Optical vs Coaxial

ok, so I have an amp with one coaxial and two optical inputs. I would lke to connect HD PVR and blu ray into the amp, and wondered if it made ANY difference which of the inputs I used...
 
I've always understood it to be coaxial - but I'm not quite sure of the reasons.

The very first thing I noticed was high end tended to have coaxial only - mid end had both - and low end had optical. Most cheaper consumer products have optical. If I've had the option, I've always chosen coaxial.

I guess the answer could depends on the length to be run - as well as the cost of each comparable cable. An optical cable of R150.00 may be cheap vs a coaxial of R150.00 ... so you'd need to spend more on the optical to get the same quality.

I've also heard about the number of conversions in the optical being more - and more conversions is bad ;)

Also keep in mind this more than likely better measurable quality and not audible.
 
they both are digital so the sound quality is identicle. Only analogue cables can degrade sound. It would be like saying which usb cable should you get so when you transfer images from your camera to your pc you get them in the best quality.
 
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Dolby said:
I've always understood it to be coaxial - but I'm not quite sure of the reasons.

The very first thing I noticed was high end tended to have coaxial only - mid end had both - and low end had optical. Most cheaper consumer products have optical. If I've had the option, I've always chosen coaxial.

I guess the answer could depends on the length to be run - as well as the cost of each comparable cable. An optical cable of R150.00 may be cheap vs a coaxial of R150.00 ... so you'd need to spend more on the optical to get the same quality.

I've also heard about the number of conversions in the optical being more - and more conversions is bad ;)

Also keep in mind this more than likely better measurable quality and not audible.
Click to expand...


Eish, nooit Dolby, I expected more of you :D

It's digital so the physical medium does not make a difference.

It's just 1's and 0's running down the line which then gets converted at some point by a DAC which could care less about the source transmission medium as it just sees 1's & 0's.

Do you by any chance buy expensive digital interconnects?
 
ponder said:
Eish, nooit Dolby, I expected more of you :D

It's digital so the physical medium does not make a difference.

It's just 1's and 0's running down the line which then gets converted at some point by a DAC which could care less about the source transmission medium as it just sees 1's & 0's.

Do you by any chance buy expensive digital interconnects?
Click to expand...

I'm not sure if I should be happy that you expected more, or upset I didn't meet your expectations ;)

Anyway - I've said numerous times on this forum (and at the bottom of that post!) that any difference is inaudible to me - but I do feel there may be people that may hear a slight difference and the results of definitely measurable.

We're all sitting on an IT forum subtopic of audio with low-mid end systems and making statements that everything is identical - where there are people with system many, many times greater than most ours where audio is a passion.

It's simplistic to say they're identical because they're 1s and 0s : this are not just a cheap cable versus a more expensive cable. This is a totally different type of cable we're comparing (optical vs coaxial) and as I mentioned, there are facts such as distance, conversion of sigals, comparable price, error correction, jitter, interference and others. Most forums and discussions focused on audio with audiophiles are saying they're slightly different.

I'm no audiophile - but judging by http://forum.ecoustics.com/bbs/messages/5/1118.html (which no one read anyway), check some of the comments by folk with a keen interest, keen ear and transparent equipment :

Coaxial and Optical are the same over short runs. Over very long runs, Optical is better at preserving the signal, since it has a lower amount of signal degradation.

one of the DIFFERENCES is an optical cable needs to have the signal converted to light pulses and the coaxial cable will pass along the digital signal without any conversion

The CD data, though optical, is converted to a electrical signal. To create an optical signal, this elctrical signal - essentially the coax signal, has to be convered to optical by a laser-diode. You could theorize that am optical signal could not be superior to a coax signal because it is derived from the coax signal. I would not worry about it though.

2. Optical connections do not carry grounds. In a pooly designed system an optical connection COULD produce less hum because there are fewer ground paths. The music to the decoder would not be any better but a crappy amp could add hum to an otherwise pristine music signal just before it got to the speakers. This hum would be faily obvious though.



Expensive is relative - but thought of connecting a R50,000.00 system together with rip cord and Stax RCA's a little off putting to me. I'd rather spend a few extra Rand and have piece of mind that everything is working as it should
 
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125Mb/s (originally 3Mb/s) is not a very high data rate. I cannot see jitter & slew rate being that critical. The circuitry accepting the signal works quite happily with non-perfect signals, it becomes more of a problem if things are seriously out of whack and you start operating at much higher speeds like used in data communications. These days on modern kit improved buffering and local re-clocking effectively negates jitter.

I reckon this is all down to people fussing over things they see on a oscilloscope and then imaging they can hear the effect. Kinda like the guys zooming in at pixel level to check noise in digital photography.

Maybe my hearing is just very bad :D

http://www.audioholics.com/education/cables/toslink-interconnect-history-basics
http://www.6moons.com/audioreviews/toslink/toslink_2.html Scroll to the conclusion
 
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