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Optical Leads...worth spending more than a tenner?

I use a cheap 5 m optical toslink between my PC and DAC. Works fine with the Audioengine DAC, but with the FiiO it doesn't work properly at 96 kHz and higher. That said, I haven't made any effort to establish whether the problem is really caused by the lead but I tend to suspect it. Since it works fine at 44.1 kHz I can't be arsed!
 
If you lost a 0 or 1, would you really get a failure? Have you tried that out?
Isn't PCM data robust enough to handle a few flipped 0s or 1s.

When you get down to the physical layer, there really isn't any 0 or 1. Just a voltage, which is interpreted either as 0 or 1 depending on whether it's greater than or less than a certain threshold.

What about timing of the data, what about jitter?

Do we really understand the PCM protocol? I think it's gross oversimplification to say 0 or 1s.

Wouldn;t all cd players sound the same too? They're just reading data from disk and converting it to analog signals?

all amp should sound the same too. They're just amplifying the anaolog signals.

I'm outta here.
 
M@ver1ck said:
If you lost a 0 or 1, would you really get a failure? Have you tried that out?
Isn't PCM data robust enough to handle a few flipped 0s or 1s.

When you get down to the physical layer, there really isn't any 0 or 1. Just a voltage, which is interpreted either as 0 or 1 depending on whether it's greater than or less than a certain threshold.

What about timing of the data, what about jitter?

Do we really understand the PCM protocol? I think it's gross oversimplification to say 0 or 1s.

Wouldn;t all cd players sound the same too? They're just reading data from disk and converting it to analog signals?

all amp should sound the same too. They're just amplifying the anaolog signals.

I'm outta here.
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If your DAC doesn't have a reasonable buffer & re-timing clock, it's a piss poor DAC.

And there is more than a kernel of truth in your last 2 sentences.

Chris
 
I'm sure I've read some optical socket implementations can't handle much past 24/96 very well, if at all. But can on coax. But this is more of an issue with the socket on said devices than a cable thing.

Other pluses with optical:
Ground isolation (as mentioned).
super thin cable, good for routing in conduit etc.

Negative points:
Long run need repeaters and other faff.
Not as easy to fit/replace plugs, if one breaks, or your doing a permanent install through walls etc.
 
The thing about comparing optical with coaxial is that it's impossible to compare just the cables. The inputs and outputs that feed them are different, obviously, so you could have a DAC that has a better coaxial input than its optical one for instance.

When my son got his DAC he played around with optical and coaxial connections between it and his computer and concluded the coaxial sounds better. I agree with him. The optical sound a bit thinner and harder. But even if this is correct you can't take it as a generalisation about the two types of cable as things may vary from box to box.

I've had some very cheap optical cables in the AV system for years, a few pounds off eBay, and they still work fine.
 
This optical over short tuns is a myth. I use 15m without a repeater. 24/192 from my DAW/desk to DAC No probs.

Listening to Coaxial vs Optical they sound and measure identical as they ought to be. If there is any difference then there is something seriously wrong with the DAC implementation as they are both SPDIF. The optical receiver simply translates bit-for-bit the data for delivery to the same chipset. This is not an analogue process and has standard CRC error checking point to point. The bitstream ought to be the same, the hardware that handles the two is the same chip. Likewise if you hear a difference between glass and plastic TOSLINK then again, look to human fallibility and desire to differentiate where there is none rather than the actual digital bits. Glass has some small cachet in long runs and very very high bandwidth applications (Muxing voice and kilostream data over kilometer lengths, usually to reduce error retries) but in teeny tiny little 15M runs or less? No.

If anything a skinny optical wire is easier to replace in wall than a coaxial as its so thin it can be threaded really easily.
 
Well, there's 1s & 0s but also there's magic - I've seen it when in an induced "dream state", so there.
As for jitter, all the research I've seen tells us that even with far higher levels than us punters ever experience, its influence is undectable. Most DACs buffer incoming data before it gets converted. This doesn't mean that there aren't some engineering challenges but it does mean that properly designed digital cables will make nothing but an imagined difference. If you don't believe that, you might as well give a local witch doctor a big bag electronic components & some psychotropic drugs & get him (or her) to concoct some shamenistic HiFi.
I guess some folk just go into denial regarding their precious hearing playing tricks on them!
 
busb said:
Well, there's 1s & 0s but also there's magic - I've seen it when in an induced "dream state", so there.
I guess some folk just go into denial regarding their precious hearing playing tricks on them!
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I think you`re neglecting the existence of audiophile 1s & 0s which obviously require higher quality cables, optical or copper, that can resolve the +/- half bits that make all the difference (to the dealers bottom line).
 
busb said:
Well, there's 1s & 0s but also there's magic - I've seen it when in an induced "dream state", so there.
As for jitter, all the research I've seen tells us that even with far higher levels than us punters ever experience, its influence is undectable. Most DACs buffer incoming data before it gets converted. This doesn't mean that there aren't some engineering challenges but it does mean that properly designed digital cables will make nothing but an imagined difference. If you don't believe that, you might as well give a local witch doctor a big bag electronic components & some psychotropic drugs & get him (or her) to concoct some shamenistic HiFi.I guess some folk just go into denial regarding their precious hearing playing tricks on them!
Click to expand...

You are actually describing a quite large proportuion of the bijou adiophile manufacturer's there, busb. A few of them have been known to post here occasionally. Others have been banned.

Chris
 
"Wouldn;t all cd players sound the same too? They're just reading data from disk and converting it to analog signals?

all amp should sound the same too. They're just amplifying the anaolog signals." - M@ver1ck

All amps and CD players sound the same? Kinda? Surely not. When i modified my Arcam CD93 (well not me, Audiocom did the hard work) the difference was immediate and very apparent. Going from a Rotel to Leema amp i could certainly tell differences, although not as big as with the cd player.

There is a lot of magic and voodoo going on under the hood of electronics that i am sure of. Its not just amplifying analogue signals or reading digital data from disks.

As for the cable issue, the roksan coax is working just fine and dandy. I still might buy a new one as i dont like how tight it is, there is no room to manoeuvre, but if i do a reasonably priced one from Blue Jeans will suffice i am quite sure.
 
I remember losing all faith in Naim when Roy George wrote in a news letter that leaving the DIN plug collars unlocked made an important difference to the music. I know when I'm being had!
 
busb said:
I guess some folk just go into denial regarding their precious hearing playing tricks on them!
Click to expand...

My son had no axe to grind. I gave him an optical and a coaxial lead to use with his DAC. The computer had both outputs, the DAC both inputs and it made no odds to him which he used. After a few days he decided the coaxial sounded better. It was easy to swap over and I agreed, the difference was clear enough. He does get very slight hiss with the coaxial but you can only hear it when it's turned up very loud so not an issue.

There was a thread not long ago where Serge argued that all turntables should sound the same as long as they are turning at the correct speed. A couple of people very patiently explained the physics behind the platter and why turntables should not all sound the same. I think it will be the same with certain aspects of digital. A lot of people don't yet understand why there should be differences in sound.
 
don't forget that what we are talking about is inside the DAC, its in the bitstream, in the domain where a digital stream is either right or wrong and if it is wrong IT IS NOT PASSED THROUGH; not made thin sounding or altered somehow. This is not something we can listen to, its data; as a DAC passes its output into the analogue domain then all bets are off: WRT Opamp stability, overshoot and so on, though you'd have to be a prize dickhead of a designer or more likely an audiophile with a totally stupid cable choice to force an opamp into overshoot.

Even if we were to somehow listen to the bitstream before analogue conversion, the likelyhood of perceived differences are vanishingly small in the digital domain. Jitter and quantisation error are now so vanishingly small as to be a total non-issue in the digital domain (for music at least) while in the analogue domain, the S/N ratio of your amps and speakers far far far outweighs any noise from the DAC's noise floor.
 
Mr Pig said:
My son had no axe to grind. I gave him an optical and a coaxial lead to use with his DAC. The computer had both outputs, the DAC both inputs and it made no odds to him which he used. After a few days he decided the coaxial sounded better. It was easy to swap over and I agreed, the difference was clear enough. He does get very slight hiss with the coaxial but you can only hear it when it's turned up very loud so not an issue.

There was a thread not long ago where Serge argued that all turntables should sound the same as long as they are turning at the correct speed. A couple of people very patiently explained the physics behind the platter and why turntables should not all sound the same. I think it will be the same with certain aspects of digital. A lot of people don't yet understand why there should be differences in sound.
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The devices being connected use different input / output circuitry for optical and coax connection. This is where any audible differences are going to be.
 
fox said:
don't forget that what we are talking about is in the bit domain, this is not something we can listen to, its data; as a DAC passes its output into the analogue domain then all bets are off WRT Opamp stability, overshoot and so on, though you'd have to be a prize dickhead of a designer or more likely an audiophile with a totally stupid cable choice to force an OpAmp into overshoot.

The likelyhood of perceived differences are vanishingly small in the digital domain. Jitter and Quantization error are now so vanishingly small as to be a total non-issue in the digital domain while in the analogue domain, the S/N ratio of your amps and speakers far far far outweighs any noise from the DAC's noise floor.
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All rational and reasonable Fox.
However I'm about to swap back to my £12 Van Damme as it sounds more to my taste-this is a little game I play now and again and I always wind up back with the vd lead.
 
Ok let's put this "it's only 1s & 0s" "it either works or it doesn't" clap trap to bed.

Electronics is NOT digital. Electronics is intrinsically analogue. Digital is just a two state voltage situation within whatever part of the electronics you choose to talk about. The actual voltages just switch between the two states at a rate dictated by the function of the component. The resulting signal is at best a square wave. It's the square wave that the electronics has to deal with. So within that fact is the mechanism by which Digital can create noise and distortion and get things wrong. In fact at an engineering implementation level digital electronics is so complex that at times I'm amazed that it works at all. Analogue electronics is childs play by comparison, (in terms of engineering).

This is not a bash at digital. Just putting the record straight about the common misconception that digital is simple. It's far removed from the general belief that "it's just on and off innit?"
 
Mr Pig said:
My son had no axe to grind. I gave him an optical and a coaxial lead to use with his DAC. The computer had both outputs, the DAC both inputs and it made no odds to him which he used. After a few days he decided the coaxial sounded better. It was easy to swap over and I agreed, the difference was clear enough. He does get very slight hiss with the coaxial but you can only hear it when it's turned up very loud so not an issue.

There was a thread not long ago where Serge argued that all turntables should sound the same as long as they are turning at the correct speed. A couple of people very patiently explained the physics behind the platter and why turntables should not all sound the same. I think it will be the same with certain aspects of digital. A lot of people don't yet understand why there should be differences in sound.
Click to expand...

A very good friend of mine shares my passion for music & has had various better than average systems. He moved his spiked rack into a new house that had nice wooden flooring that he obviously didn't want to ruin. He went out & bought some supports that cost him £100 a good 15yrs ago. This guy always maintained he had heightened hearing us mere mortals aren't blessed with & that playing the same piece of music always sounds the same but cables always sound different. I remember many discussions regarding stuff like how easily our hearing plays tricks on all of us, that sighted testing caused issues. He wouldn't have any of it - none whatsoever fullstop! As for the spikes, I'd have experimented with things like coins etc.

So I tried a bit of subterfuge during his next visit by pretending to be converted to cable differences. I showed him a new cable & sat him down to listen with it in place. I led him on by saying things like "Christ - that's much better!" & "Nothing like as good" when returning to the original. He started agreeing with me & was quite upset when I told him that I only pretended to swap the cables. It took a week to get him to listen to my point regarding expectation bias (it wasn't called that back then).

As for record decks sounding different - they're mechanical devices that have various resonant modes - mechanics can explain why they sound different as can changing the mat material, VTA & loads of other variables that plague them.
 
GTM said:
Ok let's put this "it's only 1s & 0s" "it either works or it doesn't" clap trap to bed.

Electronics is NOT digital. Electronics is intrinsically analogue. Digital is just a two state voltage situation within whatever part of the electronics you choose to talk about. The actual voltages just switch between the two states at a rate dictated by the function of the component. The resulting signal is at best a square wave. It's the square wave that the electronics has to deal with. So within that fact is the mechanism by which Digital can create noise and distortion and get things wrong. In fact at an engineering implementation level digital electronics is so complex that at times I'm amazed that it works at all. Analogue electronics is childs play by comparison, (in terms of engineering).

This is not a bash at digital. Just putting the record straight about the common misconception that digital is simple. It's far removed from the general belief that "it's just on and off innit?"
Click to expand...

And what relevance has any of that?

The transmitting code can be any thing you like, crows =1, budgies =0, will work just as well as 2 state voltages. As long as you know the sampling frequency, and have robust error correction systems in place, you can recover the analog original. The complexity of the engineeering is just that ... engineering.

Digital IS simple. It's implementation is not. But it really is "just 0 & 1s".
How it is implemented, is , fortunately, irrelevant, as long as it is implemented. The clever bit is the mathematics of the error correction algorthms. These ensure that if you input 100111001010... at 44.1Khz, you will get 100111001010... out of the other end, no matter what the coding method, be it voltage states or bird species. An accurate clock recreates the timing data and bingo, the DAC converts to analog.

Chris
 
The very problem with SPDIF however is that the clock and the data are entangled; and toslink, being very limited in bandwidth, often made for quite marked differences as a result - before adequate reclocking methods were common. And no amount of money spent on optical inteconnects can remotely alter that.

Providing your dac doesn't derive its bit clock timing from the spdif stream then optical is a nice thing - for the galvanic isloation - as Werner pointed out above.
 
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