Re: Cable my Ass

["Dennis Leas" <dennis@mdbs.com>]

Let's ALL get involved here!

Then Kim can grade our answers and let us know if we passed!

Thoughts ($0.02 USD):

1) Bear in mind that the electrons hardly move in signal transmission.
There may be some drift with a DC signal.  If the electrons had to move, 
the
signal could not propagate at light speed, could it?  The disturbance DOES
propagate at light speed however.

2) Although we think of connectors and wires as perfect conductors, they 
are
not of course.  How imperfect we find them depends on how closely we look
and what signals we use.  Capacitance and inductance effects are 
well-known,
for instance, and are frequency dependent.  Imperfect connections can act 
as
rectifiers, giving a "directionality" to the currect flow.  Is any
connection perfect?  How imperfect does it need to be to have an effect?
I'm guessing that any "directionality" of the premium wire is determined
more by the properties of the connector than the wire itself.

This leads the question: If you replace a connector on a "learned" cable, 
do
you need to send it back to school?

3) Analog audio signals *should* not have a DC component.  In the case of
transformer balanced inputs, how close is the balance?  How good is the
transformer?  How about the newer OpAmp balanced boards?  I'd believe a
small DC bias is possible and probably likely.  But also not likely to have
any effect.

4) Electrical conduction occurs in copper because the energy bands of
adjacent atoms (the electron orbitals) are close enough (physically and
energy-wise) that a EMF disturbance near one atom affects the energy levels
of neighboring atoms.  Thus, the disturbance travels as a advancing
wavefront.  In any ordinary metallic structure, the atoms are roughly
regularly spaced; however, there are impurities (atoms of another sort),
structural irregularities, and thermal agitation.  But we're talking about 
a
HUGE number of atoms in a wire.  I find it hard to believe that good 
quality
wire is much different than the oxygen-free, premium stuff.

5) I know more about AES/EBU than S/PDIF.  I find it hard to believe that
premium cabling makes much difference with AES/EBU.  For example, I can
transmit wavetables out of my Kyma's AES/EBU ports, bring the signal back 
in
another port, and I get precisely the same data.  All of the thousands of
sample values are exactly the same - every bit matches.  I'm using ordinary
mic cables (I think I got them with a batch of SM-57s I bought years ago).

6) The Stereophile article is quite interesting.  Thanks!  I need to read 
it
in more detail.  (Hey!  I'm trying to keep an open mind.)

So, does fiber optic cable have a direction?

Dennis Leas
-------------------
dennis@mdbs.com