Sy,
I don't think it would be easy but a Farro arm laser tracker with the end of the stylus as the target and an IR sensor could be rigged. Sounds easier than it would be, but possible. Not so sure I believe some of what I have read in the past about the heat produced due to the loading of the small area of the stylus actually touching the vinyl. The calculated loading was very high when looking at the mass and velocity at the contact point vs surface area. If I remember correctly it may have been Joachim who originally sighted the article I read. I would have to look and see if I kept a copy of the article.
I don't think it would be easy but a Farro arm laser tracker with the end of the stylus as the target and an IR sensor could be rigged. Sounds easier than it would be, but possible. Not so sure I believe some of what I have read in the past about the heat produced due to the loading of the small area of the stylus actually touching the vinyl. The calculated loading was very high when looking at the mass and velocity at the contact point vs surface area. If I remember correctly it may have been Joachim who originally sighted the article I read. I would have to look and see if I kept a copy of the article.
For 33.3RPM blank groove, linear velocity is ~250mm/sec for the inner grove to ~500mm/sec for the outer groove.
Even assuming 10um width of cartridge contact with the groove, this footprint will have been left behind in 1/25000 of a sec (40microseconds) for the inner groove, and 1/50000 (20microseconds) for the outer groove.
These are the most conservative numbers possible .
George
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Would it not be possible to calculate the energy from the friction of the needle over the vinyl? We know dimensions of the tip, tip force, tracking speed ...?
Then from that calculate the delta-T?
Jan
I doubt it
Fantastic micro focusing capabilities leaves us with fantastically shallow depth of field. Lateral displacement of the tip will exceed it.
Micro focus means also that strong ‘illumination’ is required, in our case, strong IR emission by the needle tip. Tip movement will also require small aperture camera settings, asking for more IR ‘illumination’. Do we have it?
Close to Jan’s idea but on experimental basis, if SY could focus over the upper portion of the cantilever that is relatively stable compared to the tip and keep note of the indicated temperature at the start of the record and at the end of the playing time, he might pick-up a temperature rise.
George
Bad idea IMHO.
Most MCs have pretty strong resonance, usually more than + 5dB at apx 20Khz, cool records are no more elastic enough, thats why they sound bright when playing immediate after cleaning with vacuum systems.
Tip pressure data, somewhere i have papers from EMT, spheric norm tips have a pressure surface of a few square micrometers each contact side, resulting in more than 1000 Kg per square centimeters if my memory serve me right.
The tip velocity will be apx between 30 and 60 cm each second( inner /outer groove), so i can image that there is some heat.
Wet playing make something bad ( noise) also with nonmodulated grooves, so the effect must come from a constant problem source.
I have no other idea and no data to proove this problem, but it is there and wet play has to be avoid IMHO.
I've played wet records in my younger days. My 'perception' (I'll iterate 'perception') was that they were quieter/smoother sounding.
Of course, it may well just have been my brain telling my ears that if you lubricate something it will go a bit more smoothly and quietly 😀
However, I stopped this practice after a while because after a listening session I always ended up with about 10 LP's lying around my apartment in various stages of drying (often overnight). Before they went back into their sleeves, they'd pick up all sorts of crap floating around in the air (I also smoked cigarettes then).
Of course, it may well just have been my brain telling my ears that if you lubricate something it will go a bit more smoothly and quietly 😀
However, I stopped this practice after a while because after a listening session I always ended up with about 10 LP's lying around my apartment in various stages of drying (often overnight). Before they went back into their sleeves, they'd pick up all sorts of crap floating around in the air (I also smoked cigarettes then).
Also we would have to factor in how well the stylus dissipates heat, diamond being a very good conductor of heat, then there is the cantilever arm which is also going to dissipate heat.
Jan, I have most of the thermal info I need for a rough calculation, but missing the dynamic coefficient of friction between stylus and groove. Anyone have a rough number for that?
Another work-around occured to me- the diamond should end up significantly hotter at the end of a side since, unlike the groove, it is subject to continuous friction. That would be pretty easy to measure.
Another work-around occured to me- the diamond should end up significantly hotter at the end of a side since, unlike the groove, it is subject to continuous friction. That would be pretty easy to measure.
Possibly a tiny drop behind the stylus of thermally sensitive liquid crystal. I have been demoed its application at >10u or so resolution and formulations are available in a huge range of temperatures.
We did that strange experiment of spot cooling of certain regions in a saturated transistor.
Another thought, one should be able to observe occasional vinyl particles that have adhered to the stylus, they should show some effect of excess heat, maybe.
EDIT - I have made thermocouples out of 1mil aluminum and gold bond wires but they were only at best a few uV/C, can't find any normal ones smaller than #30.
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Could someone comment on the Chardas test LP that uses locked grooves. Seems this would be a non-starter if any of these effects were significant.
EDIT - He says special vinyl?
EDIT - He says special vinyl?
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And just how 'cool' are they immediately after cleaning ?
Ever checked how a young's modulus curve looks like.
dE/dT isn't exactly shattering at lower temperature levels.
With solution at ambient I would think the variations are well within seasonal room temp variations.
Never measured, but somewhat lower than ambient temp, i can feel it with the fingers when used the VPI cleaning machine.
After maybe 20- 30 min its ok.
Its not a real problem, i just dont like the bright sound.
In hot summertime the sound is also slightly different, but this comes from the elasticity of the damperrubber in the cartridge.
Basically i just would like to know why wet play causes the noise thereafter and i have no real explanation. Maybe here are folks with more knowledge and instruments for tests and giving facts.
Do you mean the burn in and demagnetizing record?
Special vinyl???
Its said, the moulding granulat is more refined, thus lower noise possible.
Its said, 180 gramms is better than lesser weight. Nobody sez what is better.
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