Do magnets and electronics mix?

Ed-sawyer...Magnetic levitation in three axes is possible: it is used to "suspend" the active parts of gyros and accelerometers used in missile guidance systems. It is an ac system, where movement of the suspended part towards a point where it would "touch down" changes the impedance of the coil that is providing suspension force in such a way that the current in that coil is changed, and its force changes so as to push the suspended part away. A set of coils provides both axial and radial support of the suspended part.However the available forces are much too small to be useful in this audio application.

If you really want a vibration-free mount, and cost is no object, check out www.halcyonics.com. I have "at-work" experience with their Mod-1M model, and it really works.

The idea of isolation and "zero contact" is wishful thinking. The force that pushes the magnets apart is just as real as the force that holds up a component on any other type of footer. It isn't a magic carpet that just floats there.

Even though they aren't physically touching the two pieces are still coupled together by these forces just as if they were. Moving one will exert a force on the other. If the magnets in the base vibrate for whatever reason, this will move the magnetic field and cause the "floating" piece to vibrate as well, and vice versa..

That was Malechi Constants problem in Vonegout's "Sirens of Titan". The magnetic furniture kept sqirting around. I had Planned to tether the platform with a guide pin and a felt gasket or the cutting wheel of a pipe cutter.

Magnetic levitation in three dimensions is not really possible. In all situations that I know of, there will be some force (read: hard contact) in at least one dimension, to keep the whole assembly oriented. Would be great if it was truly suspended, but more like magnetically sprung is the reality of it. the platforms for TT and the like that are sold for the purpose have a single rod connecting/orienting the upper and lower sections, which are sprung by magnets. without the rods, the upper platform would just skate away and fall to the ground.

-Ed

Cool, Smokester, what sort of key words would I look under to get a start. Patrick

Your turn-of-phrase "zero contact under my components" is philisophically inspiring. The magnetic force is nonetheless real and is surely a viable option for isolating your equipment.

One of the attributes of such a suspension system could be continuously tuneable motion damping implemented by inserting coils with variable series resistance into the magnetic field to dissipate kinetic energy to and from the table. This damping could be custom tuned over a wide range. Such damping schemes prevent large oscilations in analogue meters, for example, and a search of the web will find other illustrations of this. You should consider this mode of damping if you are going to design your own platform.

I think that given the ability to tune the stiffness and damping of these "magnetic shock absorbers" might provide a compromise between isolation and dissipation and allow for an effective, critically damped system.

No doubt this has been thought of for audio applications in which case it would interesting to know about.

TWL,
Thankyou for confirming my fears and the insight on draining vibrations. Perhaps I'll stick to cones and floating furniture. I wonder how S.A.P. addresses these issues. Patrick

Magnetics and electronics not only mix, but are inextricably inter-related. All AC signals on a wire are surrounded by a constantly expanding and contracting magnetic field, which is changed depending upon the conditions of the signal in the wire.

However, it is precisely because they DO mix, that unwanted interactions can occur between two wires' magnetic fields or a wire's magnetic field and some other magnetic force. A moving magnet in a coil of wire is how an electric generator works or vice versa. Unwanted inductance or other interference can occur when magnetic fields are in the area of the electronics, and may produce somewhat unexpected results.

If you doubt that a magnet can move the electron stream, consider the TV tube, which has a stream of electrons moved about on the screen by magnetic fields, creating your TV picture.

But all is not lost, the magnetic fields become reduced in intensity at a distance, and may not have any effect at all, at the distances you plan to use. But they might have an effect, too. It depends on the strengths of the magnets and the distance they are from any sensitive things.

Personally, I would never decouple any of my equipment from the floor in that way. It removes any possibility of airborne vibrations ever leaving the equipment. The vibrations have no way out. I think it is a very high-tech and interesting way to screw up the sound of your system.