I have a watchmaker customer who complained to me the other day about the problems caused to him in his work by his miniture screwdrivers becoming magnetised and asked me if it is possible to demagnetise them effectively.
A minutes thought and a dip into the junkbox produced an old washing machine water valve solenoid coil.
These coils are rated for 240V operation so I connected a power lead to it and tried it out.
Inserting a magnetised screwdriver into the center hole and then slowly drawing it back out and moving it a long distance away before switching off the coil current gave a totally demagnetised screwdriver that would not pick up even the tiniest sliver of iron.
There have been comments here on the forum of deleterious sonics caused by magnetic components and component leads.
This arrangement may be very effective in demagnetising components before fitting to a pcb.
Maybe this informatiuon is useful to some of you.
Eric.
A minutes thought and a dip into the junkbox produced an old washing machine water valve solenoid coil.
These coils are rated for 240V operation so I connected a power lead to it and tried it out.
Inserting a magnetised screwdriver into the center hole and then slowly drawing it back out and moving it a long distance away before switching off the coil current gave a totally demagnetised screwdriver that would not pick up even the tiniest sliver of iron.
There have been comments here on the forum of deleterious sonics caused by magnetic components and component leads.
This arrangement may be very effective in demagnetising components before fitting to a pcb.
Maybe this informatiuon is useful to some of you.
Eric.
chris ma said:
Two points to consider:
1) CDs are read optically. There is no magnetic pick-up, which is fortunate because
2) the shiny layer in a CD is either gold or aluminum, neither of which is magnetic. There is nothing to "demagnetize".
I believe the Bedini Clarifier works on the same principle as the Mpingo disk.
MR
True MR, but laser beam has to pass thru plastic or what ever man made material, and it must has a (?) index for light to pass and if this material holds static charges and the CD being spinning at high revs so that it seems stationary relative to the beam, for electromagnetic force can bend light waves if I recall correctly, then it may affect the "read" by the laser. This is going way over my head/knowledge.
mrfeedback said:
I have the thing, work very good.
http://www.elfa.se/elfa/produkter/se/20/2023750.htm
It's two magnets. I'm still puzzled how it works but it does, very effectivly, totally passive. Cheap also, 25 USD.
Demoneytiser
Peranders, I had one of those years ago and it was not nearly as effective as the solenoid demagnetiser, although it did a good job of remagnetising.
USD$25.00 - you must be kidding me - you got seriously ripped off on that one.
BTW the solenoid version was free out of my junkbox, and I gave it free to my customer - Win/win situation.
Eric.
Peranders, I had one of those years ago and it was not nearly as effective as the solenoid demagnetiser, although it did a good job of remagnetising.
USD$25.00 - you must be kidding me - you got seriously ripped off on that one.
BTW the solenoid version was free out of my junkbox, and I gave it free to my customer - Win/win situation.
Eric.
Damage or obscuring needs to be about 2mm long on the disc surface before error concealment occurs - less than this and the Reed Soloman coding is used to properly correct data errors.
Disc static charge may perhaps attract the objective lens, and subtley change focus, or cause focus servos to draw noise currents and modulate the audio stage power supplies.
Eric.
Disc static charge may perhaps attract the objective lens, and subtley change focus, or cause focus servos to draw noise currents and modulate the audio stage power supplies.
Eric.
To put my cards on the table to start, I am very cynical about this subject.
I can see only one reason why static would affect the replay of a cd, and that is by attracting and holding small particles of dust onto the surface of the disc, which are, although tiny, large enough in relation to the size of the laser beam to cause missed or incorrect data, and thus causing the players error correction circuitry to kick in, which has audiable results.
A static charge will not effect a laser in any significant way at all, I can best illustrate this with an example. The sun will bend a light beam by a few hundredths of a minute of arc, a tiny amount only visible at astronomical distances. Despite the suns huge EM field, about 99% of this bending is due to gravity. In comparison a static charge of even 20kv , which is way more than would ever be found on a cd, is insignificant.
Yes Peter, it is quite possible that the metallic substrates on a cd could become magnetised, I have no argument with that, but the field will not affect the laser beam, for the reasons stated above.
If a disc is magnetised though, and is spun around rapidly, it will generate a EM field, as Faraday and others discovered. But, compare this field to that one produced by the highly magnetised motor that is spinning the disc and it pales into insignificance as an effector.
It must be fairy dust then
I can see only one reason why static would affect the replay of a cd, and that is by attracting and holding small particles of dust onto the surface of the disc, which are, although tiny, large enough in relation to the size of the laser beam to cause missed or incorrect data, and thus causing the players error correction circuitry to kick in, which has audiable results.
A static charge will not effect a laser in any significant way at all, I can best illustrate this with an example. The sun will bend a light beam by a few hundredths of a minute of arc, a tiny amount only visible at astronomical distances. Despite the suns huge EM field, about 99% of this bending is due to gravity. In comparison a static charge of even 20kv , which is way more than would ever be found on a cd, is insignificant.
Yes Peter, it is quite possible that the metallic substrates on a cd could become magnetised, I have no argument with that, but the field will not affect the laser beam, for the reasons stated above.
If a disc is magnetised though, and is spun around rapidly, it will generate a EM field, as Faraday and others discovered. But, compare this field to that one produced by the highly magnetised motor that is spinning the disc and it pales into insignificance as an effector.
It must be fairy dust then
Some facts for me self, self and only self for a FACT!
Can not comment on the Mpingo Disk, never try it.
I was very skeptical with the Clarifier at first, but afer borrowed one from my friend for a weekend, I was convinced to get one for myself, and can not do without one now. That said it seems it has no impact on the sound quality with the CD player in my car with the treated CDs tough.
Can not comment on the Mpingo Disk, never try it.
I was very skeptical with the Clarifier at first, but afer borrowed one from my friend for a weekend, I was convinced to get one for myself, and can not do without one now. That said it seems it has no impact on the sound quality with the CD player in my car with the treated CDs tough.
Demagnatizing CDs?
"Two points to consider:
1) CDs are read optically. There is no magnetic pick-up, which is fortunate because
2) the shiny layer in a CD is either gold or aluminum, neither of which is magnetic. There is nothing to "demagnetize".
I believe the Bedini Clarifier works on the same principle as the Mpingo disk."
1. The mechanism used to focus the laser assembly is electro-magnetic.
2. The label ink or paint on a CD can contain iron oxide pigments or other magnetic materials.
http://www.paintsrawmaterial.com/products4.htm
http://uu77.com/pigment/Default.asp
http://uu77.com/pigment/msds.asp
http://es.epa.gov/techinfo/facts/safe-fs.html
cobalt in some blue oil and acrylic paint pigments
chromium in paint pigments
Alice
"Two points to consider:
1) CDs are read optically. There is no magnetic pick-up, which is fortunate because
2) the shiny layer in a CD is either gold or aluminum, neither of which is magnetic. There is nothing to "demagnetize".
I believe the Bedini Clarifier works on the same principle as the Mpingo disk."
1. The mechanism used to focus the laser assembly is electro-magnetic.
2. The label ink or paint on a CD can contain iron oxide pigments or other magnetic materials.
http://www.paintsrawmaterial.com/products4.htm
http://uu77.com/pigment/Default.asp
http://uu77.com/pigment/msds.asp
http://es.epa.gov/techinfo/facts/safe-fs.html
cobalt in some blue oil and acrylic paint pigments
chromium in paint pigments
Alice
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