digital optical interlink vs. coaxial

The digital information travels through the cable or optical fiber with essentially no error. Problems can arise as follows:

Coax is susceptable to pickup of electrical noise, that may affect ability of the receiver to distinguish "ones" from "zeros".

Inferior wire and/or improper receiver impedance can cause distortion of the digital pulse shape, again affecting recognition of one's and zeros.

Both coax and optical drivers and receivers can be designed and built well or badly, again with the possibility of data error.

Optical transmission gives complete electrical isolation. In the case of audio circuits this may avoid hum problems. ("Optoisolators, which are just optical links about one millimeter long, were in general use for this reason before fiber optic communication links).

An interesting thing about fiber optic communication is that duplex communication (both directions) can be done simultaneously through the same fiber. (The photons you send to me don't interfere with the photons I am sending to you). Can't do that with wire.

For a "long" run (I would guess that would be more than 20 feet or so) I would prefer optical. For shorter runs there should be no difference (with good equipment).

One major difference between these two different types of connections.

Digital data from transport is sent via coax as an RF signal, captured as an RF signal and then converted to audio via the internals of the DAC. As such, you have one conversion taking place.

With optical, digital data is converted to an optical signal. This optical signal travels via the "toslink" to the DAC. The DAC receives it as optical, converts it back to RF and then into audio frequencies.

As such, you have one more conversion / extra step when using optical. How good or bad this is will depend on the devices being used, their designs and the quality of conversion that they are capable of achieving. Optical connections can reduce jitter, but at the same time, they can introduce other forms of signal degradation. Sean
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Use the Optical if your video system is inducing a ground loop hum, AT&T has the most bandwidth, followed by Coax, and then lastly Toslink. I found that toslink is vastly lacking in quality compared to coax/AT&T.

Hi there! I was using the Aural Symphonic Optimism AT & T cable. Just sold it here on the Audiogon. It was the best cable I have used. Reluctant to let it go as the replacement digital cable might not be on par. Problem is that the latest universal transport doesn't support this type of connection. The Lexicon RT-10, the Theta Compli and the Teac DV-50 and the Krell SACD standard does not have optical connections at the back. Sigh!

Might have to settle for coaxial digital cable. Some machines don't even have a XLR Balanced digital out.

Happy hunting.

Cytocycle...Please explain what you mean by "bandwidth" of an optical data transmission media. The light source is monochromatic, so any deficiency of "bandwidth" would just amount to lower transmissibility. The optical light source circuitry and the light receiver may have data bandwidth limitations, but that has nothing to do with the nature of the fiber.