[sdiy] grounding sheilded wire?

[Larry]

Okay, I'm new and I admit it.  So my, probably heard it a thousand times 
before, question is: What type of shielded wire should I get?

I now know to connect the shield at the PCB, and cover the unconnected 
shield at the front panel to prevent accidents.  But what kind of cable 
should I buy?  (I presume RG-59 is NOT a good choice.)

Actually, what is a good choice of cable for patching when using:
Banana Plugs?
1/8" Jacks?
1/4" Jacks?

Thanks to everyone for all the interesting discussions on circuits in the 
list recently.  I might finally learn to understand all this analog stuff 
at last...  (Thick as my head is, things do, eventually, soak in.)

Larry Troth

At 09:35 PM 10/1/01 -0400, you wrote:
>Its still a good idea to ground the shield at one end... even for the
>"tip only" type plugs. This will minimize capacative coupling between
>the wires.  Terminate the shield at the PCB end... and leave the jacks
>connected only by the center conductor. I like a little piece of heat shrink
>tubing at this end to make things pretty.
>
>H^) hary
>
>Dave Krooshof wrote:
>
> > >But I wonder
> > >how I am supposed to ground the sheild, do I just connect one end to 
> ground
> > >and leave the other end floating?
> > Ideally, each module of your synth is grounded in only one way.
> > This means that if you connect the shield of your wire to
> > ground on both ends, that your likely to have more then one
> > ground lead, simply because you'll probably connect more then one
> > lead to a module, and you might have chosen to connect it to ground
> > internally as well.
> >
> > What you can do, is to make a central ground somewhere in the
> > middle of your box. Then you connect each module's ground to that.
> > (like a star) The female connectors of your modules are grounded
> > to the modules ground.
> >
> > Then your wires. In a jack plug, I'd connect the shield to one connector.
> > I'd leave it unconnected on the other side. This way, you won't
> > connect two "beams" of the "star". I might be wrong, but a banana plug
> > doesn't have a ground ring, does it? What I call a banana plug is a
> > one-tip-only thing.
> >
> > I do not know is shielding is of much use then. It might even work as
> > a small capacity... Do you happen to have any hum/hf problems
> > that make you want to shield?
> >
> > >is it ok to just have wires
> > >tapping ground with loose (ie not connected to anything) ends?
> > >or does it need to go in some sort of continuous loop?
> > Synths differ from "guitars with effects" in the fact that
> > guitarist tend to patch modules in a line...
> > guitar-->fuzz-->wah-->flanger-->chorus-->amp.
> > They connect the shielding to earth in the amp, so everything
> > inline is grounded.
> >
> > ...and synthesizer players tend to build networks, in which their
> > modules can be connected in more then 2 ways. If you'd choose
> > to ground all shieldings of your wires on both ends, you'd make
> > loops in the grounding. Ground-loops are a problem because they
> > behave like a dynamo: The alternating magnetic fields of
> > electricity in your house will generate some current flowing
> > in your groundloop (a simple coil). Hummmmmmm....
> >
> > Dave
> >
> > BTW in the studio-control room, I can patch the mixerconsole
> > to either the studio, the theater, or the dance theatre. I
> > measured their grounds... 4 volt AC. I decided to connect a led.
> > I glowed! In the building are 3 rods in the ground to ground
> > the building. The Amsterdam soil is a battery...