Effect of Stylus friction on LP

H

Hans Polak

Member
Joined 2005
Hi George,

Do we know anyone having acces to this Machine.

It is cited frequently that the tip transfers heat to the cantilever and from there into the air, which may be true, but the question is how much?
A Boron cantilever has a heat transfer ratio of 2.7 W/(m.k), for the epoxy bonding even as low as 0.14 W/(m.k) against the super heat transfer ratio of 2200 W/(m.k) for the diamond tip.

So this machine that you mention could measure in one go the tip temp, the groove temp and the cantilever temp.
That could clarify a lot.

Hans
 
H

Hans Polak

Member
Joined 2005
Also interesting to know is that high temp Epoxy starts losing its strength at ca 200C and completely desintegrates at 300C.
With figures of 160C tip temp that some mention while playing 33 1/3 LP’s, it’s already very close to the 200C.
But when playing at 45rpm or even worse at 78rpm, thereby generating proportionally more frictional power turned into heat, would mean that you are facing the risk of a tip separating from the cantilever.
I’ve never heard this to happen.

Hans
 
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gpapag

gpapag

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Hans Polak said:
Hi George,
Do we know anyone having acces to this Machine.
Click to expand...
Hi hans
I've deliberately burned all my bridges with the past ;)
I don't know if you can contact any dealer for short time leasing.
Hans Polak said:
So this machine that you mention could measure in one go the tip temp, the groove temp and the cantilever temp
That could clarify a lot.
Click to expand...
Not in one go. The numbers will be wrong. I mentioned the way to do it properly in post #49

George
 
gpapag

gpapag

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Hans Polak said:
With figures of 160C tip temp that some mention
Click to expand...
Don't think about it. Try touching the tip with a sensitive finger. Anything close to 50 C will be detected.
Hans Polak said:
would mean that you are facing the risk of a tip separating from the cantilever.
I’ve never heard this to happen.

Hans
Click to expand...
For the record, I had two tip separations but none was due to heat disintegration of the epoxy (tested under microscope)
George
 
B

Bare

Member
Joined 2001
All fascinating.
BUT.. I recently inherited a Large(ish ) collection of Lps.
Most all of which were New/sealed /never removed form their sleeves, let alone played.
Directly compared to My Original and lightly played Exact same Lps.. The sounds.. on the new Lps ( thorens and a Microline stylus) .
Are Markedly .. instantly apparent.. Better sounding... a lot better.
More Sparkle, range and presence in their playback.
Very nice and gives genuine appreciation of the actual sound qualities in a simple Vinyl LP.
Also.. an instant reminder of what was clearly obvious /generally accepted knowledge in the 60's /70's ;
LPs deteriorate audibly by their 6 to 8th playback.. Period.
NO amount of analysis sophisticated 'after the fact' alters that reality.
I found this sound quality degradation thru use.. to be absolutely true, at least to MY ears.
 
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planet IX

planet IX

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I also have the strong impression, that a new (unplayed) record sounds best on the first playback.
But I cannot confirm that they deteriorate much after that.
To me, it really seems that something is happening at the first playback only. But not much on further playback…
 
Tiido

Tiido

Member
Joined 2015
tmeeco.eu
My experience with brand new discs has been that they often have huge amount of static electricity buildup on them and in case of paper sleeves, dust from it caused by motion+friction during transport. That static electricity holds that dust quite well on the disc and it takes some effort to get rid of it, and if one was to play that disc one will find that it is noisier and cracklier than it should be but after a few plays this normalizes as the stylus mechanically picks up the paper fluff from the grooves and helps to dissipate that surface charge lol.

Very interesting thread, I had great pleasure reading through it ~
 
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xrk971

xrk971

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If we look at mechanical bearing technology, one always tries to avoid “metal-to-metal” or metal to hard crystal contact. Hence, lubricants provide a thin film of oil or wax that prevents actual metal-to-metal contact. When one of the surfaces is a hard plastic such as “Delrin” a type of nylon - then liquid lubricants are not needed as it is self lubricated because the plastic is not hard and will not damage the metal. Has someone tried playing diamond stylus on steel with oil lubricant?

A vinyl LP and diamond stylus is much like a delrin/steel bearing.

The pressure is set to not cause plastic deformation. That would ruin the LP.

Ice skate blades on ice is a perfect example of metal to crystal with a liquid bearing surface of water. There is no metal-crystal contact when working properly as the blade floats on a film of water generated from pressure melting of ice. Pressure applied to ice causes interface contact point to convert from solid to liquid. The ice skate is literally like a boat floating across a pond of water. Albeit, a very skinny thin boat and shallow pond. Hence, this is why ice is so slippery when a hard smooth surface is pressed on it. This is well known.

I think the reason people don’t use steel LP’s with oil is that it is plain messy and makes the whole audio experience smell and look like an auto-mechanics garage or shop. :)
 
gpapag

gpapag

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This talk about the ice-steel interface mysteries made me search for a familiar relevant section in this old documentary (37:28 to 37:52)
George
 
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D

dennis h

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Joined 2006

About 30 minutes in Franc Kuzma talks about taking a 50 pound platter with a air bearing, spinning it up by hand to approximately 33 rpm (without belt) and waiting 30 hours for it to stop

He puts a record on, spins it up again to 33ish rpm and puts a stylus in the groove and the platter stops in 10 minutes

not scientific per say, but stylus friction none the less

those turntable, tonearm, cartridge freaks that have not listened to this interview should, lots of good info on how one of the masters sees things
 
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StevenCrook

StevenCrook

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dennis h said:
not scientific per say, but stylus friction none the less
Click to expand...
All the energy in the system comes from the TT platter so we have to consider the energy required to move the cantilever/magnet/iron regardless of anything 'lost' due to friction in the stylus contact with the groove. Also I guess, the energy required to move arm bearings too.

Interesting none the less. The idea of this 50kg (it is 50kg and not 50lb) platter continuing to rotate for 30h is pretty mind boggling, but then there's a lot of energy in a 50kg chunk of metal rotating at 33rpm. I've used a hand pedalled potters wheel, and they're a right b*****d to stop once they're up to speed.
 
M

Mark Tillotson

Member
Joined 2018
There's actually remarkably little energy in a 50kg platter spinning slowly at 33rpm, about 5 joules, about enough to lift itself a measily 1cm. Spin it at 3300rpm and its got the energy to lift itself 100 metres!!

5J dissipated in 30 hours is about 50µW of power on average lost to viscous friction, whereas the stylus pulls more like 8mW out of the system to slow it in 10 minutes, which makes sense as the groove velocity is about 0.4m/s, force = power/velocity = 20mN (about 2 grams force, part sliding friction and partly power to drive the oscillation of the stylus assembly)
 
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Mark Tillotson

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Joined 2018
Of course, its physics, but you need to know the tracking force, and measure on a silent groove as modulation creates additional dynamic load forces.
 
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