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As shown in fig.1, a propagating electromagnetic wave consists of an oscillation of energy between the magnetic and electric fields, these akin to kinetic and potential energy in a mechanical system. It is helpful to think of free-space dielectrics and conductors as distributed inductance-capacitance-resistance networks. For example, in a coaxial cable (fig.3), the electric field is everywhere radial, while the magnetic field forms concentric circles around the inner conductor (Ampere's Circuital Law). It is important to note, as commented upon earlier, that the E-Bar and H-Bar fields are…
It must be noted, of course, that the error voltage induced by the changing external field dominates, so this result would be largely masked. (The greater the conductor spacing, the greater the masking.) With loudspeaker cables (greater than, say, 2mm in diameter) that are terminated close to their characteristic impedance, the external fields will contribute minimal error. However, the loss field still produces time dispersion. If the error voltage is to be correctly predicted, skin depth must be included, a simple resistive model being inaccurate. I am not trying to say that this effect is…
The detailed characteristics of the dielectric material are also important, as the model shows that the dielectric supports the majority of the signal during its transportation along the cable (which can take many passes if the cable is not optimally terminated). Dielectric loss has been cited as a contributory factor, which can be modeled as an equivalent frequency-dependent but low-conductivity σd, where σd = ωε (power factor). Power factors vary from typically 0.0005 to 0.05 (see Skilling [2]). The attenuation and phase constants then follow, as αd = 0.05ωε√µ (Power factor) and βd = ε√µ.…
Sidebar 1: References & Further Reading
[1] Magid, L.M., Electromagnetic Fields, Energy and Waves, John Wiley and Sons, Inc. ISBN 0-471-56334-X, 1972.
[2] Skilling, H.H., Fundamentals of Electric Waves, John Wiley and Sons, Inc. 1948.
[3] Larrain, P. and Corson, D., Electromagnetic Fields and Waves, W.H. Freeman and Company, ISBN 0-7167-0331-9, 1962.
Sidebar 2: Maxwell's Equations
Faraday's Law
Ampere's Law
Gauss's Theorem
div D-Bar = r
No Magnetic Monopoles
div B-Bar = 0
The constituent relationships that define electrical and magnetic material properties are
D-Bar = ε0εrE-Bar
B-Bar = µ0µrH-Bar
J-Bar = σE-Bar (if σ is constant, then this equation represents Ohm's Law)
However, it is common to write ε = ε0εr and µ = µ0µr, thus D-Bar = εE-Bar and B-Bar = µH-Bar
where
E-Bar, electric field strength, (volt/m)
B-Bar, magnetic flux…
BRIAN WILSON: SMiLE
Nonesuch 79846-2 (CD). 2004. Brian Wilson, prod., mix; Mark Linett, eng.; Kevin Deane, Daneil S. McCoy, Pete Magdaleno, asst. engs.; Darian Sahanaja, mix. AAD? TT: 47:01
Performance ****½
Sonics **** (footnote 1)
Nonesuch 79846-2 (CD). 2004. Brian Wilson, prod., mix; Mark Linett, eng.; Kevin Deane, Daneil S. McCoy, Pete Magdaleno, asst. engs.; Darian Sahanaja, mix. AAD? TT: 47:01
Performance ****½
Sonics **** (footnote 1)
Give Brian Wilson credit. Few artists, let alone those who've had to do battle with an abusive father, drugs, quacks, chemical imbalances, and the pressure that comes from being, at age 24, a group's sole creative force, would have the guts or the inspiration to return to the scene of their greatest folly. Yet that is precisely what Wilson, 37…
Let's start with some music—three discs I recently have been using to evaluate equipment as well as listen to for enjoyment. They are as contrasting in style as one could hope for, but all on an enviably high musical plane. (Space considerations compel brevity approaching that necessary to sell screenplays to producers at cocktail parties, footnote 1)
Ensemble Amarcord: And So It Goes (Apollon Classics apc 10102): Former choristers from Bach's own church make up this German version of The King's Singers. This contemporary a cappella program ranges from Billy Joel to Supertramp to a Cuban…
His central claim is that achieving low noise and distortion numbers are Pyrrhic victories. He claims that timing errors are introduced by having the music go through more than one silicon junction at once, those varying signal paths often being of varying length, and through multiple transistors that are very difficult to match. For M. Delétraz, it is nearly all about preserving the purity of the musical timing, and to that end he is cheerfully willing, after more than two decades of wandering in the wilderness of trial and error, to write off a lot of factors other companies obsess about…
For lowest hum and noise in most applications (excluding darTZeel's own 50 ohm output preamplifier, not yet released), it is necessary to tie the negative speaker terminals together with a jumper wire. The provided plain wire was a pain to use with speaker cables terminated by spade lugs, to the extent that I asked Stereovox's Chris Sommovigo to fabricate a single banana-to-banana jumper out of Stereovox wire. I unreservedly recommend such a wire (or the spade equivalent, if your speaker cables use bananas). At some risk to my reputation for being well-oriented in space and time, I must say…
Manufacturer's Comment
Editor: Wow! John Marks' review leaves little to comment upon.
One customer told us his NHB-108 Model One was an "emotional amplifier," meaning it extended his emotions. I think John experienced something similar. The more you read what he wrote, the more you understand how much John liked the machine.
The NHB-108 Model One high-speed power amplifier is the first high-end audio gear we have brought to market, concretizing all those past years of research into what we were looking for. The companion preamplifier and the integrated amplifier will…