The best digital audio out of coaxial, or optical?

We would like to have an answer for our customers regaurding this.
Toslink is the least recommended connection electrically & sonically. It will "mud" (blur) image and separation. Blacks (background) will become gray and it will soften the bass. Do not recommended it......try to avoid it.
01011001011101001101 (digital interface) is always the same, and it should make no difference in the perfect World - but it is the jitter (Timing, wrong time - wrong note) that screws up the sound (usually during conversion process - digital to analog).
It's got to be optical, as long as the ends (glass) are clean -- nothing affects it's transmission except for a macro bend.
search the net.

You will get answers like that above who claim toslink sucks to it is the best thing since sliced bread. Sorry, you will never get an answer here. Try it and see what you prefer.
TosLink is a low cost optical interface promoted by mass market audio manufacturers as an alternative to coaxial connection. TosLink is trademarked by Toshiba corp. and it is more properly name "EIAJ" (Electronics Industries Association of Japan). Best thing since sliced bread ?????
WOW !!!!! Enough said.
I have seen several manufacturers list Toslink as the least desirable of the outputs or inputs they offer on their equipment. They must feel compelled to offer it for compatibility with other equipment. I have never seen any company recommend it as the first choice.
Tubes or SS? Digital or Analog? Silver or Copper? Optical or Coaxial? Toslink or AT&T optical?

As with all things in audio, there is no one right answer for all people, just a myriad of different opinions. You could listen to both, form your own opinion, then give your "professional" advice to your customers......just a thought.

Avoid plastic Toslink, glass based Toslink is far preferrable. Coax is good as is AES/EBU, but only if both are properly impedance matched.
Anti-Toslink people are damn funny. Cheap Toslink cables have issues sonically just like some metal-based digital cables. As an example, VDH Optocoupler is far superior to many standard digital cables and I would bet that most people would have trouble hearing the distiction. Soft bass? Yeah okay, whatever. Just like any other comparisons, listen for yourself and don't be swayed by any of us.
Most people......yes! MOST PEOPLE DOES'T APLLY HERE....OR DOES IT?
Too broad? Okay, Mrjstark, I'd wager a significant number of our Audiogon membership has never done a comparison with a high quality Toslink cable. I believe they read blanket negative comments like yours without supporting evidence (or in your case, announced experience) and turn to a lesser sonic quality metal-based cable. Like I said, make your own comparison. Just for the record, the best sounding digital cable I've heard is metal-based, but make no mistake there are some very good Toslink cables.
If both work properly (the bits arrive) and the DAC device has a re-clocking PLL then perhaps it is just a coin toss between the two....both are equally good (as good as the PLL re-clocker algorithm).
Click on this link for a Forum thread that includes a listening comparison for different cables, digital media, etc.:
"significant number of our Audiogon membership has never done a comparison with a high quality Toslink cable."

I wouldn't be so sure........"Q".

Chris,Welcome to the Gon. Cyrus
Coax is generally superior to the plastic Toslink cables. Those that use a Quartz or Glass conductor can be very good, however they tend to be much more expensive.

One nice thing about optical is that it does not link the grounds of the two components like a metal cable does, which can help resolve ground loops and even minor sonic issues.

AES/EBU properly implemented tends to be better than either.
Toslink, no matter the quality, is no comparison to SPDIF.
The reason is that to create the optical signal it must go through an additional optical EMITTER and an optical RECEIVER in addition to the rest of the circuitry. All things being equal those optical devices mess up the signal.
I use glass optical and coax interchangably and have not noticed any more changes than one would experience by trying two different cables of the same type but made by two different mfg's. These days they are all very good once you get past entry level cheapo stuff. By the length you need and avoid sharp bends and you will be good to go.
Recently I bought a Logitech transporter. I have a oppo 980 connected to it as a transport. I tried a Siltech silver cable (coax) and a Van den Hul optocoupler (toslink)as interconnects. I couln't hear any differences whatsoever between to two of them. The rest of my system consists of Mark levinson 336 and B&W n802, so resolution should be good enough.