Coaxial or Optical? - Page 2

I have a DAC, and I have a source with extremely low jitter, the QLS QA350, that has both optical and coaxial out. When I hook both up, coax is definitely clearer and overall better. Optical sounds slightly muffled after coaxial. I have not done a blind test, but I am confident that I could pick out the difference easily. However, I am using a cheap Monoprice optical cable that is 10 feet long. If you want or need to go optical, a member on here, Jamato, has had great success with the new sysconcept 1300 strand optical cable: http://www.sysconcept.ca/product_info.php?products_id=365&osCsid=sqdtfk5seqprtbvpeo2dp05vn6 I am going to get this at some point because another of my source, the old Iriver H120, only offers optical out.

Jamato says this cable makes a large difference in sound. I believe him, as he tries to be objective and helpful and is right about a lot of things. Given a really good source, I would still put my money on coaxial, although I think with very good cables the difference would be close.

i use coaxial, belden/canare, for a 5m run as i'm always treading on it and it doesn't mind :) as an aside canare coaxial plugs are really nice, good firm fit but not a vulcan deathgrip like neutrik plugs seem to be!

as for a difference in sound, no, intrinsically they should sound identical.

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Originally Posted by Todd R 

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Originally Posted by Sophonax Coax uses an electrical connection and is therefore susceptible to phenomena like a ground loop hum (I think, but I'm not sure -- or is ground loop hum only a problem in the analog domain?), which can be very annoying.  Since optical cables use light to transmit the signal, they can be useful in trying to eliminate ground loop hum in audio setups.

Hum is not an issue with digital cables.

 

To the OP:

I have a DAC with multiple inputs and a source with multiple outputs. It's real easy to hook up both optical & coax cables and compare by switching inputs on the DAC.

The Coax wins every time. The optical is still good but slightly muffled and less resolving.

On the other hand, optical cables can be bought for very little money.

 

I have no idea what you're asking about the AC3. All digital cables will be a single cable if you were concerned about needing more than 1.

ever considered that the difference in sound is either a product of your DAC or your source and not the technology used to transmit the data.

Maybe I am misreading you and a few others tone in this thread but it seems a few people are stating that all optical connections are somehow more "muffled" than coax. Am I misreading you guys?
 

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Originally Posted by ShawnSmith 

Quote:

Originally Posted by Todd R 

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Originally Posted by Sophonax Coax uses an electrical connection and is therefore susceptible to phenomena like a ground loop hum (I think, but I'm not sure -- or is ground loop hum only a problem in the analog domain?), which can be very annoying.  Since optical cables use light to transmit the signal, they can be useful in trying to eliminate ground loop hum in audio setups.

Hum is not an issue with digital cables.

 

To the OP:

I have a DAC with multiple inputs and a source with multiple outputs. It's real easy to hook up both optical & coax cables and compare by switching inputs on the DAC.

The Coax wins every time. The optical is still good but slightly muffled and less resolving.

On the other hand, optical cables can be bought for very little money.

 

I have no idea what you're asking about the AC3. All digital cables will be a single cable if you were concerned about needing more than 1.

ever considered that the difference in sound is either a product of your DAC or your source and not the technology used to transmit the data.

 

Maybe I am misreading you and a few others tone in this thread but it seems a few people are stating that all optical connections are somehow more "muffled" than coax. Am I misreading you guys?
 

They really shouldn't be, but factors like the quality of the optical cable and the quality of the optical transmitter all make a difference. It is light. The way I see it, light is harder to transfer prefectly than electricity.

Fiber optics is used extensively for data transmission by ISPs and phone companies. It is the backbone that enables us to have broadband internet today. Seems to me that if there was something inherently inferior about it, they would have stuck with copper instead of investing in the cost of laying miles and miles of fiber optic cable.

But I agree that there is likely a problem with the way some DACs and transports transmit the optical signal. TOSlink is an added layer¹ over S/PDIF. On the sending side, the transport takes an electrical S/PDIF signal and converts it to optical. On the receiving end, the optical signal must be converted back into electrical S/PDIF before being read by the DAC chip. So compared with straight coaxial there are more places where something can go wrong if the design is not done properly.

¹ Maybe layer is not the most accurate term

Originally Posted by Yoga Flame 

Fiber optics is used extensively for data transmission by ISPs and phone companies. It is the backbone that enables us to have broadband internet today. Seems to me that if there was something inherently inferior about it, they would have stuck with copper instead of investing in the cost of laying miles and miles of fiber optic cable.

Except that there are MANY differences between the optical fibers used for telecommunications and toslink. Toslink uses cheapo LED's as light sources, the aperture size is much bigger...leading to much higher optical distortion(most glass toslink cables use 280 strands to partly make up for it), it's also often made of poor quality plastic when optical fibers used for telecommunications are pure silica....really you can't compare them IMHO. The bandwidth of POF is very low compared to coax or silica fiber.

Here are more infos about how S/PDIF works: http://www.gearslutz.com/board/so-much-gear-so-little-time/172143-spdif-vs-word-clock-question.html

The stellar optical distortion of POF seriously compromises the clock extraction. You can often read +800ps jitter measurements w/ S/PDIF over toslink and <100ps w/ coax.

A while back, I had some guy tell me that coax is better for higher volumes, and optical for lower. But, as others have mentioned, it's all 1's and 0's either way.

optical and coaxial are both going to sound the same unless you are comparing a literally broken cable to a functioning one.   

I prefer optical, however, for two reasons:  

1. Optical is not metal, so it comes out of my PC and goes to my DAC without carrying any sort of weird ground loop / EMF that could conceivably come through a coaxial  
2. Optical is glass and lasers, man. How cool is that? I have to use it simply because the tech fascinates me more than copper wires.

Perhaps they should sound the same, but both on my previous and current gear there was a small but clear difference, where coax had purer treble.

Strange, because in theory coax could add noise, which teaches me once again practice is what it is all about. 

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Originally Posted by dura 

Perhaps they should sound the same, but both on my previous and current gear there was a small but clear difference, where coax had purer treble.

Strange, because in theory coax could add noise, which teaches me once again practice is what it is all about. 

There are some DSP effects that claim to increase clarity (or at least listener perception of clarity), by adding a small amount of low volume trebly background noise/distortion to the signal. I wonder if some distortion/interference in coaxial accounts for the effect?  

Still, I couldn't pass a double-blind test between coax and optical on my setup. I just don't think there's an actual difference there.

I'm sometimes wondering if there's sometimes some sort of DSP effect going on with the sound difference between the Coax/Toslink receivers. Computationally wise (I work in a related field) a bit is a bit, except for placebo (which shouldn't be discounted since it affects enjoyment).

Where I do work, we prefer optical cables by far, even with short runs. It completely isolates not only grounding issues, but also any wonkiness that one less-good PSU may have on another (usually sources have less refined PSU's and noisier electronics). Whether this makes a noticeable difference in a typical audio environment, and with the equipment you have (vs more hardcore industrial settings), I don't know. 

Laser vs LED, polymer vs glass, shouldn't mean anything. Light still goes at light speed (the CCD/CMOS/FET sensors don't care about phase) and the only difference that polymer fibres will have is that they won't work for more than 100m or so. Then again, typical audio digital coax (without dedicated repeaters or amps) won't work for nearly that far, either. If there is signal degradation, you'll hear dropouts. It'll be obvious. 

Jitter is no concern as light travels at a constant speed, as does electricity (in this sort of situation). We aren't near any black holes that I know of. 

However, Coax is generally more durable than Toslink if you have items that move around at all. Glass/polymer fibres don't like repeated bending. Also, you probably have some cheapo RCA Coax cables sitting around that you can use from your old VCR or something. I promise you. In digital, a Bit is a Bit. Analogue signals... well... let's not start there :)

I only paid for an "audio quality" coax cable in my case is because I needed a custom short run RCA to BNC that wouldn't give me a rat's nest of cables (no insult to rats- the domesticated ones are so cute and smart...), and it was only 12USD :) I'd have gone with optical if I could. 

If you have the patience, read the following link. 

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

For the lazy, this is what the signal of a good coax transport should look like:

What a Toslink trace looks like:

Ie: rubbish.

However, in practical terms how much it will matter with any DAC depends on the DAC's design. I've owned some where I couldn't detect any difference and some where it was significant and some slight. I reckon try both and see if either seems to sound better or worse to you.