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Diy Y usb cable

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hello guys, I would like to build a y-usb cable to power the dac externally (more for fun than for real necessity).
I can't find certified USB cables sold by the meter but I found among others, this belden 9829 cable...it is a low voltage cable for computer, for rs232/422 application, twisted pair,double shielded, 100ohm impedance. so it seems to me that it has many of the features of a usb cable.
Here the Datasheet:
https://catalog.belden.com/techdata/...9_techdata.pdf
Click the image to open in full size.
do you think it would be okay?
I would use only 1 pair of Wire, for data, and just the negative for the common ground.

The second option is to buy a cheap usb certified cable and cut off the ends, like a lindy cromo.
thank you so much

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USB is 90ohm +/-15%, the faster you use it the less deviation from a true 90ohm you want...

Soldering the wire to the connector is where the fun is, buy extra connectors and practice, you can get little clamps with multiple croc. clips that are great for holding everything in place and ensuring no movement of the joint while it forms. This is the most common problem when soldering wires to connectors.

I would not leave a wire unconnected, use both wires of the second pair for the 0v/return connection.

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100% agreed , but the fun bit will be getting both wires into the 0v/"Earth" return though if using normal solder type USB plugs.

 Yes, quite a bit of practice is needed, and a steady hand.

It would also be helpful to use a soldering iron like the attached too.

 

https://www.jaycar.com.au/13w-goot-leightweight-soldering-pencil/p/TS1446


"If you can't hear the difference between an original CD and a copy of your CD,

you might as well give up your career as a tester. The difference between a reconstituted FLAC and full size WAV is much less than that, but it does exist. - Cookie Marenco"

 

PROFILE UPDATED 31-10-2018

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The strain relief is really tough to get right.  I'd just buy prefab, usually have the connectors molded and it's not an issue.

 

That is very small diameter wire and it is stranded, so it will be very brittle at the solder joints. Serial is pretty low speed, there is better spec'd stuff out there.

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12 hours ago, sandyk said:

 

100% agreed , but the fun bit will be getting both wires into the 0v/"Earth" return though if using normal solder type USB plugs.

 Yes, quite a bit of practice is needed, and a steady hand.

It would also be helpful to use a soldering iron like the attached too.

 

https://www.jaycar.com.au/13w-goot-leightweight-soldering-pencil/p/TS1446

Its 0V/return NOT earth!!!

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25 minutes ago, marce said:

Its 0V/return NOT earth!!!

 

NIT PICKING !!! 

I said 0V/"earth" , with the earth in inverted commas. It can be both in a PC powered via a 3Pin A.C . mains plug. :P

 In fact, in that case when you plug in a USB memory stick or other device which has both shield and 0v connected internally, you may end up with a minor EARTH LOOP !


"If you can't hear the difference between an original CD and a copy of your CD,

you might as well give up your career as a tester. The difference between a reconstituted FLAC and full size WAV is much less than that, but it does exist. - Cookie Marenco"

 

PROFILE UPDATED 31-10-2018

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4 hours ago, Speedskater said:

There are many points in a system that might be casually called earth. Only one of those points is the correct one.

 

I am not so sure about that. :)

Earth = Earth. And possibly that is not used at all.

 

On 4/29/2019 at 1:07 PM, sandyk said:

you may end up with a minor EARTH LOOP !

 

As in from Sydney to Amsterdam and back without turning around ? :P


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11 hours ago, Speedskater said:

Not NIT PICKING at all!

'earth is a way, way overused term.  There are many points in a system that might be casually called earth. Only one of those points is the correct one.

The term "earth" should only be used for points in a circuit with a low-impedance connection to the actual earth, typically via the mains safety ground.

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36 minutes ago, mansr said:

The term "earth" should only be used for points in a circuit with a low-impedance connection to the actual earth, typically via the mains safety ground.

 

It's STILL NIT PICKING.

This an Audiophile Forum not an Engineering Society type forum.

 You aren't going to make the rest of the world conform to recent changes as much as you would like to think you can.

 We have more than enough " Political Correctness"  already..

Go preach this to people who draw schematics like the attached, which are still in common usage.

 I hope there are enough " Earth" symbols there for you ! :P

40uV schematic.jpg

figure-1groundingsymbols.bmp


"If you can't hear the difference between an original CD and a copy of your CD,

you might as well give up your career as a tester. The difference between a reconstituted FLAC and full size WAV is much less than that, but it does exist. - Cookie Marenco"

 

PROFILE UPDATED 31-10-2018

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36 minutes ago, mansr said:

Words have meanings. Get used to it.

In case you missed it, I also included the currently accepted symbols that I am well aware of, but unlike you and a few other E.Es I am not on a mission to try and force others to conform to your elitist standards.

 

 

figure-1groundingsymbols.bmp


"If you can't hear the difference between an original CD and a copy of your CD,

you might as well give up your career as a tester. The difference between a reconstituted FLAC and full size WAV is much less than that, but it does exist. - Cookie Marenco"

 

PROFILE UPDATED 31-10-2018

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12 minutes ago, sandyk said:

In case you missed it, I also included the currently accepted symbols that I am well aware of, but unlike you and a few other E.Es I am not on a mission to try and force others to conform to your elitist standards.

 

 

figure-1groundingsymbols.bmp 539.53 kB · 1 download

Pathetic response and another waste of a thread by your silliness. Its nothing to do with elitist standards, is safety, common sense and a chance for some to learn a bit more. Just having a go at people just because they are objective is childish and silly... 

Its standards, so that everyone reading a schematic understands it and more importantly its for SAFETY reasons.

So please try and stop, I've already spoken to one person who's given up here largely due to a lot of your silliness, I will be next for another hiatus, as you derail sensible conversations with your anti EE and science rants or personal put downs, you are a true troll

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1 hour ago, sandyk said:

 

It's STILL NIT PICKING.

This an Audiophile Forum not an Engineering Society type forum.

 You aren't going to make the rest of the world conform to recent changes as much as you would like to think you can.

 We have more than enough " Political Correctness"  already..

Go preach this to people who draw schematics like the attached, which are still in common usage.

 I hope there are enough " Earth" symbols there for you ! :P

40uV schematic.jpg

figure-1groundingsymbols.bmp 539.53 kB · 1 download

That schematic is wrong, you should use signal ground and show this connected to earth at one point, usually a connector.

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You are the Troll with your monologues about your expertise with  Motherboard multi layer PCB designs etc. which are of no interest to the vast majority of members, neither have I seen you offer any suggestions for the improvement of Computer Audio.

YOU started this recent bout of silliness with your NIT PICKING reply when you fully understood what I was saying, when I even  put inverted commas around " Earth" to indicate that I wasn't referring to actual mains earth.

 There was no need whatsoever for you to further reply.


"If you can't hear the difference between an original CD and a copy of your CD,

you might as well give up your career as a tester. The difference between a reconstituted FLAC and full size WAV is much less than that, but it does exist. - Cookie Marenco"

 

PROFILE UPDATED 31-10-2018

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9 minutes ago, marce said:

That schematic is wrong, you should use signal ground and show this connected to earth at one point, usually a connector.

 

 Of course I know the damn thing was wrong by today's standards. I just posted it to show that people worldwide aren't so concerned as you are, as  long as they get their message across.

Some Electronics publications still use different too, because that's what their readers are accustomed to.


"If you can't hear the difference between an original CD and a copy of your CD,

you might as well give up your career as a tester. The difference between a reconstituted FLAC and full size WAV is much less than that, but it does exist. - Cookie Marenco"

 

PROFILE UPDATED 31-10-2018

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2 hours ago, mansr said:

The term "earth" should only be used for points in a circuit with a low-impedance connection to the actual earth, typically via the mains safety ground.

The basic definition for the word 'ground' is:

Common reference point.

But unfortunately the terms "earth" or "ground" correctly refer to many different points and incorrectly to many other points.

Some real grounds/earths:

a] Safety Ground/Protective Earth connection to power company AC Neutral.

b] Planet Earth connection to power company AC Neutral.

c] Component chassis.

d] Audio circuit common.

e] Digital Circuit common.

f] DC supply common.

While there is often continuity from one to another, each of these points has it's own tasks.

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9 minutes ago, Speedskater said:

The basic definition for the word 'ground' is:

Common reference point.

But unfortunately the terms "earth" or "ground" correctly refer to many different points and incorrectly to many other points.

Some real grounds/earths:

a] Safety Ground/Protective Earth connection to power company AC Neutral.

b] Planet Earth connection to power company AC Neutral.

c] Component chassis.

d] Audio circuit common.

e] Digital Circuit common.

f] DC supply common.

While there is often continuity from one to another, each of these points has it's own tasks.

 

 I have now already twice posted the currently accepted symbols. All you need to do is open the damn posted .bmp image !!! 


"If you can't hear the difference between an original CD and a copy of your CD,

you might as well give up your career as a tester. The difference between a reconstituted FLAC and full size WAV is much less than that, but it does exist. - Cookie Marenco"

 

PROFILE UPDATED 31-10-2018

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2 hours ago, mansr said:

The term "earth" should only be used for points in a circuit with a low-impedance connection to the actual earth, typically via the mains safety ground.

While there is continuity from Planet Earth to the Safety Ground/Protective Earth system. It's not the task of the SG/PE system to connect to Planet Earth. There is a separate system that connects to the ground rods.

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4 minutes ago, sandyk said:

 

 I have now already twice posted the currently accepted symbols. All you need to do is open the posted .bmp image !!! 

Those symbols are an oversimplification for drawing schematics, but electricity doesn't read schematics.

I'm sure that 'marce' has seen countless examples of engineers that incorrectly thought that electricity would follow their schematics.

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Just now, Speedskater said:

Those symbols are an oversimplification for drawing schematics, but electricity doesn't read schematics.

I'm sure that 'marce' has seen countless examples of engineers that incorrectly thought that electricity would follow their schematics.

 This isn't the appropriate Forum to discus this kind of subject.

Neither does it have any relevance to the question originally asked by the OP.


"If you can't hear the difference between an original CD and a copy of your CD,

you might as well give up your career as a tester. The difference between a reconstituted FLAC and full size WAV is much less than that, but it does exist. - Cookie Marenco"

 

PROFILE UPDATED 31-10-2018

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