About USB cables in general

[chrisc]

A fairly good (simplified) explanation about USB cables


How USB works

USB data are in packets. This means all the 1s and 0s are packaged together as a single message. The same as your internet connection

If you use water as an analogy, USB data does not pass through the wire like a pipe.   It is more like this water is packaged in a bottle (the packets) and then these bottles passed down the line.

So if you take this bottled water home in a Mercedes and it tasted better then water carried in a Fiat, then a boutique USB cable might be for you?


.... flames awaited..!

[ogs]

There is a lot of knowledge surfacing on the 'bits are bits' thinking now. I suggest you also read a little bit of that. Then you can return with an extended knowledge on how it all works.

[Greg]

There is a lot of knowledge surfacing on the 'bits are bits' thinking now. I suggest you also read a little bit of that. Then you can return with an extended knowledge on how it all works.

That’s good to know. Please can you supply links to these knowledge sources?

I ask because my general view sides with the OP. I have always been a sceptic but recently bought a reasonable quality USB cable and I was convinced it improved the sound. My ITC friend rubbished my perception. I’m now in a quandary as to whether that was an ‘expectation bias’ experience or whether it really did make a difference.

Like, I expect, every other streaming listener, I just want to create the best sound to listen to, so look forward to your reply. No axe to grind here. I just want straight facts and information.

[ogs]

Hi @Greg.
No links I'm afraid. I do not collect them. I also generally agree with the OP. Packet data should be immune to influences, but is it? I do not use 'fancy' cables anywhere in my system. The closest I get is the USPCB between microRendu and Mutec. At $35 this is nowhere near that category, but it is sounding much better than other cables I've tried. Is the new USB cable you bought better than the old one? I suggest you trust your own ears. Read Confused's thread here on DC about his journey with SOtM, Ref10 and the microRendu. The story about the Habst cable in particular.

[Pim]

A fairly good (simplified) explanation about USB cables


How USB works

USB data are in packets. This means all the 1s and 0s are packaged together as a single message. The same as your internet connection

If you use water as an analogy, USB data does not pass through the wire like a pipe.   It is more like this water is packaged in a bottle (the packets) and then these bottles passed down the line.

So if you take this bottled water home in a Mercedes and it tasted better then water carried in a Fiat, then a boutique USB cable might be for you?


.... flames awaited..!

OK, let's have a bit of fun with this...

Your analogy with water is probably right. But only with flat water. If you were to transport 'fancy' water (carbonated or in audio 24/96) then if the roads are bad and you drive the Fiat shacking it up and down as you bump over the road, by the time it arrives you don't want to open the bottles straight away or you'll be covered in fizzy water. You will need to give the water some time to settle down (in audio; use a buffer)

[Music or sound]

Bits is a mathematical concept; in reality an electric signal is transmitted through a wire, basically an analog signal which should be transmitted with infinite frequency to generate square wave. Because this is impossible a less than square wave can be recognized by the receiver but still more bandwidth is necessary than the bit rate!

[K4680]

Basics USB!
The Universal Serial Bus is based on a serial architecture. This means that the data is transferred bit by bit, in series, from one device to another. This enables high-speed data transfer with a low error rate. In addition, you save yourself an additional power cable, since the interface also serves to transfer energy. Data is also sent and received in both directions (I / O interface).

A bus connection had in its beginnings a master-slave structure. There is a master (or host), such as a notebook or computer, that controls data transfer. Its USB port has a slave (peripheral device) connected to it which hosts the data and controls it. These include printers, cameras or keyboards. If the data is on the PC, you can send it to another device if necessary. Since 2001, the master-slave structure has eased. The data transfer is also possible between two peripheral devices. For example, a camera can send images via USB cable directly to a printer or the data from a smartphone can be stored on a stick. This technology is called USB On The Go (OTG) and is indicated in the USB symbol by a green arrow with the words "On-The-Go". As a rule, the functionality is limited in this type of data transfer.

Low speed / high speed
In addition to the two lines for the power supply (+ 5V and GND), there are two data lines. The data transmission takes place symmetrically over two twisted lines. The one line transmits the data signal, the other the inverted data signal. One speaks of a differential transference. The voltage difference in the signal voltage is twice as large as if the data signal were transmitted to ground. At the receiver, the difference between the two signals is formed, with signal interference are hidden. This increases transmission safety, suppresses common-mode noise and improves electromagnetic compatibility.

To route slow devices such as the keyboard, mouse, and even fast devices such as modems or video cameras over the same bus, the transmission has been divided into channels.
There is a low-speed channel up to 1.5 Mbit / s (mouse, keyboard) and a medium-speed channel with 12 Mbit / s (ISDN, audio) which are routed via the same interface. A high-speed channel with 480 MBit / s (video, storage media) is also provided (USB 2.0).

In addition to the speed category, there are also different priorities in the transmission. The highest priority is given to devices that provide data in real time and where data flow must not be interrupted. The middle priority is for interrupt transmissions when z. B. a device wants to get the attention of the processor. The lowest priority is mass transfer devices. The transmission of this data is usually not particularly urgent.

[Jean-Marie]

There is a lot of knowledge surfacing on the 'bits are bits' thinking now. I suggest you also read a little bit of that. Then you can return with an extended knowledge on how it all works.

That’s good to know. Please can you supply links to these knowledge sources?

I ask because my general view sides with the OP. I have always been a sceptic but recently bought a reasonable quality USB cable and I was convinced it improved the sound. My ITC friend rubbished my perception. I’m now in a quandary as to whether that was an ‘expectation bias’ experience or whether it really did make a difference.

Like, I expect, every other streaming listener, I just want to create the best sound to listen to, so look forward to your reply. No axe to grind here. I just want straight facts and information.

The only way for you to determine for sure if this is expectation bias or outside of your brain would be to go through a often considered tedious ABX test between the two cables. 

This being said, and for full disclosure I’m leaning more on the bits are bits side of the fence and cables are cable, if you perceive the overall result at being better and if you can afford it, why not just enjoying it?

Here is the trick in my mind, although there is an objective and measurable part of the path of the music (basically between the source and our ears or brain) the last few inches (within our brain) is where a lot of the magic occurs. 

Jean-Marie

[Pim]

Here is the trick in my mind, although there is an objective and measurable part of the path of the music (basically between the source and our ears or brain) the last few inches (within our brain) is where a lot of the magic occurs. 

Jean-Marie

That's the best post I've read in a very long time.

[Confused]

What I would like to see with things like USB cables is a bit more rigorous testing. Blind testing, tests regarding the ability to eliminate RFI / EMI, this kind of thing. Even taking the EMI stuff into consideration, there appears to be very little information as to how EMI interacts with the DAC, or if it is simpler just to accept the EMI and filter it out at the end. How are DAC's influenced by noise, what kind of noise matters, does the USB eye pattern influence sound quality? I think all of this could be rigorously tested, but I cannot recall reading anything genuinely conclusive on the subject.

So I fear that until the world offers some decent hard data, we will continue to have cable debates, lots of claims each way, but nothing conclusive.

And then when you think you have seen it all, this arrives. A USB cable with fully configurable shielding. This is based on the "JSSG". This is John Swenson's idea that shielding generates a current from EMI, so you need a cable to connect each end of the shielding to create a Faraday cage effect around the cable, this can then be extended into two layers of shielding, and so on. But a USB cable with configurable shielding? What next?

https://stordiau.com/collections/cables-...udio-cable

https://www.computeraudiophile.com/forum...ent-863307

I do wonder just how far this kind of thing can go in the absence of real hard data, further than I could ever imagine probably.

And a note to @Pim - Forget the fizzy Fiat stuff, try some spring water delivered by unicorns.