Someone is trying to sell some fancy (used and 2 ft long) USB cable for $497.50. I am genuinely curious since I am no expert. What does this ultra expensive USB cable do to your audio system (besides transferring digital data)?
I described how cables affect the sound and it has nothing to do with "data" being wrong. Audio optical cable (Toslink) has different problems. Transmitter's transitions are very slow, making them susceptible to system noise induced jitter on both ends. Measurements of jitter induced artifacts you can find in pretty much every Stereophile review of CDPs or DACs. The fact that cables (digital or optical) induce jitter is basic EE.
You cannot compare simple transmission of music over Toslink (limitted by design to 33 ft) to optical data transmission, where LEDs were replaced by laser, light modulated by external device, different modulation etc.
I have a hard time picturing an optical transmission of very slow data stream for 50 centimeters being much wrong. A single optical cable of similar diameter is able to stream data for cities of millions for kilometers. Do you have any data or measurements that suggest what you're saying is correct?
People assign analog attributes to digital cables. Warmer, colder, brighter etc. I just wonder which bits are added, changed, or entirely missed when the sound turns warmer or brighter etc.? If bits are missed or added it will likely cause nasty noises (if not corrected by the error correction mechanism of the receiving end).
There is no error correction in S/Pdif transfer, but that is not the point. S/Pdif is coded such way that word clock for D/A converter can be extracted from it (from transitions) to keep CDP and DAC synchronized. This clock has to be rock solid (no time jitter) otherwise additional sounds will be added on analog side. For instance, if you play pure 1000Hz tone and have a lot of 60Hz noise then your S/Pdif stream of 1s’ and 0’s might have 60Hz jitter (vibrate in time back and forth 60 times a second). It will produce on analog side pure 1000Hz tone plus (mainly) 940Hz and 1060Hz tones (sidebands). These tones will be at very low level but still audible, since not harmonically related to the root frequency of 1000Hz. Amplitude of these extra tones will be proportional to the amplitude of the vibration (jitter). Since music has a lot of tones there will be a lot of additional tones added that will be perceived as noise or lack of clarity. There is a lot of sources of jitter, digital cable being one of them. It might add jitter because of reflections in the cable affecting/deforming edge of transition or it might be susceptible to ambient electrical noise, that when added to signal affects recognition (threshold) point hence affecting moment when transition is recognized. Jitter might also be caused by noise added to signal in CDP or DAC itself. Since different digital cables affect jitter differently (one has better shielding while the other less reflections) there will be a difference in sound.
A little addition about synchronous data transfer. Assuming there is no buffer implemented in the dac (very unlikely) and all packets sent in correct (synchronous) order it would take 200 failed attempts to transfer a package before it would affect the sound stream.
I have a degree in computer science have some knowledge of how data is transmitted between devices. The data is split up in packages of bytes. Then the procedure is basically the same as when you mail a letter at the post office. There is no data loss since if the package is verified by checksum when received and if not correct requested again. Since the bandwidth capabilities of the cable is many times that of our (audio) stream a buffer makes sure our bits can be aligned in correct order even if we would need to request a package again. A 3 minute song in uncompressed CD quality is about 31 MB. An old USB 2.0 cable can transfer 35 MB/s and would be able to transfer the whole song in less than one second (assuming that the dac has large enough buffer). USB 3.0 specced cable can transfer 625 MB/s (5Gbit/s) the whole song could transferred in 1/200 th path of a second. The rather old tech USB 2 can even transfer the same 3 minute song of uncompressed 192/24 in less than 6 seconds. What seems to confuse some people is that a CD transport might not be able to read a disc that migh have fingerprints or scratches and tiny read errors might end up as what we know as jitter. Much of this is solved by buffering that will allow the CD transport to try again to read. Many modrn dacs also have the ability to estimate the data and smooth out possible errors . This is however not the case with files on you computer. There are no read errors. The data is perfectly packaged and shipped to you dac.
If you hear a difference between USB cables, it's likely that your DAC is not using asynchronous USB but rather synchronous USB. The latter is much more susceptible to cable quality than the former. Because in synchronous USB the jitter contributed by the cable can affect sound quality. With asynchronous USB there should be no difference in sound quality between USB cables assuming the receiving DAC does not rely on the USB power which any reasonable DAC won't.
psickerson75 posts02-04-2017 2:05amWho guarantees the 0 and 1 sent are correctly?
No need to guarantee either: Wire has nothing to do with right or wrong zeros or ones sent. DACs don't care if 'complete or incomplete zero or one' it received. DACs treat zero as ZERO and one as ONE. USB or any digital wire simply cancels out from both part of equation. That's where simple arithmetic kills all the science, hypothesis and beliefs behind. You can check answer with calculator LOL.
I just finished counting up all the blind testing results for cables over the past 40 years and the results might surprise you. 32,455 heard differences, 54 did not hear differences. I suggest we behave like adults and throw away the 54 outliers, pick up the pieces and move on.
Why would some people spend that much money on a USB cable when they already know what it does?
I hoped someone could explain to me in a manner that doesn't require a professional degree in electromagnetism.
Magical thinking and G.A.S. Or it just looks cool.
I don't require a degree if I analogize it with DTV. Many of us grew up with rabbit ears and distant transmitters. We'd fiddle with the antenna to reduce static in the audio and clear up the picture. With DTV, as long as you can receive an uninterrupted signal stream you will have a great picture. Owning an expensive roof antenna vs a cheap FlatWave thing hanging on the wall makes absolutely no difference to that picture quality. Same concept with a USB cable and audio.
To me 1s and 0s are just that, but @geoffkait makes a very good point about just being representations of 1s and 0s. That tells me it’s about the source, not the cable. Personally, I think one must consider the resolution of the system. Maybe a difference with $10k components but probably not $2k components.
My primary system would price out at roughly 10k. I bought 3/4s of it secondhand, so I spent a little more than half that much. I’ve done the testing and I cannot hear the difference. And you can buy decent secondhand cable at bargain prices from guys ’upgrading’ their cables. That’s what I did. But I didn’t spend more than $25 for a pair of used interconnects.
Logically, you have to say to yourself that if high-end audio component manufacturers don’t use pixie-dust wire inside their components then I don’t need to either. Something that faithfully carries a signal and rejects interference is the only requirement. And that same metric stands for every connection made in the system. A fancy braided jacket and reams of wholly unsubstantiated marketing jargon do absolutely nothing to improve a signal. The manufacturers know this because they know the science and have done the testing.
If spending up to $5 (w/bulk purchasing) for some braided covering over Belden, or similar quality wire, made a measurable -- by any metric -- difference over jumper bars, don’t you think a speaker company would install them on their speakers in excess of $1000 a piece? Certainly on $5000 speakers, right? But they don’t. And probably because they value their integrity enough not to claim that glossy picture worthy jumper cables open up and warm the soundstage without sacrificing depth or richness of timbre while making their cat happy or [insert more marketing horse**** here]. It’s simply something a company with class would not want to risk.
What you have in consumer audio concerning cable is exactly what you have on the music-making side with the endless G.A.S. people who claim they’re "searching for the sound in their head" when all they’re really searching for is another way to use their credit card.
The salient reason why blind testing cables doesn't produce results favorable to the expensive cables is that people can't hear any appreciable difference. If you can't tell the difference then why do people buy them? Confirmation bias and gear G.A.S., that's why.
"We can throw out blind tests that have negative results since the are outliers. There are many reasons why someone doesn't get positive results. If you like I can list them"
wmarkhall 18 posts 02-04-2017 4:04pm Cable sales hinge on confirmation bias and gear G.A.S. I've done blind testing with interconnects and speaker cables. I failed miserably, and I'm a musician. Then I examined the science. Cables are snake oil. There's nothing else to be said.
We can throw out blind tests that have negative results since the are outliers. There are many reasons why someone doesn't get positive results. If you like I can list them.
Cable sales hinge on confirmation bias and gear G.A.S. I've done blind testing with interconnects and speaker cables. I failed miserably, and I'm a musician. Then I examined the science. Cables are snake oil. There's nothing else to be said.
To me 1s and 0s are just that, but @geoffkait makes a very good point about just being representations of 1s and 0s. That tells me it's about the source, not the cable. Personally, I think one must consider the resolution of the system. Maybe a difference with $10k components but probably not $2k components.
To those saying spend more than five or ten dollars on a USB cable ... when you bought that aftermarket mains cable, did you R&R the wall socket? What about the wire in the wall? Or in the breaker box or from the house to the pole? Why not? And that $500 run of speaker cable - did you replace the cable within the speaker box? It’s standard cable off a spool, not $50 a foot. More like .50 a foot. So why didn’t you replace it? Doesn’t the relatively inexpensive wire used inside your amp/pre obviate the use of inanely expensive outboard wire? This can only mean that you are willing to believe that high dollar wire not only sounds better, but it removes any and all bad audio stuff from the ’substandard’ cables earlier in any of the chains. Like it or not, that’s magical thinking.
Edit: And in the case of speaker wire, later in the chain, as well. The waves leave the amp through standard wires and connectors, travel through $50 a foot boutique wire, then inside the box to wire you could buy at Home Depot. But the $50 a foot wire improves what comes before and after it. No wonder it's so expensive!
All signals are analog. The only difference is the information contained in the signal. In one case it’s an analog waveform, in the other a series of square waves representing voltage levels. So actually the so called digital signal doesn't contain ones and zeros, but representations of ones and zeros. Both types of signals are electromagnetic waves, I.e. Near Light Speed, I.e., photons.
Who guarantees the 0 and 1 sent are correctly? not the DAC receiving it. I just had a scenario with a wireless signal to my laptop Tidal App (MQA) > coax > DAC was garbled. The 0 and 1s where being sent otherwise no sound. But the DAC just took and played what it was sent.
The dac is known to be very good with identifying the quality of the signal and sending to one of two filters for processing. But it just processed the bad signal.
The USB cable didn't have anything to do with this problem, but that did make me realize the DAC doesn't know good from bad.
ill audition multiple $100,$200,$300 cables and make my mind up it it sounds better than the $24 one. There are many forums where people have positive results from regens.w4sound, LPs to ignore.
I will chime to say that a fool and his money are soon parted and there are tons of audio snake oil salesmen out there. By all means, try different USB cables to see if you perceive a difference, but make sure you get a 30-day money-back return deal when you buy them. I have recently been on a foray to upgrade my IC's and PC with significant benefit to my system with gear from Silnote and Shunyata, but I have in the past auditioned both IC's and PC's with no benefit to my system so I sent them back. USB connections are a different kettle of fish. Almarg, who we can count on for solid advice, gives you the straight scoop above. Cheers.
that 'someone' realizes there is a fool born every minute and he or she is hoping you the next victim ! for only a real fool would spend 500 bucks on a 2' USB cable !
People assign analog attributes to digital cables. Warmer, colder, brighter etc. I just wonder which bits are added, changed, or entirely missed when the sound turns warmer or brighter etc.? If bits are missed or added it will likely cause nasty noises (if not corrected by the error correction mechanism of the receiving end). Try to transfer a high-resolution camera picture via a reasonable quality ($15) USB cable and observe the resulting picture. Do you see any distortion? Hardly ever. Or transfer a large software package to your computer via a USB drive. Do you get errors? Hardly ever. So why do you think you need such a special USB cable for music? I agree that if SPDIF interface is used, the receiving DAC can introduce distortion if the jitter is high, so there the cable has to be of high quality (as well as the source equipment) to minimize that. However when it comes to asynchronous USB, there is no jitter induced from the interface (no PLL is needed) and hence the quality of the cable is not critical as long as it's well shielded to prevent noise. I've tried many USB cables in my system, expensive and cheap, and could never detect differences. (I had golden eared audiophiles agreed). So if you think you detect differences in your system, it is likely a psychological effect IMO. Needless to say, the cable industry will not agree.
Have heard/read the "0 - 1" process explained numerous times, but not as good as you did. Interesting what one can read in the audio online glossies. The article that statement came from was only a year old.
I did a lot of research before I bought the DAC I use. As an old school computer guy, the fact that it advertised USB design, with performance that equalled S/PDIF was a big selling feature to me. It has lived up to its claim.
Been part of the IT industry my whole adult life. Still remember using the IBM 360-370, Amdahl, Tandem etc... mainframes and all those reel tapes. :^)
The two sentences you quoted are referring to two different things.
The first sentence refers to the likelihood that under normal circumstances the circuit receiving the data will not mistake a 1 for a 0, or vice versa, despite the presence of noise that may be conducted in the cable.
The second sentence refers to the possibility that noise that may be conducted in the cable may find its way into D/A converter circuitry, causing jitter, or into other circuitry further downstream (including analog circuitry), where it may have audible consequences even though the data has been received correctly. Conceivably it may "find its way" via unintended circuit paths such as stray capacitances, grounds which behave in a less than ideal manner at frequencies that are contained in the noise, by radiation of RFI (as Kijanki mentioned), etc. And that could very conceivably occur to an audibly significant degree under normal circumstances, depending on the specific designs that are involved. And that kind of effect is the only way I can think of by which sonic differences could occur between reasonably well designed USB cables, when used in reasonably well designed asynchronous USB applications.
When I was drafting my post it occurred to me that those two statements might be conflated, when they were meant to refer to different things. Which is why I added the words "when that determination is made" at the end of the following sentence, although perhaps I should have added clarification that was more explicit:
The receiving circuitry just has to determine which of the two signals in the differential pair is at a higher voltage and which is at a lower voltage than the other, during each bit interval. And noise that is present on both signals (i.e., common mode noise) will be ignored under any reasonable circumstances, when that determination is made.
Very informative post Al. Thanks. Trying to better understand what you are saying in a couple of areas.
When you say USB communicates data via a differential pair of signals, and specifically regarding noise.
And noise that is present on both signals (i.e., common mode noise) will be ignored under any reasonable circumstances, when that determination is made.
I don’t doubt that USB cables can make a difference in many applications, mainly as a result of coupling or radiation of noise into D/A converter circuitry or even analog circuitry further downstream.
So do you mean that noise can be introduced into D/A circuits, only by un-reasonable (not normal?) circumstances?
The statement attributed to Mr. Aud does not reflect how a USB interface operates. First of all USB communicates data via a differential pair of signals, which greatly enhances noise immunity. The receiving circuitry just has to determine which of the two signals in the differential pair is at a higher voltage and which is at a lower voltage than the other, during each bit interval. And noise that is present on both signals (i.e., common mode noise) will be ignored under any reasonable circumstances, when that determination is made. Secondly, 1s and 0s are not distinguished from each other based even on that determination. They are distinguished based on whether or not there is a **change** in which signal is higher and which signal is lower, relative to what that relation was during the previous bit interval. There are other differences as well.
I don’t doubt that USB cables can make a difference in many applications, mainly as a result of coupling or radiation of noise into D/A converter circuitry or even analog circuitry further downstream, as alluded to by Kijanki and Williewonka. However, that does not mean that a $500 cable necessarily has any particular likelihood of outperforming a $50 cable or even a $10 cable in a given application. Also, I would disagree with any attribution of specific tonal or other sonic characteristics, such as warmth, to a particular USB cable. While making such attributions may often be appropriate in the context of analog cables, the sonic effects of electrical noise in a digital application will depend on the designs of the specific circuits that it may couple into, on the degree to which that coupling occurs at various circuit points, and on the specific spectral and other technical characteristics of the noise itself. Therefore any such effects can be expected to have little or no predictability, and little or no consistency from system to system.
My opinion is that Jim Aud and Purist Audio design cables are practically AND factually full of feces. It does NOT matter weather they're 'completely uniform' Completely or partially uniform 0 will still be 0.
When thinking about a digital signal over USB, it can seem natural to think of it as a straightforward expression of 1's and 0's. However, it is more nuanced than that. Below a certain voltage, the signal says: "this is a 0." Above a certain voltage, it says "this is a 1." So, a 1 may be a 3.2 volt signal, and a 0 might be a 2.9. Since data transfer happens fast and often, it doesn't take much to skew a 1 to a 0, or a 0 to a 1. The digital signal isn't this series of neatly packaged squares, all labeled 1 or 0. They are in the ballpark, but they aren't completely uniform.
Any opinions on these statements from Jim Aud - Purist Audio Design ?
Digital coax cables are very different. In most cases D/A clock frequency is based on average frequency of the transfer while any time variations appear as jitter (noise in frequency domain). We can say that any S/Pdif cable (coax or Toslink) transfers the music (since timing is attached) while asynchronous USB transfers data. I hope you see the difference.
kijanki Perhaps we should understand what is happening to fully understand insanity of expensive USB cables. In asynchronous USB, computer transfers the data in frames at about 1kHz rate. USB DAC places the data in the buffer and responds with under/over buffer signal causing less or more data in the next frame. This data is clocked into D/A converter with internal DAC clock that is independent of the transfer or computer. The only thing that can remotely affect the sound is noise injected/radiated by the cable.
as fate would have it the same arguments can be applied to digital cables, both metal conductors and fiber optic cable TOSlink. Yet, in the case of digital cables there are obvious differenes in sound quality depending on the cable type and manufacturer. Consequently I'm not ready to buy into the similar arguments for USB cable, either.
"mgreen27 we all know what it does as I mentioned in my first post "transferring digital data" then again in my second post. That was not an answer to my own question."
In your first post you asked a question. In your 2nd post, it looks like you had your mind made up all along. I would go over it with you, but I can't because you had my post removed.
Perhaps we should understand what is happening to fully understand insanity of expensive USB cables. In asynchronous USB, computer transfers the data in frames at about 1kHz rate. USB DAC places the data in the buffer and responds with under/over buffer signal causing less or more data in the next frame. This data is clocked into D/A converter with internal DAC clock that is independent of the transfer or computer. The only thing that can remotely affect the sound is noise injected/radiated by the cable.
Many hood observations . Trust me if I could get away with a $10 Beldon USB cable i would use it Ihave personally tested several cables directly from Audiophile friends and I would say starting at the $100 range it is a major step up in USB sonic vs the $20 cable l. Then say Silver starlight -Wireworld very respectable at $300 . All depending how well your audio system is your digital for sure should. Be very resolving to spend $300 end up. i will say the Cardas for $200 is a very respectable warmer sounding cable and not break the bank. I got my AQ Diamond for under $400 as a package with a Aurender 100 player. I will say install a synergistic black fuse the writing on the fuse left to right installed towards the source these fuses especially after 100 hours of play time resolution Very much improved for $120 well worth the effort And comes with a 30 day like it or get your money back . you have nothing to loose.
Chrisr, you're correct, in asynchronous USB timing makes no difference and the only thing affecting sound is injected (or radiated) noise by the cable. Digital S/Pdif cables are different - characteristic impedance mismatching causes reflections in the cable - hence time jitter. Jitter equals to noise within the music.
mgreen27 we all know what it does as I mentioned in my first post "transferring digital data" then again in my second post. That was not an answer to my own question. Why would some people spend that much money on a USB cable when they already know what it does? Are there really some serious science associated or could there be some other practical or psychological reasons that I didn't know? I hoped someone could explain to me in a manner that doesn't require a professional degree in electromagnetism. sbank "
by improving the digital source(to a microRendu fed by Synology NAS
using CAT6A ethernet cable) and a good quality linear power supply, I
can now use an inexpensive(i.e. basically free!) USB connector... " I agree with you 100%... I would spend my $500 to upgrade my DAC.
There's no loss of 0s and 1s in a usb cable, it is proven. How can it make a difference? The debate over cables has not changed a bit (no pun intended); just getting more and more bizarre.
But it doesn't. Making things more confusing is that fact that the source outputting the USB signal and the USB output implementation in that source have an effect. So does the amount of voltage required and the quality of the power supply to that source. It sure would be simple to bury our heads in the sand and get comfort by muttering "bits is bits" use the $10 USB. In my tests some high price cables like Lightspeed 10G and the AQ Diamond were obviously better, but not by a ton, over Black Cat, AQ Carbon and other "giant killer" medium priced USB cables.
Ironically, by improving the digital source(to a microRendu fed by Synology NAS using CAT6A ethernet cable) and a good quality linear power supply, I can now use an inexpensive(i.e. basically free!) USB connector to the dac and not hear tremendous levels of improvement with expensive USB cables like I always did when connecting Mac Mini output to the same DAC. Cheers, Spencer
Its role is to transfer "digital data", i.e., 0(zero)s and 1s, not "audio signal". As long as your $10 USB cable is structurally solid, it should work as good as the $500 one.
audioman58 makes a very nice comparison, but I would add a little to it. With cables, results vary. If you were to evaluate the AQ and WW cables in your system, you may agree with audioman58's assessment, hear something different, or maybe here no difference at all. All 3 scenario's are completely valid. That's why its so important to try them first.
I have had a few currently the Audio Quest Diamond it is very good at the harmonic structure and tonal balance of the song. I have had the Wire World Platinum 2 it had slightly better resolution at the expense of warmth and and density of image. If you have a warm tube system the Wireworld is better being more neutral. The Audio Quest Diamond if you want a bit more warmth and image saturation .
First - the function of the USB cable depends on what component it is plugged into.
1. If the component DOES NOT utilize he power from the USB port, then all the cable is doing is passing data - better quality conductors will improve sound quality
2. If the component DOES use the power provided by the USB port then the cables is sending data and providing power.
By having the power and signal cables separate there is no possibility of noise being induced between the signal conductors and power conductors, since they are separate cable runs
Using the Doukmall cable you can then experiment with different USB power supplies to get the very best SQ.
The better USB cables will employ carious cable geometries (i.e.how the conductors are positioned within the cable) to minimize the noise issue.
e.g. - tightly twisting the signal conductors together will help minimize the noise - ensuring there is some "space" between the signal and power conductors again assists in defeating noise.
If you have ever striped the outer insulation off a piece of CAT 5 and CAT6 cables you will see both of these methods have been employed in CAT 6 to improve the throughput.
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