Difference between optical and coaxial? (1 Viewer)

[Ted Kim]

Hi everyone,
I just wanted to let everyone know that the glass fiber optical cable that Jerry Davis posted on the link above is a really high quality cable, when compared to much more expensive, name brand wires. Some rumblings on this cable have been reported on Audio Asylum have been very positive -- by ears of those I trust. While that auction is closed, there is a more current auction running. I just put an order in for two cables, myself. So if you need a quality optical cable at a very cheap [it's all relative] price, give this cable your consideration.
This cable is also sold under the Sound Professionals name at twice the price.
http://www.soundprofessionals.com/cg...i?category=220

 

[Ted Kim]

delete

 

[Brett DiMichele]

If it looks like BullSpit and it smells like BullSpit then
it must be BullSpit.
That's my take..
Now excuse me while I go make up a new glass fiber cable
with sappire lenses and diamond polished tips terminated
in only the finest 24Karat Gold (obviously for looks...)
and sheathed in genuine South American Pigmi Forskin, very
rare and hard to come by! Ohh and after the Pigmi Skin is
set in place I am going to spray them with some 3M trim
Adhesive and sprinkle liberal amounts of that new IBM
Server Healing Pixie Dust on the jacketing.. Hey it has to
work for cables too!
Have fun

 

[Ted Kim]

Bret, I don't understand your "bullspit" comments. You don't have to believe it if you don't want to but that doesn't change the fact that the quality of the glass does matter -- just try to be objective rather than invoking all the voodoo.
Hey there are alot more important things going on in the world than cables, like the potential war with Iraq.

 

[Mat_M]

What Brett said.




Digital cables 'sounding' different...rubbish. Show me some proof, not 'oh, it sounded better.'

 

[Mark Amayao]

this post seemed interesting to me ...

Since traffic at the Goodguys has been thinning out lately we havent had much to do. Weve had a lot of time to play.
Playing with the new Parasound gear and shopping for cables.

One of my colleagues called 3 of us into our main presentation room and told us to listen to something.
He then proceeded to play some Keb' Mo "I was wrong".(HDCD
The source component was a Denon DVD3800 Amp/Reveivr was the AVR5803 and speakers were Veritas 2.3 towers.

He played the firt 30 seconds of the trck 3 times&3 of usimmediatey noticed something funny theyall soundeddifferent The 3 of us came to the consesus that the first play was god but sounded cold, not bright mind you,just cold and 2 dimensional compared to the succeeding play.

He then quickly stopped and played it again the song started and the 3 of us looked at each other and I immediately chimed in and said that the sound had more body was more three dimensional and we were all laughing at each other that we had noticed the difference.

Again stop and play and this time it sounded even better ... not substantially better but better. More airy and expansive.

geez i didnt know it would be this long a post .... but to cut it short. 1 optical 2 dig.coax 3 multichannel outputs
1 ILSR-2M 79.99 2 IDL100-2M 39.99 3 IL400MKII-2M 49.99

We proceeded afterwards to play a guessing game and optcal was picked out evey single time and we sometimes got the mutichannel analog output and dig coax output mixed up.

Not to say that one would be better than the other in this little surprise blind test, I mean it was tested on about a
$8000 system (just playing two channel. dvd3800 avr5803 veritas 2.3 towers) On any other lower tier system I would suggest you not worry. (sorry about typos hd too much coffee

 

[Brett DiMichele]

Ted,

There is room in this audio world for those of us who believe
and those of us who do not.

My post was said in jest of course. My belief is that a
good quality cable will make a difference over a poor
quality cable. But does that mean a plastic Tos is low
quality compared to glass? Nope.. We are not transmitting
signals over miles of distance nor are we transmitting huge
amounts of data to require massive bandwidth either.

That's my take on it..

I believe that a cable can be scientificaly tested and if
the signal that goes in, comes out the same (and that is
the goal is it not?) then it's not going to make any difference
in sound.

IMHO

 

[Ted Kim]

Brett, I totally understand where you are coming from Myself, I have made my own cables and done a bit of experimenting on the DIY front, but I will say the magnitude of any differences in cables is always reflected by the quality of the associated equipment. I will also say that the magnitude of the differences between cables is sometimes overblown by people.
Going back to the original question of the opening thread, coax cable and connectors have to be 75 ohms to be in spec for the digital connection. If you can, using BNC connectors for the coax connection will deliver a true 75 ohm connection. From what I've read, even some of the best nominal 75 ohm RCA's (Canare) don't measure a true 75 ohms. Unfortunately, HT gear rarely supports the use of BNC's so unless you are a tweaker (or wealthy), you have to live with RCA's for the digital connection. I recently purchased a DAC with BNC's so I will be able to do my own listening with these types of connectors.

 

[Bob McElfresh]

Admin Note: I like how most posters are focusing on the science, knowledge and personal experiments. Please keep it that way.
Ground Loop/interference issue: Yes an optical cable avoids the issue of cross-talk/ground loops. But you have to consider:
- Ground loops are caused by 2 or more AMPLIFIERS in a system fighting over who owns the zero-volt reference. (Receiver and self-powered sub are the most common). Your DVD player is NOT a amplifier device so concern about ground loops is not a great criteria to pick optical over coaxial. In fact, look at your DVD player power cord. Does it even have a ground pin? If not, a coaxial cable is likely a SUPERIOR choice because the outer shield of the cable becomes the zero-volt reference from the receiver to the DVD player. This might explain why some people hear differences between optical and coaxial - better common ground with coaxial.
- Cross-Talk: If you run your coaxial-digital cable in a tight, long bundle with POWER cords (AC power or speaker wires) you could induce some signals into the shield/ground-plane of the DVD player. But the solution is obvious: keep the interconnects away from power cords.
Home Theater magazine did an article called "Bits are Bits?" where they compared optical vs coaxial. Several coaxial cables were used and the reviewers heard little difference. Then several optical cables were used and nearly everyone agreed that one of the cables sounded different! This was never explained very well.
I have used/am using both and heard no difference on my modest HT system. But I prefer/suggest people use coaxial because:
- cheaper price/better availability
- robustness of the cable
- seems to be less cable-to-cable variation with coaxial

 

[Raj Kumar]

For the original question of Optical Vs Coax:
I would think that coaxial cable has to be better than the optical cable because, the conversion for electrical to optical and back to electrical done to transmit and receive using optical cable has to have some losses..though in small amount.

Raj

 

[Mat_M]

I disagree. This is still all digital. The conversion from electrical to digital and back is such a trivial thing to do. If there is enough loss such that actual data is obscured, the product is defective.

 

[Shane Martin]

If there is enough loss such that actual data is obscured, the product is defective.

If I used that saying, all of the radio shack(and other cheapo) cables I've used before were defective

IMHO you get what you pay for.

 

[Raj Kumar]

I do not believe that there can be no losses however trivial the conversion is. There is no such thing as 0% error in engineering problems IMO.

 

[Mat_M]

Oh I agree that there's no such thing as perfect, but the loss in the conversion in this case can be considered negligible because it is so small.

 

[Mat_M]

Shane we're not talking about cables, Raj and I are talking about the electrical/optical conversion circuit.

 

[Jonathan M]

Just to clear up a few things (hopefully!)

Firstly a DVD player can cause a ground loop, but ONLY if it has a 3 pronged plug where the mains ground is at some point connected to the signal ground. Any audio equipment that has this setup has the potential to cause a ground loop.

Secondly, the idea that coax could be better due to the grounding of the outer shield is not an issue, as optical needs no ground - it is the absense of light and light that gives the 0 and 1's. Coax ofcourse is a voltage difference between the inner and outer conductors.

Also, the impedance rating of coax connectors is nothing to do with how they "measure" but is rather due to how they are constructed. At the frequencies that we are dealing with (In the early MHz - eg a 44.1kHz 16bit stereo signal = 44100*16*2=1.4Mhz signal without error correction), the cable is acting like a transmission line, so it's impedance at these frequencies is determined by it's topology. This applies equally well to connectors. As was said, however, very few RCA connectors are constructed the correct way - how much of an issue this is is debateable, as with most things audio.

I personally prefer coax over optical as:

1. It's cheaper and I can easily build them myself.
2. I can use the excess wire for other interconnects, including video
3. The connectors are more robust
4. I have no problem with bending the cable.

Can I hear a difference - no, I tried. YMMV

 

[larry crimmins]

I bought the glass optical cable from the earlier post on this topic and also found it to give excellent performance. It does seem to be the same product as sold on the Sound Professionals website and very favorably reviewed on AudioAsylum and sold for a lower price.
I used it between my Cambridge Audio DVD300 and Arcam receiver on the optical output and used a coax digital, Synergistics Research Digital Corridor No.2, on the coax output and compared them on DVD movies. Granted, I knew which cable was which but I preferred the optical to the coax for a few reasons. The sound was more extended and crisp in the treble range and revealed greater detail. The coax cost roughly 6 or 7 times what the optical cost. Maybe the coax cable was a lousy deal but I believe that the optical cable was a superior hookup.
When I finally purchase a STB for my HT, I plan to use the Wireworld optical cable I mentioned in my earlier post, for my sound connection, as the new Sony/Zenith STB only permits optical connections for sound out.
The subject of cables seems to make everything personal on any forum I've ever visited. I think we are all after the "best" quality for the smallest investment and I recommend this particular product from my personal experience. Your mileage may vary.