Had to add these. Jazz from Hell, Return of the Son of Shut Up and Play Your Guitar, and Dweezil with some of the best musicians in the business.
Zappa nobody played, programed Synclavier: YouTube
Zappa live guitar:YouTube
And finally, if you like Franks music go see Zappa plays Zappa. Frank would be proud of his son:YouTube
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That the PU needle becomes very hot because of friction, even causing the Vinyl to melt, can be easily rejected with simple math, showing that no more than 3mW/sec results from this friction using a friction coeff. of 0.3, a needle pressure of 2 gram and the speed on the outer track of a 33 1/3 rpm LP.
Given the very short contact time, this is way too low energy to let the vinyl melt.
The generated heat will be absorbed by the LP and by convection to the air from the cantilever.
But more and more I get the feeling that this Ice Skating thesis is not that mad at all when doing some math:
The yield point where Vinyl goes from elastic behaviour into a fluid plastic behavior lies at ca 200Mpa, or 2,000Kg/cm2.
This figure is independent of the surface area as far as I can find.
Now taking a contact area of 3um2 that doubles to 6um2 because of the elastic vinyl properties, results for a 2gram needle pressure into 0.33gr/um2.
This translates into 3,333Kg/cm2 or well above the yield point of 2,000Kg/cm2
I could also have converted the yield point to 0.2gr/um2, this would of course have given the same outcome, but the weight/Kg gives a much better idea of the formidable pressure.
At the same time the consideration that using a fluid at playback may negatively influence the proces of exceeding the yield point and back to below seems not at all that unlikely.
It could even be that because of some lift from aqua surfing, the vertical pressure area becomes (much) larger and the liquify phase is not even met, resulting in the needle scraping some vinyl of the groove walls instead.
When examining the LP's that I herited from my father in law, always been played with Lencoclean, an unbelievable amount of a very fine smudge, almost like grease, is on the bottom of the grooves, not at all like the dirt that I find in my always dry played LP's.
Could this smudge be composed of vinyl particles ?
Looking forward to read your comments.
Hans
Given the very short contact time, this is way too low energy to let the vinyl melt.
The generated heat will be absorbed by the LP and by convection to the air from the cantilever.
But more and more I get the feeling that this Ice Skating thesis is not that mad at all when doing some math:
The yield point where Vinyl goes from elastic behaviour into a fluid plastic behavior lies at ca 200Mpa, or 2,000Kg/cm2.
This figure is independent of the surface area as far as I can find.
Now taking a contact area of 3um2 that doubles to 6um2 because of the elastic vinyl properties, results for a 2gram needle pressure into 0.33gr/um2.
This translates into 3,333Kg/cm2 or well above the yield point of 2,000Kg/cm2
I could also have converted the yield point to 0.2gr/um2, this would of course have given the same outcome, but the weight/Kg gives a much better idea of the formidable pressure.
At the same time the consideration that using a fluid at playback may negatively influence the proces of exceeding the yield point and back to below seems not at all that unlikely.
It could even be that because of some lift from aqua surfing, the vertical pressure area becomes (much) larger and the liquify phase is not even met, resulting in the needle scraping some vinyl of the groove walls instead.
When examining the LP's that I herited from my father in law, always been played with Lencoclean, an unbelievable amount of a very fine smudge, almost like grease, is on the bottom of the grooves, not at all like the dirt that I find in my always dry played LP's.
Could this smudge be composed of vinyl particles ?
Looking forward to read your comments.
Hans
Ok one more Zappa video. An MTV interview where he slams music videos and what they have done to popular music. YouTube
You're considering only the static situation, as if the record were not turning. The dynamic situation, with the groove trying to accelerate the stylus effective mass (inertial components referenced to the contact tip) is much, much larger peak pressures, that also vary with modulation.
The Ice Skating theory was the accepted one back in the days of vinyl records, and large temperature numbers were thrown around. Pressure is easy enough to ballpark from simple Newton, but translating to temperature rise is a whole different ballgame.
All the best fortune,
Chris
Thanks for your reaction.
You are right that I did not take the forces into account because of signal modulation, but on average this results in zero.
So for the sake of keeping things simple just assume a turning blank groove, already showing that the yield point is exceeded.
Modulation does makes peak pressure higher, as a skater making a corner at high speed where pressure increases significantly.
However I don’t see where large temp numbers should come from, very unlikely, temperature is not the cause of entering the plastic phase.
While skating you don’t get boiling water under your skates, the state changes from solid into fluid because of the pressure with only a very small temp rise.
Behind the skates you never see water, because almost immediately after releasing the pressure below the yield point, the water goes back to it’s solid state.
Hans
Modulation peak pressures are orders of magnitude larger than blank groove. I hesitate to even conjecture about temperature rise because of the tiny dimensions and the extreme pressures. Pretty certain that our ordinary size world experience and "common sense" will lead us into large errors. It's, for sure, not a PV=RT world down there. What it is, I don't know.
Much thanks for your excellent thoughts,
Chris
I was away from the thread for a day and it has shot forward lots.
people easily forget that in the middle ages and before a standard poodle was often used as a war dog in battle.
people easily forget that in the middle ages and before a standard poodle was often used as a war dog in battle.
You don't see standards as much as when I was a kid and I knew instinctively to be wary of them, proud beasts who looked like they would quite happily rip your head off!
As a kid I was scared ******** by the black standard poodle (called Guy ISTR) that lived at the post office. Of course I should have been wary of the local farmer's jack Russell and wasn't so it bit me!
Akita I haven't decided on yet. They always look at you as if they are about to eat your face/liver/arm etc but I suspect that's more them doing their job and watching out for the boss.
Akita I haven't decided on yet. They always look at you as if they are about to eat your face/liver/arm etc but I suspect that's more them doing their job and watching out for the boss.
75 lbs. pure breed Dalmatian male, FWIW. Has a PhD in dog training (over two years of a daily training/obedience schedule since he was 6 mths old).
Hans: I think your contact area is out by at least a factor of 10. See Stylus Tip | Adamant Namiki Precision Jewel Co., Ltd.
If the ice is at -40c it still melts under skate blades with a 40c temp change, imediatly, and changing state takes a lot more energy than raising the temperature.
YouTube @1mn15
Bukowski, most of the time, could not qualify anything, not even himself ....
Alcoholism a major art?
It confirms you are probably ... a super computer.
Musiciens/Francais/Compositeur - Google Search
To what do you recognize that the petomane is French, with the smell, or the phrasing? And why is he forgotten in the previous list ?
Or are-you a super computer with a xenophobia bug ? Big smiley, here.
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You assumption is that the ice always melts at zero degrees, which is not the case.
Under pressure the transition from solid into liquid and from liquid into gas changes significantly.
When Ice is practically zero degrees, it does not go to >40c while skating to follow your line of thinking.
Hans
I checked the ice slippery thing some day ago and it's allegedly according to some research so that the upper most molecular layers is in semi-liquid form, and at somewhere around -40C it's only one layer thick and the slippery effect is diminishing, that's why two ice cubes do attach to each other and freeze together, next topic please...
edit: couldn't find that particular article, but another paper for those whom it may interest.
http://www.physics.ohio-state.edu/~jay/846/skating.pdf
edit: couldn't find that particular article, but another paper for those whom it may interest.
http://www.physics.ohio-state.edu/~jay/846/skating.pdf
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Plastic speaker chassis, eg Markaudio speakers, pros and cons.......
Pros - non resonant
Cons - not thermally conductive - easily remedied with heatsinking if necessary
Pros - non resonant
Cons - not thermally conductive - easily remedied with heatsinking if necessary
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