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Record wear article

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cafe latte said:
Google is you friend here if you want tocheck me.
A tiny tiny area with lets say 1kg dragged along is the same friction a much larger area with the same mass this is fact.
A conical at 2g has the same friction as a stylus with a greater area at 2g but the pressure on any given area is less meaning less wear.
Chris
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That is for a plain groove. A stylus that trace the groove modulations has more sideway move than a stylus that just rides over them. More movement cause more friction and more skating force.
 
Thomas_AA said:
That is for a plain groove. A stylus that trace the groove modulations has more sideway move than a stylus that just rides over them. More movement cause more friction and more skating force.
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Friction is a function of force. Unless you change the stylus pressure, the amount of friction seen by the stylus into the groove is a constant.

A conical has about half the contract area of a microline. That means that for every equivalent area of contact, the conical is applying twice the amount of force as the microline. The coefficient of friction is the same for both stylus being the same (same material), the amount of wear on the conical should be about twice.

A badly aligned microline can do more damage as when it twists, as that contact area decreases very rapidly vs a conical which sees no change.
 
loudnoises said:
Friction is a function of force. Unless you change the stylus pressure, the amount of friction seen by the stylus into the groove is a constant.

A conical has about half the contract area of a microline. That means that for every equivalent area of contact, the conical is applying twice the amount of force as the microline. The coefficient of friction is the same for both stylus being the same (same material), the amount of wear on the conical should be about twice.

A badly aligned microline can do more damage as when it twists, as that contact area decreases very rapidly vs a conical which sees no change.
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Friction constant. You can do the experiment. Is friction force the same on a modulated groove vs a plain groove.
 
Sammcamos said:
I wonder what the ethics of that AI article are, because if I saw something like this happen to my research without my knowledge, I would be rightfully pissed off.
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I am!

While his copyright infringement is illegal, it's difficult to enforce. I have alerted Audio Technica since the misrepresentations and exaggerations hurt them more than they do me, but who knows if they will do anything?
cafe latte said:
The original is over at VE.
It seems the issue was faulty suspensions on AT95ml not thr stylus shape. Thr suspension is loose on the test stylus and wiggles and is able to rotate, nothing to do with the profile. That thread at headphonesty should be deleted.
Chris
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Thomas_AA said:
As I understand, it is not just one example though. Unless AT has a lot of faulty suspensions around.
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To be clear, and complete the story, I had two VM95MLs with loose suspensions. I sent one back to AT and told them what I was doing with it, and they sent me a QC checked review sample as a replacement, which I called "VM95ML REV" in SWS3. The REV sample suspension was not "loose", but that doesn't mean it didn't have a problem. After the VM95ML REV showed groove damage and faster than expected wear in SWS3, I sent it back to AT, and they sent me another replacement, along with the cryptic explanation that they have not had any complaints regarding their current production VM95MLs. I called this one VM95ML-3 and tested it for groove damage. It caused similar damage to the grooves as the VM95ML REV, and I sent it back to AT as defective. They sent a message that they don't believe the VM95ML-3 is defective, but they would send it back to Japan for their QC folks to test it further. That's where we stand today.
 
Thomas_AA said:
That is for a plain groove. A stylus that trace the groove modulations has more sideway move than a stylus that just rides over them. More movement cause more friction and more skating force.
Click to expand...
Area still does not affect friction for a given tracking force
 
Thomas_AA said:
Are you saying a modulated groove has the same friction force as a plain groove? Research does not back it up.
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Friction is surface area touching.
A smooth stylus is not grabbing the modulations. More grooves the friction is less.
What I am saying we are not breaking thr laws of physics in hifi.
Chris
 
loudnoises said:
Friction is a function of force.
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Yes, and force is a function of mass and acceleration.

loudnoises said:
Unless you change the stylus pressure, the amount of friction seen by the stylus into the groove is a constant.
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Yes, but the modulated groove changes pressure without you fiddling with tracking force, as the stylus constantly accelerates/deccelerates in the zig-zag groove resulting in additional force (on top of the gravitational pull) to the walls, hence more pressure. How big of a difference in drag this makes is above my paygrade, but it's real.
 
cafe latte said:
Friction is surface area touching.
A smooth stylus is not grabbing the modulations. More grooves the friction is less.
What I am saying we are not breaking thr laws of physics in hifi.
Chris
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It is not breaking any laws, a stylus in a modulated groove is moving/accelerating, hence the force is increased. It is the same force that may throw a stylus out of a modulated groove or causing the stylus to leave one groove wall (mistracking) if the tracking force is too low.
 
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Thomas_AA said:
It is not breaking any laws, a stylus in a modulated groove is moving/accelerating, hence the force is increased. It is the same force that may throw a stylus out of a modulated groove or causing the stylus to leave one groove wall (mistracking) if the tracking force is too low.
Click to expand...
This though is not a friction issue.
Friction is not different re area and profile.
Laws of friction are not up for debate.
Chris
 
Take a look here

On the records, the speed can even reach 40–41.2 cm per second. So what do we see? The friction force arises when the plate moves, as a result of the needle catching on the grooves' irregularities. The needle pulls on the tonearm, causing the float on the water to tilt, which in turn moves the string with the 5 g weight. The weight is also in a glass of water to prevent unwanted vibrations. The greater the friction force on the needle, the more the string with the weight deviates relative to the suspension. For the vertical setup, the head used is an average Corvette 008 with an elliptical needle. The weight on the needle is set to 1.5 grams according to the instructions for the head. When the groove is silent, meaning without a signal, the small weight deflects by 5 cm, which corresponds to a friction force of 0.5 g. So, the coefficient of friction for a silent groove is close to 0.3. When the needle hits a groove with a signal, different frequencies create different deflections, with the maximum deflection...


2:38 deviation, maximum deviation 8 2:42 so it turns out that the added friction force 2:46 when the needle hits 2:49 modulated 50% of the value for silent 2:52 groove, and this measured addition, by 2:55 analogy, through conjugation 2:58 by computer or average value. But after all, 3:03 then it has an amplitude value which 3:05 is greater for a musical signal 3:08 amplitude effective values can be 3:12 in this case measured by the effect 3:16 of transverse recording in deep recording 3:19 results more impressive, this is due to 3:22 less vertical flexibility of the head. About 3:26 what constancy of friction force there can be is 3:29 clearly not the case, now I’ll tell you what 3:33 this inconsistency leads to. With the usual correction angle 3:37 of the tonearm at 22°, a third of the needle's friction force 3:41 turns into 3:50 sliding per second, though sometimes it happens even 3:53 in the orchestra, for such oscillation 3:56 speed the measured addition to the friction force 3:58 is 4:02 15%, the same addition will also be added to 4:28 the sliding.
 
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