[Traddad]

I just purchased a Beresford DAC to address some computer/amp ground differential problems and I want a better Toslink cable than the plastic one usually comes with retail units.

Is there a good "bang for the buck" glass toslink cable out there? I'm looking for about 1' 6" to 3' in length.

I'm not a huge cable fanatic and firmly believe there is a point of diminishing returns that is reached fairly quickly when it comes to spending money on cables.

 

[xenithon]

I recall reading suggestions for Monoprice toslink cables.

 

[Herandu]

Didn't you see the Beresford own version on his site? I think it is called TC-3618. 200 odd glass fibre strands the specs say.

 

[Traddad]

I bought a used 6/4 unit from another lister here so I don't know what cable will be coming with it (if any). It would be nice if they were stocked here in the US.
Would one ilke this be OK?

Amazon.com: 6 Ft. Toslink Glass Digital Audio - Highest Quality Cable: Electronics

 

[kydsid]

Serious question as I have the same thought on cables as the OP.

Toslink is digital. My understanding with digital cables of any type is that their is a spec for the cable. As long as the cable meets the spec, two cables that meet spec should transmit exactly the same 1's and 0's, right?

How does glass versus plastic change a 1 or 0?

 

[Traddad]

My ameture interpretation is that a good glass fiber cable will have less signal degradation per unit length than a plastic.

 

[Greymoor]

This is true but it would take a long run to show any measurable loss of signal. Over most IC distances there would be no loss as long as both optical cables were of decent quality (not junk

)

 

[Traddad]

I guess the genesis of my question is my experience in that:
Manufacturers will usually cut costs on the "includeds" knowing that the buyer is more interested in the main product.
Most cars come from the lot with REALLY crappy shocks that have to be replaced after about 20K. There are much better shocks out there but this is a place to cut costs. Same with cables, etc. I figure the unit might just come with a really low cost cable and I would really just like to have one that I know is spec-ed well, has nicely polished ends, etc.
Of course just getting some dust in the socket would screw everything up....

 

[apatN]

So true Traddad. I have exactly the same though with digital cables there should be no difference. But who the heck cares, I want one that is well made as well.

 

[csroc]

I'll second the Monoprice suggestion. Cheap cables and you have a selection of various quality cables depending on how durable you want it to be or how fancy looking you want it to be. I have a couple of their optical cables which have a braided looking material on them (these guys). They're nicely made and don't look half bad either.

 

[dBs]

I just got out of a Fiber Optics engineering class last semester so lets see how much I remember XD

When it comes to fiber optics of a short length (like this), dispersion doesnt matter any longer. Dispersion is when the light wavelengths traveling down the fiber take different paths (think how a smaller sine wave travels less distance than a larger sine wave) and so travel different distances and the signal on the output is literally stretched lengthwise from the original signal. This is a major problem for analog signals. Digital signals do have some problem from it but it only becomes a factor when it comes to how fast the signal can be sent down the fiber before overlap of 0 and 1 occurs. Because the signal being sent in audio is very low compared to that of most fibers bandwidth limitation, this shouldnt be a factor.

Attenuation is the next major factor. Just like sound, attenuation is the diminished amplitude of the signal being sent. This only becomes a problem at long distances (longer than what you would be using fiber for in audio). If the distance becomes to great then a repeater station must be set into place so that the signal can be reamplified and retransmitted. This is more of a problem for analog than digital.

Im not going to thoroughly into these because theres distinction for these when it comes to multimoded and singlemoded fibers (meaning only one mode of light can propagate, or many). I will say though that multimoded fibers arent as good as single moded fibers because the bandwidth is smaller, though the cost is greater. Singlemode>GRIN Multimode>Multimode (GRIN is Graded Index where the refractive values of the fiber core are graded so as to lessen dispersion).

There is the factor of back scattering, but that shouldnt be a major factor for something like this.

If its a digital signal being sent a distance less than what would be used for a WAN network, then a plastic/plastic multimode fiber should be more than adequate. Just like digital TV vs analog TV, you have the wall effect of the signal for digital. Either the signal will be "loud and clear", or it will be completely nonsensical.

...though this is Head-Fi, so if you really REALLY want the best of the best, you would go for a dispersion shifted, vapor formed glass/glass single mode fiber with a LASER diode source at 1550nm with a Faraday isolater in the line.

Hope this cleared things up =X I can clarify anything if there is confusion.

 

[Traddad]

Infidel. Unbeliever.

What would these guys think if you weren't co-operating with seperating me from my money?

Audioquest cables review, JUN03 AUDIOPHILE AUDITION

Of course their point about construction and durability is valid. People can make some cheap S__T out of passable materials.

 

[Andrew_WOT]

Monoprice sells excellent "premium" toslinks
For only $2.79 each when QTY 50+ purchased - PREMIUM 3FT Optical Toslink Cable w/ Metal Fancy Connector | Toslink to Toslink
But AFAIK they are fiber, not glass.
Here's the glass ones
Parts Express:SonicWave Glass TosLink Cable 0.5m
Parts Expressayton GOC-1.5 Glass Optical Digital Cable 1.5 ft.

 

[dBs]

Quote:

Originally Posted by Traddad /img/forum/go_quote.gif Infidel. Unbeliever. What would these guys think if you weren't co-operating with seperating me from my money? Audioquest cables review, JUN03 AUDIOPHILE AUDITION Of course their point about construction and durability is valid. People can make some cheap S__T out of passable materials.

Well there is something to be said about construction quality, especially when it comes to fiber optic cable. Fiber cable is actually quite fragile. You can have problems with microbending (imperfections in the fiber itself that can cause reflection in multimode fibers), macrobending (bending the cable too much increases the losses in the fiber), crushing (same effect as microbending), and cracking in the fiber itself. Not much study has been done into the nature of cracking itself, but for distances like these, you should be fine. Its more of a concern for communications fibers. Leakage can also be a problem with foreign materials getting into the fiber (like gasses, and such). These can change the refractive indexes of the core and cladding (outer sheathing of the fiber) and causing losses of the signal. These can be factors as to the quality of the fiber, they may have one up over competitors in these respects.

Sometimes these factors can actually be a benefit to the fiber if its being used for strain gauging, measuring oxidation levels or rusting of a metal, temperature, smoke detection, etc.

 

[dBs]

Quote:

Originally Posted by Andrew_WOT /img/forum/go_quote.gif Monoprice sells excellent "premium" toslinks For only $2.79 each when QTY 50+ purchased - PREMIUM 3FT Optical Toslink Cable w/ Metal Fancy Connector | Toslink to Toslink But AFAIK they are fiber, not glass. Here's the glass ones Parts Express:SonicWave Glass TosLink Cable 0.5m Parts Expressayton GOC-1.5 Glass Optical Digital Cable 1.5 ft.

I might actually caution against the glass fibers myself if you are using an LED source. The thing about glass fibers is that they are smaller diameter, and have a smaller numerical aperture (NA, the cone angle that will allow the light to propagate down the fiber, anything larger will be lost). LED sources have a very broad cone of light so much of the transmitted power will be lost. Laser sources are used with glass fibers because the light is much more focused, it allows them to better match the glass fibers properties (as well as other major benefits).

You could probably get away with using an LED source with a glass fiber because the distances are so short, but otherwise I would be concerned about sending enough optical power down the line.