In article . com,
Sseadoubleyou wrote:

Was wondering if anyone knew anything here about digital audio
connections on audio systems? My system has both optical (fiber optic)
as well as coaxil. I want to connect my DVD player up digitally to the
system. Which digital connection is better, optical or coaxil? I
thought I heard somewhere that coaxil is a 'slower' connection and
optical gets the signal thru faster?

Can anyone confirm this?

In one sense, coaxial may be "slower". The electrical signal
propagating through a typical coax will be travelling at somewhere
around 66%-80% of the speed of light in a vacuum, while the signal on
an optical cable may be travelling faster than that (it depends on the
index of refraction of the plastic). Hence, a coax cable may take a
few nanoseconds longer to get the signal to your A/V receiver/preamp
than an optical cable would.

You are *not* going to hear a difference from this effect, even if it
occurs. Period.

There are those who feel that consumer-electronics-type optical links,
using the inexpensive plastic TOSLINK cables (or even the expensive,
boutique TOSLINK cables), may sound somewhat inferior, because the
inexpensive LEDs used to drive them can have a slow rise time, and
that this can lead to timing "jitter" in the receiver, if the optical
receiver circuitry and DACs are poorly designed or implemented. A
good coax-cable driver can have a very fast rise time and would not
suffer from this problem.

I don't know of any actual, reliable, repeatable tests which show that
this is actually an issue.

In some situations, with some equipment, using an optical connection
might produce better sound, because it allows the DVD player and the
A/V preamp to be electrically isolated from one another. A coax cable
connects the two components via its shield, and if they're plugged
into outlets on different electrical circuits this could create a
ground loop and introduce some amount of hum into the sound (and not
just the sound on the digital input, either).

In most situations, however, I believe that the two connections would
result in sound which is indistinguishable - it doesn't matter which
one you use. Use whichever is most convenient, and don't let yourself
be seduced into spending large amounts of money on an expensive
"pro-grade" coax or optical cable with which to make the connection.

If you only need a short cable, I see that Radio Shack currently has a
3-foot "composite video cable, and TOSLINK optical cable" combination
on sale for $2.48 (!!). Catalog nubmer 15-1591. You could buy this,
hook up *both* cables (a composite-video cable is 75 ohms, and is
close to ideal for a digital-audio coax link), and switch your A/V
receiver back and forth to see whether you can hear a difference.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
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