Hi Mark,
If that is true, why the heck don't they use one??? I should mention that some oscilloscopes do run north of $250K USD.
I guess they don't want to pay for trained staff, that's the only thing I can think of.
Only a fool turns down information that is pertinent to a discussion or decision to be made. Making decisions that require a better understanding of the subject material without that understanding is a failure of management. I can't conceive of any competent management group failing in this way. Of course, the issues being decided may not have anything to do with product quality. They may be cost cutting decisions only, and quality decline is often an acceptable trade-off. This type of group would actually want metrics such as the ones you are pushing as being adequate. That way they can make those decisions with deniability built right in. Now that is far more likely to be the explanation. However, for our purposes, quality is very much a central concern. Given that this is the case, it precludes the use of cheap, commodity hardware. Wouldn't you agree?
The test report was close enough, given the subject material. But you are right, it was incomplete and you are attempting to draw conclusions based on information that doesn't apply to the question, that being relative performance of various CD playing technologies.
-Chris
If that is true, why the heck don't they use one??? I should mention that some oscilloscopes do run north of $250K USD.
I guess they don't want to pay for trained staff, that's the only thing I can think of.
Only a fool turns down information that is pertinent to a discussion or decision to be made. Making decisions that require a better understanding of the subject material without that understanding is a failure of management. I can't conceive of any competent management group failing in this way. Of course, the issues being decided may not have anything to do with product quality. They may be cost cutting decisions only, and quality decline is often an acceptable trade-off. This type of group would actually want metrics such as the ones you are pushing as being adequate. That way they can make those decisions with deniability built right in. Now that is far more likely to be the explanation. However, for our purposes, quality is very much a central concern. Given that this is the case, it precludes the use of cheap, commodity hardware. Wouldn't you agree?
The test report was close enough, given the subject material. But you are right, it was incomplete and you are attempting to draw conclusions based on information that doesn't apply to the question, that being relative performance of various CD playing technologies.
-Chris
If you had spent more time testing discs you would know that not all errors are visible on the eye-pattern. Every eye-pattern contains errors that will be corrected by C1/C2. Are you able to see the difference between 2 and 220 errors per second?
There are also no reports or tests that prove that the old players are better, or that low mass is good, or which is the best slide design. Would you have accepted the results if they had proven your point.
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Hi Mark,
What results? Nothing in that report commented on old vs new vs computer drive transports.
If you have a good eye pattern, chances are your error rates are well below the threshold you are talking about. The errors wouldn't be due to the CD transport in that case anyway unless you could see pattern violations (a non-clear eye).
Without getting some real practical experience yourself, you are not equipped to argue any aspect of drive quality. You continue to go down the same tired path, and not once have you attempted to learn anything about the technology involved beyond error counts. If you figure that you can know everything you need to know without looking at the actual analog servo and RF signals, continue on being fat, dumb and happy. I have used error rate counters, and also have a great deal of experience with the base operation. So I have seen both sides where you have unfortunately not. Unfortunately for both you and other members reading this thread.
I find that you are holding up development for no particularly good reason. You do intend to use some flavor of CDROM drive, and therefore have no real reason to even comment here.
Until you can demonstrate that you have learned something of the real world of signals before the DSP is reached, I'm not going to waste my time replying to your posts. It's entirely pointless to try when every other industry does make use of these signals as part of signal quality control.
-Chris
What results? Nothing in that report commented on old vs new vs computer drive transports.
If you have a good eye pattern, chances are your error rates are well below the threshold you are talking about. The errors wouldn't be due to the CD transport in that case anyway unless you could see pattern violations (a non-clear eye).
Without getting some real practical experience yourself, you are not equipped to argue any aspect of drive quality. You continue to go down the same tired path, and not once have you attempted to learn anything about the technology involved beyond error counts. If you figure that you can know everything you need to know without looking at the actual analog servo and RF signals, continue on being fat, dumb and happy. I have used error rate counters, and also have a great deal of experience with the base operation. So I have seen both sides where you have unfortunately not. Unfortunately for both you and other members reading this thread.
I find that you are holding up development for no particularly good reason. You do intend to use some flavor of CDROM drive, and therefore have no real reason to even comment here.
Until you can demonstrate that you have learned something of the real world of signals before the DSP is reached, I'm not going to waste my time replying to your posts. It's entirely pointless to try when every other industry does make use of these signals as part of signal quality control.
-Chris
No, no, no... It was just taken as example from very cheap (obsolete) VCD player I have lying around. The error correction scheme is not "top of the line".
I think I prefer the ones used in top sounding CD players, which I don't have access to 😀 Yes, I'm behind in the source electronics as I don't purchase from Ebay and don't have SMD soldering skill.
I honestly didn't really agree with the concept/idea of building quality mechanism from scratch. Why not just pick the old stuff for transport and use modern electronics (DSP/DF/DAC/IV)...? I myself don't have access to BU-1 or CDM-1 but old Pioneer laser disc players are accessible for me and they have long lasting mechanism as well.
LNE test report, pages 7 and 8. Here you can see the graphs generated by each analyser. Comparing the data/graphs of the Pioneer recorded disc, the Clover has the lowest error rate (ave BLER 0.5 24X) and the Philips player used in the SA3 has a higher error rate (ave BLER 9.9 1X).
The graph/data on page 14. Here we can see the HF (eye-pattern) data. As the disc is exposed to light it becomes less reflective and the signal is reduced. You can also see increased jitter, this shows that the pit and land lengths are not correct and will cause an increase of errors too.
Page 15. Here we can see an increase of errors caused by the light exposure. Again this has been tested on the three analysers. No surprise when again the Clover has the lowest error rates.
Does this prove that older CD players like the Philips are Bad? I don't think so. But it does prove that some ROM drives do outperform the old players.
Looking into the future? This is probably the most advanced AV player yet.
Panasonic Ultra HD Blu-ray player hits Japan November 15 | Digital Trends
The graph/data on page 14. Here we can see the HF (eye-pattern) data. As the disc is exposed to light it becomes less reflective and the signal is reduced. You can also see increased jitter, this shows that the pit and land lengths are not correct and will cause an increase of errors too.
Page 15. Here we can see an increase of errors caused by the light exposure. Again this has been tested on the three analysers. No surprise when again the Clover has the lowest error rates.
Does this prove that older CD players like the Philips are Bad? I don't think so. But it does prove that some ROM drives do outperform the old players.
Looking into the future? This is probably the most advanced AV player yet.
Panasonic Ultra HD Blu-ray player hits Japan November 15 | Digital Trends
Hi Jay,
-Chris
Still okay - cool. By focusing on service and seeing what lasts and what doesn't, I tend to think along the lines of transports. Since the chip set isn't something I can change easily, I have never given them much thought. The two main considerations would be (in order) availability and performance. I bet I surprised you there.
Okay, that's fair. Just realize that you can't develop an electronics package for changing transports and head types. The guy to talk to on this issue is Salar. He is the mechanical guru who can make these things. I would trust his judgement. I have a good feel for the transports, and one good one is not that difficult to come up with. I'm very lucky to have direct exposure to many, if not all of the best transports and have a fair idea of what is smooth and reliable, and what isn't. One thing is for sure. I am perfectly willing to use whatever Salar comes up with - happily. The rough idea is a three beam pickup on a transverse linear motor slide. I know it will work reliably for years to come, and to be repairable when the time comes.
-Chris
Hi Mark,
Mark, I honestly wish that you had more experience working with CD transports. I do. The information in that report does not support any conclusions for one. You are lacking first hand experience for another. I think that once you did have the required experience, we would very probably agree on most major questions. I don't think you are incompetent or stupid, rather probably the opposite. But you can't argue these points effectively without that first hand knowledge.
I wish a $16 CDN drive would perform near the ability of a purpose built good CD player. But, they do not. You can't understand that until you have the missing experience. You might even find that adjusting them is enjoyable. Once you can learn to adjust CD player transports, it would lead you to improve the performance of your own computer CDROM drives. Just invest some time and effort into yourself.
-Chris
Tenuous at best. The eye pattern was only available on one drive of the three. The service history of these machines are completely unknown. Each transport of the same make and model perform differently as well. You simply do not have anything even close to an acceptable pool of devices to be statistically valid. These tests can go either way in other words. Then there is the fact that I am not a Philips fan to boot.
Mark, I honestly wish that you had more experience working with CD transports. I do. The information in that report does not support any conclusions for one. You are lacking first hand experience for another. I think that once you did have the required experience, we would very probably agree on most major questions. I don't think you are incompetent or stupid, rather probably the opposite. But you can't argue these points effectively without that first hand knowledge.
I wish a $16 CDN drive would perform near the ability of a purpose built good CD player. But, they do not. You can't understand that until you have the missing experience. You might even find that adjusting them is enjoyable. Once you can learn to adjust CD player transports, it would lead you to improve the performance of your own computer CDROM drives. Just invest some time and effort into yourself.
-Chris
I don't think you are incompetent or stupid either. What has surprised me is your lack of knowledge of the CD technology. Your advice to use a DVD laser for CD is a good example. How can you come to this conclusion? Do you understand how the eye-pattern is formed?
Most of the technology seems new to you, or misunderstood. I am not sure how tinkering with players is going to help me understand basic disc technology, when is has clearly not worked for others.
Most of the technology seems new to you, or misunderstood. I am not sure how tinkering with players is going to help me understand basic disc technology, when is has clearly not worked for others.
Hi Mark,
DVD mechs are CD / DVD.
I am more than well aware how an eye pattern is formed. How do you think they are created?
The technology is old hat to me. I have kept up with advances and am proficient in servicing them. Now the question is, do you handle these on a bench, or do you just read the spec sheets? How dirty do your hands get?
Other folks aren't cut out for technical activities. From your more recent comments, you might possibly be in that group. Only by looking at the truth, and that is an operating CD transport doing it's thing, will you ever understand the difference between what some folks write and what the actual reality is. Once you have looked at a variety of eye patterns, you will begin to be educated on what various impairments can do compared to what they look like. You might even discover that an eye pattern that is close to perfect has extremely low error rates, and what a closed eye does to error rates.
Your position is that you don't need to know the details on what stresses do to the error rates. That's perfectly fine since it is clear you've only read about this stuff. You are hardly in a position to comment on anything until you become educated. This is easy for you to do, given the availability of sophisticated instrumentation to you. I'm more than certain you have access to some expensive scopes (mine is only worth about $20K CDN, Agilent 54642D - look it up). Getting a CD player is easy enough also. So try these elementary tests before your fingers bother the keys here any further. Making excuses as to why you aren't going to teach yourself some basic stuff just doesn't wash. You have access to equipment, and maybe even a lowly technician running around at your work could spare a few minutes for you.
Up to you. I understand these topics cold, so you'd better at least look up eye patterns and how they are used for all examples of data transfers. They even use them when looking at hard drives. You are surrounded by folks who understand and actually use eye patterns on a daily basis. Yet you are the only person who doesn't use them while claiming they are not necessary for QC.
-Chris
DVD mechs are CD / DVD.
I am more than well aware how an eye pattern is formed. How do you think they are created?
The technology is old hat to me. I have kept up with advances and am proficient in servicing them. Now the question is, do you handle these on a bench, or do you just read the spec sheets? How dirty do your hands get?
Well, let's see. You have a history in this thread you can check on. You can learn how an eye pattern is formed and what makes a good one or a stressed eye pattern. You can learn these things by reading, but you have not.
Other folks aren't cut out for technical activities. From your more recent comments, you might possibly be in that group. Only by looking at the truth, and that is an operating CD transport doing it's thing, will you ever understand the difference between what some folks write and what the actual reality is. Once you have looked at a variety of eye patterns, you will begin to be educated on what various impairments can do compared to what they look like. You might even discover that an eye pattern that is close to perfect has extremely low error rates, and what a closed eye does to error rates.
Your position is that you don't need to know the details on what stresses do to the error rates. That's perfectly fine since it is clear you've only read about this stuff. You are hardly in a position to comment on anything until you become educated. This is easy for you to do, given the availability of sophisticated instrumentation to you. I'm more than certain you have access to some expensive scopes (mine is only worth about $20K CDN, Agilent 54642D - look it up). Getting a CD player is easy enough also. So try these elementary tests before your fingers bother the keys here any further. Making excuses as to why you aren't going to teach yourself some basic stuff just doesn't wash. You have access to equipment, and maybe even a lowly technician running around at your work could spare a few minutes for you.
Up to you. I understand these topics cold, so you'd better at least look up eye patterns and how they are used for all examples of data transfers. They even use them when looking at hard drives. You are surrounded by folks who understand and actually use eye patterns on a daily basis. Yet you are the only person who doesn't use them while claiming they are not necessary for QC.
-Chris
My 5 cents:
-Drive will be linear - no gear, only magnets and coils with a brushless disc motor.
-For the coarse movement, the CD will be moved - not the laser.
This, BTW, might need a sensible amount of mass to dampen the movement from off-centered CDs.
Reason for moving the CD: Freedom of choosing a laser head- Built from scratch or fitting an existing one. There are Zillions of different rail distances out there.
This can be better addressed when the laser is fixed. This will also give a better opportunity to shift and tilt the laser for alignment.
Maybe even switching to SACD/DVD and Blu Ray in the future without the need for redesigning the whole mech.
But again, first goal: Also built the laser from scratch.
Toploader preferred but I also have an idea for a slim loading mech.
For CD, all servos should be "analogue" and "open"so to say - with the ability to trim them and get the servo into ballpark. By hand or some code.
I am not a mechanical guru. Will need a lot of advice on magnets and motors.
Again, servos are completely out of my knowledge.
All the best,
Salar
-Drive will be linear - no gear, only magnets and coils with a brushless disc motor.
-For the coarse movement, the CD will be moved - not the laser.
This, BTW, might need a sensible amount of mass to dampen the movement from off-centered CDs.
Reason for moving the CD: Freedom of choosing a laser head- Built from scratch or fitting an existing one. There are Zillions of different rail distances out there.
This can be better addressed when the laser is fixed. This will also give a better opportunity to shift and tilt the laser for alignment.
Maybe even switching to SACD/DVD and Blu Ray in the future without the need for redesigning the whole mech.
But again, first goal: Also built the laser from scratch.
Toploader preferred but I also have an idea for a slim loading mech.
For CD, all servos should be "analogue" and "open"so to say - with the ability to trim them and get the servo into ballpark. By hand or some code.
I am not a mechanical guru. Will need a lot of advice on magnets and motors.
Again, servos are completely out of my knowledge.
All the best,
Salar
Anatech, the reality is that you don't know the details. A quick look at your posts demonstrates this. Posts 28 and 30. You have never heard of E32 and E22. And, don't know the limits of BLER. This is just basic CD technology.
In post 187 you advise salar to use a DVD laser for CD and your explanation on why this should work is wrong. Again, basic CD technology. DVD uses two lasers, Blu-Ray uses three.
Previously I have linked to videos of the type of equipment I have designed, improved, bought, sold, used, installed and maintained. Then trained operators and maintenance personnel to use them. It is impressive to see these machines work 24/7 and know that you are in some way responsible for that.
In post 187 you advise salar to use a DVD laser for CD and your explanation on why this should work is wrong. Again, basic CD technology. DVD uses two lasers, Blu-Ray uses three.
Previously I have linked to videos of the type of equipment I have designed, improved, bought, sold, used, installed and maintained. Then trained operators and maintenance personnel to use them. It is impressive to see these machines work 24/7 and know that you are in some way responsible for that.
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To bring some facts into the discussion:
I have ripped a CD with "Exact Audio Copy" 3 times. Then i have done a binary comparison of the resulting wave files.
Result: The 3 copies are bit for bit equal.
This is a strong hint that my cheap non audio optimized Laptop CDROM drive can read audio data without producing random errors.
But i am sure that some CDROM drives are better for audio (maybe plextor).
Who wan't to repeat this experiment instead of producing hot air?
This is the script is used for comparison (runs under cygwin / windows or Linux):
#!/bin/sh -
A=Temp1
B=Temp2
C=Temp3
ls "$A"/*.wav | while read i
do
j="$B"/"`basename "$i"`"
k="$C"/"`basename "$i"`"
cmp "$i" "$j"
cmp "$i" "$k"
done
I have ripped a CD with "Exact Audio Copy" 3 times. Then i have done a binary comparison of the resulting wave files.
Result: The 3 copies are bit for bit equal.
This is a strong hint that my cheap non audio optimized Laptop CDROM drive can read audio data without producing random errors.
But i am sure that some CDROM drives are better for audio (maybe plextor).
Who wan't to repeat this experiment instead of producing hot air?
This is the script is used for comparison (runs under cygwin / windows or Linux):
#!/bin/sh -
A=Temp1
B=Temp2
C=Temp3
ls "$A"/*.wav | while read i
do
j="$B"/"`basename "$i"`"
k="$C"/"`basename "$i"`"
cmp "$i" "$j"
cmp "$i" "$k"
done
Hi Salar,
Moving the CD sounds interesting. Do you foresee any difficulties moving a gyro sideways? This is an honest question.
I would prefer a tray for a number of reasons. These days dealing with the effects of an accident, sometimes I drop things or have difficulty with finer actions. A tray would allow me to use it much more easily. I have top loaders too. They are more difficult to use for many people, not just me. When you're young, no problem. But these are built to last ages.
I am more than comfortable with the rest of the design as you've laid out.
Just thinking here. A sled that moves the head so that the motor remains stationary would also allow head changes and a reference plane. All you need to do is create a standard sled that can be adjusted. The head would mount to it in an identical manner that you have planned for the stationary head. You would have to set either the motor or head up the same no matter which moves. But mounting the motor on the sub-chassis along with the sled would achieve the same thing. I do see an advantage in keeping the head stationary though. It allows the higher number of wires to remain still and can then run to an RF amplifier / servo PCB much more closely. Moving the motor only requires one pair of flexible wires that are not sensitive to objects. The wires coming off the pickup diodes are very sensitive to close conductive objects or noise injection from nearby objects.
I think I'm beginning to like the idea of a moving disc motor over a moving head.
-Chris
Moving the CD sounds interesting. Do you foresee any difficulties moving a gyro sideways? This is an honest question.
I would prefer a tray for a number of reasons. These days dealing with the effects of an accident, sometimes I drop things or have difficulty with finer actions. A tray would allow me to use it much more easily. I have top loaders too. They are more difficult to use for many people, not just me. When you're young, no problem. But these are built to last ages.
I am more than comfortable with the rest of the design as you've laid out.
Just thinking here. A sled that moves the head so that the motor remains stationary would also allow head changes and a reference plane. All you need to do is create a standard sled that can be adjusted. The head would mount to it in an identical manner that you have planned for the stationary head. You would have to set either the motor or head up the same no matter which moves. But mounting the motor on the sub-chassis along with the sled would achieve the same thing. I do see an advantage in keeping the head stationary though. It allows the higher number of wires to remain still and can then run to an RF amplifier / servo PCB much more closely. Moving the motor only requires one pair of flexible wires that are not sensitive to objects. The wires coming off the pickup diodes are very sensitive to close conductive objects or noise injection from nearby objects.
I think I'm beginning to like the idea of a moving disc motor over a moving head.
-Chris
Dear Chris,
this is the idea-keep wires short.
The very first CD-Player, CDP-5000, not designed for mere mortals
but for pros used the princple of moving disc. I assume it was simply easier to wire the motor than the laser.
But the CDP-101 half a year later had a moving laser.
Moving the disc was later used in the mid nineties with the CDP-X5000, SCD-777, SCD-1. No indication in mechanical
design that a moving gyroscope could cause difficulties.
Check also:
Sony CDP-5000 on thevintageknob.org
Sony SCD-1 on thevintageknob.org
Sony SCD-777ES on thevintageknob.org
Sony CDP-X5000 on thevintageknob.org
this is the idea-keep wires short.
The very first CD-Player, CDP-5000, not designed for mere mortals
but for pros used the princple of moving disc. I assume it was simply easier to wire the motor than the laser.
But the CDP-101 half a year later had a moving laser.
Moving the disc was later used in the mid nineties with the CDP-X5000, SCD-777, SCD-1. No indication in mechanical
design that a moving gyroscope could cause difficulties.
Check also:
Sony CDP-5000 on thevintageknob.org
Sony SCD-1 on thevintageknob.org
Sony SCD-777ES on thevintageknob.org
Sony CDP-X5000 on thevintageknob.org
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Hi Salar,
No problem. I just had to get my head wrapped around the idea, then examine it mentally. Basically, it was a change in thinking and humans don't like change, but I can clearly see where you are coming from. The mechanism is identical to a moving head, but with fewer wires bending. So I have come to like the idea.
On forth!
-Chris
No problem. I just had to get my head wrapped around the idea, then examine it mentally. Basically, it was a change in thinking and humans don't like change, but I can clearly see where you are coming from. The mechanism is identical to a moving head, but with fewer wires bending. So I have come to like the idea.
On forth!
-Chris
I agree with UDOK, if the data coming out of the drive is "perfect" then why do we obsess about CD mechanisms. After all the data has been retrieved successfully. Why cant we concentrate on a simple CD drive and then tune, if necessary, to obtain desired results, instead of designing something from scratch ?
Because your f*****g Cd Rom drive was not designed nor built to last.
I do not need to contribute to the growing mountains of electronic waste.
I do not need to contribute to the growing mountains of electronic waste.
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Salar, not build to last? You have tested this? I have 8 drives in a duplicator that have each made at least 5000 copies. All 8 drives are operating as new. I have seen automated duplicators with over 350,000 per drive on the counters, cant confirm that the drives were not replaced without resetting the counters though.
Using EAC is probably not a good method of testing a drive. It does extremely well at extracting the most out of a bad disc and/or a bad drive. It does demonstrate what can be done by monitoring C2 and re-reading at a lower speed.
Using EAC is probably not a good method of testing a drive. It does extremely well at extracting the most out of a bad disc and/or a bad drive. It does demonstrate what can be done by monitoring C2 and re-reading at a lower speed.
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Mark, have you read the title of this thread?
So, if headlines stick to your brain, do you have to contribute anything to the design of a mechanism which is as much as independent
from suppliers as possible, completely serviceable and
aligneable, where the only weareable parts over decades are
the replaceable bearings and some flexible cables besides
the laser diode? Or do you want to pile this thread with remarks
that deserve their own thread?
So, if headlines stick to your brain, do you have to contribute anything to the design of a mechanism which is as much as independent
from suppliers as possible, completely serviceable and
aligneable, where the only weareable parts over decades are
the replaceable bearings and some flexible cables besides
the laser diode? Or do you want to pile this thread with remarks
that deserve their own thread?
Make decisions based on facts or preferences, no need to twist the facts to promote the preferences.
Well I did make this sketch of your Linear Drive. How far are you with the optics and laser?
View attachment slede CD1.pdf
View attachment slede CD2.pdf
Please don't forget that is was me that got you the answer to how the servo slide works. Was that not at least a little useful?
Well I did make this sketch of your Linear Drive. How far are you with the optics and laser?
View attachment slede CD1.pdf
View attachment slede CD2.pdf
Please don't forget that is was me that got you the answer to how the servo slide works. Was that not at least a little useful?
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