[Chris J]

Ho yes, it's such an important issue that there is regulation around this to limit the source of Electromagnetic Interference (EMI):

From Wikipedia:

"[COLOR=252525]In the [/COLOR]United States
[COLOR=252525], the 1982 Public Law 97-259 allowed the [/COLOR]Federal Communications Commission
[COLOR=252525] (FCC) to regulate the susceptibility of consumer electronic equipment.[/COLOR][COLOR=252525]^[6]
[/COLOR]
Potential sources of RFI and EMI include:^[7]
 various types of transmitters
, doorbell transformers, toaster ovens
, electric blankets
, ultrasonic pest control devices, electric bug zappers
, heating pads
, and touch controlled lamps. Multiple CRT
 computer monitors or televisions sitting too close to one another can sometimes cause a "shimmy" effect in each other, due to the electromagnetic nature of their picture tubes, especially when one of their de-gaussing
 coils is activated.



Switching
 loads (inductive
, capacitive
, and resistive
), such as electric motors, transformers, heaters, lamps, ballast, power supplies, etc., all cause electromagnetic interference especially at currents above 2 amps
. The usual method used for suppressing EMI is by connecting a snubber
 network, a resistor in series with a capacitor
, across a pair of contacts. While this may offer modest EMI reduction at very low currents, snubbers do not work at currents over 2 A with electromechanical
 contacts.^[8]
[9]
"



 



While a cable with a good shield will prevent radiative noise from those appliance, it won't shield against what is already in your electrical network. EMI transfer as well on conductive (so if it's connected on the same electrical network (which by the way it is, that's why we call it an electric grid), it can get by the cable). 



 



That's why you sometime see cable that look like this:


It's a ferrite bead, it can be used to cut interference before it get into an appliance (one of the most effective and least expensive way). It can also cut interference going out of an appliance to meet government regulation. Now why the gov did regulate on this? Because it was cause issue. Electric network have to filter interference as well so they don't transfer between house, and to do that successfully, the best way is to limit them directly at the source. So yes your electrical network is clean enough, but there is already noise in it, but not enough to cause issue with your sound and nothing that your expensive cable will filter out since the shield only block what could radiate into it. And even then a Ferrite bead would be actually better, it will not only filter out the EMI from that got in on that 6 feet cable just before getting into your amp, but it will filter what was actually already on your electrical network. Personally I have already try a cable with one, and I did not notice any difference, probably because the equipment I use already have all the filter embedded in them or they are simply not sensible to them by the way they are designed. 




I know it won't convince anyone, and since a cable with a ferrite bead is so less expensive then your $1000 cable, the placebo won't work as well. So you will actually notice a degradation in sound quality. 

You're talking to the wrong guy.
I've performed EMC testing.

 

[Aradea]

Guys, just wanna share my experience
 
I just tested three different $5  (A to B) USB cables (one with a ferrite bead, other two without) to connect my laptop to my ADL GT40 amp-DAC.
All three sounded differently: one sounded muffled but with sufficient definition of vocals and instruments , the next one sounded open but lean (a bit harsh in some songs), and the last one just sounded between the two. This last one was the one I use at the end, the one with the ferrite bead.
 
My silly conclusion is: if you really have to use cheap USB cables, find the one which looked solid and has a ferrite bead hahaha! 

 
Just for laughs guys.. honestly, using a high quality USB cable is not my priority right now but I may get one someday.
 
Cheers

 

[Lorspeaker]

  just bot an audioquest micro-usb cable for my portable ext harddisk... lets see how this 0.75m cable affect my library

 
been listening for 3 hours to my setup with the audioguest cable attached to the harddisk...
my dt150 has never sounded clearer, v happy with this small investment.
 
http://www.custom-cable.co.uk/audioquest-forest-usb-micro-digital-audio-cable.html

 

[ampair]

oh, those facepalm moments...
 
@Lorspeaker: i truly hope you set this as a sarcasm trap, if so then shame on me. otherwise i have bad news for you.
the only way that a "better" usb cable for the ext-hdd may have an influence (if any) on the sound, is when (a) the ground rails of your computer are noisy as hell AND (b) the usb-input of your dac is crappy enough to not isolate the usb ground connectors from the rest of the device. so, either you're a victim to autosuggestion, or your audio-gd generally sucks with usb. your choice
 
(if you like, i can elaborate further on the matter. in that case, beware of a veeeery lengthy post.)

 

[Tablix]

  oh, those facepalm moments...
 
@Lorspeaker: i truly hope you set this as a sarcasm trap, if so then shame on me. otherwise i have bad news for you.
the only way that a "better" usb cable for the ext-hdd may have an influence (if any) on the sound, is when (a) the ground rails of your computer are noisy as hell AND (b) the usb-input of your dac is crappy enough to not isolate the usb ground connectors from the rest of the device. so, either you're a victim to autosuggestion, or your audio-gd generally sucks with usb. your choice
 
(if you like, i can elaborate further on the matter. in that case, beware of a veeeery lengthy post.)

You bought the can of worms AND opened it  But I cant argue with your post

 

[ampair]

  You bought the can of worms AND opened it  But I cant argue with your post

 
oh yes, i do like worms. big and juicy ones. perfectly suited for throwing them in the face of whoever sold you the can

 

[Chris J]

oh, those facepalm moments...

@Lorspeaker
: i truly hope you set this as a sarcasm trap, if so then shame on me. otherwise i have bad news for you.
the only way that a "better" usb cable for the ext-hdd may have an influence (if any) on the sound, is when (a) the ground rails of your computer are noisy as hell AND (b) the usb-input of your dac is crappy enough to not isolate the usb ground connectors from the rest of the device. so, either you're a victim to autosuggestion, or your audio-gd generally sucks with usb. your choice

(if you like, i can elaborate further on the matter. in that case, beware of a veeeery lengthy post.)

I think Lorspeaker is sincere.
Lorspeaker is also entitled to his opinions.

 

[Lorspeaker]

Just a user, I replaced that stock USB cable betw the laptop n the external portable hard disk...
With an Audioquest with a micro USB cable.

been sleeping with this dt150 for months now, it is like a hd650 kind of sound in a closed can form..
The improved clarity is significantly to my ears...
And pushing the mt220 towards being a tat too bright.

Seems to runs against known digital knowledge which I hv v v little...
Always tot USB cable is just another wire in my setup...
So I tried them out with no mental resistance.
gone thru Furutech,,wireworld., LAT, cabledyne, Audioquest....
Some are bright, one bodacious, one is holographic.

Gonna plug it into the fiio e18 next session n give the fx850 a listen...can't wait.


U can start boiling the can of worms..I go enjoy my music..chow!

 

[x838nwy]

oh, those facepalm moments...

@Lorspeaker
: i truly hope you set this as a sarcasm trap, if so then shame on me. otherwise i have bad news for you.
the only way that a "better" usb cable for the ext-hdd may have an influence (if any) on the sound, is when (a) the ground rails of your computer are noisy as hell AND (b) the usb-input of your dac is crappy enough to not isolate the usb ground connectors from the rest of the device. so, either you're a victim to autosuggestion, or your audio-gd generally sucks with usb. your choice

(if you like, i can elaborate further on the matter. in that case, beware of a veeeery lengthy post.)

If the usb ground is crappy, how can the cable help? The AQ, afaik has no isolating properties. Please elaborate.

Edit: spl

 

[x838nwy]

Oh, and Lorspeaker was talking about the cable between his hdd and his pc. How does his dac's usb input have anything to do with the hdd->computer connection?

 

[Boris Bollokov]

There is no difference between £1 cable and £500 if it is built in line with the original specs. But I hear SQ improvement... no you don't, it is placebo. But I ..... no god dammit!
 
I am an Audiophile I use my ears, the real deal, not science.... Yeah cool story bro.
 
Quote:

   
I agree.
Looks crazy.  

6,500 UKP/M cables....sheer insanity
The narrow bits are high frequency content.......................I'm not expert in digital transmission, but that DOES NOT sound correct to me.   

 
When i read Jimmer's original post with that quote I LAWLED very hard. But then again not everyone knows the fundamentals of digital signals and technology standards, USB in this case.
 
Back at Uni I used Data Communications Networking 4th edition by Behrouz A Forouzan. I consider this guy to be the Boss. I wonder how he would have reacted to £500 USB cables
 
USB uses digital baseband transmission. The encoding scheme is NRZI. The USB interface never actual sends 1/0s that your PC audio driver generates. The data signal is first NZRI encoded. 
 
This NZRI encoded digital signal (square wave) is in fact a composite aperiodic analogue signal, not that it matters, just saying. If the USB cable had the bandwidth from 0Hz to Infinity the square wave would always be perfect at the receiving end. In USB binary state 1 is represented by no transition, and binary state zero by a transition.
 
Below is an example of data signal encoded via NRZI:
 

 
You can see from the above image that there simply is NO concept of narrow and wide bits. It is just transition states, in case of NRZI transition happens for binary state 1. Each USB packet starts with synchronization (SYNC) field, which is a coded sequence that generates a maximum edge transition density. 
 
I have oppo-ha 1 that uses isochronous transfer mode. The main purpose of isochronous transfer is for applications such as audio data transfer, where it is important to maintain the data flow, but not so important if some data gets missed or corrupted.  If a USB cable is made according to USB 2.0 specs, the PC and the DAC both use USB 2.0 interfaces, then the will be no corruption to the transmitted square wave, no data loss, it will be bit perfect, it will be recovered correctly by the receiver.
 
Of course if you have a source of serious EMI next to the cable, then it can corrupt the square wave, and the receiver might not be able to distinguish. 
 
Some further reading o USB clock recovery:
 
http://www.cypress.com/?docID=25374

 

[Boris Bollokov]

If the usb ground is crappy, how can the cable help? The AQ, afaik has no isolating properties. Please elaborate.

Edit: spl

 
So true, how buying a different cable going to help?
 
Within the PC chassis it is a very noisy environment. If ground noise is picked up and carried over USB pin 4 (GND), then regardless of what cable you use the noise WILL be carried.
 
Decent motherboards are likely to be engineered with USB Host EMI Layout Considerations to ensure minimal noise is picked up buy USB circuitry. Also, I would have though a decent DAC will filter pin 4.
 
http://www.ti.com/sc/docs/apps/msp/intrface/usb/emitest.pdf - Page 5

 

[Chris J]

When i read Jimmer's original post with that quote I LAWLED very hard. But then again not everyone knows the fundamentals of digital signals and technology standards, USB in this case.

Back at Uni I used Data Communications Networking 4th edition by Behrouz A Forouzan. I consider this guy to be the Boss. I wonder how he would have reacted to £500 USB cables

USB uses d[COLOR=252525]igital baseband transmission. [/COLOR]The encoding scheme is NRZI. The USB interface never actual sends 1/0s that your PC audio driver generates. The data signal is first NZRI encoded. 

This NZRI encoded digital signal (square wave) is in fact a composite aperiodic analogue signal, not that it matters, just saying. If the USB cable had the bandwidth from 0Hz to Infinity the square wave would always be perfect at the receiving end. In USB binary state 1 is represented by [COLOR=252525]no transition, and binary state zero by a transition.[/COLOR]
 
Below is an example of data signal encoded via NRZI:




You can see from the above image that there simply is NO concept of narrow and wide bits. It is just transition states, in case of NRZI transition happens for binary state 1. Each USB packet starts with synchronization (SYNC) field, which is a coded sequence that generates a maximum edge transition density. 

[COLOR=252525]I have oppo-ha 1 that uses[/COLOR] isochronous transfer mode.[COLOR=252525] [/COLOR]The main purpose of isochronous transfer is for applications such as audio data transfer, where it is important to maintain the data flow, but not so important if some data gets missed or corrupted.  If a USB cable is made according to USB 2.0 specs, the PC and the DAC both use USB 2.0 interfaces, then the will be no corruption to the transmitted square wave, no data loss, it will be bit perfect, it will be recovered correctly by the receiver.

Of course if you have a source of serious EMI next to the cable, then it can corrupt the square wave, and the receiver might not be able to distinguish. 

Some further reading o USB clock recovery:

http://www.cypress.com/?docID=25374

Wow!
I posted that way back in February 2014!

Interesting explanation, BTW.

 

[Boris Bollokov]

I was reading this thread from the start only today and that part about bits made me laugh

 

[Chris J]

I was reading this thread from the start only today and that part about bits made me laugh

Right, now I remember, Jimmers supplied us with a very funny quote from a Hi Fi magazine about "the little bits being high frequency content".
Ummm, OK.:rolleyes: