Kalman Rubinson wrote in message news:17C2b.196531$cF.65961@rwcrnsc53...
On 26 Aug 2003 00:38:31 GMT, "Yoan Paquet"
wrote:

Is there a major difference between the output quality of RCA jacks compared
to Coax?

RCAs are one form of coax connector.

Kal

I am not sure that this is the right place in this dicourse to post
this note but I'll do it anyhow

Below is one man's opinion. It is the result of forty years in the
digital data transmission business. This could be the result of one
years experience taken forty times or a progression of learning
experiences. I would be interested in contrary opinions, especially
if they have some rationale for them.

The ONLY important issue in optical vs. coax is whether the bit stream
input is the bit stream received. If the answer to this is "yes" then
there can be NO POSSIBLE difference in the sound that results from the
transmission! Bits are bits independently of how they are
transmitted.

In the world of analog transmission, many effects can alter sound
because the information (sound) is dependent on the INSTANTANEOUS
amplitude of the signal and that, in turn, is affected by the
instantaneous frequency of that signal. Digital signals are not
altered in their information content in the same way. It is much more
difficult to get a faithfully reproduced signal in the analog domain;
in fact, it is tantamount to impossible at any cost.

Fundamentally, coax is more susceptible transmission line effects than
is optical cable. Both media have loss as a function of length, but
coax is subject to signal degradation due to reflections and other
transmission line effects (the same bugaboos that plague analog
reproduction). Properly designed drivers and receivers minimize this
effect so that, in the ‘sloppy' world of digital data, they only
‘tighten up' the data clocking requirements on the system. The speed
and sensitivity of modern IC's make detection and clocking of the less
than 4 MHz data rate required for digital audio cheap and easy to
obtain for either coax or optical cables. Consider the fact that we
can obtain very cheap, very reliable data transmission at 100
Mbits/sec. or even 1 Gbit/sec. over CAT-5 cable, which is a more
difficult medium than is coax.

It is highly unlikely to have a driver, receiver, transmission line
trio that will pass some digital audio data streams and NOT others.

Further observations:

If an optical line works at all, then it will work with all data
streams. Reasonably well designed audio equipment (coax drivers and
receivers) are wildly unlikely to garble the stream because of
transmission line effects. Most drivers and receivers used in modern
gear are off-the-shelf IC's that do an admirable job. It is beyond
rationality for a manufacturer to design its own drivers, receivers,
and data clocking devices when cheap, effective devices are so widely
available. I certainly would not consider designing my own unless I
anticipated a production run of at least 1 million units. Even then,
I would probably specify an off-the-shelf device.

Net:

Optical is more likely to faithfully reproduce the input data stream
than is coax, but neither is at all likely to fail as implemented in
today's equipment.

It is SILLY to argue that one transmission line produces better sound
than another does. That argument is reserved for salespersons on
commission pay or who receive manufacturer's spiffs.