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How to solder a braided shield? - Page 2

post #16 of 20
4/12/10 at 10:59pm
Thread Starter 

interconnects

As I've stated before, I intend to use it as a pair of interconnects. On the belden site, it is stated a 75 ohms impedance. However, on the takefiveaudio site, where I bought the cable, it was stated that it could be well-used as interconnects OR coaxial cables. It was a pretty good deal so I jumped on it (and my preamp's output is really high so I figured it wouldn't be so bad after all) and the plugs I bought were regular instead of 75ohms ones.

Also, if it is used as interconnects, doesn't the shield carry a signal only going outwards, i.e. going straight to ground? I know there is no such thing as an unidirectionnal current but does it also go to the speakers?
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post #17 of 20
4/13/10 at 12:23am
Quote:
Originally Posted by freakydrew View Post
What if the shield is soldered at one end and not the other?
will reduce the "antenna" issue?
Yes this is the only way a shield should be used. Using it as a ground channel will make a very dirty RFI filled ground.
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post #18 of 20
4/13/10 at 12:33am
in RCA audio cable the signal reference is the shield - you want the least extra V possible so you want the lowest resistance = most copper possible

Quote:
Originally Posted by jcx View Post
MOGAMI - The Cable of the PROS

or if you can diy:
"'Exotic cables will not stop noise. Expensive cables, even if double or triple shielded, made of 100% unobtainium, and hand woven by virgins will have no significant effect on hum or buzz. Only the resistance of the grounded conductor can make a difference.' If you have to use coax, Belden 8241F, with a low-resistance copper-braid shield, works well for audio and video."
from:
Washington June AES - SMPTE.org

to reduce RF EMI entry it is best practice to have "360 degree" shield termination - not always easy with RCA - BNC often use crimp connections that keep the whole connector coaxial throughout - in video you can often see the consequence of unsymetric shield connections

dividing the braid into 2 or more symetric bundles and symetrically soldering them to the connector would be better than just a single braid termination
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post #19 of 20
4/13/10 at 1:46am
JCX, thanks for the link.

The paper was a good read and will probably save me a ground loop in the future.
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post #20 of 20
4/13/10 at 6:19am
I have much better luck using 2 conductor cable with a shield terminated at one end.

Old school cables always had the end where the shield was connected to ground marked, so you would hook them up (L & R) the same way and not introduce a new ground loop.

Maybe I'm showing my age? But this new way of doing things seems odd, you're getting no shielding if you ground the shield at both ends as current is travelling thru.


Quote:
Originally Posted by jcx View Post
in RCA audio cable the signal reference is the shield - you want the least extra V possible so you want the lowest resistance = most copper possible




to reduce RF EMI entry it is best practice to have "360 degree" shield termination - not always easy with RCA - BNC often use crimp connections that keep the whole connector coaxial throughout - in video you can often see the consequence of unsymetric shield connections

dividing the braid into 2 or more symetric bundles and symetrically soldering them to the connector would be better than just a single braid termination
Reply
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