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In Reply to: RE: Your personal experience notwithstanding,... posted by Tre' on August 25, 2016 at 11:37:55
Fortunately, your understanding or lack thereof doesn't alter the laws of physics.
Best regards,
John Elison
Follow Ups:
Please explain.
When the stylus is in the groove there are two contact points. One on each side of the groove.
If friction is part of the cause of skating force wouldn't the friction be very different vs. the tip of the stylus contacting the flat vinyl?
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
It's not "very" different. It might be different but it is more likely to be "very" similar. However, all stylus shapes will react differently, but it's often thought that the tip of the stylus against a flat surface will produce more friction than the stylus in a groove. That means there might be more pull from a flat surface than from a groove. It really depends on the particular stylus shape.
Even though there are two contact points when the stylus is in the groove, the force against each of the contact points is smaller than the force of the tip against a flat surface. For example, if you were tracking at 2-grams, the force of the tip against a flat surface would be 2-grams. The force against each wall of the groove would be only 1.4-grams.
Best regards,
John Elison
I will take that as a victory.
I got you to explain yourself instead of just "making a proclamation".
You make some very good contributions to the forum here but that doesn't give you the right to make "proclamations" without explanation.
Thank you very much for explaining yourself.
I still believe that setting AS using the flat surface method is a crap shoot. There are too many variables. (as you just admitted to, "all stylus shapes will react differently")
I'm not saying that I have a better method though.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
First of all, my analogy of a stylus tip on a flat vinyl surface compared to the stylus in a groove was not meant to suggest they would produce the same skating force. However, logic would suggest that both cases would react the same to vertical tracking force. Therefore, if you discovered that skating force always increased when increasing tracking force on a flat vinyl surface, it would be logical to believe that skating force would react in a similar way to tracking force with the stylus in a groove.
Secondly, with a special type of cartridge designed to measure skating force, it can be shown that even though skating force from a flat vinyl surface is not exactly the same as skating force with the stylus in the groove, the two are more similar than they are different. Therefore, I believe that Frank Schroder and Peter Ledermann have developed a reasonable method for setting antiskating using a flat vinyl surface. Personally, I have never found the perfect method for setting antiskating and I now believe that Frank and Peter's method is as good as any and better than most. Even you state:
> I'm not saying that I have a better method though.
The method I use for setting antiskating is to follow the instructions from my tonearm owner's manual. I set antiskating on both of my tonearms by turning the antiskating dial to the same number as the tracking force setting. When I test this setting by Frank and Peter's method, it normally comes out very similar -- almost identical every time. Therefore, if you don't have a calibrated antiskating dial such as with VPI tonearms, I believe the method presented by Frank Schroder and Peter Ledermann is perhaps the best method to use.
Best regards,
John Elison
Is a close approximation of the forces involved. You are probably within the margin of error when adjusting on the flat surface. The only possible differences are caused by the tip not being polished the same as the side of the stylus, and also the force needed to accelerate the moving mass of the cartridge, which is probably a tiny fraction of the kinetic friction.dee
;-D
True terror is to wake up one morning and discover that your high school class is running the country.
quote by Kurt Vonnegut
Edits: 08/25/16
.
Have Fun and Enjoy the Music
"Still Working the Problem"
compared to the contact area the the groove is not that much rougher than the flat surface. so the coefficient of friction aka mu is probably the same within a tiny fraction. the whole idea with this constant is that it ignores the shape of the contact areas. you do not need to know that the contact surface is 10 sqrt micron or 10 sqrt feet. you know the vertical force, multiply it by mu and you got the kinetic friction force. There is a minuscule difference in forces when one has to accelerate the moving mass of the stylus assembly around the modulation but that is negligible compared to the kinetic friction. Newtonian physics is very well modeled :)
decided to add this tidbit.....
The force due to friction is generally independent of the contact area between the two surfaces. This means that even if you have two heavy objects of the same mass, where one is half as long and twice as high as the other one, they still experience the same frictional force when you drag them over the ground. This makes sense, because if the area of contact doubles, you may think that you should get twice as much friction. But when you double the length of an object, you halve the force on each square centimeter, because less weight is above it to push down. Note that this relationship breaks down when the surface area gets too small, since then the coefficient of friction increases because the object may begin to dig into the surface. If that happens when you are in the groove of a record you have bigger problems than the skating force.
dee
;-D
True terror is to wake up one morning and discover that your high school class is running the country.
quote by Kurt Vonnegut
Edits: 08/25/16 08/25/16
Penguin,
Thanks for posting this video. I'm frustrated by my inability to do the math even at this basic level, but I was able to follow it in this case and learned a lot.
Doug
"Note that this relationship breaks down when the surface area gets too small, since then the coefficient of friction increases because the object may begin to dig into the surface. If that happens when you are in the groove of a record you have bigger problems than the skating force."
The tip of the stylus is not meant to come into contact with the vinyl so "digging in" might just happen with the tip riding a flat surface. But, as has already been said, the shape of different styli will be different so it (the flat surface method of adjusting AS) is still a crap shoot.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
if no scratch on the smooth part, then everything else is the same as in the groove. So the kinetic friction force is closely equal. everything else is negligible.You are grasping your straws :)
dee
;-D
True terror is to wake up one morning and discover that your high school class is running the country.
quote by Kurt Vonnegut
Edits: 08/25/16
I was pointing out what Peter has already said.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
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