Optic vs coax - AVS Forum
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post #1 of 9 Old 07-31-2013, 05:52 PM - Thread Starter
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Does anyone know the difference between coaxial and fibre optic
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post #2 of 9 Old 07-31-2013, 06:14 PM
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Hi Jordan,
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Originally Posted by Jordan1126 View Post

Does anyone know the difference between coaxial and fibre optic
Yes.

They carry the exact same data, they just have different physical interfaces. Both interfaces are referred to as S/PDIF (Sony/Philips Digital InterFace). If you have both on a device, they are typically wired in parallel. Because they are so different physically, they each have some advantages over the other. Here are some differences between them, with "+" being an advantage and "-" being a disadvantage:

Digital Coax
+ It will work with standard audio/video cables .
+ It can be run a longer distance than optical, and supports many connections along the way.
- It can sometimes cause ground-loops between equipment, typically causing hum and/or no audio down the coax.

Optical (Toslink)
+ It will not cause ground loops.
+ It is immune to electrical noise.
- The signal doesn't survive long runs, or more than a couple of connections.

It is often said that Toslink can contain more clock-jitter than coax, but that is not necessarily true. Even if it were true, current architectures make it no longer relevant.

There may be other differences that I can't remember right now.
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post #3 of 9 Old 07-31-2013, 06:16 PM - Thread Starter
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Okay this Is awesome. Thank you
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post #4 of 9 Old 07-31-2013, 07:51 PM - Thread Starter
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So both can send dd and dts
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post #5 of 9 Old 07-31-2013, 08:18 PM
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Hi Jordan,
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Originally Posted by Jordan1126 View Post

So both can send dd and dts
Yes, the three formats that S/PDIF can carry are DTS 5.1 (core DTS, not any of the high definition DTS versions), DolbyDigital-5.1 (again, not any high-definition versions), and 2-channel 24-bit PCM, up to 96kHz (some manufacturers have pushed the specification to include 192kHz). Both optical and coax are equal with regard to this.
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post #6 of 9 Old 08-01-2013, 05:06 AM
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Quote:
Originally Posted by Jordan1126 View Post

So both can send dd and dts

Toslink is sometimes called "Optical SP/DIF" because they generally handle all of the same formats (of which there are zillions) and coax-based SP/DIF came first. The information in the signal is the same, but one carries the information as electrical pulses and the other carries the same information via a blinking light.

BTW Mark already answered this question in post 2.
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post #7 of 9 Old 12-17-2013, 05:02 PM
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- The signal doesn't survive long runs, or more than a couple of connections.

Any specific lengths you may be referring to ? I plan on running 25-35 foot run from TV to AVR, Any issue ?
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post #8 of 9 Old 12-18-2013, 04:51 AM
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Quote:
Originally Posted by roadking00 View Post

Quote:
- The signal doesn't survive long runs, or more than a couple of connections.

Any specific lengths you may be referring to ? I plan on running 25-35 foot run from TV to AVR, Any issue ?

Toslink optical used to be limited to 10 meters (ca. 30 feet), but people discovered that there is money to be made by extending that limit which is now possible by making the plastic fiber more transparent and less dispersive internally.

I've used toslink cables in the 50 foot range and had good results.

The line transmitters used in a lot of equipment also incorporates more powerful laser diodes or leds to transmit the signal, probably to extend the range, or provide more reliable operation at reasonable ranges.

For really long lengths you probably want to use coax, which is effective over 100s of feet, especially with low loss coax that has a larger solid copper center conductor. A lot of coax is copperweld which is mostly steel and has a higher series resistance, but has more tensile strength.
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post #9 of 9 Old 12-21-2013, 03:49 AM
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Quote:
Originally Posted by arnyk View Post

Toslink optical used to be limited to 10 meters (ca. 30 feet), but people discovered that there is money to be made by extending that limit which is now possible by making the plastic fiber more transparent and less dispersive internally.

I've used toslink cables in the 50 foot range and had good results.

The line transmitters used in a lot of equipment also incorporates more powerful laser diodes or leds to transmit the signal, probably to extend the range, or provide more reliable operation at reasonable ranges.

For really long lengths you probably want to use coax, which is effective over 100s of feet, especially with low loss coax that has a larger solid copper center conductor. A lot of coax is copperweld which is mostly steel and has a higher series resistance, but has more tensile strength.

Thanks for the explanation, I just received my 35' optical in the mail and will give that a shot, coax would have been nice but my TV only has a opt output....
Thanks again....
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