The Absolute Sound "review" of USB cable reads suspiciously like a press releaste

First in order to convince that USB cables do make a difference, people in the business have to be able to articulate at least in theory why would a USB cable would make a difference.  Using common sense, if you can't prove that something on paper make a difference, then how can you convince that it would make a difference in real life or in practice.

Here is a question posed to some of the more prominent cable designers in the industry and, at least IMO, after reading through all their responses, they can't seem to articulate why such USB cable would make a difference in theory.  This comes from a HiFi+ article awhile ago.

How do you answer those who argue that specialised digital cables don’t and can’t make a difference since digital audio is ‘all ones and zeros’ anyway?

“(Laughs) No argument there—you would
not be talking to an audiophile. The fact is
that digital audio is ‘all ones zeros’ and time.
In digital cables, clocking and time arrival
integrity is crucial to musicality. When the
timing aspects of digital cables are right,
the sonic differences should be (and are)
obvious, so if you can’t hear a difference, don’t buy the cable.” George Cardas of Cardas Audio

“First, there is no music until something
vibrates, electrically or acoustically. Second,
in terms of cables, a digital cable “pulses” off
and on quickly. If the cable does not vibrate
in sync with the music signal, there will be errors. “ Bruce Brisson of MIT


“I don’t argue this point. All cables affect
the final sound of a system so if they don’t
understand this, it’s obvious they have not
listened or can’t overcome their negative
expectation bias. Amusingly there is no
such thing as a “one” or a “zero” where
digital transfer through a cable is concerned.
There is only an analogue signal, which
is “interpreted” as a one or a zero, so
there really is no difference between why
analogue cables effect sound vs digital
cables effecting sound. All cables affect sound in a system.” Ted Denney
of Synergistic Research

“Sit down and shut up and have a listen! Any digital cable
(with the exception of optical cables) in a
hi-fi system is carrying an electrical signal.
That signal is as subject to interference and
mechanical noise as any analogue cable is.
We’ve already mentioned how critical we
think the relationship between conductor
and dielectric material is and if anything, this
is more so when it comes to digital cables.
For the same reason, the quality of shielding
and the ability of that shielding to work
at high frequencies are also critical. One
of the areas of musical performance that
digital cables seem to have a profound effect
on is the coherence with which music is
presented. Producing cables that are able to
carry a musical signal coherently is, we think,
fundamental to every cable design.” Nigel Finn of
The Chord Company
“It might start out as “all ones and zeros”, but
the signal from the output must change from
one to the other and the input device has
to determine at which point a one becomes
a zero and vice-versa. If a cable causes
the voltage rise time to lag or linger it will cause problems.” Ray Kimber of Kimber Kable


“Digital signal is ones and zeros, a lot of them!
However, those who argue against the use
of specialized digital cables overlook one
exceedingly important factor which is the
“timely conveyance” of all of those ones
and zeros. In some digital components the
lack of timely conveyance of digital signal
is referred to as jitter. The electric current
in all cables, by which digital information
is conveyed, is impacted by conductivity,
dielectric absorption, impedance, eddy
current resistance and correspondingly
the integrity of the timely conveyance of
the massive amount of digital information
is also altered. At the end of the day, I use
the most sophisticated and precise test
instrumentation in the world, the human
hearing system. And, by that standard alone
it is clear that different digital cables have a big impact on the sound.” John McDonald of Audience


“The digital signals that are used in our audio
equipment are not dissimilar to an analogue
signal, only that they are constant amplitude
but still constitute numerous frequencies.
Exact representation of these frequencies in
relation to triggering and lack of unwanted
interferences influences the end result—the
music that we hear. It is really the DAC that
interprets the signal as ‘zeros & ones’. The
signal itself is just made up of waves, albeit
square waves.” Touraj Moghaddam
of Vertere Acoustics


“We are confident that we can demonstrate
the positive differences that come through
using our digital cables in music systems,
making for a far more enjoyable listening experience.” Graham Nalty of Black Rhodium

“We the only specialized manufacturer
of HMDI and 4K UHD cables in North
America, Nordost has put a lot of R&D into
digital transmission. We have found that
when digital cables are being used, it isn’t
numerical 1s and 0s, but analog square
waves that represent 1s and 0s that are
actually being transferred. The “less square”
a wave is, the harder it is for a DAC to make
a distinction between the so-called 1s and
0s, which results in timing errors. In order to
achieve sharp analog square waves, the cable
must have a large bandwidth and be capable
of high transmission speeds. Therefore,
quality cable design makes a tremendous
audible impact in digital cables.” Joe Reynolds of Nordost

“I explain that those ones and zeros pass
through cables as streamed waveforms with
jitter that creates measurable data errors
that change the sound we hear. I also offer
to send them white papers published by test
instrument manufacturers on that very issue.” David Salz of Wireworld

“They’re correct in that the ones and zeros in
the data remain ones and zeros through the
connecting cable. Where it all goes to hell is
when it’s converted to analog at the other
end, and that is where the connecting cable
and equipment interactions wreak havoc
with the clarity of the sound.
A digital source outputs data, and noise.
The quality of the cable determines both
the integrity of the data and how noise
travels. Today’s digital gear should be looked
upon as an RF system and while designed
to play through faults, the quality of the
analog output, particularly the very low-level
signal portions that brings about a sense of
space and other life-like qualities, is highly
dependent on the care taken in the transport
of the digital signal. Resolution is not black
and white, but rather shades of grey.” Joe Skubinski of JPS Labs

“The zeros and ones are not the problem. It
is about jitter and noise causing a different
sound. Jitter causes timing errors, easily
heard as an unpleasant sonic effect.” Edwin and Gabi Rijnveld
of Siltech and Crystal Cable

Nonoise,

Today, most, if not ALL, USB DAC use asynchronous USB architecture which uses a local clock to clock in the data, so data jitter is no longer an issue.  Therefore you have to be able to explain at least in theory why data jitter would affect the clock.  In other words, the data is buffered in a memory bank so jitter coming in from the USB cable is neutralized.  

I am playing the devil advocate to force you to explain.  

The OP link to the TAS article was not meant to be a "review". I don’t think TAS made any claim that they actually reviewed the cable so the OP opinion was not accurate.

Here is a better review of various USB cables. It was an old review so some of the USB DAC hardware architecture used was somewhat obsolete and today it is much better but it was informative. Today we use asynchronous USB DAC architecture so it may not be as sensitive to USB cables as in the past as was done around the time of this article.
http://mvicha.sweb.cz/test%20USB%20kabelu.pdf

Again, the OP link to the TAS article is a not a review.  It is clearly an advertisement for the USB cable.  

2. If the DAC is receiving a degraded waveform and the data recovery circuitry is working hard to sort through it, does this circuitry not increase the electrical noise in the DAC? If so, is it negligible or does that just depend on the DAC design?

It's a bit complicated because it's not like you have a usb data hooked up directly to DAC.  You have a usb data that has to go to different hardware protocol before it gets to the actual DAC.  And on top of that, you have the software on top of it to control everything.

This could be a long explanation especially if one may not have a background in electrical engineer.  

Now there two different USB DAC architectures - synchronous and asynchronous.  Synchronous was an old architecture which was susceptible to jitter and clock.  Most DAC nowaday probably use asynchronous.  This architecture essentially, at least in theory, eliminate the effects of jitter, which means even if the input USB data has a lot of jitter, the DAC will be affect.  The detail why is a bit complicated.  

Now my turn to pose the question (especially to wynpalmer4 since he claims to have a design background), because the asynchronous architecture essentially eliminates the effects of jitter, why then the USB cable would make any difference?  (Assuming you still have bit perfect which is not that unreasonable)

Just a FYI.

The reason redbook format has such low resolution, because at the time, you know back in the early digital age, the CD storage could not hold as much information as it does now.  If redbook was to have the same resolution as SACD, the size of the disk would be huge which made it impractical for portability (for example a hand carried player).

A poor value even if it does make a difference.

Why would it make a difference though?  That is a question I'd like to know.

1. Can a 1 be mistaken for a 0 at the usb receiver if the waveform is degraded enough?

It can get complicated. For CD, their is error correction. If a byte comes in with error, and if the error is not catastrophic, the error can be corrected. But if the error is catastrophic enough that cannot be correct, the next layer of defense is the missing data will be interpolated. Because the music data stored in the CD is interleaved, interpolated is possible. For example, if there are 20 consecutive bytes of error, they do not comprised a continuous stream of musical data, because of interleaved, the 20 bytes come from different segment of music. Based on CD spec, you could potentially drill a small hole on the surface of the CD and it can still work. Most of the differences you hear from different CD player probably not because of error because of power supply design, noise, the output stage, and of course JITTER.

I am not quite familiar with USB protocol but I CANNOT imagine that it would not have error correction and interpolation, and that the data is not interleaved. If USB has all this characteristic, I don’t see how what I said above would not apply to USB as well. Again, I don’t think most audible differences you here is from bit error because it is just a small percentage of all the variables. Now if you hear scratchy sound or spikes like a damage cd, well that’s different.

There is an excellent article from the late Charles Hansen Ayre designer about the USB DAC.  Although the article does not about USB cable specifically, but it will give you understanding of USB DAC architecture in general and how the cable "COULD" affect the sound.  I don't remember where it is but it used to be on Ayre website.  If I can find it I'll post it here.

For very high frequency applications like USB cables wouldn’t pure silver strands or silver plated copper strands be best, given that the signals travel very close to the surface of the conductors? Controlling the USB cables for directionality - as Audioquest does - also seems like a splendid idea. 🤗 I also like their “shield the shield” idea.

Actually for very high speed data, they don't really want it very fast.  If you look at those signal on the scope, the rise time looks more like a sine wave than a square wave.  High edge rate may cause a lot of EMI issues.

If you’re referring to the speed of the signal there is virtually no difference through copper or silver. In both cases it’s near lightspeed.

I was referring to the data edge rate, not the speed in term of data rate or propagation speed.  The edge rate is the signal slew rate measured in V/sec.  You were referring to propagation speed which is measured by (radiant/meter). What I was saying is that fast edge rate might not be desirable.  If a cable made of silver, it will increase the edge rate which can potentially cause EMI issues and may end up having more jitter.  It's not a simple one rule fit all sort of thing, and silver may improve other aspect of the data transmission, but with respect to edge rate, it does not mean the faster the better.

With respect to USB asynchronous architecture, the jitter from the USB data stream is not an issue because the data is buffered before it is clocked to the DAC using a local clock that does not depends on the USB data stream.  It's how the USB data stream may cause jitter down stream to the DAC.  The faster the edge rate, the more like EMI will cause interference to ground, power and so on and ultimate jitter to the DAC. 

For synchronous USB, then may be silver could be better since it has faster edge rate and that could improve jitter.  That's why I am saying there is no one rule fit all but depends on other factors.

Isn’t slew rate a function of the amplifier? Not the conductor. The advantage of silver is that the resistance is lower. Maybe someone should come up with copper-plated silver wire.

Yes, but the conductor does play a role.  All cables act like some sort of low pass filter.  If you model out a simple resister and a cap as a low pass filter, the higher the resistance will result in more low pass filtering.  As you said silver does have lower resistance so the rise time won't be degraded as much as copper.  In some cases having a higher rise time improves jitter but high rise time will also result in higher EMI.  That's why most high speed data rate will have only enough rise time to get away with.  It's a balanced act so it depends what you want to achieve,  

Also as I mentioned, there is no one single factor.  It depends on the situation.