Gordon Rankin Says I'm Wrong About USB Cable Sound!

[Blizzard]

This thread is just going in circles. It's almost like the movie "Groundhog Day"

[jabbr]

Yes, well as the math behind such tests haven't changed what else would you expect?

 

Now as for me now vs then, I don't much care to discuss DBT in an open forum full of people already intent on not believing them. You end up explaining why the most common objections offered aren't true. Only to find them brought forward again, and again by people intent on not believing. I did reply to Daudio with the formula.

 

Incidentally if you want 3 sigma results for 20 trials the number is 17 or better.

 

If someone is doing a DBT I would discuss the ins, outs, experiences, pitfalls and what I know which isn't all that much. As for discussing whether it works or not not? My opinion is it works, if you don't believe it too bad not my problem.

 

Seriously: I will believe *any* DBT you do. I believe in DBT. Honestly. Now the conclusions you may draw from a specific DBT, perhaps that is where we may disagree. For example: a DBT does not equal a proof of a given question, nor does it guarantee extension to a larger population.

 

As a member of the NAS stated just before giving a lecture that I attended over 30 years ago: "Half of what I am going to tell you today is completely false. The problem is that I don't know which half." He went on to explain that if every breakthrough published in "Science" or "Nature" went on to actually be a breakthrough, that we would (collectively) be a lot smarter today than we are. Its not that the math behind the statistics is faulty, rather that the study hasn't been designed properly or can't be extended to the general population (hidden or overt bias in the sample population).

 

Real science is very hard. Casual get togethers for blind listening sessions are fun but ... best to drink wine and have fun:) ***

 

*** corollary is that if you have enough $$$$ to blow cash on snake oil then consider for any silly spending on a fancy cable, or some widget that you have no idea how it works or what it does, donating $/$ to a good charity. That will make your audiophile Ethernet cable sound just that much better!

[Paul R]

Apparently, what you're saying is that it's perfectly okay to call another member "dumba$$" and tell them to "GFYS" (go F yourself), if they call you out for deliberately ignoring OP thread instructions, and for making multiple OT posts (which you have a known history of doing).

 

Strange site (CA). Some of the more professional sites ban that type of behavior.

 

esldude's profile

 

(amusement) And which ones would those be?

 

The level of civilized behavior here, despite the occasional lapses, is quite significantly higher than on most other audio sites. Oh, except for the ones strictly moderating content because they are trying to sell you something or another...

 

-Paul

[YashN]

Now if the company was Monstrous, and hated by nearly everyone

 

I think I see what you did there!

[AudioBang]

I did an experiment in shielding all of my cables based on a Stereophile review of JPS Aluminata cables.

I recently bought an Antipodes DX and a Vega DAC. I started with a 20" Belden USB cable, got used to its character for two weeks and then tried a shield over it using roughly a one-inch bicycle tube the length of the cable filled with copper shot around the USB cable. As with the interconnects, AC and speaker cable, the sound got a little squirrely at first but after five minutes it began settling in and presented a smoother presentation - most noticeably, less irritating sparkle in the treble and deeper, more controlled bass. I recently bought a 20" WireWorld Platinum Starlight 7 and got similar results.

Interestingly, out of the box, the first thing I noticed was deep, powerful bass on the WireWorld USB. After a week the bass became more subdued.

I have no way of measuring to confirm but I am convinced RF has a way of contaminating any signal. I read a whitepaper that discussed how a grounded foil shield has a way of acting as an antennae that then radiates absorbed RF into the conductors of the cable. The interconnects made the most difference and is the best place to start. I thought this experiment with the USB was relevant to the blog...

[THLucius]

i would like to ask if i want to made a USB cable with 90ohms

shall i connect the resistors in both D- and D+ add up to 90ohms?(about 45ohms in each channel)

Or i could just connect the resistors in either D- or D+ with a single resistor?

Thank you

[gmgraves]

On 12/16/2018 at 3:12 AM, THLucius said:

i would like to ask if i want to made a USB cable with 90ohms

shall i connect the resistors in both D- and D+ add up to 90ohms?(about 45ohms in each channel)

Or i could just connect the resistors in either D- or D+ with a single resistor?

Thank you

None of the above. If you want a 90Ω USB cable, buy a 90Ω USB cable. You can't get there with resistors. 

[yamamoto2002]

On 12/16/2018 at 8:12 PM, THLucius said:

shall i connect the resistors in both D- and D+ add up to 90ohms?(about 45ohms in each channel)

Or i could just connect the resistors in either D- or D+ with a single resistor?

 

This 90Ω is characteristic impedance. This means, if that usb cable has infinite length and when register value between D+ and D- is measured by resistance meter, the meter will indicate 90Ω no matter what connects to other end of the cable. Characteristic impedance varies on cable structure and insulation material. It becomes more important when signaling rate increases

[mansr]

1 hour ago, yamamoto2002 said:

This 90Ω is characteristic impedance. This means, if that usb cable has infinite length and when register value between D+ and D- is measured by resistance meter, the meter will indicate 90Ω no matter what connects to other end of the cable.

No, that is not what it means. https://en.wikipedia.org/wiki/Characteristic_impedance

[marce]

Heaviside rules.? The basics have stood the test of time...

[Ralf11]

was he on the Sven & Ollie show?

[yamamoto2002]

15 hours ago, mansr said:

No, that is not what it means. https://en.wikipedia.org/wiki/Characteristic_impedance

Thanks for your reply. I read the description above about characteristic impedance from some local magazine. My memory is faded but the description continues as follows: in order to test the characteristic impedance using this method, really long cable is needed and there is a illustration of the earth and moon and a cable to measure. On other end of the cable, an incandescent lamp is connected. From my understanding, first 1.3 seconds or so resistance meter shows 90Ω when cable characteristic impedance is 90Ω

[mansr]

4 hours ago, yamamoto2002 said:

Thanks for your reply. I read the description above about characteristic impedance from some local magazine. My memory is faded but the description continues as follows: in order to test the characteristic impedance using this method, really long cable is needed and there is a illustration of the earth and moon and a cable to measure. On other end of the cable, an incandescent lamp is connected. From my understanding, first 1.3 seconds or so resistance meter shows 90Ω when cable characteristic impedance is 90Ω

That's not a very helpful way of describing it. Characteristic impedance is an AC phenomenon and is best analysed in terms of steady state sinusoidal signals.

[yamamoto2002]

3 hours ago, mansr said:

That's not a very helpful way of describing it. Characteristic impedance is an AC phenomenon and is best analysed in terms of steady state sinusoidal signals.

I agree it is much better to analyze with AC signal for practical purpose. But this very long cable experiment example provides some basic aspect of this phenomenon to person who never need to measure cable characteristic impedance

[yamamoto2002]

On 12/23/2018 at 2:32 PM, yamamoto2002 said:

Thanks for your reply. I read the description above about characteristic impedance from some local magazine. My memory is faded but the description continues as follows: in order to test the characteristic impedance using this method, really long cable is needed and there is a illustration of the earth and moon and a cable to measure. On other end of the cable, an incandescent lamp is connected. From my understanding, first 1.3 seconds or so resistance meter shows 90Ω when cable characteristic impedance is 90Ω

 

I found the experiment video about this topic. Interesting video.