Optical Toslink Cables - What, which, eh?!

Optical Toslink Cables - What, which, eh?!

Author
Discussion

beanbag

Original Poster:

7,346 posts

247 months

Thursday 21st January 2010
quotequote all
I thought an optical cable was an optical cable. It carries a binary light source with lots of 1's and 0's from point A to point B. HTPC to HT Amp.

Apparently it isn't as simple as this, according to What Hifi magazine reviews. According to them, some sound "warmer" and carry more detail....Que?!

Now I'm a fan of hifi and I have some nice cabling in the back of my amp, however how on earth can an optical cable vary so much and is it all marketing BS or for real?!

I'm in the market for a 2m-3m optical cable but now I'm utterly confused as to what to get.

Any ideas and reason for a particular with a budget of £40?

wiggy001

6,561 posts

277 months

Thursday 21st January 2010
quotequote all
I'm no expert but how on earth can 1's and 0's be warmer or cooler?!

I call BS.

Yes a dearer one could be better made, more robust etc, but I wouldn't spend more than £15 on one.

bogie

16,568 posts

278 months

Thursday 21st January 2010
quotequote all
not this old chestnut, thats argued about on hi-fi forums infinitely i.e. how can digital cables sound different ?

surely the same 0's and 1' at one end, arrive at the other end as the same 0's and 1's to be decoded

Personally, if the cable is shielded properly, so there is no interference and transmission loss, I cannot see or hear, how a £1000 cable carrying digital data, can sound any different to a £10 one

its the usual case of hi-fi magazine reviewer self justification and marketing bull ....but of course, if it didnt exist, then hundreds of companies that sell all these snake oil products in the hi-fi/av industry would have gone bust when the move from analog to digital came LOL wink

Thudd

3,100 posts

213 months

Thursday 21st January 2010
quotequote all
Why would an optical cable need to be shielded? I thought the signal was carried by internal reflection within the fibre.
Only issue I could see would be the quality of the fibre as flaws may possibly cause dropouts in transmission?

SJobson

13,081 posts

270 months

Thursday 21st January 2010
quotequote all
Are you a believer or not? If you believe, then it will sound better.

beanbag

Original Poster:

7,346 posts

247 months

Thursday 21st January 2010
quotequote all
bogie said:
not this old chestnut, thats argued about on hi-fi forums infinitely i.e. how can digital cables sound different ?

surely the same 0's and 1' at one end, arrive at the other end as the same 0's and 1's to be decoded

Personally, if the cable is shielded properly, so there is no interference and transmission loss, I cannot see or hear, how a £1000 cable carrying digital data, can sound any different to a £10 one

its the usual case of hi-fi magazine reviewer self justification and marketing bull ....but of course, if it didnt exist, then hundreds of companies that sell all these snake oil products in the hi-fi/av industry would have gone bust when the move from analog to digital came LOL wink
Not really. My point is a coaxial cable should be well made and shielded as an electrical signal can suffer from interference. So in this instance, I agree with a good quality cable. I've spent 100's on my interconnects and speaker cable / plugs so I accept this.

I can't however see how (apart from the quality of the fibre), affect an optical cable. Fibre optics do not suffer from electrical interference (perhaps massive electromagnetic fields, but I think at this point I'd be more concerned about other things than shielding on a fibre optic cable).

Seriously though. I'm very open-minded about this topic and would like to get the inside knowledge on this.

Should I spend 10 or 40 quid on a 2m optical cable?

SJobson

13,081 posts

270 months

Thursday 21st January 2010
quotequote all
Spend as little as you can to get one which doesn't fall apart and whose end plugs don't fall out of the sockets.

telecat

8,528 posts

247 months

Thursday 21st January 2010
quotequote all
I don't think that there is any difference providing the Sheath and connections don't allow light to "leak".

headcase

2,389 posts

223 months

Thursday 21st January 2010
quotequote all
I wouldnt be spending bajillions on one. Surley a purist wouldt touch any kind of digital signal with a barge pole anyways!

The only problems you get with Toslink (Optical) is if the length is too long for the quality of the fibre then you will get the audio cutting out on you, as previously stated get one that is good enough to not fall apart on you and especially make sure it is gold plated :P

Edited by headcase on Thursday 21st January 15:57

beanbag

Original Poster:

7,346 posts

247 months

Thursday 21st January 2010
quotequote all
headcase said:
I wouldnt be spending bajillions on one. Surley a purist wouldt touch any kind of digital signal with a barge pole anyways!

The only problems you get with Toslink (Optical) is if the length is too long for the quality of the fibre then you will get the audio cutting out on you, as previously stated get one that is good enough to not fall apart on you and especially make sure it is gold plated :P

Edited by headcase on Thursday 21st January 15:57
How do you think CD players, 5.1, 7.1, BR, DVD, and so forth work then if we don't touch digital??? scratchchin

Plus I never said I was a "purist". I just like something that sounds good.

I have a beautiful set-up for my CD player and for movies I like the full 5.1 malarky. smile

Either way, I think I'll just spend the £40 on a bottom end AudioQuest Optilink G cable.



Unless I step up the mark and go for a real glass fibre, this should be as good as I can get, although the only feedback I can seem to get is that from the chap at the shop. Not many review on this on-line....

Anyone any experiences of AudioQuest?

malman

2,258 posts

265 months

Thursday 21st January 2010
quotequote all
Not sure I'd spend that much although it is a pretty colour and has a nice knitted jacket.


Alternatively - these do the same job
http://cpc.farnell.com/jsp/search/browse.jsp?N=411...


im

34,302 posts

223 months

Thursday 21st January 2010
quotequote all
There's some tosh floating about concerning this subject thats for sure.

2m optical...get this:

http://www.tvcables.co.uk/cgi-bin/tvcables/2m-opti...

25 year warranty, all the 'shielding' you'll ever need, gold plated, £11.49 +P&P.

I got one last week and it does what it says on the box.

Alternately, pay through the nose for no discernable difference in audio quality to anyone other than the AV snob residing in your head.

Its a no-brainer really.

Super Slo Mo

5,368 posts

204 months

Thursday 21st January 2010
quotequote all
I work with fibre optic stuff a fair bit at the sharp end of the Broadcast world.

Basically, a fibre will either work or it won't.

The construction, internally varies, some of the cheap stuff isn't really glass, it's plastic, so is only suitable for lower bit rates, and short lengths (bearing in mind that a long length of fibre can be many kilometres.

There are also a number of different 'sizes' of the actual strand of glass within the cable. The larger diameter, also known as multi-mode, are generally around 50 microns, while the thinner are around 9 microns diameter (aka singlemode). Perhaps contrary to what you'd expect, the thinner stuff is better for long distances. This is because with the wider diameter, a phenomena can occur that's known as dispersion, which causes the light to scatter. There comes a point where the 'scatter' is too great to be of any use, in effect, the receiving equipment can't tell the difference between the various pulses of light, it all becomes mush.

However, from a practical point of view, by far the most important thing with regards to fibre is the cleanliness of the end faces. With a 9 micron central core (that's less than a human hair), it takes only the tiniest spec of dust to block the light, and it won't work. Any scratches or other damage, all of which will be microscopic, will ruin the fibre.

The generally accepted advice when connecting fibre cables is to remove the dustcaps, clean the fibre ends with a proper cleaning tool, then make the connection. Anything less than this, and we find it can be hit and miss whether the things work.

With regards to the actual cables used in Broadcast, and this is stuff that's carrying circa 1.5 Gb/s from a camera (or a 1080i uncompressed HD SDI signal) which, although it's glass, single-mode cored, it's not expensive, around £2 to £3 for a metre patch cable.

So to sum up, the expensive cables for hifi/audiovisual stuff is mostly window dressing and snake oil.

Sorry it's a long winded post, hopefully it explains things a little though.

lonny

424 posts

249 months

Thursday 21st January 2010
quotequote all
I bought a few cheap ones on fleabay for about £4 for 1m lengths. They work fine passing 6.1 dts signal around.

headcase

2,389 posts

223 months

Friday 22nd January 2010
quotequote all
beanbag said:
headcase said:
I wouldnt be spending bajillions on one. Surley a purist wouldt touch any kind of digital signal with a barge pole anyways!

The only problems you get with Toslink (Optical) is if the length is too long for the quality of the fibre then you will get the audio cutting out on you, as previously stated get one that is good enough to not fall apart on you and especially make sure it is gold plated :P

Edited by headcase on Thursday 21st January 15:57
How do you think CD players, 5.1, 7.1, BR, DVD, and so forth work then if we don't touch digital??? scratchchin

Plus I never said I was a "purist". I just like something that sounds good.

I have a beautiful set-up for my CD player and for movies I like the full 5.1 malarky. smile

Either way, I think I'll just spend the £40 on a bottom end AudioQuest Optilink G cable.



Unless I step up the mark and go for a real glass fibre, this should be as good as I can get, although the only feedback I can seem to get is that from the chap at the shop. Not many review on this on-line....

Anyone any experiences of AudioQuest?
Sorry that reply wasnt aimed directly at yourself more of a generalisation to the thread. 5.1 yes needs a toslink but high end audio stuff dosent need it, the way these audiophiles bang on about it they even reckon that if you pull out a digital coaxial lead an then reverse it then they can haer a difference in the audio!! Im suprised they bother with digital at all.

Plotloss

67,280 posts

276 months

Friday 22nd January 2010
quotequote all
If you need a digital interconnect use coaxial rather than TOSLink, if available.

telecat

8,528 posts

247 months

Friday 22nd January 2010
quotequote all
Plotloss said:
If you need a digital interconnect use coaxial rather than TOSLink, if available.
TOSLINK does allow higher Bandwidth but the translation to and from Light pulses does add in a bit of "woolliness".

Plotloss

67,280 posts

276 months

Friday 22nd January 2010
quotequote all
telecat said:
Plotloss said:
If you need a digital interconnect use coaxial rather than TOSLink, if available.
TOSLINK does allow higher Bandwidth but the translation to and from Light pulses does add in a bit of "woolliness".
TOSLink's bandwidth is limited by licence, sadly.

Less jitter in coax, so it's the better choice in the vast majority of situations.

It's also easier to work with (terminate in field etc) but this isn't a consideration for home users, largely.

Lord Flathead

1,288 posts

185 months

Saturday 23rd January 2010
quotequote all
Super Slo Mo said:
I work with fibre optic stuff a fair bit at the sharp end of the Broadcast world.

Basically, a fibre will either work or it won't.

The construction, internally varies, some of the cheap stuff isn't really glass, it's plastic, so is only suitable for lower bit rates, and short lengths (bearing in mind that a long length of fibre can be many kilometres.

There are also a number of different 'sizes' of the actual strand of glass within the cable. The larger diameter, also known as multi-mode, are generally around 50 microns, while the thinner are around 9 microns diameter (aka singlemode). Perhaps contrary to what you'd expect, the thinner stuff is better for long distances. This is because with the wider diameter, a phenomena can occur that's known as dispersion, which causes the light to scatter. There comes a point where the 'scatter' is too great to be of any use, in effect, the receiving equipment can't tell the difference between the various pulses of light, it all becomes mush.

However, from a practical point of view, by far the most important thing with regards to fibre is the cleanliness of the end faces. With a 9 micron central core (that's less than a human hair), it takes only the tiniest spec of dust to block the light, and it won't work. Any scratches or other damage, all of which will be microscopic, will ruin the fibre.

The generally accepted advice when connecting fibre cables is to remove the dustcaps, clean the fibre ends with a proper cleaning tool, then make the connection. Anything less than this, and we find it can be hit and miss whether the things work.

With regards to the actual cables used in Broadcast, and this is stuff that's carrying circa 1.5 Gb/s from a camera (or a 1080i uncompressed HD SDI signal) which, although it's glass, single-mode cored, it's not expensive, around £2 to £3 for a metre patch cable.

So to sum up, the expensive cables for hifi/audiovisual stuff is mostly window dressing and snake oil.

Sorry it's a long winded post, hopefully it explains things a little though.
There you go. FACTS from someone in the industry. Thanks for that thumbup

tank slapper

7,949 posts

289 months

Saturday 23rd January 2010
quotequote all
beanbag said:
Not really. My point is a coaxial cable should be well made and shielded as an electrical signal can suffer from interference. So in this instance, I agree with a good quality cable.
It really doesn't matter that much for a digital signal if it is over a short distance. A digital signal either has enough strength for the receiving equipment to discriminate the bits above the noise or it doesn't. A bit of bell wire with phono plugs on each end will do the job just as well as some expensive toss from a hifi magazine.

In a home environment, if there is enough electrical noise to cause a digital audio signal to fail, you will have noticed it through the analogue parts of the system long beforehand.

If you are transmitting it long distance, then attenuation becomes an issue and it is worth using decent cable, but even then it won't cost hundreds.