, 8:21 pm, "
wrote: question for those who have experience with A/D clock design: Is there more to it than just swapping out the crystal with a better spec'd part? The crystal is just part of the clock. The actual clock signal, if this is typical of an A/D converter, comes from a phase locked loop circuit which uses the crystal as a reference, but because of a long time constant, has greater short term stability than the crystal itself. Better clocks have better PLLs. So he may be using better grade capacitor, he may change the loop gain, he may even change the circuit. The thing about people who upgrade commercial product (like Black Lion and Audio Upgrades) is that they study out the whole circuit and most of the time do more than the obvious. And often the obvious (like use a "better" op amp) requires changing or adding some other circuit components. The thing is that they have the schematic and you and I (or at least I) don't. What you're paying for is what they've learned. Due to the low cost of both the soundcards and the crystals, it would be pretty easy to set up a comparative test. If you have more than one card, you normally sync them up via SPDIF and choose one as the "master clock". You could install the new crystal in one card, then run a parallel A/D and/or D/A test, specifying a different card as the master clock for each run. Sound good? Great! But how do I analyze the results? Arny, I know you're familiar with these cards- any recommendations on how I can test for jitter? (sorry to single you out, but I've read your posts on the 1010LT, and I figured you'd sympathize with a fellow user). Thanks in advance for your replies- this should be interesting! (and hopefully useful!) -dave M. |
#3
Posted to rec.audio.pro
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A/D converter- replace crystal unit?
Due to the low cost of both the soundcards and the crystals, it would
be pretty easy to set up a comparative test. If you have more than one card, you normally sync them up via SPDIF and choose one as the "master clock". You could install the new crystal in one card, then run a parallel A/D and/or D/A test, specifying a different card as the master clock for each run. Sound good? Odds are he's doing more than just changing the crystal to clean up the clock. I do question, though, the wisdom of spending money on a cheap soundcard to improve the sound quality, when there are known-good A/D boxes available off the shelf for a little more money. You upgrade this, then upgrade that, and next thing you know you could have bought the Benchmark with what you spent. Great! But how do I analyze the results? Arny, I know you're familiar with these cards- any recommendations on how I can test for jitter? (sorry to single you out, but I've read your posts on the 1010LT, and I figured you'd sympathize with a fellow user). Problem is that you need a signal source that is really good. For example, if you record a 1 KC sine wave, clock jitter will show up as little sidebands around the main peak if you do an FFT. But, if you record a 1KC sine wave from a 200CD oscillator like the one on my bench, you'll see lots of little sidebands that came from the oscillator itself and aren't artifacts of the conversion. In order to measure the converter quality, you need accurate signal sources and analysis tools that are an order of magnitude tighter than what you're trying to measure. That's why this is so hard. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#4
Posted to rec.audio.pro
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A/D converter- replace crystal unit?
On Mar 25, 8:03 pm, (Scott Dorsey) wrote:
Due to the low cost of both the soundcards and the crystals, it would be pretty easy to set up a comparative test. If you have more than one card, you normally sync them up via SPDIF and choose one as the "master clock". You could install the new crystal in one card, then run a parallel A/D and/or D/A test, specifying a different card as the master clock for each run. Sound good? Odds are he's doing more than just changing the crystal to clean up the clock. I do question, though, the wisdom of spending money on a cheap soundcard to improve the sound quality, when there are known-good A/D boxes available off the shelf for a little more money. You upgrade this, then upgrade that, and next thing you know you could have bought the Benchmark with what you spent. Well, I guess it's not a matter of wisdom, per se, but more a matter of trying to extend the usefulness of a given device, while learning about the general class of device in the process. I feel it helps me to understand what to look for when I'm "kicking the tires" on the next potential new vehicle. Great! But how do I analyze the results? Arny, I know you're familiar with these cards- any recommendations on how I can test for jitter? (sorry to single you out, but I've read your posts on the 1010LT, and I figured you'd sympathize with a fellow user). Problem is that you need a signal source that is really good. For example, if you record a 1 KC sine wave, clock jitter will show up as little sidebands around the main peak if you do an FFT. But, if you record a 1KC sine wave from a 200CD oscillator like the one on my bench, you'll see lots of little sidebands that came from the oscillator itself and aren't artifacts of the conversion. In order to measure the converter quality, you need accurate signal sources and analysis tools that are an order of magnitude tighter than what you're trying to measure. That's why this is so hard. --scott That's what I was afraid of... but for less than a dollar and five minutes of my time, I might just go ahead and do it. The worst cast would be that there's no improvement, or I have to replace the card (at which point I will hopefully remember your previous reference to wisdom! Thanks for the $.02! -dave M. -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#5
Posted to rec.audio.pro
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A/D converter- replace crystal unit?
"
wrote in message oups.com OK, I'd like to get some input on this one, as there may be some "unknown unknowns" to consider: (opens can of worms) I have several M Audio Delta 1010LT souncards that I have been using successfully for multitracking in a DAW of my own assemblage. Recently, a friend of mine mentioned that Black Lion Audio is offering an upgrade package for the 1010. I was intrigued, and did some comparative listening to recordings I've made through the 1010's and recordings I made a few years back on a Roland VSR-880. I noticed a difference in the sound quality- I perceived less clarity in the newer recordings. There's your first logical mistake - the use of a less-than-reference quality standard, the Roland VSR-880. I'm not saying that *your* Roland VSR-880 is less than sonically transparent, but there's no a priori reason to believe that it remains perfectly transparent. I'm not saying that *your* 1010LT is sonically transparent, but there's no a priori reason to believe that it is less than sonically transparent. What I'm saying is that you are comparing 2 unknowns. If they are the same or different, what does that mean? On top of that, there's some doubt that your comparison was carefully-controlled, IOW recordings of the identical same inputs, level-matched and blind. I'm not saying that *your* 1010LT is sonically transparent, but there's no a priori reason to believe that it is less than sonically transparent. What I'm saying is that you are comparing 2 unknowns. If they are the same or different, what does that mean? The *right* way to test an audio interface is to loop the outputs to the inputs, re-record some representative music, and then do a blind, level matched comparison of the origional recording to the copy. Then, you're comparing your audio interface to a known standard - whatever you used to tie the inputs to the outputs, which in the case of the 1010LT is its built-in connector bundle. If you have even the most basic DAW software and skills, you can set this up as a comparison of 2 level-matched, time-synched stereo .wav files using test administration software that you can download for free from www.pcabx.com . You can apply this technique to both the 1010LT and the Roland VSR-880. You might be surprised by the results. |
#6
Posted to rec.audio.pro
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A/D converter- replace crystal unit?
On Mar 26, 9:23 am, "Arny Krueger" wrote:
"main wrote in message oups.com OK, I'd like to get some input on this one, as there may be some "unknown unknowns" to consider: (opens can of worms) I have several M Audio Delta 1010LT souncards that I have been using successfully for multitracking in a DAW of my own assemblage. Recently, a friend of mine mentioned that Black Lion Audio is offering an upgrade package for the 1010. I was intrigued, and did some comparative listening to recordings I've made through the 1010's and recordings I made a few years back on a Roland VSR-880. I noticed a difference in the sound quality- I perceived less clarity in the newer recordings. There's your first logical mistake - the use of a less-than-reference quality standard, the Roland VSR-880. I'm not saying that *your* Roland VSR-880 is less than sonically transparent, but there's no a priori reason to believe that it remains perfectly transparent. I'm not saying that *your* 1010LT is sonically transparent, but there's no a priori reason to believe that it is less than sonically transparent. What I'm saying is that you are comparing 2 unknowns. If they are the same or different, what does that mean? On top of that, there's some doubt that your comparison was carefully-controlled, IOW recordings of the identical same inputs, level-matched and blind. I'm not saying that *your* 1010LT is sonically transparent, but there's no a priori reason to believe that it is less than sonically transparent. What I'm saying is that you are comparing 2 unknowns. If they are the same or different, what does that mean? The *right* way to test an audio interface is to loop the outputs to the inputs, re-record some representative music, and then do a blind, level matched comparison of the origional recording to the copy. Then, you're comparing your audio interface to a known standard - whatever you used to tie the inputs to the outputs, which in the case of the 1010LT is its built-in connector bundle. If you have even the most basic DAW software and skills, you can set this up as a comparison of 2 level-matched, time-synched stereo .wav files using test administration software that you can download for free fromwww.pcabx.com. You can apply this technique to both the 1010LT and the Roland VSR-880. You might be surprised by the results. This is completely correct and reasonable. I may very well have heard a difference because I wanted to. Does Rightmark provide any useful tools for this kind of test? Man, what I wouldn't do for some really high-grade testing equipment! -dave M. |
#7
Posted to rec.audio.pro
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A/D converter- replace crystal unit?
"
wrote in message oups.com On Mar 26, 9:23 am, "Arny Krueger" wrote: "main wrote in message oups.com OK, I'd like to get some input on this one, as there may be some "unknown unknowns" to consider: (opens can of worms) I have several M Audio Delta 1010LT souncards that I have been using successfully for multitracking in a DAW of my own assemblage. Recently, a friend of mine mentioned that Black Lion Audio is offering an upgrade package for the 1010. I was intrigued, and did some comparative listening to recordings I've made through the 1010's and recordings I made a few years back on a Roland VSR-880. I noticed a difference in the sound quality- I perceived less clarity in the newer recordings. There's your first logical mistake - the use of a less-than-reference quality standard, the Roland VSR-880. I'm not saying that *your* Roland VSR-880 is less than sonically transparent, but there's no a priori reason to believe that it remains perfectly transparent. I'm not saying that *your* 1010LT is sonically transparent, but there's no a priori reason to believe that it is less than sonically transparent. What I'm saying is that you are comparing 2 unknowns. If they are the same or different, what does that mean? On top of that, there's some doubt that your comparison was carefully-controlled, IOW recordings of the identical same inputs, level-matched and blind. I'm not saying that *your* 1010LT is sonically transparent, but there's no a priori reason to believe that it is less than sonically transparent. What I'm saying is that you are comparing 2 unknowns. If they are the same or different, what does that mean? The *right* way to test an audio interface is to loop the outputs to the inputs, re-record some representative music, and then do a blind, level matched comparison of the origional recording to the copy. Then, you're comparing your audio interface to a known standard - whatever you used to tie the inputs to the outputs, which in the case of the 1010LT is its built-in connector bundle. If you have even the most basic DAW software and skills, you can set this up as a comparison of 2 level-matched, time-synched stereo .wav files using test administration software that you can download for free fromwww.pcabx.com. You can apply this technique to both the 1010LT and the Roland VSR-880. You might be surprised by the results. This is completely correct and reasonable. I may very well have heard a difference because I wanted to. Or, due to level mismatch, or actual defective equipment. Hard to say for sure. Does Rightmark provide any useful tools for this kind of test? Yes. You can Rightmark the 1010LT and compare your results to these: http://www.pcavtech.com/soundcards/d...10lt/index.htm Testing the Roland VSR 880 might take a little careful mouth-holding, but in prinicple you can Rightmark anything that records and plays. For example, I've rightmarked CD players by burning my own test CD. Man, what I wouldn't do for some really high-grade testing equipment! You probably already have a good approximation of it in the 1010LT. The performance shown here is not too far from the origional Audio Precision test set: http://www.pcavtech.com/soundcards/d...010lt/2496.htm But, no way can it be confused with a System 2. You can come close to a System 2 with a LynxTwo. The 1010LT might be equal or better than anything that HP or Sound Technology ever sold. |
#8
Posted to rec.audio.pro
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A/D converter- replace crystal unit?
On Mar 26, 10:11 am, "Arny Krueger" wrote:
"main wrote in message oups.com On Mar 26, 9:23 am, "Arny Krueger" wrote: "main wrote in message groups.com OK, I'd like to get some input on this one, as there may be some "unknown unknowns" to consider: (opens can of worms) I have several M Audio Delta 1010LT souncards that I have been using successfully for multitracking in a DAW of my own assemblage. Recently, a friend of mine mentioned that Black Lion Audio is offering an upgrade package for the 1010. I was intrigued, and did some comparative listening to recordings I've made through the 1010's and recordings I made a few years back on a Roland VSR-880. I noticed a difference in the sound quality- I perceived less clarity in the newer recordings. There's your first logical mistake - the use of a less-than-reference quality standard, the Roland VSR-880. I'm not saying that *your* Roland VSR-880 is less than sonically transparent, but there's no a priori reason to believe that it remains perfectly transparent. I'm not saying that *your* 1010LT is sonically transparent, but there's no a priori reason to believe that it is less than sonically transparent. What I'm saying is that you are comparing 2 unknowns. If they are the same or different, what does that mean? On top of that, there's some doubt that your comparison was carefully-controlled, IOW recordings of the identical same inputs, level-matched and blind. I'm not saying that *your* 1010LT is sonically transparent, but there's no a priori reason to believe that it is less than sonically transparent. What I'm saying is that you are comparing 2 unknowns. If they are the same or different, what does that mean? The *right* way to test an audio interface is to loop the outputs to the inputs, re-record some representative music, and then do a blind, level matched comparison of the origional recording to the copy. Then, you're comparing your audio interface to a known standard - whatever you used to tie the inputs to the outputs, which in the case of the 1010LT is its built-in connector bundle. If you have even the most basic DAW software and skills, you can set this up as a comparison of 2 level-matched, time-synched stereo .wav files using test administration software that you can download for free fromwww.pcabx.com. You can apply this technique to both the 1010LT and the Roland VSR-880. You might be surprised by the results. This is completely correct and reasonable. I may very well have heard a difference because I wanted to. Or, due to level mismatch, or actual defective equipment. Hard to say for sure. Does Rightmark provide any useful tools for this kind of test? Yes. You can Rightmark the 1010LT and compare your results to these: http://www.pcavtech.com/soundcards/d...10lt/index.htm Testing the Roland VSR 880 might take a little careful mouth-holding, but in prinicple you can Rightmark anything that records and plays. For example, I've rightmarked CD players by burning my own test CD. Man, what I wouldn't do for some really high-grade testing equipment! You probably already have a good approximation of it in the 1010LT. The performance shown here is not too far from the origional Audio Precision test set: http://www.pcavtech.com/soundcards/d...010lt/2496.htm But, no way can it be confused with a System 2. You can come close to a System 2 with a LynxTwo. The 1010LT might be equal or better than anything that HP or Sound Technology ever sold.- Hide quoted text - - Show quoted text - Nice! Very helpful- I downloaded Rightmark about a week ago, haven't gotten to use it yet but now I can't wait to test my system. I'll grab a copy of that ABX software, too. Thanks, Arny! What about the issue of jitter when using multiple Delta cards? Could I try testing one card internally clocked vs. clocked from another delta? Would jitter show up as the difference between noise figure of each test? Or will it even be measurable? -dave M. |
#9
Posted to rec.audio.pro
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A/D converter- replace crystal unit?
"
wrote in message oups.com What about the issue of jitter when using multiple Delta cards? There is always jitter, the question is whether or not it is audible. Could I try testing one card internally clocked vs. clocked from another delta? I don't see why not? Would jitter show up as the difference between noise figure of each test? In the spectrum analyzer plots made by the Rightmark program, jitter shows up as sidebands near large sine waves. For example compare this plot showing relatively high jitter: http://www.pcavtech.com/soundcards/d...0_2496/thd.gif to this similar plot showing relatively low jitter: http://www.pcavtech.com/soundcards/d...T-2496/thd.png The relatively high jitter in the delta 1010 plot had a known cause - a weak cap in the power supply that was not properly filtering the DC power to the audio circuits. This did not cause audible hum as such, but it did cause FM modulation of the clock which led to the jitter. Or will it even be measurable? http://www.pcavtech.com/soundcards/d...010lt/2496.htm shows miniscule but barely measuarable amounts of jitter. It could probably be made more apparent with a more specialized test. However, its more than 120 dB down. Jitter is inaudible when it is 100+ dB down, so the 1010LT tested was doing very well indeed. |
#10
Posted to rec.audio.pro
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A/D converter- replace crystal unit?
On Mar 26, 12:53 pm, "Arny Krueger" wrote:
"main wrote in message oups.com What about the issue of jitter when using multiple Delta cards? There is always jitter, the question is whether or not it is audible. Could I try testing one card internally clocked vs. clocked from another delta? I don't see why not? Would jitter show up as the difference between noise figure of each test? In the spectrum analyzer plots made by the Rightmark program, jitter shows up as sidebands near large sine waves. For example compare this plot showing relatively high jitter: http://www.pcavtech.com/soundcards/d...0_2496/thd.gif to this similar plot showing relatively low jitter: http://www.pcavtech.com/soundcards/d...T-2496/thd.png The relatively high jitter in the delta 1010 plot had a known cause - a weak cap in the power supply that was not properly filtering the DC power to the audio circuits. This did not cause audible hum as such, but it did cause FM modulation of the clock which led to the jitter. Or will it even be measurable? http://www.pcavtech.com/soundcards/d...010lt/2496.htm shows miniscule but barely measuarable amounts of jitter. It could probably be made more apparent with a more specialized test. However, its more than 120 dB down. Jitter is inaudible when it is 100+ dB down, so the 1010LT tested was doing very well indeed. OK, I've run some tests using Rightmark on both the 1010LT and the AP 2496 (which I have been using as my 2 buss back into the box) and the results are interesting. Unless my cards differ greatly from the average M Audio card, then it seems the AP 2496 has a noisier clock circuit, or else the card itself is just more sensitive to clock noise. I also found that I may have some 60 cycle hum to track down, probably in my patch bay/ effects rack. I don't have anywhere to post the results, but I can email the html report if anyone is interested in viewing the results. Remove the obvious from my address to get in touch with me. I don't think I need to be concerned with jitter at this point. I only wish I had thought to use rightmark before *and* after the PSU upgrade, so I could draw some more definitive conclusions. Jitter and noise are well below -100 dB almost across the board, even when using the AP 2496 clock- even better with the 1010LT clock calling the shots. I plan to do some ABX listening tests as well, to confirm the RMAA results. Based on this testing, I think I can live with the Delta 1010LT clock for now, but I might be able to do better than the AP 2496 for my stereo bus return. Anyone have any cards they like for this purpose? RME, Lynx, maybe a different M Audio card? Arny- how would I go about testing microphones and monitors with RMAA, considering the fact that there is no perfect microphone/ speaker to use as the controlled variable? I can borrow an earthworks omni from a friend of mine, which has a good rep. as a measurement mic, but is there more to consider? BTW- Thanks for making such a useful program! I will be testing everything I own, just to see how things measure. -dave M. |
#11
Posted to rec.audio.pro
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A/D converter- replace crystal unit?
"
wrote in message ps.com Arny- how would I go about testing microphones and monitors with RMAA, considering the fact that there is no perfect microphone/ speaker to use as the controlled variable? I can borrow an earthworks omni from a friend of mine, which has a good rep. as a measurement mic, but is there more to consider? There's an acoustic measurement option in the options, on the acoustics test tab. BTW- Thanks for making such a useful program! It isn't anything I wrote - I think a Russian wrote it. I will be testing everything I own, just to see how things measure. Enjoy! |
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