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Old January 3rd 04, 02:36 PM posted to uk.rec.audio
David
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Posts: 66
Default "What HiFi" - can it be trusted?

......."basically the Fibre call for in the spec is many times larger in
diameter that the wavelenght of the light used so instead on the light
bouncing down the fibre in a controlled fashon it bounces about in a
lot more random fashon and after a metre or three the uncontrolled
light bounces interfere with the main light signal generating extra
noise. This can cause misreading of the recieved signals, hence
errors, noise, distortion.
So by using a better fibre (which is not as cheap) that has a smaller
diameter, will improve the quality (by reducing the noise) at the
recieving end, resulting in less errors etc"............

Mmmmm

Wavelength of light used is?
Diameter of cable used is?

Even the finest fibre is many many times greater in diameter than the
wavelenghth / amplitude of teh transmitted light but that's not relevent!
DIGITAL data is transmitted as a series of pulses.
Light on = 1
Light off = 0.
Interference is insignificant unless you think that some form of lasing is
taking place within the fiber to smear the time base.

I can almost believe that analogue interconnects make a difference (but then
didn't we all throw up our hands in horror at the thought of tone controls
"interfering" with the signal) but I have yet to hear any difference
between digital interconnects given that the plugs and sockets are kept
clean.

Most differences in analogue leads also disapear given a few hours use or a
clean up of the "old" plugs Any lead which sounds significantly different
to a "standard" interconnect is almost certainly "damaging" the sound in
some way - whether by phase shifts or by acting as a filter and I can't see
that any such "change" is a good thing!

Use your ears, get out more, listen to some live music then see whether your
hi-fi sounds real - don't compare it with other hi-fi systems. Most of the
big name set-ups at shows or in dealers demo rooms sound awfull - start from
there and try to improve things from there - and if they even suggest a sub
woofer set the dogs on them!

"chris" wrote in message
...

"Oliver Keating" wrote in
message ...
I was flicking through "What HiFi" magazine and I came across

something very
odd - a series of reviews on *digital* audio cables, for connecting

a CD
player to an amp.

There are comments such as "this cable brings across a crisp sound a

cut
above the rest"

Now, at this point I have to shake my head in disbelief. Surely a

digital
cable about 1 metre long can easily carry a 1mbit data stream with

no
errors. Bear in mind ethernet has to carry 100mbits.


Yes a "DIGITAL cable most certainly can, but a lot of so called
"digital" interconnects arn't made with DIGTAL grade cables, and the
plugs also are not true 75 ohm, so you will start to get line
reflections, ringing on the recieved pulses (and if they are of
sufecent signal level cause pulse signal coruption and drop-outs) this
could start adding to the error rate, resulting in a less "good a
sound".

about optical cables. There is absolutely
*no* way an optical pulse can be distorted sufficiently over 1 metre

that it
could result in an error.


This should be true ! BUT. Unfortunatly due to the design spec this
is not true.
There was some deep discussion on this whole issue a while back on
RAHE,
I too had thought like you. Then The Man from Belden explaind it
rather well: you could do a google on it his expanation should be a
lot better than mine.
But basically the Fibre call for in the spec is many times larger in
diameter that the wavelenght of the light used so instead on the light
bouncing down the fibre in a controlled fashon it bounces about in a
lot more random fashon and after a metre or three the uncontrolled
light bounces interfere with the main light signal generating extra
noise. This can cause misreading of the recieved signals, hence
errors, noise, distortion.
So by using a better fibre (which is not as cheap) that has a smaller
diameter, will improve the quality (by reducing the noise) at the
recieving end, resulting in less errors etc.

I can only think that the testers suffered some sort of placebo

effect, or
they are in cahoots with the industry in order to provide a supply

of
customers who will shell out £350 for the "best" optical cable.


No, what they heard in the test is valid.
Sorry, its just good engineering to fix, bad engineering in the first
place.
As to the question is a cable worth £350 ? Well only your ears, brain
and wallet can make that value judgment.
I personaly would look for a much less expensive option (good dacs are
less than that).

snip

Who ever said life was easy :¬)

Happy New Year
Chris