Thanks LD.
I don't understand figures but I trust your evaluation and verdict.
And also that of J. Walton because after so much elaborate painstaking study no reason to use different pictures in the book. He has written articles in Wireless World and authored a book (Probably many books). He must be highly reputed. And besides there is no valid reason.
Little confusing and intriguing.
Regards.
I don't understand figures but I trust your evaluation and verdict.
And also that of J. Walton because after so much elaborate painstaking study no reason to use different pictures in the book. He has written articles in Wireless World and authored a book (Probably many books). He must be highly reputed. And besides there is no valid reason.
Little confusing and intriguing.
Regards.
The old SEM remains a mystery. Like you, I can't get it to fit the Decca test record.
But we should move past it, leave it to history. We need to do our own tests with recordings and micro photographs.
We should find someone capable of making clear micro photographs with a FOV ranging from 100-400 microns. 100μ would be a nice close up, 400μ could show 3 or 4 grooves, which might be useful. The test LP should be new, and photographed before any play. More photos should be taken, and recording done, after 1 play, 5 plays, 10, 50, 100. Or whatever intervals we deem relevant.
Since in our recording we have not seen horrible wear after 100 or more plays, it would be nice to photographically document that, as well as record and analyze it. That could be a big help for vinyl loves.
I can volunteer to abuse a test LP with a vintage EV ceramic cart and heavy tone arm.
But we should move past it, leave it to history. We need to do our own tests with recordings and micro photographs.
We should find someone capable of making clear micro photographs with a FOV ranging from 100-400 microns. 100μ would be a nice close up, 400μ could show 3 or 4 grooves, which might be useful. The test LP should be new, and photographed before any play. More photos should be taken, and recording done, after 1 play, 5 plays, 10, 50, 100. Or whatever intervals we deem relevant.
Since in our recording we have not seen horrible wear after 100 or more plays, it would be nice to photographically document that, as well as record and analyze it. That could be a big help for vinyl loves.
I can volunteer to abuse a test LP with a vintage EV ceramic cart and heavy tone arm.
I've asked someone who is doing some pretty trick stuff with optical if he can try. I think he is up for the challenge. Problem is, once we understand if the optics are up to it is making something that will take a 12" record without it needing to be sliced up.
Once place I haven't checked is lathetrolls. As most lathes have a microscope on them there must be some pics to show the resolution there taken with modern digital cameras.
Once place I haven't checked is lathetrolls. As most lathes have a microscope on them there must be some pics to show the resolution there taken with modern digital cameras.
Record label can be marked with pencil for specific location on groove tangentially and specific frequency band can be played repeatedly. Since test record will be sacrificed repeated chance will not be there to test multiple time. What would be the ideal criteria for test ? From the book vertical tracking force, stylus mass looks like the main component. Any other ? Typical playing specs. at home of popular cartridge and tonearm will be good ? Higher frequency band will be more appropriate as amplitude on groove will be higher so even minor damage can stand out.
Regards
Regards
Well, it's not about reputation, which is undoubted - rather about scrutiny and validity of detail concerning a pivotal point of principle that might well have influenced decades of beliefs and behaviours for the industry and consumers alike.
Set out on this thread is how one might challenge both theory and evidence, and point out fundamental contradictions, on the face of it.
Philosophically, I suspect much of the writing of the relatively few protagonists of the time who published publically in JAES, WW etc is/was treated as beyond challenge. Though some people at the time plainly did, because of published errata and letters etc. I think the skills needed to critique and form one's own opinion are within the grasp of many people these days, especially on forums as well skilled as this.
Personally, I don't like sitting on fences or tolerating loose ends in such things. When pivotal principles or axioms apparently don't stand scrutiny, one should call them out and discuss to a resolution - not least because that's an interesting and constructive thing to do, IMO.
If it looks like a duck and quacks, it's probably a duck. So if such things appear incomplete, contradicted by theory, and supporting evidence doesn't stand scrutiny, such things are probably wrong, IMO. Technical matters which are true stand scrutiny, and lack contradictions.
Anyways, I shall get off my soapbox now, or take it to speaker's corner - it is Sunday after all..............
LD
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I think this may be the clue/answer. I found J. Walton article in 1963's April wireless world magazine. He has mentioned that SEM micrographs are flattened. It was also mentioned in Book scans Bill posted. Probably what he meant from flattened is that they are stretched vertically. Since SEM pictures are viewed from above the vinyl surface and groove walls being 45 degree the plane would have been seen at inclination. To compensate for that the pictures are stretched to see better details. In the link below we can see in page 172 of magazine (22 of pdf file) where actual real small image is at bottom and top one is stretched. Incidentally this later article mentions wearing of groove walls on first play it self and after 5 plays.
http://www.americanradiohistory.com/Archive-Wireless-World/60s/Wireless-World-1963-04.pdf
I know I am bothering you too much LD. Please do enjoy music. Have a good day.
I presume most of your listening will be on vinyl. I mostly listen to vinyls as music I listen to dont have quality digital audio CDs.
Regards.
http://www.americanradiohistory.com/Archive-Wireless-World/60s/Wireless-World-1963-04.pdf
I know I am bothering you too much LD. Please do enjoy music. Have a good day.
I presume most of your listening will be on vinyl. I mostly listen to vinyls as music I listen to dont have quality digital audio CDs.
Regards.
Hiten, thanks so much for the WW link. There is good info and some idea of scale there, which is a big help. Reading it now.
For our own tests, I'd say for them to be taken seriously we'd have to use well known good carts and arms, starting with MM carts. Shure, AT or Ortofon carts could be used. Nothing exotic, just high quality carts and arms that typical enthusiasts would use. As I said earlier, I can supply the torture tests with vintage 1960s ceramic carts, or new ones. Showing the differences in damage will make the test all that much more convincing.
For our own tests, I'd say for them to be taken seriously we'd have to use well known good carts and arms, starting with MM carts. Shure, AT or Ortofon carts could be used. Nothing exotic, just high quality carts and arms that typical enthusiasts would use. As I said earlier, I can supply the torture tests with vintage 1960s ceramic carts, or new ones. Showing the differences in damage will make the test all that much more convincing.
You are welcome.
Just little weird thought.
Do we need test vinyls ? If a position and area of grooves can be fixed (marked) we can see results on regular vinyls. I suppose for frequency bands stylus would be moving in monotonous way (i.e. same way repeatedly) But with music we get variety of movement.
Only if we had microscope with video camera we can see the action live.
Regards.
Just little weird thought.
Do we need test vinyls ? If a position and area of grooves can be fixed (marked) we can see results on regular vinyls. I suppose for frequency bands stylus would be moving in monotonous way (i.e. same way repeatedly) But with music we get variety of movement.
Only if we had microscope with video camera we can see the action live.
Regards.
I've thought the same thing, special disc not needed. But a single sine wave is going to make any damage or polishing much easier to see, I think. Also, with a FOV of just fractions of a millimeter, what are the chances of getting exactly the same area each time? At least with a test disk the signal is the same over a large area.
It would be nice to do this with a normal music pressing, but is it practical?
It would be nice to do this with a normal music pressing, but is it practical?
Back on cantilevers for a second. I hadn't realised that there was a spiritual successor to the plastic cantilever Deram in the AT-91 AT91 - Entry Level Moving Magnet Cartridge | Audio-Technica. As only £19 one to add to the list to be tested to see how a CF and plastic cantilever works!
And does anyone have access to audio magazine from the 1980. At some point (not jan, feb, march, june or october) there was an article by W.Davies on tracking wear. Quote below I found on VE.
. He also doesn't buy plastic deformation at sane VTF!
EDIT: Own question answered. Here it is https://www.vinylengine.com/turntable_forum/viewtopic.php?t=25548. I shall see what else it says.
Now whilst george has shown that 50 plays does not appear to tear a record apart, the fact that he mentions stick/slip friction suggests LD will find a kindred spirit here
. He also doesn't buy plastic deformation at sane VTF!EDIT: Own question answered. Here it is https://www.vinylengine.com/turntable_forum/viewtopic.php?t=25548. I shall see what else it says.
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Dang, well that was a disappointment. That paper was written by a LAST employee, well actually the guy who runs the place*. Sadly the pictures did not scan well and there were no attempts in the article to measure distortion, noise levels or anything else before chopping the records up. Ah well saves you wasting your time reading it.
*ABOUT US – The Last Factory scan down to see Walter and his amazing beard.
*ABOUT US – The Last Factory scan down to see Walter and his amazing beard.
Oh and just for LD https://www.vinylengine.com/turntable_forum/viewtopic.php?f=46&t=34155 . This is the 1970 article by Michael Gerzon. Now as far as I can tell from what I have read Gerzon was brilliant and mad as a box of frogs in equal measure. I am not sure LD will agree with any of the derivations in here, despite a whole field of spherical cows used as input. If I were cynical I would say he took the results from Walton and forced the maths to fit it. But Gerzon gave us ambisonics, so I'll figure he was just having a bad day...
ahh ok got that. signal being same over large area would be helpful.
How about dynamic level ? We play music record (First track with loud music would be helpful. I have Hollies Hits with 'Long cool woman' song at the start of vinyl. The initial passage had loud drums which used to shake glass in our wooden cabinets or similar high DR tracks) and we measure change in dynamic level. Possible ? Worth Doing ? suppose we test 1K frequency tones even with slight wear we still get 1K fq. But if record wear is there say after 100 plays the groove modulation amplitude will decrease so will be the levels.
Regards.
Unlistenable after 50 plays!? I spent a while a few weeks ago looking for any record wear discussions by reviewers that do a lot of vinyl, found little and considering some old Mercuries or Shaded Dogs are big money to replace I doubt they are useless for phono evaluation after 50 plays. OTOH I wonder how many of my lp's have seen 50 plays (not OCD enough to have kept records).
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Quite. Someone over at purge central was arguing that 10 plays made an audible difference to a record. I asked him to name a record where this had happened so I could try and kill it. Oddly he couldn't remember...
And no sh*t sherlock of last nights research was that a Shure M3D at 9g VTF can wear vinyl!
And no sh*t sherlock of last nights research was that a Shure M3D at 9g VTF can wear vinyl!
The 150+ repeated plays in succession with logical VTF and a barely descent cart/arm, don't support any horror stories.
One day when Luchy will show his analysis results, we will be able to put this subject to rest.
If someone wants the test disc on which I performed these tests for visual investigation, I may post it to him, provided he will return it (or a copy of the same) back
George
One day when Luchy will show his analysis results, we will be able to put this subject to rest.
If someone wants the test disc on which I performed these tests for visual investigation, I may post it to him, provided he will return it (or a copy of the same) back
George