Who has tried out different USB Cables?

[barrows]

21 minutes ago, mansr said:

Tell, me what is the Vbus data rate?

Why ask me a question I assume you know the answer to?  You mean the data packet rate?  As I recall I think it is 8 KHz, but do not quote me on that. 

[mansr]

22 minutes ago, barrows said:

Why ask me a question I assume you know the answer to?  You mean the data packet rate?  As I recall I think it is 8 KHz, but do not quote me on that. 

So the Vbus data rate of the high-frequency DC is 8 kHz? Did I get that right?

[barrows]

1 hour ago, mansr said:

So the Vbus data rate of the high-frequency DC is 8 kHz? Did I get that right?

Dude, come on, be real!  I think everyone in this discussion understands that DC is DC and has no "frequency"!  If you have something to offer, great, otherwise, I doubt anyone finds your childish attempts to rile things up here amusing.

[mansr]

1 minute ago, barrows said:

Dude, come on, be real!  I think everyone in this discussion understands that DC is DC and has no "frequency"!

Tell that to Superdad. He's the one who started talking about high-frequency DC.

[Ralf11]

ok, now Let's re-read post #79, then get back to USB cable listening comparisons

[John Dyson]

On 10/14/2019 at 1:04 PM, xyzzy1 said:

 

Thank you... thank you... thank you...!

 

I have had so many similar discussions On circuitry that’s involved and that it’s not so simple as just 1’s and 0’s. It takes careful design of electronics and good cable to reduce electrical noise that will leak into the dac and it’s analogue amp and that there is no perfect isolation.

 

 

 

Audio quality limitations in this regard (about electronics noise leaks) can happen anywhere, and the matter of a cable working is not necessarily about the cable being higher quality, but instead matching the other poorly designed components in the system.   The issue can also come from almost all cables not being standards compliant -- best just to purchase true industrial/commercial quality wiring and equipment (when appropriate), and not be impressed by crazy snake oil claims that distract from the fact that the HW (or cable) doesn't fully comply with standards or good practices.   A lot of cr*p is 'designed' by bean-counters, and the engineers have to work within impossible constraints...   Refer to recent problems with new Boeing jets....   Quality and quality control are REALLY important, but apparently isn't a selling point anymore.  (Designing jet airplanes and subsystems are indeed complex endeavors, but well understood...  There is no excuse for the Boeing jet problems other than terribly irresponsible management being impressed by cheap and substandard design teams.

 

The audio cable issues that shouldn't need to be discussed -- all should mostly be passe, except for the case of very bad designs.   Alas, apparently such bad designs are all too common?

 

SO, there are multiple dimensions to the issue -- making comparisons with various designs with varying EMI/EMC behaviors along with poor impedance matching and various kinds of shielding make the matter of selecting the 'best' cable an almost foolish attempt of exhuastively searching out a cable with characteristics that JUST HAPPEN to work better with other portions of the system with equivalent and matching defects.

 

Instead, the audiophile press (and those of us who COULD actually measure the behavior of hardware and cables), should help the consumer to select good equipment that isn't so fragile as to need to benefit from selected consumer components. 

 

*Really good* cables and *properly designed/laid-out HW* are not all that high tech (unless the design itself needs to be high tech), it is a matter of 'cheapness'. and gullibility.   The audio world is definitely the world of caveat emptor.

 

Unless being guided by cheapness concerns, this whole thing about design tweakiness should be (and mostly is) long gone, diminishing quickly when vacuum tubes and their very variable characteritics (along with point to point wiring), started disappearing.   Nowadays, a good electronics design can be incredibly precise, and must include the circuit and connector layouts as part of the design.   Starting with bipolar transistors and further ICs with on-chip matching and trimming, the devices being governed relatively cleanly and accurately by the good old Ic=Is(1+e^(vbe*q/kT)), and that is the big-time rule.   There are scaling and temperature issues, but the problems of electrode location are all handled in chip design.

 

Technology has moved FAR FORWARD from what I have described, and if there are tweakiness issues nowadays, it is practically an issue similar to purchasing JUNK quality.   We are talking audio frequencies, easily achieveable accuracy, RF frequencies not much higher than maybe 100MHz, and layout technology that can easly handle 1GHz or better, and that is not even the ideal case!!!!   There is no excuse for the problems I keep hearing about in some of these discussions, other than just simple ineptness...  Period.

 

Hacker ware, basement designs, and snake-oil will always benefit from 'special' asscessory selection.   There are more important things in life than searching out the single available cable that JUST HAPPENS to work best with a given piece of toy hardware with almost professional quality packaging...  (e.g. impedances match best, for these tweaky deisgns, etc.)

 

Sure, hardware of any kind can make a difference, but what is the designer's excuse that their hw design/layout isn't very tolerant of bad cable impedances, using cr*ppy connnectors, or perhaps the cables smiply have very poor characteristics?   There ARE cases where EMI can be an issue, so -- there are a lot of cables out there that aren't even spec compliant...

 

Believe me -- searching around trying to match components because *someone* happened to purchase poorly designed electronics (all caught up in snake-oil claims) can be a full time job.   Note that there are actually important things that need to be done in this world, and would rather avoid trying to make a silk purse out of a sow's ear.  (Sadly, some aspects of my own project sometimes seems like the sow's ear issue, but it is off topic here.)

 

John

[mansr]

16 hours ago, Superdad said:

No, I referring to the data rate of high-speed (480 Mbit/s for USB 2.0) of the differential D+ and D- signaling--both in the mV DC range.

Well, what of it? You said it was "high-frequency DC" which makes no sense. What did you actually mean to say?

[barrows]

I use Sonore Renderers which have very, very clean USB outputs (measured), the entire thing is running only on ultra low noise linear supplies, including a dedicated LT 3045 for the USB bus power, and most of my regular DACs also have full galvanic isolation on their USB inputs.  Still, the USB cable used matters, now that cable does not make as big a difference as it does if I try a standard MacBook Pro as a source for testing, but it does still matter.

What do you know, I am not really surprised that in the context of a high end audio system the USB cable matters, hell, video folks see differences in video from different HDMI cables...

John Swenson has repeatedly (why I will not ping him here, he does not need to waste his time on this anymore) explained how/why USB signal integrity matters, and HiFi News has published eye diagrams of various USB cables which show significant variances in signal integrity.

[marce]

Was the eye opening within the USB spec?

[barrows]

@marce, Look it up and see for yourself.  I am sure some (audiophile, and cheap Chinese) cables do not meet spec.  But the spec is only for accurate data transmission.  I am sure in 99.99% of cases there is accurate data transmission, and that data errors have absolutely nothing to do with hearting different performance from different USB cables.  This has been discussed on this site over and over, and I am not going to bother to re-hash it all here again.  If you would actually like to learn some theories as why this may be (and no, I am not aware of any proof of these theories yet: measurements) search for John Swenson's posts on the topic..

If you would actually like to make a positive contribution here, with your considerable knowledge of high speed data transmission, as to why and how the different cables actually do result in different sonic results, that would be appreciated.  Otherwise, the constant badgering of people who already know that different cables do sound different contributes nothing, and is just more noise.

[Ralf11]

ok, does everyone agree agree that [1] the eye pattern can look fine even tho there is noise on the USB lines?

 

and that [2] some level of noise on the USB lines could theoretically cause a decrease in SQ (whether it has been measured on the ground plane or wherever inside a DAC)?

 

 

[barrows]

1.  I would suspect that the question is overly simplistic in nature: what is "fine" when looking at the eye?  If there is "noise" on the USB lines, at what frequencies and levels would/could this be problematic?  And, if that noise is problematic, could/would it be solved by those USB cables which separately shield the data lines from the power/ground lines?  

 

2.  My understanding of John Swenson's theories on USB issues also includes USB signal integrity itself as a potential problem for increasing noise in the USB receiver-that signal integrity may be a function of how well the USB hub chip is functioning (and they are not all equal...).  this signal integrity can be a separate issue from noise on the USB lines (data and power).

 

OK, off to the PO for product shipping now... 

[mansr]

3 hours ago, barrows said:

what is "fine" when looking at the eye?

Whatever the relevant spec says.

[marce]

On 10/18/2019 at 3:39 PM, barrows said:

@marce, Look it up and see for yourself.  I am sure some (audiophile, and cheap Chinese) cables do not meet spec.  But the spec is only for accurate data transmission.  I am sure in 99.99% of cases there is accurate data transmission, and that data errors have absolutely nothing to do with hearting different performance from different USB cables.  This has been discussed on this site over and over, and I am not going to bother to re-hash it all here again.  If you would actually like to learn some theories as why this may be (and no, I am not aware of any proof of these theories yet: measurements) search for John Swenson's posts on the topic..

If you would actually like to make a positive contribution here, with your considerable knowledge of high speed data transmission, as to why and how the different cables actually do result in different sonic results, that would be appreciated.  Otherwise, the constant badgering of people who already know that different cables do sound different contributes nothing, and is just more noise.

Wow tetchy, I only asked a question...

And have on many occasions mentioned stuff often to be pulled down😁.

 

[marce]

On 10/18/2019 at 7:56 PM, barrows said:

1.  I would suspect that the question is overly simplistic in nature: what is "fine" when looking at the eye?  If there is "noise" on the USB lines, at what frequencies and levels would/could this be problematic?  And, if that noise is problematic, could/would it be solved by those USB cables which separately shield the data lines from the power/ground lines?  

 

2.  My understanding of John Swenson's theories on USB issues also includes USB signal integrity itself as a potential problem for increasing noise in the USB receiver-that signal integrity may be a function of how well the USB hub chip is functioning (and they are not all equal...).  this signal integrity can be a separate issue from noise on the USB lines (data and power).

 

OK, off to the PO for product shipping now... 

EMC/Siganl integrity are two sides of the same coin...

To understand the effect of the signal on the receiver, requires a good look at the waveform at the receiver (the eye diagram is an overall view). From this waveform possible issues can be determined, such as monotonicity of the rising and falling edges, over shoot and ringing (something that does stress the receiver silicon, its over-voltage on the input. The way to do it properly is to simulate the circuit and wiring, as often the loading of the scope can skew the results. So simulate, model the scope lead, and simulate with scope model and compare the two waveforms to correlate the simulation. EMC testing will confirm the circuits and cabling work in the presence of external noise...

I am sure USB.org will have lots of relevant info pertaining to the USB bus.

Sunday morning going to do something with my life/Wife now... Shopping....😫

[Ralf11]

I have to say that we badly need some valid testing to show that different cables do sound different, and on which DACs...

[marce]

Conducted immunity tests on the DAC's... 

[gmgraves]

On 10/18/2019 at 7:39 AM, barrows said:

@marce, Look it up and see for yourself.  I am sure some (audiophile, and cheap Chinese) cables do not meet spec.  But the spec is only for accurate data transmission.  I am sure in 99.99% of cases there is accurate data transmission, and that data errors have absolutely nothing to do with hearting different performance from different USB cables.  This has been discussed on this site over and over, and I am not going to bother to re-hash it all here again.  If you would actually like to learn some theories as why this may be (and no, I am not aware of any proof of these theories yet: measurements) search for John Swenson's posts on the topic..

If you would actually like to make a positive contribution here, with your considerable knowledge of high speed data transmission, as to why and how the different cables actually do result in different sonic results, that would be appreciated.  Otherwise, the constant badgering of people who already know that different cables do sound different contributes nothing, and is just more noise.

WRT to audio, one would have to really try to make a cable that didn't "meet spec". A lot of audiophiles are hung-up on the notion that there is something "special" about an audio signal. There is not. It is a low-frequency AC signal that puts no particular demands on any conductor. USB cables, while carrying higher frequencies than an audio cable are still relatively low frequency conductors. The problems with USB, as I see it, lie in the way the data is arranged on both ends of the cable. While it is certainly possible that different USB cables mess with the timing of the packets somehow (I, personally, don't see how, though), the best that I have heard* still sound mediocre when compared to even Toslink SPDIF. 

* And, the best that I have heard is an AudioQuest Diamond cable (with the "bias" battery) and two Jitterbugs in tandem. Still nowhere near as good sounding as a simple Toslink cable plugged into the combo headphone jack on my MacBook Pro. 

[barrows]

Wow!  Really, as mentioned so many times before: no one is claiming there is any problem with losing data!

That does not change the fact that different USB cables sound different.  If you do not believe so, that is your opinion, but trying to convince people of such who knows better than you is a lost cause, a waste of your time, and mine.  I would your posts if they actually had anything to offer, but they do not.  You just keep stating your opinion, which is wrong according to my own direct experience testing such.  I have no time for wrong opinions, they are just more noise.

The proposed theory is that different levels of signal integrity give rise to different noise results in the USB receiver circuitry, and this noise makes its way to the important sections of the DAC circuitry (perhaps clock ground plane, perhaps analog stage, etc) where they create distortions/artifacts in the analog output.  this is just a theory at this point, as an explanation for what many people actually hear.

 

Again:  Who has listened to the Curious Evolution cable, in an attempt to get back on track.

[marce]

14 hours ago, barrows said:

Wow!  Really, as mentioned so many times before: no one is claiming there is any problem with losing data!

That does not change the fact that different USB cables sound different.  If you do not believe so, that is your opinion, but trying to convince people of such who knows better than you is a lost cause, a waste of your time, and mine.  I would your posts if they actually had anything to offer, but they do not.  You just keep stating your opinion, which is wrong according to my own direct experience testing such.  I have no time for wrong opinions, they are just more noise.

The proposed theory is that different levels of signal integrity give rise to different noise results in the USB receiver circuitry, and this noise makes its way to the important sections of the DAC circuitry (perhaps clock ground plane, perhaps analog stage, etc) where they create distortions/artifacts in the analog output.  this is just a theory at this point, as an explanation for what many people actually hear.

 

Again:  Who has listened to the Curious Evolution cable, in an attempt to get back on track.

You are starting to attack people's opinion who don't share your views a lot, me now gmgraves, and call it worthless... Who is to say you ( with a stake in audio sales) is correct, maybe you should respect others views a bit...

[marce]

3 hours ago, Blackmorec said:

 

 

So Ralf, here’s your chance to prove that you actually do know something about hi-fi rather than just operating like some autonomous forum NAND gate. 

Did you read my post...

Conducted immunity... a good place to start.

[Blackmorec]

59 minutes ago, marce said:

Did you read my post...

Conducted immunity... a good place to start.

Yes I did. Would that test cables? Or DACs? 

[Blackmorec]

16 hours ago, gmgraves said:

WRT to audio, one would have to really try to make a cable that didn't "meet spec". A lot of audiophiles are hung-up on the notion that there is something "special" about an audio signal. There is not. It is a low-frequency AC signal that puts no particular demands on any conductor. USB cables, while carrying higher frequencies than an audio cable are still relatively low frequency conductors. The problems with USB, as I see it, lie in the way the data is arranged on both ends of the cable. While it is certainly possible that different USB cables mess with the timing of the packets somehow (I, personally, don't see how, though), the best that I have heard* still sound mediocre when compared to even Toslink SPDIF. 

* And, the best that I have heard is an AudioQuest Diamond cable (with the "bias" battery) and two Jitterbugs in tandem. Still nowhere near as good sounding as a simple Toslink cable plugged into the combo headphone jack on my MacBook Pro. 

Hi GM,  seems you have a lot of variables there. There’s Toslink vs USB cable, the MacBook Pro’s clocks, interfaces and power supplies and the receiving end’s clocks, interfaces and power supplies, all of which have the possibility of influencing the signal. As far as I can see, the only conclusion you could reliably reach from your example would be in relatIon to your exact implementation of USB and Toslink...which is why people are advised to try stuff in their system.  As far as I can see, you are just as likely to see the opposite result in terms of SQ in a system where USB has been optimised throughout.   I am 100% certain that USB cables affect the sound although I don’t know why. I do accept that the USB cables are unlikely to modify the bitstream per-se but I do think that clocks, PSs and interfaces on either side of the cable could have a major influence as can EMI picked up by a cable

[pkane2001]

5 minutes ago, Blackmorec said:

I am 100% certain that USB cables affect the sound although I don’t know why.

 

How did you get to this 100% certainty? I've done both, audio listening and measurements on multiple USB cables with multiple DACs. Found only one old DAC that was obviously affected by a USB cable at more than just the level of background noise. Maybe the level of EMI is low in my environment, but I don't think so. I have multiple PCs, Macs, two UPS units, NAS, external hard drives, WiFi base, cable modem, wireless phone system, two printers and even a 3-D printer, among other electronic equipment all in the same office, so I don't know how much more EM-noisy the environment has to be to affect USB cables to an audible degree.

 

[marce]

1 hour ago, Blackmorec said:

Yes I did. Would that test cables? Or DACs? 

Both you would test the DAC with the cable in position, you could also blast RF at the cable as well to do radiated susceptibility.

They are the basic EMC tests that would be a good place to start...