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#1
Posted to rec.audio.high-end
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Löfgren's paper on cartridge alignment/tone arm geo
When talking about tone arm geometry and cartridge alignment, usually
Baerwald's paper from 1941 is mentioned. However, Erik Löfgren was actually the first to publish the solution, identical to Baerwald's, in 1938 in Germany. In the following years other solutions were proposed by Bauer 1945, Seagrave 1956, Stevenson 1966. In 1983 Graeme Dennes made an analysis of these papers and found that the different solutions are mathematically identical. Last year Graeme asked me if Löfgren's paper had ever been translated into English. To the best of my knowledge it had not so I thought I'd give it a go. Today, exactly 70 years later, with the help of Graeme and members of the Vinyl Engine, the translation is ready and can be downloaded from the VE website. http://www.vinylengine.com/phpBB2/viewtopic.php?t=15876 Klaus |
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#2
Posted to rec.audio.high-end
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Löfgren's paper on cartridge alignment/tone arm geo
wrote in message
When talking about tone arm geometry and cartridge alignment, usually Baerwald's paper from 1941 is mentioned. However, Erik Löfgren was actually the first to publish the solution, identical to Baerwald's, in 1938 in Germany. In the following years other solutions were proposed by Bauer 1945, Seagrave 1956, Stevenson 1966. In 1983 Graeme Dennes made an analysis of these papers and found that the different solutions are mathematically identical. Last year Graeme asked me if Löfgren's paper had ever been translated into English. To the best of my knowledge it had not so I thought I'd give it a go. Today, exactly 70 years later, with the help of Graeme and members of the Vinyl Engine, the translation is ready and can be downloaded from the VE website. http://www.vinylengine.com/phpBB2/viewtopic.php?t=15876 Some of the more knowledgeable people around here have been talking about inherent distortions that are part and parcel of the LP format. This paper describes one of the more significant ones and even calculates the amount of inherent nonlinear distortion involved. The relationship between distortion and record wear is discussed on page 12. Skeptical readers with short attention spans are directed to the Abstract on page 13 of the article. |
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#3
Posted to rec.audio.high-end
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L�fgren's paper on cartridge alignment/tone ar
On Nov 26, 9:08�am, "Arny Krueger" wrote:
wrote in message When talking about tone arm geometry and cartridge alignment, usually Baerwald's paper from 1941 is mentioned. However, Erik L�fgren was actually the first to publish the solution, identical to Baerwald's, in 1938 in Germany. In the following years other solutions were proposed by Bauer 1945, Seagrave 1956, Stevenson 1966. In 1983 Graeme Dennes made an analysis of these papers and found that the different solutions are mathematically identical. Last year Graeme asked me if L�fgren's paper had ever been translated into English. To the best of my knowledge it had not so I thought I'd give it a go. Today, exactly 70 years later, with the help of Graeme and members of the Vinyl Engine, the translation is ready and can be downloaded from the VE website. http://www.vinylengine.com/phpBB2/viewtopic.php?t=15876 Some of the more knowledgeable people around here have been talking about inherent distortions that are part and parcel of the LP format. This paper describes one of the more significant ones and even calculates the amount of inherent nonlinear distortion involved. The relationship between distortion and record wear is discussed on page 12. Skeptical readers with short attention spans are directed to the Abstract on page 13 of the article.- Hide quoted text - You do realize that this is limited to pivoting pickup arms and therefore is not about any inherent distortions in the medium don't you? Yes, record wear was a big deal in 1938. You do know why don't you? Incase you don't I'll give you a hint. They were made out of shellac. |
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#5
Posted to rec.audio.high-end
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L?fgren's paper on cartridge alignment/tone ar
wrote in message
On Nov 26, 9:08?am, "Arny Krueger" wrote: wrote in message When talking about tone arm geometry and cartridge alignment, usually Baerwald's paper from 1941 is mentioned. However, Erik L?fgren was actually the first to publish the solution, identical to Baerwald's, in 1938 in Germany. In the following years other solutions were proposed by Bauer 1945, Seagrave 1956, Stevenson 1966. In 1983 Graeme Dennes made an analysis of these papers and found that the different solutions are mathematically identical. Last year Graeme asked me if L?fgren's paper had ever been translated into English. To the best of my knowledge it had not so I thought I'd give it a go. Today, exactly 70 years later, with the help of Graeme and members of the Vinyl Engine, the translation is ready and can be downloaded from the VE website. http://www.vinylengine.com/phpBB2/viewtopic.php?t=15876 Some of the more knowledgeable people around here have been talking about inherent distortions that are part and parcel of the LP format. This paper describes one of the more significant ones and even calculates the amount of inherent nonlinear distortion involved. The relationship between distortion and record wear is discussed on page 12. Skeptical readers with short attention spans are directed to the Abstract on page 13 of the article.- Hide quoted text - You do realize that this is limited to pivoting pickup arms and therefore is not about any inherent distortions in the medium don't you? So, then you believe that almost everybody who listens to vinyl uses a straight-line tracking arm? Do you always listen to vinyl with a straight-line tracking arm? Yes, record wear was a big deal in 1938. You do know why don't you? Incase you don't I'll give you a hint. They were made out of shellac. So you really believe that vinyl records are immune to wear? |
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#6
Posted to rec.audio.high-end
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L?fgren's paper on cartridge alignment/tone ar
On Nov 27, 12:29�pm, "Arny Krueger" wrote:
wrote in message On Nov 26, 9:08?am, "Arny Krueger" wrote: wrote in message When talking about tone arm geometry and cartridge alignment, usually Baerwald's paper from 1941 is mentioned. However, Erik L?fgren was actually the first to publish the solution, identical to Baerwald's, in 1938 in Germany. In the following years other solutions were proposed by Bauer 1945, Seagrave 1956, Stevenson 1966. In 1983 Graeme Dennes made an analysis of these papers and found that the different solutions are mathematically identical. Last year Graeme asked me if L?fgren's paper had ever been translated into English. To the best of my knowledge it had not so I thought I'd give it a go. Today, exactly 70 years later, with the help of Graeme and members of the Vinyl Engine, the translation is ready and can be downloaded from the VE website. http://www.vinylengine.com/phpBB2/viewtopic.php?t=15876 Some of the more knowledgeable people around here have been talking about inherent distortions that are part and parcel of the LP format. This paper describes one of the more significant ones and even calculates the amount of inherent nonlinear distortion involved. The relationship between distortion and record wear is discussed on page 12. Skeptical readers with short attention spans are directed to the Abstract on page 13 of the article.- Hide quoted text - You do realize that this is limited to pivoting pickup arms and therefore is not about any inherent distortions in the medium don't you? So, then you believe that almost everybody who listens to vinyl uses a straight-line tracking arm? I am quite certain that any distortions due to tracking errors of pivoting arms are not inherent distortions in the medium. I do not pretend to know what everybody listens to. Do you always listen to vinyl with a �straight-line tracking arm? At home yes. Yes, record wear was a big deal in 1938. You do know why don't you? Incase you don't I'll give you a hint. They were made out of shellac. So you really believe that vinyl records are immune to wear? I believe that it is not a major issue with modern equipment and vinyl. The effects of record wear are of little consequence if one knows how to take care of their vinyl and one has the right rig that is propperly set up. |
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#7
Posted to rec.audio.high-end
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L?fgren's paper on cartridge alignment/tone ar
wrote in message
On Nov 27, 12:29�pm, "Arny Krueger" wrote: wrote in message On Nov 26, 9:08?am, "Arny Krueger" wrote: You do realize that this is limited to pivoting pickup arms and therefore is not about any inherent distortions in the medium don't you? So, then you believe that almost everybody who listens to vinyl uses a straight-line tracking arm? I am quite certain that any distortions due to tracking errors of pivoting arms are not inherent distortions in the medium. That's not an answer to the question, that is an irrelevant declaration. Not a responsive answer to the question that was asked. I think that that if you answered my question in a responsive way, you would have to admit that audiophiles that listen to vinyl don't as a rule use linear tracking tone arms. Therefore, the audible distortions due pivoting tone arms are inherent in the way that almost all people listen to LPs. Yes, record wear was a big deal in 1938. You do know why don't you? Incase you don't I'll give you a hint. They were made out of shellac. So you really believe that vinyl records are immune to wear? I believe that it is not a major issue with modern equipment and vinyl. Do you have any evidence for that assertion that overcomes the technical information that has been published by various reliable technical sources that says that wear is a major issue with modern equipment and vinyl. The effects of record wear are of little consequence if one knows how to take care of their vinyl and one has the right rig that is propperly set up. Assertion without proof or even relevant reliable evidence. |
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#8
Posted to rec.audio.high-end
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L?fgren's paper on cartridge alignment/tone ar
On Nov 28, 8:42�am, "Arny Krueger" wrote:
wrote in message On Nov 27, 12:29 pm, "Arny Krueger" wrote: wrote in message On Nov 26, 9:08?am, "Arny Krueger" wrote: You do realize that this is limited to pivoting pickup arms and therefore is not about any inherent distortions in the medium don't you? So, then you believe that almost everybody who listens to vinyl uses a straight-line tracking arm? I am quite certain that any distortions due to tracking errors of pivoting arms are not inherent distortions in the medium. That's not an answer to the question, that is an irrelevant declaration. Sure it is. Lets look at the original declaration by you in the second post on this thread. "Some of the more knowledgeable people around here have been talking about inherent distortions that are part and parcel of the LP format. This paper describes one of the more significant ones and even calculates the amount of inherent nonlinear distortion involved." You are in effect claiming that tracking errors of pivoting arms are an inherent coloration of the medium. Clearly they are not. i shoudl know, my arm does not suffer from them. Not a responsive answer to the question that was asked. I think that that if you answered my question in a responsive way, you would have to admit that audiophiles that listen to vinyl don't as a rule use linear tracking tone arms. �Therefore, the audible distortions due pivoting tone arms are inherent in the way that almost all people listen to LPs. Your question lacked relevance to the issue at hand. That would be your claim that tracking errors of pivoted arms are an "inherent coloration of the medium." Clearly they are not. It would be no less intelectually insincere for me to claim that digital only has about 10 db of dynamic range because that is what the majority of consumers hear when they listen to any digital playback. You are once again using a logical fallacy "Special pleading, or ad-hoc reasoning This is a subtle fallacy which is often difficult to recognize. In essence, it is the arbitrary introduction of new elements into an argument in order to fix them so that they appear valid." http://www.theskepticsguide.org/logicalfallacies.asp Any discussion of the 'inherent' colorations of any medium have to be all inclusive. Clearly tracking errors of pivoting arms are not all inclusive. Your special pleading about common usage of pivoting arms is irrelevent and a logical fallacy. Yes, record wear was a big deal in 1938. You do know why don't you? Incase you don't I'll give you a hint. They were made out of shellac. So you really believe that vinyl records are immune to wear? I believe that it is not a major issue with modern equipment and vinyl. Do you have any evidence for that assertion that overcomes the technical information that has been published by various reliable technical sources that says that wear is a major issue with modern equipment and vinyl. What technical information has been published that claims record wear is a significant problem with modern playback equipment and modern vinyl formulations? All that has been presented on this thread is a paper that referes to the wear of shellac records played with a metal needle with tracking forces that are on an order of magnitude greater than that of modern cartridges. The effects of record wear are of little consequence if one knows how to take care of their vinyl and one has the right rig that is propperly set up. Assertion without proof or even relevant reliable evidence Please show some reliable and relevant proof that says otherwise. Remember the need for relevance. You apparently forgot that when you cited this 1938 paper that deals with the playback of shellac 78s as evidence of the problem with the wear of modern vinyl on modern rigs. |
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#9
Posted to rec.audio.high-end
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L?fgren's paper on cartridge alignment/tone ar
wrote:
"Arny Krueger" wrote: wrote in message When talking about tone arm geometry and cartridge alignment, usually Baerwald's paper from 1941 is mentioned. However, Erik L�fgren was actually the first to publish the solution, identical to Baerwald's, in 1938 in Germany. In the following years other solutions were proposed by Bauer 1945, Seagrave 1956, Stevenson 1966. In 1983 Graeme Dennes made an analysis of these papers and found that the different solutions are mathematically identical. Last year Graeme asked me if L�fgren's paper had ever been translated into English. To the best of my knowledge it had not so I thought I'd give it a go. Today, exactly 70 years later, with the help of Graeme and members of the Vinyl Engine, the translation is ready and can be downloaded from the VE website. http://www.vinylengine.com/phpBB2/viewtopic.php?t=15876 Some of the more knowledgeable people around here have been talking about inherent distortions that are part and parcel of the LP format. This paper describes one of the more significant ones and even calculates the amount of inherent nonlinear distortion involved. The relationship between distortion and record wear is discussed on page 12. Skeptical readers with short attention spans are directed to the Abstract on page 13 of the article. You do realize that this is limited to pivoting pickup arms And what do you use ? and therefore is not about any inherent distortions in the medium don't you? Yes it IS inherent. Tracking or tracing distortion is a result of fundamental physics / mathematics.. Graham |
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#10
Posted to rec.audio.high-end
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L?fgren's paper on cartridge alignment/tone ar
On Nov 29, 8:45�am, Eeyore
wrote: wrote: "Arny Krueger" wrote: wrote in message When talking about tone arm geometry and cartridge alignment, usually Baerwald's paper from 1941 is mentioned. However, Erik L fgren was actually the first to publish the solution, identical to Baerwald's, in 1938 in Germany. In the following years other solutions were proposed by Bauer 1945, Seagrave 1956, Stevenson 1966. In 1983 Graeme Dennes made an analysis of these papers and found that the different solutions are mathematically identical. Last year Graeme asked me if L fgren's paper had ever been translated into English. To the best of my knowledge it had not so I thought I'd give it a go. Today, exactly 70 years later, with the help of Graeme and members of the Vinyl Engine, the translation is ready and can be downloaded from the VE website. http://www.vinylengine.com/phpBB2/viewtopic.php?t=15876 Some of the more knowledgeable people around here have been talking about inherent distortions that are part and parcel of the LP format. This paper describes one of the more significant ones and even calculates the amount of inherent nonlinear distortion involved. The relationship between distortion and record wear is discussed on page 12. Skeptical readers with short attention spans are directed to the Abstract on page 13 of the article. You do realize that this is limited to pivoting pickup arms And what do you use ? A Forsell Air Reference TT/arm and therefore is not about any inherent distortions in the medium don't you? Yes it IS inherent. Tracking or tracing distortion is a result of fundamental physics / mathematics.. Please show me the math that shows the tracking errors of pivoting arms also affect linear tracking arms. |
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#11
Posted to rec.audio.high-end
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L?fgren's paper on cartridge alignment/tone ar
"Eeyore" wrote in message
... wrote: "Arny Krueger" wrote: wrote in message When talking about tone arm geometry and cartridge alignment, usually Baerwald's paper from 1941 is mentioned. However, Erik L�fgren was actually the first to publish the solution, identical to Baerwald's, in 1938 in Germany. In the following years other solutions were proposed by Bauer 1945, Seagrave 1956, Stevenson 1966. In 1983 Graeme Dennes made an analysis of these papers and found that the different solutions are mathematically identical. Last year Graeme asked me if L�fgren's paper had ever been translated into English. To the best of my knowledge it had not so I thought I'd give it a go. Today, exactly 70 years later, with the help of Graeme and members of the Vinyl Engine, the translation is ready and can be downloaded from the VE website. http://www.vinylengine.com/phpBB2/viewtopic.php?t=15876 Some of the more knowledgeable people around here have been talking about inherent distortions that are part and parcel of the LP format. This paper describes one of the more significant ones and even calculates the amount of inherent nonlinear distortion involved. The relationship between distortion and record wear is discussed on page 12. Skeptical readers with short attention spans are directed to the Abstract on page 13 of the article. You do realize that this is limited to pivoting pickup arms And what do you use ? and therefore is not about any inherent distortions in the medium don't you? Yes it IS inherent. Tracking or tracing distortion is a result of fundamental physics / mathematics.. Graham I suppose it depends what you mean by "inherent". If you use a parallel-tracking arm, then you don't have tracking distortion, and if you use something like the Finial laser turntable, you don't get tracing distortion, so it's not necessarily "inherent" in the medium, just in the "normal" way of playing LPs. However, there are several distortion mechanisms inherent in the cutting of LPs to do with lacquer springback and cutter angles that are fixed in the subsequent LP and therefore can be thought of as genuinely "inherent" S. -- http://audiopages.googlepages.com |
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#12
Posted to rec.audio.high-end
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L?fgren's paper on cartridge alignment/tone ar
wrote in message
om Please show me the math that shows the tracking errors of pivoting arms also affect linear tracking arms. Any tracking errors that are internal to the cartrdige, including those due to the radius of the stylus and the fact that the stylus of a cartridge rotates around an internal pivot, also affect linear tracking arms. We've cited a number of AES papers that discuss these problems. Have you yet analyzed them for errors in their math? |
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#13
Posted to rec.audio.high-end
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L?fgren's paper on cartridge alignment/tone ar
On Nov 29, 8:09�pm, "Arny Krueger" wrote:
wrote in message om Please show me the math that shows the tracking errors of pivoting arms also affect linear tracking arms. Any tracking errors that are internal to the cartrdige, including those due to the radius of the stylus and the fact that the stylus of a cartridge rotates around an internal pivot, also affect linear tracking arms. That is an interesting *new* assertion. But it does not address the assertion that there is some sort of mathematical proof that linear tracking arms suffer from the same tracking errors as do pivoting arms that was addressed in the paper by Erik Lofgren. Perhaps you should start a new thread about this *other* alleged form of tracking distortion and post the actual relevant data and analysis of any actual academic papers on the subject as did the OP of this thread. |
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#14
Posted to rec.audio.high-end
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L?fgren's paper on cartridge alignment/tone ar
wrote in message
On Nov 29, 8:09�pm, "Arny Krueger" wrote: wrote in message om Please show me the math that shows the tracking errors of pivoting arms also affect linear tracking arms. Any tracking errors that are internal to the cartridge, including those due to the radius of the stylus and the fact that the stylus of a cartridge rotates around an internal pivot, also affect linear tracking arms. That is an interesting *new* assertion. It's not new at all. Symptomatic of not reading any of the JAES articles that have been cited here. |
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#15
Posted to rec.audio.high-end
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L?fgren's paper on cartridge alignment/tone ar
On Nov 30, 4:25�pm, "Arny Krueger" wrote:
wrote in message On Nov 29, 8:09 pm, "Arny Krueger" wrote: wrote in message news:EY6dne3kR5de6qzUnZ2dnUVZ_vadnZ2d@pghconnect .com Please show me the math that shows the tracking errors of pivoting arms also affect linear tracking arms. Any tracking errors that are internal to the cartridge, including those due to the radius of the stylus and the fact that the stylus of a cartridge rotates around an internal pivot, also affect linear tracking arms. That is an interesting *new* assertion. It's not new at all. It is quite new to this thread. Symptomatic of not reading any of the JAES articles that have been cited here. Send them to me and I will read them. Thus far you have had a pretty miserable track record of making logical connections between technical papers such as the Lofgren paper cited in this thread and your assertions about the realities of vinyl playback. For all we know the papers you have cited from the JAES are just as irrelevant to the topics being discussed as was your assertion that the Lofgren paper was relevant to the inherent colorations of vinyl playback and the issue of record wear with modern equipment and modern vinyl formulations. I am not going to spend any money just to find out you are making more of the same illogical connections. Send them to me and I will read them. |
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#16
Posted to rec.audio.high-end
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L?fgren's paper on cartridge alignment/tone ar
wrote in message
On Nov 30, 4:25�pm, "Arny Krueger" wrote: wrote in message On Nov 29, 8:09 pm, "Arny Krueger" wrote: wrote in message om Please show me the math that shows the tracking errors of pivoting arms also affect linear tracking arms. Any tracking errors that are internal to the cartridge, including those due to the radius of the stylus and the fact that the stylus of a cartridge rotates around an internal pivot, also affect linear tracking arms. That is an interesting *new* assertion. It's not new at all. It is quite new to this thread. Symptomatic of not reading any of the JAES articles that have been cited here. Send them to me and I will read them. That involves a great expense to me, or me breaking the law. It is customary for people to pay for their own educations, not panhandle it from strangers. Thus far you have had a pretty miserable track record of making logical connections between technical papers such as the Lofgren paper cited in this thread and your assertions about the realities of vinyl playback. Speaks to your inability to understand technical papers in general. For all we know the papers you have cited from the JAES are just as irrelevant to the topics being discussed as was your assertion that the Lofgren paper was relevant to the inherent colorations of vinyl playback and the issue of record wear with modern equipment and modern vinyl formulations. I am perfectly content to let you continue to be ignorant. I am not going to spend any money just to find out you are making more of the same illogical connections. Send them to me and I will read them. Send me $250 and I will be your agent and order several of them from the AES, and ship them to your address. But for far less money, you can send me that transcription of a side of a vinyl LP with no edits or other processing, that has no tics, or pops, or other problems that you claim the LP simply does not have. Of course, if no such recording is ever delivered to me, we know that the many claims you have made about the LP have zero substance, because you can not provide even one example that supports your claims. |
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#17
Posted to rec.audio.high-end
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L?fgren's paper on cartridge alignment/tone ar
On Dec 1, 3:07�pm, "Arny Krueger" wrote:
wrote in message On Nov 30, 4:25 pm, "Arny Krueger" wrote: wrote in message On Nov 29, 8:09 pm, "Arny Krueger" wrote: wrote in message news:EY6dne3kR5de6qzUnZ2dnUVZ_vadnZ2d@pghconne ct.com Please show me the math that shows the tracking errors of pivoting arms also affect linear tracking arms. Any tracking errors that are internal to the cartridge, including those due to the radius of the stylus and the fact that the stylus of a cartridge rotates around an internal pivot, also affect linear tracking arms. That is an interesting *new* assertion. It's not new at all. It is quite new to this thread. Symptomatic of not reading any of the JAES articles that have been cited here. Send them to me and I will read them. That involves a great expense to me, or me breaking the law. A great deal of expense? How much is it to email files? I thought that was free. Breaking the law? You mean copywright law? Isn't that the same law you are asking me to break by making a CD transcription? You could easily send me relevant excerpts which falls under fair usage and would avoid any violation of copywright laws. IOW those excuses don't hold water. You can do it for little or no cost without breaking any laws. It is customary for people to pay for their own educations, not panhandle it from strangers. Then why are you "panhandling" for free music from me? Thus far you have had a pretty miserable track record of making logical connections between technical papers such as the Lofgren paper cited in this thread and your assertions about the realities of vinyl playback. Speaks to your inability to understand technical papers in general. Pure ad Hominem. For all we know the papers you have cited from the JAES are just as irrelevant to the topics being discussed as was your assertion that the Lofgren paper was relevant to the inherent colorations of vinyl playback and the issue of record wear with modern equipment and modern vinyl formulations. I am perfectly content to let you continue to be ignorant. More Ad Hominem. �I am not going to spend any money just to find out you are making more of the same illogical connections. Send them to me and I will read them. Send me $250 and I will be your agent and order several of them from the AES, and ship them to your address. Wouldn't *that* be breaking the law? I'm betting you are not an authorized agent for the JAES But for far less money, you can send me that transcription of a side of a vinyl LP with no edits or other processing, that has no tics, or pops, or other problems that you claim the LP simply does not have. Why would you ask me to break the same laws you are so concerned about breaking yourself? Of course, if no such recording is ever delivered to me, we know that the many claims you have made about the LP have zero substance, because you can not provide even one example that supports your claims Faulty Logic. Non sequitor. The validity of my claims don't hinge on me giving you free music? You still haven't explained how you plan to do a biased controlled evaluation of such a transcription. So what would be the point in sending you such a transcription with no evidence that you could or would do a bias controlled evaluation? Your prejudices against vinyl are already well documented. |
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#18
Posted to rec.audio.high-end
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L fgren's paper on cartridge alignment/tone ar
On 27 nov, 05:34, wrote:
"You do realize that this is limited to pivoting pickup arms..." Actually no, at least not on paper, because tracking error is caused by non-tangentiality of the vertical plane of the playback stylus and this can occur in linear tracking arms as well. As far as record wear with modern styli and low tracking forces is concerned, here are some excerpts that might be of interest: Anderson, "Some Aspects of Wear and Calibration of Test Records", JAES Volume 9 Issue 2, pp. 111-114; April 1961 HIGH FREQUENCY WEAR An experiment which has been performed many times is to plot successive response curves, starting with a new record, and noting the changes which occur. A typical result is shown in Fig. 8, measured on the RCA 12-5-49 record with RIAA equalization applied. Here, the decrease in high frequency response due to progressive wear on an experimental laboratory pickup at 1- gram needleforce is contrasted to the wear resulting from a standard M3D cartridge at the extreme needleforce of 9 grams. The experimental pickup is a modified M21 cartridge having a compliance of 25 X 10.C cm/dyne and an equivalent mass of 1.0 milligram. The standard M3D cartridge has a compliance of 4.5 ) 10_c cm/dyne, and an equivalent mass of 2.0 milligrams. The observed wear from 20 playings varies from effectively zero for the modified M21 to about 5 db for the M3D, due to the differences in compliance, equivalent mass and, to a large extent, needle- force. Curves of this type have long been used as a measure of record wear. However well these curves may express the record wear resulting from progressive playings, they cannot express the difference between the condition of the new record and its condition after the first playing. Our experience has been that the first playing, especially at high needleforce, accomplishes a large part of the wear observed after 20 plays. To assess the damage resulting from the first playing, we utilize the experimental laboratory pickup, which occasions no detectable wear. The new record is played on the lightweight pickup. then on the test pickup, and then on the lightweight pickup again. These results are shown in Fig.9. It is noteworthy to observe that the first play at 9 grams has worn off 1.5 db. This illustrates the misleading results that may accrue from measuring different types of pickups on the same record. Anderson, "Phonograph reproduction - 1978, Audio Magazine 1978, June, pp.42-58 Wear: Comparative tests were conducted to evaluate tip and record wear. In one test V15 Type IV styli with biradial, hyperbolic, and hyperelliptical tips were played continuously on the ShureTTRllO record at 1.25-grams tracking force. All cartridges were mounted in the same model record changer. The tips and records were cleaned regularly. Based on photographs of the tips, no significant difference in the rate of tip wear was observed in these tests. Record wear tests were conducted as well. Second harmonic distortion was measured after 100 plays. The results showed no significant difference among biradial, hyperbolic, and hyperelliptical tips. Although extensive testing has been performed on noise generation, record wear, and tip wear, we have found little in the way of significant differences among tips of different shapes. We have confirmed that playing at higher tracking force accelerates wear and recommend a force of no more than 1.5 grams. We have also confirmed, once again, by measurement that mis tracking is disastrous in terms of noise and record wear. Davies, "Close-up look of record wear", Audio Magazine 1980, September, pp.38-42 For these tests, all of the records were played with a new Shure M91ED cartridge (elliptical) loaded at 1 gram with proper anti-skate adjustment. The records were cleaned with 50 percent isopropyl alcohol. (Dirt could have caused erroneous interpretation by gouging out the groove surface.) Records had adjacent serial numbers so that they came from the same master and presumably pressed within minutes of one another, Figure 4 is the sequence or SEM photos of a Kotekan record played 50 times. The loss of audio quality is easily heard. The SEM photos show that there are now many small pieces of vinyl that have come off of the surface. These little depressions are very reminiscent of glass surfaces that have been chipped by fine sand, that is, these impertections appear to be due to surface conchoidal fractures. Examples or conchoidal fractures are broken or shattered glass. Note that by comparison with Fig. 3. there are many more imperfections or this kind and that their Individual sizes are larger than those or Fig. 3. Notice too the distinct wear lines that are parallel to tho record groove. Flgure 3 is a sequence or SEM photos taken at a record of Holst's "The Planets". This record was also played 50 times. After 50 plays, it is almost unlistenable. The groove walls clearly show enormous damage. Notice that the damage is mainly of the conchoidal fracture type and that there are many longitudinal wear lines. In Figure 5F, we can clearly see why high frequencies become distorted by the wear process. The wall modulations in th right channel are very badly damaged by the conchoidal fracturing that has occurred. In this photo, the dimensions of the fractures are a sizable fraction of the width of the wall modulations. The wear damage shown in Figs. 4 and 5 is predominantly of the conchoidal fracture type. But this is not the only kind of wear damage that can occur. Figures 6A, B, and C show examples of another kind of wear process, tearing and gouging in addition to the conchoidal fracture, which may be associated with a "stick-slip" frictional phenomenon. These photos were taken from a recording of Rachmaninoff's Symphony No. 1, used as demonstration record in an audiophile specialty house. The pickup was a moving-coil type loaded at 2.5 grams, and the record was thoroughly cleaned prior to each playing. Kogen, "The elliptical stylus", Audio Magazine 1964, May, pp.33-36, 60, 61 1. Background Noise. The test record employed in this test was the CBS-STR 100 band 6A and 7A which is modulated at 1000 cps at a recorded velocity of 3.54 cm/ sec. A wave analyzer was used to measure output at discrete frequencies across the audio range. Measurements were made during the first playing of the record with a 0.2- mil radius elliptical tip, played at 1.5 grams. The record was played 30 times and the measurement was repeated after every ten playings. Figure 7 shows output versus frequency after the first and after 30 playings. The output at 1000 cps, 2000 cps, 3000 cps, and so forth indicates the modulation cut into the record plus residual distortion products. Output at other frequencies shows background noise. Our conclusion from this test was that background noise did not change to any measurable degree even at the maximum tracking force for this cartridge. Some increase in output was noted at about 12,000 cps, the resonance of the stylus and record. Additional tests indicated that this small amount of wear can be eliminated under identical test conditions by reducing the tracking force to 1 gram or less. A second test for broadband noise was run at 10,000 cps using the elliptical tip at 1.5 grams. For this test a harmonic distortion meter was employed which measured the output of all frequencies except 10,000 cps. Total distortion plus noise measured 2.2 per cent during the first playing and 2.8 per cent during the 70th playing. This is a rather moderate change in noise for 70 playings of the record. 2. Frequency Response. Alteration of the groove modulation should be indicated by a change in frequency response as measured on a new versus a worn record. Tests were performed using the CBS-STR 100 record, bands 1A and 2A. Recordings of cartridge output-versus-frequency for a variety of tracking forces and tip radii on new records and after a significant number of playings. The results of these tests we a. At 1 gram with the 0.2-mil elliptical tip, no measurable change in frequency response could be detected. b. At 1.5 grams with the elliptical tip, a slight alteration in response was noted between 10,000 and 20,00 cps after 100 plays. c. At 3 grams with the elliptical tip, a significant effect on the output in the 10,000 to 20,000 cps range was detected. d. A 0.7-mil circular tip at 3.0 grams influenced the 10,000 to 20,000 cps response to a small degree after 100 playings, about the same as the 0.2- mil tip at 1.5 grams. Our conclusion is that, if this test has significance, the tracking force for 0.2-mil elliptical tip should be no greater than 1.5 grams maximum and more optimally 1.0 gram. 3. Square Wave Tests. As an alternate for the frequency response measurements a series of tests were run on square wave modulation using the CBS-STR 111 record. This record has bands of 1000-cps square waves modulated laterally, vertically, left channel and right channel stereo. Tests were performed with the 0.2-mil elliptical tip at 1.5 and at 3.0 grams. Results were as follows: a. At 1.5 grams a very small change was detected after 25 plays. This change showed up as about 10 per cent increase in amplitude of the first overshoot. This correlates with the frequency response tests in that the frequency and amplitude of the overshoot is directly related to the upper frequency response. The effect of the elliptical tip at 1.5 grams appears to be reasonably small for the vertical and lateral, as well as stereo modulation. b. Wear after 25 playings at 3 grams was much more pronounced for this test on the stereo channels. After 25 playings the first overshoot increased in amplitude to roughly twice what it was on a new record. Very little change was noted in the laterally modulated groove and, surprisingly, the vertical groove. These tests were all relative, of course, and provide no indication of how much change would be significant. Nevertheless, the square wave tests do correlate with the frequency response and coroborate our conclusion that 1.5 grams is the top limit in tracking force for a 0.2- mil elliptical tip. Klaus |
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#19
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#20
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L fgren's paper on cartridge alignment/tone ar
On Dec 5, 12:15*pm, Steven Sullivan wrote:
wrote: fascinating stuff I think some of this work has been much-referenced here and other audio groups , but without exact citations; it's good to see them cited bibliogpahically. *I'd love to see the SEM photos from the Audio article, I'll have to see if I can find that somehere. FWIW, wasn't Davies the inventor of LAST? His research is great, but he did have a vested interest in the matter The comments on staying under 1.5 grams to avoid HF tip-groove resonance issues is *extremely* fascinating. It flies in the face of a lot of modern wisdom about tracking close to the upper recommended limits of the cartridge. I do wonder, though, about 'square waves' on test records. *How can anyone expect soemthing as crude as a stylus in contact with a rotating platter, to accurately navigate the successive 90 degree angles of a square wave? Is there some 'trick' to it? Yeah, integration  A reproduced square wave has a groove with theshape of a triangle wave. (A square-wave groove would reproduce electrically as a Dirac impulse train, if it actually tracked.) |
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#21
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On Nov 27, 3:29*pm, "Arny Krueger" wrote:
So, then you believe that almost everybody who listens to vinyl uses a straight-line tracking arm? No, of course not. Why would you even ask? Do you always listen to vinyl with a *straight-line tracking arm? Yes, since 1974. Yes, record wear was a big deal in 1938. You do know why don't you? Incase you don't I'll give you a hint. They were made out of shellac. So you really believe that vinyl records are immune to wear? No, of course not. Why would you even ask? But, just to rub it in a little: Assume an 8 ounce tracking force on a steel needle for a 78 rpm record. The diameter of a new steel needle designed for 78 rpm use is 0.08mm (3mil). The diameter of a typical eliptical diamond stylus for a 33 rpm record is ~0.02mm x 0.005mm with considerable variations, but that is average. Assume a contact area of one (1) mil x 1/2 the diameter for the steel stylus, and 0.02mm x the short side for the eliptical stylus. Assume a 2 gram tracking force for the eliptical stylus. 8 ounces = 226 grams +/- 1 x 1.5 = 1.5 square mils or .0381 square mm. Or, 5.931 kilograms/square mm. Comes to something over 8000 pounds per square inch. Moving without lubrication at a speed of approximately 36.75 feet per second, or ~25 miles per hour. Not to mention bouncing up and down and from side-to side to make the sound. This is for the steel needle on shellac. For a diamond stylus on vinyl, that calculates to about 340 pounds per square inch, traveling at about 15.6 feet per second or about 10.6 mph. Also with bouncing up and down and side to side. NO mechanically transduced medium is immune to wear. But which do you think will wear faster, and for which medium do you think will be more affected by poor geometry (and that is a trick question - remember that the steel stylus is presumably round - but is *not* vertical). Bunch-O-Red Herrings. The Edison Cylinder machines had it right - a vertical stylus on the cylindar that was driven by a screw calibrated to the exact width of the groove. I have a very nice 2-minute Edison Home machine - some of those cylinders are surprisingly dynamic for media recorded over 100 years ago and played many times, I am sure. But I would never suggest that they were the cat's meow or even the bee's knees as to fidelity. And the Edison Diamond Disc machines also used a vertical (diamond) needle. Peter Wieck Melrose Park, PA |
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#22
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L fgren's paper on cartridge alignment/tone ar
On Dec 5, 2:20 pm, Richard Tollerton
wrote: Yeah, integration A reproduced square wave has a groove with theshape of a triangle wave. (A square-wave groove would reproduce electrically as a Dirac impulse train, if it actually tracked.) Actually, no. The electrical output of the cartridge is proportional to the instantaneous velocity of the stylus tip, to some reasonable approximation. That voltage is then integrated by the biggest feature of the RIAA playback equalization. A square wave impressed on the vinyl will get differentiated by the cartridge, resulting in the Dirac impulse train you suggested: Integrate that voltage train in the phono preamp and there's your square wave. Or, more accurately, some reasonable approximation thereof. It's a little different, of course, due to the RIAA shelf. |
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#23
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L fgren's paper on cartridge alignment/tone ar
"Steven Sullivan" wrote in message
... wrote: fascinating stuff I think some of this work has been much-referenced here and other audio groups , but without exact citations; it's good to see them cited bibliogpahically. I'd love to see the SEM photos from the Audio article, I'll have to see if I can find that somehere. I do wonder, though, about 'square waves' on test records. How can anyone expect soemthing as crude as a stylus in contact with a rotating platter, to accurately navigate the successive 90 degree angles of a square wave? Is there some 'trick' to it? [quoted sig deleted. -- deb ] A square wave audio signal becomes a triangle wave on the record due to the action of the RIAA equalisation, modified further by the limited bandwidth of the medium, and levels would have to be kept modest so the cutter could cut the groove. Although a severe test for a stylus, it's within possibilities. S. -- http://audiopages.googlepages.com |
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#24
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L fgren's paper on cartridge alignment/tone ar
On Dec 5, 1:15 pm, Steven Sullivan wrote:
I do wonder, though, about 'square waves' on test records. How can anyone expect soemthing as crude as a stylus in contact with a rotating platter, to accurately navigate the successive 90 degree angles of a square wave? Is there some 'trick' to it? A "square wave: is not a square wave mechanically on a record, for a number of reasons. First and foremost, it's severely band-limited. Assume a real top-end of 20 kHz, even 25 kHz and non phase- linear response: no "90 corner" got impressed in the vinyl to begin with. Absolute best case you'd be looking at a rise time on the order of 0.018-0.020 mS assuming critically damped response, which is a pretty tall order. |
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#25
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On Dec 5, 3:16 pm, Peter Wieck wrote:
For a diamond stylus on vinyl, that calculates to about 340 pounds per square inch, traveling at about 15.6 feet per second or about 10.6 mph. Not that it's relevant, but however did you come up with 15.6 feet per second? I assume you're talking about the linear groove velocity, greatest at the outside of the record. The circumference is 37.6 inches, rotation is 0.555 RPS (33.3 RPM), thus the velocity is 0.555/s * 37.6 inches = 20 in/s or 1.7 ft/s, a blistering 1.2 mph. I almost sit faster than that. Also with bouncing up and down and side to side. And all this imparts confidence in the medium, ... how? :-) |
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#26
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L?fgren's paper on cartridge alignment/tone ar
On Dec 5, 5:50*pm, wrote:
On Dec 5, 3:16 pm, Peter Wieck wrote: For a diamond stylus on vinyl, that calculates to about 340 pounds per square inch, traveling at about 15.6 feet per second or about 10.6 mph. Not that it's relevant, but however did you come up with 15.6 feet per second? I assume you're talking about the linear groove velocity, greatest at the outside of the record. The circumference is 37.6 inches, rotation is 0.555 RPS (33.3 RPM), thus the velocity is 0.555/s * 37.6 inches = 20 in/s or 1.7 ft/s, a blistering 1.2 mph. I almost sit faster than that. *Also with bouncing up and down and side to side. And all this imparts confidence in the medium, ... how? :-) 12" record. Average 9" diameter. 9 x 78 x 3.14159 = 2205.4 ipm. 2205.4/60/12 = ~3.07fps. A bit over 2 mph... A moderate walking speed. Yeah, yeah. Divide everything by 12 on the speed ------ conversions. Sorry about that. But the point still stands. Still, lots-O-weight at a considerable speed. OOOps again. Peter Wieck Melrose Park, PA |
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#27
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#28
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#29
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L fgren's paper on cartridge alignment/tone ar
On Sat, 6 Dec 2008 07:48:33 -0800, Greg Wormald wrote
(in article ): In article , wrote: *snip* Klaus Interesting. Some complications with the tests that may be relevant (if my memory serves): According to the Disk Doctor, washing with isopropyl alcohol can strip plasticisers and increase wear. This is apparently true as far as it goes. But one must take into consideration the fact that most people don't wash any one record all that often. I doubt seriously if one or two washings with alcohol-based cleaners over the life of a record will harm it. If you want the very best record cleaning possible, go to Old Colony Sound's website: http://www.audioxpress.com/bksprods/products/km-9.htm and order Reg Williamson's record cleaning kit. This is essentially the same system that Audio Empire used to sell back in the seventies. One spreads a film of a thick goo all over one's record and then let's it dry. This water soluble substance gets down into the bottom of the grooves where it solidifies AROUND all of the detritus in the groove. One then takes a piece of scotch tape and adheres it to the dried goo from near the label to the outside edge of the record. With the tape firmly adhered to the dried goo coating, one merely lifts the tape and a thin, clear film 'negative' of the record peels off, taking ALL the dirt, oils, fingerprints dust, mold release agents left over for manufacturing, everything off the record leaving it pristine. Its the best record cleaning system EVER devised, It has nothing in it to harm the vinyl, and does an even better job than the expensive VPI vacuuming systems. It's only $20 for the starter system and refills are $5. Repeated playing without resting times increases wear because of the brittleness of the vinyl due to heating and deformation. This too is true. the contact between the stylus and the groove at any given point is fleeting, but the forces exerted at the actual contact point are enormous and the temperature can momentarily approach that of melting the vinyl. This stretches the groove. Now, given time, the plastic "memory" nature of the vinyl will cause it to re-form its original molded shape, but without this "rest" the vinyl can be permanently deformed. This reduces high-frequency content and increases noise and distortion. |
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#30
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L fgren's paper on cartridge alignment/tone ar
On Dec 5, 4:01*pm, wrote:
The electrical output of the cartridge is proportional to the instantaneous velocity of the stylus tip, to some reasonable approximation. That voltage is then integrated by the biggest feature of the RIAA playback equalization. Right, but was the STR 111 square wave meant for RIAA playback or flat playback? The physical interpretation of the square wave seems far more meaningful to me when the RIAA curve is entirely ignored. |
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#31
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L fgren's paper on cartridge alignment/tone ar
On Dec 5, 11:14 pm, Steven Sullivan wrote:
Cutting a square wave, then, is modestly analogous to hearing one -- that is, our ears also bandlimit them into something that would not look 'square' in a visual representation. The concept of a perfect square wave is one that is simultaneous with the concept of infinite energy in pretty much any domain. You could impress a true square wave on a record surface, by any number of means OTHER than with a standard cutter. But now let's look at the requirements that imposes on the stylus: it must change position between the minimum and maximum in zero time. That means it's moving at infinite velocity. Since in Newtonian mechanics, e = 1/2 mv^2, the kinetic energy imparted on the stylus is infinite. In Einsteinian electrodynamics, this situation is not even remotely possible, as the fastest velocity relative to any observer is the speed of light, and any finite mass traveling at the speed of light possesses infinite energy. And let's even pretend that's possible. The output is the differential with respect to time of the stylus position, which means the cartridge must put out infinite current into that 47 kOhm phono preamp and that dissipates infinite p=power since P = i^2 R. And even if we dealt with that, assume the lowly wire connecting the cartridge to the preamp had infinitesimal but non-zero capacitance: propogating voltages whose rate of changes are infinite requires infinite current, since I = C dv/dt. In any case, I would not concern myself much with the square wave performance of LP systems: first, true square waves are impossible and second, even the imperfect ones are pretty useless. |
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#32
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On Dec 6, 2:50 pm, Richard Tollerton
wrote: On Dec 5, 4:01 pm, wrote: The electrical output of the cartridge is proportional to the instantaneous velocity of the stylus tip, to some reasonable approximation. That voltage is then integrated by the biggest feature of the RIAA playback equalization. Right, but was the STR 111 square wave meant for RIAA playback or flat playback? The physical interpretation of the square wave seems far more meaningful to me when the RIAA curve is entirely ignored. To answwer that question, you need to understand what "RIAA playback" means. Playing back a velocity cartridge (ALL phono cartridges are, in essence, velocity devices) without ANY frequency- dependent equalization makes no sense. Take your square wave on your record: the output of the cartridge WILL NOT be a square wave: it will be a train of very narrow pulses alternating positive and negative. The output MUST be integrated (integrated as in the mathematical operation of integration WRT time) for it to be "more meaningful" to ANYBODY. Thus, the dominant feature of what MOST people consider the "RIAA curve:" an electrical integration WRT to time which looks like a -6 dB/octave slope across the entire bandwidth. You cann;t igore it entirely: it is required by the very physics of the domain. Now, the "RIAA" part is in fact the shelf you see from about 500 to 2000 Hz, which exists to deal with the physical limitations of the medium. But, as I and other have pointed out SO many times in the past, this portion (and indeed, the basic integration portion) meets the criteria for minimum- phase response (e.g., the frequency domain and time domain are duals of one another through the Hilbert transform). Imposing the RIAA equalization DOES NOT restrict, in any way, the amount of information available through the system in the context you seem to be speaking. Directly to your point: the physical interpretation of the square wave will be IDENTICAL whether it's done in a symmetrical non-RIAA system situation or a symmetrical RIAA-equalized system. But to a larger point, as identical as it is, square wave response itself as a single-value indicator of quality or performance is, essentially, useless. The domain of knowable and useful parameters is far wider than that. |
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#33
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L fgren's paper on cartridge alignment/tone ar
In article ,
Steven Sullivan wrote: wrote: fascinating stuff I think some of this work has been much-referenced here and other audio groups , but without exact citations; it's good to see them cited bibliogpahically. I'd love to see the SEM photos from the Audio article, I'll have to see if I can find that somehere. I do wonder, though, about 'square waves' on test records. How can anyone expect soemthing as crude as a stylus in contact with a rotating platter, to accurately navigate the successive 90 degree angles of a square wave? Is there some 'trick' to it? Oh, that's easy. The shape of the groove on the disc that results in a "square wave" in your amplifier, is very different from "square". What that shape is, is left as an exercise to the student. (Hint: pay attention to what the EQ network in the preamp does.) Once you understand why that particular shape produces a "square wave", you'll have a far better grasp of *some* of the problems with high-quality reproduction from vinyl recordings. Isaac |
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#34
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L fgren's paper on cartridge alignment/tone ar
On Dec 6, 5:18*pm, wrote:
On Dec 6, 2:50 pm, Richard Tollerton wrote: Right, but was the STR 111 square wave meant for RIAA playback or flat playback? The physical interpretation of the square wave seems far more meaningful to me when the RIAA curve is entirely ignored. To answwer that question, you need to understand what "RIAA playback" means. None of your following explanation is news to me, but thank you anyway for repeating it. Playing back a velocity cartridge (ALL phono cartridges are, in essence, velocity devices) without ANY frequency- dependent equalization makes no sense. Take your square wave on your record: the output of the cartridge WILL NOT be a square wave: it will be a train of very narrow pulses alternating positive and negative. Whoever said there ever was a square wave on the record? I certainly didn't. I said there was a triangle wave on the record in question (which is a wholly sensible signal to cut and track). The output MUST be integrated (integrated as in the mathematical operation of integration WRT time) for it to be "more meaningful" to ANYBODY. I disagree. Certain tests require constant-slope test grooves - I am reminded most notably of Bauer's work on laquer springback, but also White/Gust's work on VTA measurement with square wave-based test bands. All of this is easily locatable in JAES. RIAA equalization (or integration compensation in general) would only hinder such tests. A square wave certainly doesn't cut to a triangle wave anymore if it's subjected to inverse RIAA! So to me, it is entirely reasonable (even expected!) that STR 111 would have a square wave track that was not cut with RIAA eq, and is not expected to be reproduced with RIAA eq. |
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#35
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L fgren's paper on cartridge alignment/tone ar
Greg Wormald wrote:
"According to the Disk Doctor, washing with isopropyl alcohol can strip plasticisers and increase wear." Pisha, "Record cleaners revisited", Audio Magazine 1976, May, pp. 40-42, 44, 48, 50 "Record cleaning fluids are generally mild detergents such as Alconox or a formulation containing varying strengths of alcohol. From our experience, we question the use of these types of cleaners, particularly since it has been established that contact with alcohol, Alconox, and certain anionic detergents does, in effect, oxidize the surface of the vinyl disc after a period of time. Alcohol, in almost any strength, has been identified as one of the cleaning fluids that leech out from the vinyl surface the important stabilizers and lubricants necessary for the longevity of records. Stabilizers are needed to counteract the high-heat conditions created by the stylus and for subsequent vinyl integrity, while lubricants assist in good stylus/surface contact and slippage. Unfortunately, these important chemicals are extractable from the record surface by almost any solution, but in varying degrees. By way of comparison, on a 0-100 continuum, extractions of fatty acid chains and the polyolefin groups from vinyl records by three solutions are shown in the accompanying table. Fatty Acid and Olefin Extraction (Volume/Volume GLC Quantification) Solution/Contact Time/Relative % Extraction 60% Isopropyl Alcohol/10 min/38% 60% Isopropyl Alcohol/30 sec/12% DII Fluid/10 min/8% DII Fluid/30 sec/1.4% Distilled Water/10 min/6.5% Distilled Water/30 sec/0.9% Fortunately, the integrity of the vinyl compound is not damaged to the point of making a record unplayable until the cleaning solutions have been applied to the record surface over long periods of time. The process is insidious and eventually will cause damage. It appears that any liquid put on the surface of a vinyl record will exhibit some extraction characteristics, be it distilled water, alcohol, detergent, or the Discwasher DII solution; there just isn't a perfect record cleaner." Klaus |
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#36
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#37
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Greg Wormald wrote:
"My memory made we wonder about the previous post on the wearing of LP's by styli because I noticed they were washing the test LP's fairly frequently with an alcohol solution, and (probably) with inadequate rest between playings." G. Alexandrovich, “Disk recording and playback”,chapter 25 in “Handbook for sound engineers” by G. Ballou, 2nd edition 1991 “Because of the small contact area that exists between the stylus tip and the groove, the pressure against the groove wall can rise up to many thousands of psi. For instance, if each wall receives 0.7 gram of force applied through the contact area equal to 2 ten millionth of an inch, the pressure is 7726 psi. It has been experimentally shown that with such high pressures and force of friction between the stylus and the vinyl, that the outer skin layer of the record material melts as the tip slides over the plastic and then refreezes almost as fast as it melted.” Looks as if the audio myth of "rest-between-playings" has been laid to rest many moons ago. Klaus |
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#38
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#39
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On Dec 10, 6:07*am, wrote:
Greg Wormald wrote: "My memory made we wonder about the previous post on the wearing of LP's by styli because I noticed they were washing the test LP's fairly frequently with an alcohol solution, and (probably) with inadequate rest between playings." G. Alexandrovich, “Disk recording and playback”,chapter 25 in “Handbook for sound engineers” by G. Ballou, 2nd edition 1991 “Because of the small contact area that exists between the stylus tip and the groove, the pressure against the groove wall can rise up to many thousands of psi. For instance, if each wall receives 0.7 gram of force applied through the contact area equal to 2 ten millionth of an inch, the pressure is 7726 psi. It has been experimentally shown that with such high pressures and force of friction between the stylus and the vinyl, that the outer skin layer of the record material melts as the tip slides over the plastic and then refreezes almost as fast as it melted.” Looks as if the audio myth of "rest-between-playings" has been laid to rest many moons ago. Klaus Seems to me that one urban myth has been laid to rest by yet another urban myth. I actually work from time to time with plasticized vinyls. The melting point varies from formula to formula but I am pretty sure we are talking about somewhere in the neighborhood of 300 to 350 degrees. That would mean the stylus would be sustaining temepratures well in excess of 350 degrees if it is actually melting the vinyl in the brief moment it is in contact with it at any given point. And when I say well in excess I mean *way* well in in excess given the extremely short duration of it's direct contact with any single part of the vinyl. I am quite skeptical that the stylus and subsequently the assmebly, the cateliver and the suspension are sustaining these extreme temperatures for the duration of 20 minutes or more when an entire record side is played. One would think that at the very least, the dust and fine hairs that acumulate around the stylus when one plays an uncleaned record would be going up in flames. I doubt the cartridge could hold up under such conditions. |
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#40
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L fgren's paper on cartridge alignment/tone ar
"Greg Wormald" wrote in message
In article , wrote: Greg Wormald wrote: "My memory made we wonder about the previous post on the wearing of LP's by styli because I noticed they were washing the test LP's fairly frequently with an alcohol solution, and (probably) with inadequate rest between playings." G. Alexandrovich, “Disk recording and playback”,chapter 25 in “Handbook for sound engineers” by G. Ballou, 2nd edition 1991 “Because of the small contact area that exists between the stylus tip and the groove, the pressure against the groove wall can rise up to many thousands of psi. For instance, if each wall receives 0.7 gram of force applied through the contact area equal to 2 ten millionth of an inch, the pressure is 7726 psi. It has been experimentally shown that with such high pressures and force of friction between the stylus and the vinyl, that the outer skin layer of the record material melts as the tip slides over the plastic and then refreezes almost as fast as it melted.” Looks as if the audio myth of "rest-between-playings" has been laid to rest many moons ago. Not at all. Two different processes are involved. This one takes place at the surface, while the plastic deformation takes place deeper in the vinyl. It may have been put to rest--but the quote doesn't do it for me. That quote is about melting, and would also seem to contradict the "minimal wear" research quoted earlier in the thread. I suspect that melted vinyl would quite easily move under thousands of pounds of pressure and distort the groove modulations, although I am not a materials scientist at all. The melting is so localized that any smoothing of the groove is pretty small. It's like the melting of the ice under the blade of an ice skate. One difference is that the stylus is smooth, and lacks the sharp edges of an ice skate blade. So, LP's don't get superficial scarring like ice rinks do. |
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| Cartridge Alignment Problem | High End Audio | |||
| Cartridge Alignment Problem | Tech | |||
| - Cartridge Alignment Tool - | Tech | |||
| - Cartridge Alignment Tool - | General | |||
| - Cartridge Alignment Tool - | Marketplace | |||
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