Diamond
• 280 Narrow-Aperture Quartz (Fused-Silica) Fibers
• Low-Jitter (Digital Timing Errors)
• Precision Polished Fiber Ends
The audio frontier is all abuzz these days with the pleasure possible
though HDMI, USB, FireWire® and Ethernet connections. However, these
current generation digital technologies are only part of the story, just
as the challenge of designing, manufacturing and choosing the best
analog interconnects and speaker cables is as important as ever. The
S/P-DIF (Sony® Philips Digital InterFace), which arrived in 1983 along
with the CD, is still very much a part of our world today. S/P-DIF is
transmitted through Digital Coax and Toslink fiber optics (EIA-J),
making them still some of the most important cables in
electronic entertainment.
While, thanks to HDMI, Toslink is not so often used to connect a DVD
player to an A/V receiver, Toslink connectors are common on cable-boxes,
TV sets, subwoofers, all sorts of products. And now, the 3.5mm Mini
Optical connector, also somewhat incorrectly known as Mini-Toslink, is
everywhere … from the 3.5mm dual-purpose headphone jack on a Mac laptop,
to inputs on some of the finest portables.
For these many reasons, AudioQuest has refined and renewed our high
performance OptiLink cables. All models and all lengths are now
available Toslink to Toslink and Toslink to 3.5mm Mini Optical.
When the question is “how can a fiber-optic cable change the sound?” …
the answer is easier to explain than for almost any other type of
cable. If the light source were a coherent laser, firing into a vacuum,
all the light would stay straight, arriving at its destination at the
same time. Even if the LED light source in a Toslink system were
coherent, the light entering a fiber-optic cable is scattered and
dispersed by imperfections and impurities in the fiber. This can be
measured as a loss of amplitude … but amplitude is not the problem, a
50% true loss would have no effect on sound quality.
The problem is that the dispersed light does get through the cable,
but only after it has taken a longer path, like a pool ball bouncing off
the side-rails, causing it to arrive later. This delayed part of the
signal prevents the computer charged with decoding this information from
being able to decode properly, or even at all. The inability to decode
shows first at higher frequencies (not audio frequencies, this is a mono
stream of digital audio information), so reduced bandwidth is a
measurable signature of light being dispersed by a fiber. The punch
dispersion in the fiber, the less distortion in the final analog audio
signal presented to our ears.
There is another serious dispersal
mechanism in the Toslink system. The fiber is a relatively huge 1.0mm
in diameter, and the LED light source is also relatively large, spraying
light into the fiber at many different angles. Even if the fiber were
absolutely perfect, the signal would be spread across time because light
rays entering at different angles take different length paths and
arrives with different amounts of delay.
The almost complete solution to this problem is to use hundreds of
much smaller fibers in a 1.0mm bundle. Because each fiber is limited as
to what angle of input can enter the fiber, there is far less variety,
and far less dispersion over time. This narrow-aperture effect is
similar to how a pin-hole camera can take a picture without a lens … by
letting in light at only a very limited range of angles, a picture can
be taken, whereas removing the lens from a wider aperture would make
photography impossible. Less light gets through a multi-fiber cable, but
the light that does get into the fibers comes out within in a much
smaller time-envelope.
So there is one problem, the dispersion of light across time … and
two avenues towards a better result: less dispersion in the fiber
(better polymers and ultimately quartz), and less dispersion by
filtering the input angle. How simple is that! Listen and enjoy.