Coax vs optical...

[xdd]

Conventional wisdom item 2: Optical cables introduce jitter in the digital signal.

Its not so much the optical cable as the receiver element that introduces the jitter.

Really? Does that mean that the fiber optic cables that deliver the internet signal from my cable internet provider to the local digital hub are full of jitter? Likely not.

The reason being - you're not using a Toslink connector to get your internet from your fibre. An internet connection will be a much wider bandwidth receiver circuit than a Toslink connector. Take the spec of a typical Toslink receiver - TORX173 - you'll note, if you examine the datasheet that the spec given for pulse width distortion is +/-20nS worst-case.

 

[Bill Ferris]

They are. Think the one that connects my Wiim to my miniDSP is 20 cm or so. Neat.


Bill, what do you think could be the root cause of this issue?

Both technologies transfer data as 1s and 0s, reconstructed at the receiving end. Any deviation from the original signal would likely stem from noise or jitter, but these effects would typically be inaudible with high-quality equipment. It’s worth considering that the signals might be processed differently, perhaps using distinct filters or roll-off characteristics, which could lead to subtle variations but that would be indicative by a frequency response for each output in the manual.

To whom it may concern; let’s keep the discussion focused on the technical aspects and approach it constructively. I encourage everyone to engage thoughtfully and address the topic directly. This isn’t an attempt to derail the conversation or provoke reactions; it’s an effort to explore the issue thoroughly and in good faith.

Don`t know why there was a SQ difference between the 2 different digital "1s & 0s signal types at that time as I was mostly ignorant of any fundamental specs of either or the Sony test player`s 2 different digital output specs to compare.
When I went the external digital output route to a external DAC. I hadn`t been a A/K member but for a few months, and had not bothered to research for digital output types opinions on here, or elsewhere on the web prior.

Just as I described above, I bought both type digital cabling what I thought was a balanced and fair digital output comparison and let my ears be the judge with no outside influence.
After all I`m the one who listens to my WAV. ripped music all day via my house`s operating and of various quality from quite HQ to upper midFi stereo systems, all day, every day from wakeup to bed time.

And if I felt I could reasonably improve the quality of the music delivery in my house I would rightly pursue so, as I`m not financially restricted to change/upgrade in any manner I deem valid, with no wife/GF`s restrictions to consider either.

My house is considered by many visiting folks to be a audio based "Man Cave" !

I`ve made a rewarding and satisfactory living using my ears for most of my adult life (from 1970 on), and trust my perception of sound quality.
If I have any doubts, I have a frequent visiting Bat eared classically trained flute playing long time audiophool friend B-I-L who lives next door who would not hesitate to point out any playback sonic anomalies that I may somehow have missed and can/should be addressed.

Though I have a HQ Denon test CD and a HQ set of various analog measuring test equipment that I could have setup to see if there might have been any measurable numerical differences, but decided to just trust my ears as the final and rightly judge the playback SQ, as I previously described.

 

[fredgarvin]

I have Wiim pro plus connect to Smsl su1 dac and I can hear differences between coax and optical outputs. Coax sound richer, fuller, warmer, optical sound, flatter, colder thiner. I don't have golden ear nothing like that but I can hear the differences almost from the first notes. I tried Tidal streaming both ways, also my CD player has both outputs. Same results. My friend have same stremer connected to Topping D30.Same results,coax fuller, richer, optical thiner colder. I Didn't expect that much differences between digital outputs. Any other opinions?

The times I have compared the two, coax sounded better. I doubt that is universal.

 

[AudioAvarice]

QED do a reasonably priced glass toslink cable if anyone is interested, I use one for my 'vintage' DAC/transport to connect the clocks.

 

[RogerA]

The debate over optical versus coax has resolved itself over time. Here's why:

Conventional wisdom item 1: Optical cables typically are less robustly built than coax and more likely subject to damage.
Well, this may be possible, but damaged optical cable is readily apparent: either it passes the digital signal or it doesn't. Otherwise undamaged, it delivers the same digital signal that the coax cable would.

Conventional wisdom item 2: Optical cables introduce jitter in the digital signal.
Really? Does that mean that the fiber optic cables that deliver the internet signal from my cable internet provider to the local digital hub are full of jitter? Likely not. Again, if the signal originating from your digital source arrives at your DAC, whether its optical or coax, then you're fine. Most DAC's - whether built into a CD player or standalone DAC - are able to internally correct for jitter anyway.

Conventional wisdom item 3: Optical cables have limited bandwidth, and can only pass digital streams up to 96khz.
Please don't tell my DAC this. I'm listening to a digital stream at 192khz at the moment. Besides, how did those digital streams at 192khz from Amazon or Qubuz arrive at your home? They most certainly passed through fiber optic cable at some point on their journey.

Anyway, my 2 cents is to plug in the cable, relax and enjoy the music. Doesn't much matter if the cable is coax or fiber optic.

Both the fiber and laser modulator driving your internet are much higher quality than the optical driver in the digital source. (Likely).

 

[whell]

Both the fiber and laser modulator driving your internet are much higher quality than the optical driver in the digital source. (Likely).

if true, the difference is driven by the requirements for capacity and distance. Those considerations aren’t relevant in home audio where the distance from the source to the DAC is typically a meter or two in cable length.

 

[Mike_S]

Both the fiber and laser modulator driving your internet are much higher quality than the optical driver in the digital source. (Likely).

For sure network fiber is much higher quality, so is data fiber. Used a Cisco data switch for a storage array at work, the switch alone was $45,000, that was before support and add-ons. Also the cables (under 1m) were around $300 each, then on top of that you need to terminate that with SPIF connectors, each of them are $200-1000, each cable needs 2.

Oh, this was also a redundant network, so 2 of everything so if one failed, there is a backup. Each array had at least 4 cables per channel. In the end, the entire array was over $1m.

if true, the difference is driven by the requirements for capacity and distance. Those considerations aren’t relevant in home audio where the distance from the source to the DAC is typically a meter or two in cable length.

Besides internet/network between sites, a lot of fiber is 1m or less. Even if you have a "top of rack" fiber switch, the lowest cable will be 3m.

Have seen a few DACs that use SPIF cables, not sure it's really necessary, but will be interesting to see everyone start talking about SPIF connectors changing sound, using different ones on each end of the cable.

 

[egellings]

If you have a ground loop problem causing hum, an optical cable, being non conductive, would break that loop.

 

[Bill Ferris]

If you have a ground loop problem causing hum, an optical cable, being non conductive, would break that loop.

Or look for converters that use galvanic isolation with their S/PDIF coax RCA connector, like my Peachtree X-1 does perfectly eliminating all hum, at least in my laptop USB to S/PDIF coax conversion`s use.

And no optical based high res. data rate restriction, which is beneficial when purchasing high res music tracks like 96/24 or 192/24 and putting them on the laptop`s 1 Terabyte SSD after installing the Windows USB drivers that Peachtree Audio provides on their website, though they indicate that Apple OS` doesn`t need upgraded drivers for the use of the X-1.

I`ll have to take their word in that case, being a Windows operating kind of guy with no experience with that.

 

[egellings]

Or look for converters that use galvanic isolation with their S/PDIF coax RCA connector, like my Peachtree X-1 does perfectly eliminating all hum, at least in my laptop USB to S/PDIF coax conversion`s use.

And no optical based high res. data rate restriction, which is beneficial when purchasing high res music tracks like 96/24 or 192/24 and putting them on the laptop`s 1 Terabyte SSD after installing the Windows USB drivers that Peachtree Audio provides on their website, though they indicate that Apple OS` doesn`t need upgraded drivers for the use of the X-1.

I`ll have to take their word in that case, being a Windows operating kind of guy with no experience with that.

Either the converter of the optical link can provide the isiolation.

 

[Bill Ferris]

Either the converter of the optical link can provide the isolation.

Yes, I`m clearly aware, but one of my points to consider was that TosLink`s data rate pass through is lower than S/PDIF coax`s data rate capacity, and might be a consideration if higher resolution music files are future contemplated, or in fact in use in the host computer, that optical will not data throughput handle.

I don`t use optical so I`m not familiar with the TosLink`s max data rate limitations are, just what I`ve remember reading on A/K on & off for the 8 + yrs. as a member.

 

[twiiii]

My experience has been with older products with less sophisticated capabilities that optical had a bit stridency coaxial did not have. But with Equipment designed in the last 10 years or so I haven't been able to tell any difference. Even when wearing my STAX electrostatic head phone. They are very critical by the way. The difference between analog and digital electronics of the same manufacturer are almost impossible to tell apart also. Now tube analog and digital is a totally different can of worms.

 

[AudioAvarice]

Technically we're never actually listening to digital electronics, as there is always an analog conversation. It's all just comparisons of different analog circuit implementations.

 

[mcgjohn]

I have Wiim pro plus connect to Smsl su1 dac and I can hear differences between coax and optical outputs. Coax sound richer, fuller, warmer, optical sound, flatter, colder thiner. I don't have golden ear nothing like that but I can hear the differences almost from the first notes. I tried Tidal streaming both ways, also my CD player has both outputs. Same results. My friend have same stremer connected to Topping D30.Same results,coax fuller, richer, optical thiner colder. I Didn't expect that much differences between digital outputs. Any other opinions?

a lot depends on the optical devices used to convert the optical signal back to electrical. Usually your better off using coax if its an option.

 

[Houas07tc]

I am comparing them at the moment switching back and forth. My ears can’t tell the difference, but something about the coaxial. The top end sounds kind of like when you have the speaker wires reverse on one side.

 

[egellings]

Either the converter of the optical link can provide the isiolation.

'Isolation'

 

[Bill Ferris]

'Isolation'

Ground Loop possibilities in some source/DAC/amplification equipment connection configurations can be an issue for some users of S/PDIF coax due to the grounded coax cable`s shield`s connection between the source and the DAC on through its RCA L/R audio outputs.

 

[Mart Mccall]

Anytime optical is an option I always try it and after a few weeks I go back to coax. Don't know why, nothing I can put my finger on. Quite happy if it's just in my head, but always the same result through lots of combos over decades.

 

[Visit Vegas]

In the right situations fiber is unbeatable. Last I knew the the limiting factor for bandwidth was the equipment. Meaning they have not built a SM system that could max the cable.

The problem is fiber is not a great consumer product. They use LEDs to send the signals instead of lazers to avoid eye injury and it's cheaper.
Users don't have a proper microscope & cleaners for the connectors. I guarantee most connections would be dirty. The glass is said to be stronger than steel but it can be damaged easily by over bending. The user has no way to test except to replace the cable.

When Toslink standard was made in 1983 they didn't make it compatable with comercial standards of fiber size, wavelength, and connector. 40 years ago they probibly wanted to keep the cost down with plastic fiber. It's more forgiving than glass. They could charge big money for their plastic cable. But the standard limited the length and the badwidth. The trouble is there has been no desire to update tosslink to better standards.

Curently comercial single mode patch cables can be had for about the same price as the Toslink with or without the worthless gold plating.

 

[audiobliss]

My only problem with toslink is the little funny shaped plug. Always a PITA to get it in the funny shaped hole.
Why couldn't it be round like normal plugs.