[GreenKeys] Incredible . . .

[Craig Sawyers]

> Super special wire but they
> don't even think about the 25 to 100 feet of plain old wire to
> the fuse box.

But the true audio nut knows about this, and wires a dedicated spur from the
fuse box using super special wire.  The really wise audio nut then adds a
technical earthing system purely for the audio system.

Of course, none of this is new - professional recording studios have done
just this sort of thing since Adam was a lad.  In fact, Pink Floyd's studio,
run by hard-nosed and cynical recording engineers, ended up using "Kimber
Kable" throughout - starting with the mains wiring.  This made such a
singular improvement to the sound quality, they moved on to signal wiring
and used Kimber on all the patch bays and mixing desks.  Miles of the stuff.

Instrumentation engineers, and standards labs (like NBS, PTB and NPL) use
this approach with bells and whistles.  Triple shielded mains power
transformers with much less than 1pF effective interwinding capacitance are
commonly specified, and grouding strategy is the subject of significant
study and planning.  Signal cabling is usually Gore screened twisted pair,
using PTFE (Teflon) insulation throughtout.

Just for laffs measure the interwinding capacitance of the typical
unshielded transformer that is in even a high-end audio product.  I've just
measured 750pF on a 500VA toroid on my bridge.  Given that the rectifier
diodes are turned on for at least 10% of the time, and that the reservoir
capacitors are inductive at high hundreds of kHz and you will soon see that
the audio amp is actually connected directly to the incoming mains at modest
supersonic frequencies.  Just to complicate things, the (say) 10,000uF
reservoir caps resonate with the 750pF interwinding capacitance at 58kHz
with rather a high Q.  Most amps simply can't handle power supply ripple at
high frequency, and end up producing intermodulation products downmixed into
the audio band - and unlike the usual harmonic and intermodulation
distortion introduced by amplifiers, this electrical rubbish is only
correlated with the audio signal in an anharmonic way that is described as a
mushy or cluttered or hard sound quality.  This is at least the plausibility
argument behind the improved, or at least different sound of
different-construction mains cables.  It depends on the amp and the mains
transformer of course - and some products respond more audibly to mains
upgrades.  Interestingly, the most audible improvement tends to be with
lower powered units like preamps and CD players.  Dedicated power amplifiers
unexpectedly don't show as great an improvement.

Craig