I saw an ad. the other day for an interconnect with a battery on the side. The manufacturer states having a constant voltage across the dieletric aligns it in some way (or some such nonsense). Is there any merit to this at all? I'm curious since SNAICS also have a constant voltage in them (at least those from *cap/some amps to pre). In contrast, some have claimed removing the power from the signal cable leads to a sonic improvement.
yours skeptically,
Dan
Posted on: 21 October 2003 by prowla
A dielectric material is a substance that is a poor conductor of electricity, but an efficient supporter of electrostatic fields. If the flow of current between opposite electric charge poles is kept to a minimum while the electrostatic lines of flux are not impeded or interrupted, an electrostatic field can store energy. This property is useful in capacitors, especially at radio frequencies. Dielectric materials are also used in the construction of radio-frequency transmission lines.
In practice, most dielectric materials are solid. Examples include porcelain (ceramic), mica, glass, plastics, and the oxides of various metals. Some liquids and gases can serve as good dielectric materials. Dry air is an excellent dielectric, and is used in variable capacitors and some types of transmission lines. Distilled water is a fair dielectric. A vacuum is an exceptionally efficient dielectric.
An important property of a dielectric is its ability to support an electrostatic field while dissipating minimal energy in the form of heat. The lower the dielectric loss (the proportion of energy lost as heat), the more effective is a dielectric material. Another consideration is the dielectric constant, the extent to which a substance concentrates the electrostatic lines of flux. Substances with a low dielectric constant include a perfect vacuum, dry air, and most pure, dry gases such as helium and nitrogen. Materials with moderate dielectric constants include ceramics, distilled water, paper, mica, polyethylene, and glass. Metal oxides, in general, have high dielectric constants.
The prime asset of high-dielectric-constant substances, such as aluminum oxide, is the fact that they make possible the manufacture of high-value capacitors with small physical volume. But these materials are generally not able to withstand electrostatic fields as intense as low-dielectric-constant substances such as air. If the voltage across a dielectric material becomes too great -- that is, if the electrostatic field becomes too intense -- the material will suddenly begin to conduct current. This phenomenon is called dielectric breakdown. In components that use gases or liquids as the dielectric medium, this condition reverses itself if the voltage decreases below the critical point. But in components containing solid dielectrics, dielectric breakdown usually results in permanent damage.
Paul Rowlands
Posted on: 21 October 2003 by Dan M
well, glad that one's sorted
Perhaps I should clarify -- this powered cable has a conductor along its length connected to one end of a battery and the other end is connected to a shield that wraps the entire cable outer. So, in theory the dielectric sees a field all the time. This is supposed to achieve the same as effect as cable break-in but more quickly since the field is always on and constant. (Does anyone else know of this cable ?- can't remember where I saw it)
Now, my question was/is does having the 24V from the psu inside a snaic achieve the same effect? Or is this a bunch of snake oil, and in fact having no DC in the cable is preferable?
cheers,
Dan
Posted on: 23 October 2003 by Andrew L. Weekes
Dan,
The basic physics behind the principle is perfectly sound (no pun intended) and can be demonstrated both audibly and by measurement.
I know of at least one commercial product that applied a DC bias to it's interconnect for the same reasons.
Similar effects are audible and measurable in capacitors, a component utilising a dielectric to function. There are clearly audible non-linearities that vary with applied AC and DC potentials, but applying a fixed DC bias is not always the best solution.
Andy.
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