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Is this a new phenom? Hardly. A professor Henry A. Rowland working at the John Hopkins University in the late 1870s was send to Europe for studies of laboratories and instruments. On his tour he met and studied with Hermann von Helmholtz in Berlin. Here he found the time to finish his study of the magnetic effects of a charged rotating disk. At that time, Maxwell’s equations on electromagnetism were the subject of heavy debate. Rowland’s experiment was difficult as it demanded extensive mathematical calculations as well as measurements at the edge of detectability but Rowland pulled it off. The experimental setup consisted of a disk of hard rubber or an old phonograph record connected to the shaft of an electric motor.
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The disk was given an electrostatic charge by rubbing it first with a piece of woolen cloth. Then the disk was spun and a magnetic compass brought in close proximity. This deflected the compass needle. The faster the spin, the greater the deflection. It appeared that a magnetic field got set up not merely by a current moving through a wire but by a moving electrostatic field as well. Rowland’s work, the first demonstration that a charged body in motion produces a magnetic field, attracted much attention.
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So what do we have here in our modern time regarding CDs, LPs and the Furutech DeMag? We have a medium very much prone to static build-up. Thus charged, we spin this medium at up to 500RPM for CD and a bit slower for vinyl. From Rowland’s experiments we learn that such activity creates its own magnetic field. With magnetisable particles embedded in the CD structure, label print ink and colorants to make basically clear vinyl look black, we have permanent magnets on our hands. For LPs, the magnetic field of the spinning disk is in very close proximity to the sensitive structure of the cartridge and thus influences the pickup. And because CD processing is for the major part analog, something similar happens there too and is additionally powered by faster revolutions. By degaussing and thus applying an opposite magnetic field with the DeMag, the disc’s static magnetic field is lowered enough to make an audible difference. By playing, handling and restoring the disc to its case or sleeve, the disc is being recharged. As we learned from professor Rowland, this is the necessary condition to recreate a magnetic field when the disc is spun again. That field causes the ferromagnetic parts to get re-magnetized to create the need for another DeMag session later.
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Anyone ridiculing the workings and effects of the Furutech DeMag should read up some on the experiments Rowland performed way back in the 1880s. Or, visit a local Furutech dealer with an old LP under your arm and do the ol’ before-and-after test. May we suggest you keep quiet until then? |
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