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Are there differing qualities of optical cable?

I currently have my Gungnir Multibit DAC connected by optical cable to my Oppo player which I use as a transport. I also have a Cardas coax cable connected to a different input.  The optical sounds better. My question is, are there different qualities of optical cable you can use, or is one the same as the other?
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willemj
1,036 posts
 
http://archimago.blogspot.nl/2013/05/measurements-toslink-optical-audio.html
rvpiano's avatar
rvpiano OP
2,653 posts
 
After reading the above blog, I can only assume my observations are delusional.
After all, how can the ear of a musician match the accuracy of scientific instruments?
I’ll return the cables immediately!
auxinput
2,920 posts
 

Yep, willemj has been a strong proponent of publishing measurements that are supposed to indicate the be-all-end-all of audio quality. After 17+ years of listening in this hobby, I do not agree with him at all.

The following link was found by another poster when he was trying to find some documentation after I told him that toslink was not as good of a interface as digital coax.

http://www.lampizator.eu/LAMPIZATOR/TRANSPORT/CD_transport_DIY.html

When you read through and get to the measurements of the toslink interface, I thought it was really interesting how bad the toslink waveform was. You would assume that light transmission would be better than electrical transmission, but in truth the LED light emitting diode just cannot "light up" fast enough to keep the true square waveform.

It also shows that not all SPDIF outputs are created equal. lol.

willemj
1,036 posts
 

First, about methodology. Yes, a modern audioanalyzer like a DScope or Audio Precision is indeeed more discerning than even the best human hearing. They can measure subtleties that no human can hear because they are beyond the threshold of human hearing acuity. Think of the parallel with microscopes or telescopes.
As for interfaces and cables, this discussion was about the cables, not the respective merits of the interfaces. If you compare digital interfaces, usb is best for jitter, distortion and noise, followed by coaxial and just after that optical. Do these differences matter? I doubt it, as they are at such elevated levels that no human is likely to hear them (under controlled conditions, of course).
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shadorne
7,467 posts
 
@willemj

The interface is indeed the issue and it depends on the methodology of implementation.

I would argue that USB digital has been a disaster for many years.

Even today day I think the approach can be worse than Coax or Toslink because of logic induced modulation noise induced back into the power supply of the USB DAC.

Does it matter - absolutely! Non random Jitter is quite audible even at picosecond levels. Check out Cranesong website for some jitter demonstrations.
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