Coaxial or Optical ?? (1 Viewer)

[JeremyFr]

I know you ain't talkin bout me!!! hehe

 

[Zach Foster]

It appears we're having fun talking about Circuit City and everything, but I just wanted to put my 10 cents in about Coax or Optical...


I asked the same question as Mark to a relative of mine who installs audio/ video equipment, and he said that they found optical to be buggy and not as reliable as coaxial. So Mark I'd have to say go with coax, but that's just my opinion.

 

[JohnSch]

I had optical between my old dvd player & amp for over a year - works fine, sounds good. New progressive DVD player only had coax digital connect, amp has both - plugged in a digital cable (nothing fancy - $20 or so) works fine, sounds good

I'll be able to reuse the optical when my HDTV turner comes in THREE DAYS from now. You could go with either. I would think the only advantage of optical is that it would be free from interference, so if you live under high tension power lines you might get a slightly cleaner signal via optical

 

[Steve Owen]

Regarding the need for a "75 ohm coax", what about the now famous coat hanger experiment? I'm trying to find the website, the but gist of it was someone got some fairly sophistcated measurement equipment and detected no bit or timing errors when using a piece of coat hanger instead of a cable.

I've had zero problems using any old RCA cable. YMMV.

-Steve

 

[Dave Poehlman]

a cheaper optical is about $20-$25.

$2.80 at Partsexpress!

The shipping costs more than the cable.. but you still come out ahead of Radio Shack!

 

[Ted Lee]

that poor dead horse.....

anyway, regarding the durability of optical -- i have been using the same monster optical cable i bought somewhere around 8 years ago. while i certainly don't thrash it i don't take real good care of it either.

it's worked fine from day one.

 

[Jeff Kleist]

Any Gamestop store or EB for that matter has a Pelican Optical cable for $7.99

 

[Bob McElfresh]

Regarding the need for a "75 ohm coax", what about the now famous coat hanger experiment? I'm trying to find the website, the but gist of it was someone got some fairly sophistcated measurement equipment and detected no bit or timing errors when using a piece of coat hanger instead of a cable.

I've had zero problems using any old RCA cable. YMMV.

The coat-hanger experiment worked because the equipment was all on a test-bench and a separate wire was used to be the zero-volt reference. It only needed 1 wire to transmit the signal so the coat-hanger worked fine.

But in YOUR HT system, the coaxial-digital cable is really 2 wires: the center conductor and the shield. The 'shield' connects the ground/zero-volt reference. But because the two wires are physically close together - you have to worry about "Impedence Matching" with the destination electronics (the coaxial-digital input on your receiver).

"Any Old" RCA cable will appear to work. But we have had several members mention/nearly return equipment because the Dolby Digital sound would drop-out every few minutes. This was traced to them using "any old" RCA cable. The drop-outs were solved when they switched to a video cable with the proper impedence.

Audio cables can be made with 50, 75, 110, 300 ohm coax - it's a gamble when you use "any old" cable. And it's kind of silly to gamble like this when the correct cable is cheap and easy to get.

 

[JeremyFr]

I think it depends on the equipment to, as to what type of coaxial to use. Some seeming to be more sensitive than others.

I remember my old old setup where I had a Sony reciever (cheap one at that) and my computer was my DVD player at the time, the problem was that my computer unfortunately had to be far away from the TV about 10-15 feet or so.

I ended up having to hook 3 cables together to make a run long enough to reach my reciever. Now mind you I was using a Digital soundcard that was passing DD5.1 to the reciever through a digital output, at any rate the digital out on the sound card was a 1/8" miniphone jack, so 1st cable in the chain was a $4 1/8" to RCA y cable like you'd use for a portable CD player. This was coupled using a cheap $.50 coupler to a 6' RCA-RCA speaker wire which was coupled once again with a cheap $.50 coupler to another 6' RCA-RCA speaker wire. All in all I had around 15' of wire between the computer and the reciever and it was coupled twice in between the 2 and never once had any audio dropout problems.

Sometimes I've wondered if the more you pay for equipment the less sensitive they make it so you have to buy better cabling hehe

but yeah moral of the story is I've used some not so great stuff for a digital audio cable and never had any issues though now all my stuff is fed through optical.

 

[ChrisMcL]

Coaxial is a better way to send digital than Toslink. Toslink provides a worse connection (it comes loose more easily), it has lower bandwidth than coaxial, and it just sounds worse in general.

 

[Ted Lee]

chris - those are some pretty bold statements.

>> provides a worse connection...
mine has *never* come loose

>> it has lower bandwidth...
really? i never heard that.

>>it just sounds worse in general
i think about half the people here would disagree with that statement.

btw - no offense meant. your opinion is just as valid as anyone elses ... but you may want to qualify those statements.

 

[ChrisMcL]

"TosLink is by far the worst interface, both mechanically (the physical connection between cable and jack), electrically (it has the lowest bandwidth), and sonically. TosLink connection tends to blur the separation between individual instrumental images. adds a layer of grunge over instrumental textures, softens the bass, and doesn't have the same sense of black silence between notes. Better results can be achieved with a high-end glass-fiber TosLink cable, but my advice is to forget about TosLink unless you have a [unit] that only has TosLink output and are forced to use it."
-Robert Harley from The Complete Guide to High-End Audio

Mr. Harley's experience with TosLink is congruent with my own. Anyone should be able to hear what is described above.

Toslink has a potential 6MHz bandwidth
Coax has a potential 500MHz bandwidth

Depending on implementation, one could get worse reproduction from coax, but all things being equal, coax is better.

Congratulations on getting your TosLink cable to stay attached. None-the-less, it is not as good a connection in terms of information transmission and grip as a good coaxial connection.

All opinions aside, coax is better.

 

[Ted Lee]

thx chris. i'm glad your experiences jive with robert harley's - but again it's just someone's opinion. it's not a hard fact...but that's a different thread.

do you have any additional info about this bandwidth thing? i'm amazed that there could be such a *huge* discrepancy.

 

[HienD]

It seems like the bandwidth on a toslink cable is limited by the interface used and not the cable itself. Toshlink is limited by the transmitting LED. I can not hear the difference between a optical cable adn coax.

 

[JohnAJR]

ChrisMcL's argument is based on established fact.

The optimal bandwidth for the transmission of digital signals is 330MHz.

The severe bandwidth restriction of Toslink results in a much lower rise time, changing what should be a square wave into something with a much more gradual slope.

This makes an audible difference when the signal enters the voltage comparator of the D/A. Because the slope is gradual, the voltage comparator has a difficult time assessing exactly when a "1" becomes a "0", and vice versa, resulting in what is known as "jitter."

One of the audible effects of jitter is harshness.

Regards,

 

[Ted Lee]

pretty interesting. in all my time here, i don't think i ever caught that point in the ol' optical vs. coax debate.

thx for the info guys!

 

[ChrisMcL]

I believe that you put too much faith in "hard facts." Facts have their place, but they are highly contextual. Do a fair listening test. You will hear the difference. Coax sounds better.

"Plastic filament Toslink is very high loss by comparison and only has a bandwidth of 6 Mhz.
It would be very hard indeed to find an Audiophile who would choose Plastic Toslink over high bandwidth Electrical Coax. "
-Quote from another forum

The bandwidth issue is common knowledge. How can someone have an opinion without knowing something so central to the issue? Coax sounds better.

 

[Jonathan_E]

Just a little note on the bandwidth limitations of toslink: Why is the medical science industry researching the use of fiber optic in MRI applications if the bandwidth is only 6 mhz? For a 1.5T MRI, you need to transmit a 63.86 Mhz signal, and for a 3T, you need 127.72 Mhz. Maybe a really cheap peice of fiber optic only has a bandwidth of 6 mhz, but millions of dollars wouldn't be pouring in to fiber optic research with MRI if that limitation really existed.

 

[ChrisMcL]

Jonathan:

If you had read this thread, you would have seen HeinD address the issue that you bring up. And by the way, What the F**K does an MRI have to do with high-end audio?

 

[Ted Lee]

And by the way, What the F**K does an MRI have to do with high-end audio?

uhh....maybe we can all relax just a tidbit???

i think jonathan's point is that optical has the capacity to handle high-end applications (like medical research). if t it can be useful in that field, then why can't the same technology be used in audio.

i think i'm gonna post a separate thread about this bandwidth thing. it definitely has me intrigued.