[Superfly]

I have a length of silver conductor instrumentation cable from a major power plant project that I was working on. I'm thinking of using it for some single ended and also some balanced interconnects and would like to hear any suggestions of how to terminate (I'm a mechanical type with almost zilch for electronic/electrical experience).

The cable has 3 insulated conductors plus a braided shield and I'm wondering how best to terminate with RCA connectors, and also with XLR connectors. For example for RCA, would you recommend using all three conductors? Should the shielding be used? If so then how/where is it terminated and is it terminated at both ends of the cable?

For XLR, three pins with three conductors seems a no-brainer but what about the shielding? Any help you could offer would be greatly appreciated.

very best regards, JJ

 

[Superfly]

Anyone willing to provide advice?

 

[Dwagun]

you can always try it and find out

here iswhat I think- for RCAs - get rid of one wire so that you're using 2 of the three wires - and use some Eichmann bullet plugs you can find them at the following places in alberta:

Audio 5.1, Edmonton
The Gramophone, Edmonton
Sarah Audio, Edmonton
General Audio, Calgary

Alternatively they are available online at www.takefiveaudio.com and are currently onsale

As for the shielding - try a set with them - then try a set without them. I imagine since they are instrument cable that they are shielded for EMI and RF interferance which is a good thing depending on how "noisy" your environment is.

Good luck

edit: sorry I forgot to also give you the net address of one of my fave DIY websites

www.tntaudio.com

there is a cable primer in there as well...good luck

 

[tommyatkins]

I think it is also often common pratice to ground one end of the shielding. Of course this is always debated...

TA

 

[Dreamslacker]

For the RCA, just use 2 of the conductors to carry the signals. Connect the shielding to ground on one side of the cable only.

 

[4fatcatz]

You've probably found the info you need but here is some additional info on the solder/mechanical end of it.

If you are using silver wire I would also suggest silver solder
as well. RadioShack sells it. Its very thin so I double up on the strands and twist them together. Its not expensive at all.

Also, when you finally solder the wires onto the RCA connector
some major cable manufacturers like to fill the RCA plug with
molten glue from a hot glue gun. I also do this and it provides for
a very very secure mechanical connection. Do this after you
try out the cable for a couple of weeks and are pleased with
its performance. The glue makes for a somewhat permanent
connection. This trick works great if you are using thin silver
wires. Good luck. Let us know how they come out.

Lots of interesting debate on silver vs silver plated vs copper.
The only thing that matters is how they work in your system.

4fatcatz

 

[puppyslugg]

You can try connecting one of the shield and 'float' the other end thru a small cap.

 

[Superfly]

Thank you all for your excellent and helpful advice,

Some follow-up questions regarding connection of the shielding: Quote:

You can try connecting one of the shield and 'float' the other end thru a small cap.

Puppyslugg: What do you mean by this (where do I connect the shield to, what value and type of capacitor, etc.)?

Quote:

For the RCA, just use 2 of the conductors to carry the signals. Connect the shielding to ground on one side of the cable only.

and Quote:

I think it is also often common pratice to ground one end of the shielding. Of course this is always debated

What is the preferred or at least typical locations for grounding? Maybe it's a dumb question but does the shield get connected to the RCA plug? to a ground connection such as on a pre-amp? elsewhere?

Final question, for XLR connectors there is a solder point connected to the connector body (and one to each of the pins). I assume the solder point on the conn. body is where to connect the shield - am I correct?

best regards and thanks once again.

 

[puppyslugg]

Superfly,

For RCA's, at one end, connect shield+negative leads to ground(body). At the other end, connect the neg. leads to the ground and connect the shield to one end of the cap and the other cap lead to the ground of the RCA. Use about a 10pf ceramic cap.

This method in theory, would eliminate ground loops and provide some RFI protection. This assume you can fit a small cap inside your RCA connector. Otherwise, try just floating(unconnected) the shield at one end.

 

[Prune]

Quote:

Originally posted by puppyslugg Use about a 10pf ceramic cap.

Where are you getting this number from? According to both pro audio folks Rane note 110, and Jon Risch (audioasylum) it should be 0.01uF (10nF).

 

[Demolition]

Quote:

Originally posted by Dwagun www.tntaudio.com

I visit TNT Audio on occasion, so I thought I'd point out the correct link: http://www.tnt-audio.com/

Quote:

Originally posted by prune Where are you getting this number from? According to both pro audio folks Rane note 110, and Jon Risch (audioasylum) it should be 0.01uF (10nF).

I've heard of people using cap values ranging from 5 pf up to 10 nf. Seems to be quite a bit of debate on what the ideal value actually is.

D.

 

[A3rd.Zero]

on XLR's:

You will want to use 2 of the center wires one for pin 2 and one for pin 3, the shield will be run to pin 1, ignore the third. you do not connect a wire to the body tab of the XLR connector, some people jumper the ground pin (pin 1) to the body, somtimes just with wire sometimes with a cap. I typically find this unnecessary.

Milo

I like Neutrik XLR's a lot.

 

[seiko_citizen]

Quote:

Originally posted by Demolition I visit TNT Audio on occasion, so I thought I'd point out the correct link: http://www.tnt-audio.com/ D.

thanks for the correct link.

was lookin at the first web link and the content was one of the incorrect content