Optical cable

[Dwaindibly]

Are toslink cables all the same? as from what I've read so far most can only handle 24/92 is this correct ? my wiim is capable of 24/192 I have the output set to that and it sounds fine is the signal being downgraded? Or are optical cables quite capable of 24/192 most cables I've looked at don't specify bitrate etc
Thanks

 

[staticV3]

If you've set your WiiM to 192kHz fixed sample rate and it's playing audio fine, then the WiiM, Optical cable, and Optical receiver all support native 192kHz.

There are indeed differences in quality between Optical cables, which become more important with increasing cable length.

If you get smooth audio playback without stutter, then there's no reason to upgrade the Optical cable.

 

[solderdude]

It's the receiver in the DAC that is the limiting factor, not so much the cable. A longer POF (Plastic Optical Fiber) cable can give problems with some DACs.
There are some TOSLINK cables that consists of multiple glass fibers with which one can make longer lengths.
Some TOSLINK receivers can do up to 96/24 and do not play or have drop-outs on 192 but others do 192/24 just fine.

 

[DonDish]

Mutec has long cables that work. Not expensive either. If cable is broken signal can bounce, throw it away

 

[MaxwellsEq]

The standard officially does not support 192kHz. However, many receivers, coupled with good enough fiber connectors and transmitters can handle 192kHz. I've never had any problems.

 

[Zek]

Are toslink cables all the same?

Not really, some are made of plastic and better ones are made of multiple glass fibers.

 

[Dwaindibly]

Would using coax be a better connection choice ?

 

[DonDish]

Not really, some are made of plastic and better ones are made of multiple glass fibers.

You dont need glass for tos. Throw out money. Made to work with plastic well over 10m with good equipment. 6m Glass is just 10x more expensive.

Its important not to break or bend the the fiber. If bad it can send light back into the fiber, weakening and distorting the signal.

 

[Killingbeans]

my wiim is capable of 24/192 I have the output set to that and it sounds fine is the signal being downgraded?

If the fiber couldn't handle it, you'd get dropouts or in worst case the receiver would refuse to lock on the signal. Nothing subtle, and you wouldn't need to ask if it was happening

 

[staticV3]

Would using coax be a better connection choice ?

I'd choose Toslink over Coax, due to the electrical isolation.

 

[BJL]

You dont need glass for tos. Throw out money. Made to work with plastic well over 10m with good equipment. 6m Glass is just 10x more expensive.

Its important not to break or bend the the fiber. If bad it can send light back into the fiber, weakening and distorting the signal.

+1 on this reply. Plastic toslink is just as good as glass. I used a 40 foot plastic toslink cable from Monoprice (maybe $12) for years and it worked perfectly. For home use, fancy and expensive toslink cables are purely marketing and for the cosmetics. What is great about toslink is the electrical isolation (they are immune to interference), they are cheap, and they are durable. Don't waste money on expensive toslink.

 

[kemmler3D]

I would agree with the rest of the thread, if your cable isn't doing the job you will know it, (no signal, or random dropouts) so don't upgrade until the problem actually appears.

 

[Rja4000]

Same comment than above.

I'd add the following: "HiFi"-looking Toslink cables often have weaker connectors than simple Home studio ones.
A firm, positive, connection is important.

I use simple, thin -but quite rigid- TosLink plastic cables of variable length for years and hardly had any issue. (Mutec or similar - Major music shops sale them for a few € in Europe).
While I had several issues with thicker, more flexible cables.

Keep them as short as possible.

 

[MaxwellsEq]

Would using coax be a better connection choice ?

Several decades ago, subjective reviewers claimed coax based S/PDIF sounded slightly better than Toslink. I wonder if some transmitter / receiver combinations had sufficiently high enough jitter for it to be audible. Anyway, modern equipment will be indistinguishable between the two, except for the coax solution potentially leading to ground currents.

 

[DonDish]

Would using coax be a better connection choice ?

Ive been putting my head to some digital breakout box these days. Scraping the surface of coaxial 75ohm tech, I cant escape the felling its kind of obsolete in home audio. AES and Tos is just better. Somebody arrest me on this subject. I wanted to figure out a way to maintain impedance through the box, but cost just skyrocketed so scrapped it. No real return for my short cable stretches. So whats the use? Of cource my DVD only has coax so I need it. AES and Tos just does the same in an optimal system. You can buy a reasonably priced optical swithchbox, and AES is much better to wire and solder IMHO. I can do 192khz here, but I cant tell for your system. Dont worry. 192khz is mostly a space-hugger(huge files), and youll be hard to find any real material to play. Any digital sound system with self respect should be able to do 24/96 regardless of sender, reciever and interconnects.

 

[DonDish]

Same comment than above.

I'd add the following: "HiFi"-looking Toslink cables often have weaker connectors than simple Home studio ones.
A firm, positive, connection is important.

I use simple, thin -but quite rigid- TosLink plastic cables of variable length for years and hardly had any issue. (Mutec or similar - Major music shops sale them for a few € in Europe).
While I had several issues with thicker, more flexible cables.

Keep them as short as possible.

I like the Mutec too, extremely priceworthy! I think you could make these cables yourself. Get a roll of those fibers. Ive seen the same contacts wholesale, very cheap. Figure out how to polish the ends. Wire just go through contact.

Im a bit unsure about supply of mutec tos. Only longer runs left it seems.

 

[DonDish]

You dont need glass for tos. Throw out money. Made to work with plastic well over 10m with good equipment. 6m Glass is just 10x more expensive.

Its important not to break or bend the the fiber. If bad it can send light back into the fiber, weakening and distorting the signal.

I want elaborate on the broken tos theory. When a transparent object like an optical fibre is shattered, the cleaveage planes will acts as semitransparent mirrors. Sending a large portion of the light back into the fiber. Maybe even 50%? Ie signal loss On top of that, signal bounces around and reflects in an unwanted fashion(fiber is actually made to reflect the signal forward through the wire, not necesarily move in a straight path) this will cause echoes and time smearing of signal. Ie. jitter like effects. This sure is true for a large system like broadband connections. The broken cable would be replaced. Maybe the DAC can grab the signals or the PLL could get confused in a small home audio system. With a long run, lesser equipment and HI-res speed who knows.

I read up on this and compiled it here, bcs I switched a really, really crappy tos to just a normal quality and it was revelatory. This was a 5 meter cheapo fed to an old surround reciever. Straight to garbage can.

 

[solderdude]

Typical end reflection of a straight (glass fibre) surface to air is around 0.3dB (4-7%) as there are 2 you end up with a 0.6-1dB loss (or thereabouts).
It is even less when broken at an angle.
When the broken fibers are spaced apart the losses will be higher of course and also depends on the Numerical Aperture.

POF = 1dB attenuation per meter (for visible red) for your typical 1mm POF and is by far the biggest contributor in attenuation.

 

[MaxwellsEq]

I want elaborate on the broken tos theory. When a transparent object like an optical fibre is shattered, the cleaveage planes will acts as semitransparent mirrors. Sending a large portion of the light back into the fiber. Maybe even 50%? Ie signal loss On top of that, signal bounces around and reflects in an unwanted fashion(fiber is actually made to reflect the signal forward through the wire, not necesarily move in a straight path) this will cause echoes and time smearing of signal. Ie. jitter like effects. This sure is true for a large system like broadband connections. The broken cable would be replaced. Maybe the DAC can grab the signals or the PLL could get confused in a small home audio system. With a long run, lesser equipment and HI-res speed who knows

I've installed, QC-ed or project managed the installation of 1000s of miles of fiber. You are right in some regards. Fiber has a bend radius (which is different for each type). Assuming you never bend it more than this radius, the fiber will stay in spec. At the termination of fibre runs, there are often loop managing systems to control bends.

If a fiber is bent too much, the effects are slightly different for mono mode vs multimode, but in general more light is reflected back, the far end gets less light and increased reflections result in reduction in edges of pulses. The loss of light means the receiver has a harder job on reception and the edge effect results in increased likelihood of 1s being read as 0s and vice versa. But this can all be spotted because Bit Error Rates go up. Higher level protocols recover flawlessly with relatively low BERs, but beyond a certain point you get junk at a higher level. In terms of audio, it will either work flawlessly or you get dropouts / splats. You might also get nothing. All this can be tested with BitPerfect tests.

 

[solderdude]

I have made fibre optic sensors that rely on the bending of (MM) optical fibers...