Wouldn't demagnetising a cartridge be a bit like daft?
🙂
I wont even comment on burn in.....
🙂
I wont even comment on burn in.....
Of course its stupid to demag a cart.
Burn in you can do also with normal records and music. It helps mainly with brandnew speakers to reach the final condition of the suspension and rubber surrounds. Thats all.
Maybe this happens also with a new damping rubber in a cardtridge.
Poor trackability can be made better for 10 u with a hot light source making the rubber softer. Lamp off and 30 Min later its like before heat up.
Burn in you can do also with normal records and music. It helps mainly with brandnew speakers to reach the final condition of the suspension and rubber surrounds. Thats all.
Maybe this happens also with a new damping rubber in a cardtridge.
Poor trackability can be made better for 10 u with a hot light source making the rubber softer. Lamp off and 30 Min later its like before heat up.
Wet grinding is used for things from sharpening stones to optical polishing, there is probably some mechanism at that scale that keeps the dirt embeded between stylus and vinyl. We also observe once wet always wet.
No endorsement of their claims, just that a tone in a locked grove should easily show something from immediate contiuous replay. There is a 500 locked groove LP each submitted from a different artist, I did not observe any change when playing any one for several minutes. A fresh copy of this would make an easy experiment using cross-corellation techniques to quantify any gradual groove changes.
http://www.discogs.com/Various-RRR-500/release/94233
Last edited:
I see that all you hard-core objectivists refuse to consider JC’s pearl.
During one of my internet wanderings, I found what effect may have triggered Ed’s later posts. From:
Thermo-Electric Generators.
George
One phenomena that I would think you would have to look at with a wet surface would be the hydraulic function of any liquid and how that would change the tracking of the groove. You can not compress a liquid so any liquid that could be under the stylus may cause miss tracking of the fine scale modulation of the groove walls.
As far as a special vinyl due to a special grinding of the particles I would question that. If we ground a vinyl to a smaller particle size before manufacturing you would have to consider that the vinyl would be introduced into a hot barrel of an injection machine where it would be heated to a liquid or near liquid state where any effect from the finer grinding would make no real difference, the molten state would overcome any finer grinding of the plastic beads at that point and I would find it difficult to believe this would make any difference. Now a different compound is something completely different and different additives would produce a different physical material. Modification of elasticity would be a more likely cause of a change in the final product.
As far as a special vinyl due to a special grinding of the particles I would question that. If we ground a vinyl to a smaller particle size before manufacturing you would have to consider that the vinyl would be introduced into a hot barrel of an injection machine where it would be heated to a liquid or near liquid state where any effect from the finer grinding would make no real difference, the molten state would overcome any finer grinding of the plastic beads at that point and I would find it difficult to believe this would make any difference. Now a different compound is something completely different and different additives would produce a different physical material. Modification of elasticity would be a more likely cause of a change in the final product.
Thanks Sy. I didn't look at the exact manufacturing process, but finer particle size made little sense to the end product.
Short a battery with 10 Ohms and eventually the current goes to 0. I see now but that information was left out.
George,
I'll get back to it when I have more time. Ohm's law originally did not use R but instead derived it from the wire length and diameter. It really was a chore for him to get it right.
Of course today we just use R and then when the wire heats up, it is the non "Ohmic" behavior we blame on the wire, not on the formula!
Sort of like saying SY is very much so not stupid. (SY will get the joke.)
Now I didn't want to get into low level contacts or sealed relays, but anything with a Kovar seal distorts the signal. Ask SY about using mercury to wet silver contacts!
Other issues were confusing voltage and current and even AC behavior vs. DC.
When I go to measure very low DC voltages the method is to use a very low value resistor such as .01 ohms and connect it to the voltage source under test through a very sensitive current meter. When a current applied to the .01 ohm resistor shows no current in the meter then you know the voltage being tested. Note that at equilibrium there is no burden to the source under test. However the low source resistance lowers the system noise.
As Demian noted even with a 22K load it is the source resistance that determines the noise. So if you assume you have a 100 ohm source (Typical for many reasons) from your CD player that is capable of producing 2 volts, how many dB of dynamic range can you get over a 20 kHz bandwidth?
Last and least I sort of assume most folks who play in electronics have a feel for wire resistance. So a simple quiz; match the wire gauge with the approximate resistance or as Rocky & Bullwinkle's announcer would have said "That old fashioned wire gauge committee just might have known what they were doing!"
10 1000
20 10
30 1
40 100
ES
Last edited:
Northern Telecom. Canadian tech types still get misty-eyed at the mention, unless they were also investors.
Actually, it is quite possible that the groove just after being tracked by the stylus is cooler than before.
look at it in refrigerator terms. Compression, heat removal by the best thermal conductor known to man, followed by adiabatic expansion.
For those not accustomed with effect of adiabatic expansion in elastic materials, nice little experiment with flat rubber band. Stretch (compress sideways), let it decompress while using upper lip as temperature sensor.
look at it in refrigerator terms. Compression, heat removal by the best thermal conductor known to man, followed by adiabatic expansion.
For those not accustomed with effect of adiabatic expansion in elastic materials, nice little experiment with flat rubber band. Stretch (compress sideways), let it decompress while using upper lip as temperature sensor.
Last edited:
Vacuphile,
Since it is the diamond or sapphire itself that is causing the friction and the loading I wouldn't count on it as being the heat removal source. The stylus is moving away from the localized heat as it is making it, how would that also be the heat sink or removal method? I think you would only have the ambient air to remove the heat from the vinyl as the stylus moves away from the moving heat front.
Since it is the diamond or sapphire itself that is causing the friction and the loading I wouldn't count on it as being the heat removal source. The stylus is moving away from the localized heat as it is making it, how would that also be the heat sink or removal method? I think you would only have the ambient air to remove the heat from the vinyl as the stylus moves away from the moving heat front.
About 40 years ago I knew a grad student in materials science who was
doing work on creep with regard to vinyl records. He explained that playing
the record created deformations in the groove which tended to slowly restore
themselves over a period of hours.
I'm not sure what the end of that story was, but probably SY will jump in
and tell us.
😎
doing work on creep with regard to vinyl records. He explained that playing
the record created deformations in the groove which tended to slowly restore
themselves over a period of hours.
I'm not sure what the end of that story was, but probably SY will jump in
and tell us.
😎
I don't think that the significant part of vinyl heating during playback will turn out to be from friction. The way it used to be talked about was that the contact area is so small and the accelerations of the effective tip mass are so big that pressures in the tons per square inch occur at the contact point and for a (very) short way below the surface.
The high dynamic pressure deforms the vinyl by compression, and the compression makes it get hot in a tiny bit of vinyl under the stylus. I'm not smart enough to calculate this, but it was commonly accepted "back in the day" that the temperature numbers are pretty big over a very tiny volume of vinyl. Of course, a lot of things commonly believed then aren't believed now.
Believable numbers for effective moving mass and contact area aren't hard to come by, so calculating pressure isn't difficult. But how do you get from there to temperature rise in an elastically deformed medium?
Thanks,
Chris
The high dynamic pressure deforms the vinyl by compression, and the compression makes it get hot in a tiny bit of vinyl under the stylus. I'm not smart enough to calculate this, but it was commonly accepted "back in the day" that the temperature numbers are pretty big over a very tiny volume of vinyl. Of course, a lot of things commonly believed then aren't believed now.
Believable numbers for effective moving mass and contact area aren't hard to come by, so calculating pressure isn't difficult. But how do you get from there to temperature rise in an elastically deformed medium?
Thanks,
Chris
Last edited:
Nelson.
Vinyl is not my area of plastics but from what I know of thermoplastic materials they do have what is called a memory and will revert to the state they were in when molded and cooled. It is a common phenomena of thermoplastic materials. Creep is usually associated with pressure applied over time and the deformation of the plastic. I'll let Sy go into details if he wants to do that. My area is thermoset plastics which are affected in different ways than most thermoplastic materials.
Vinyl is not my area of plastics but from what I know of thermoplastic materials they do have what is called a memory and will revert to the state they were in when molded and cooled. It is a common phenomena of thermoplastic materials. Creep is usually associated with pressure applied over time and the deformation of the plastic. I'll let Sy go into details if he wants to do that. My area is thermoset plastics which are affected in different ways than most thermoplastic materials.
- Status
- Not open for further replies.