Shorting plugs - get some!

[Doc B]

Here's a link to instructions for making a shorting plug. Make two of these and use them when someone tells you to "short the inputs and listen for noise" - very simple and useful tools that should be on every bench. Thanks to our bud Voltsecond for writing this up, oh, so many years ago.

http://www.siteswithstyle.com/VoltSecond/Shorting_plug_rca/shorting_plug.html

 

[JC]

Absolutely essential in certain situations.  When I did commercial installations years ago, we carried a variety to cover the various input connectors we might encounter.

 

[VoltSecond]

Wow, 9 years ago. It doesn't seem like that long ago.

 

[Grainger49]

If you like to break in cables a pair of these and a pair of barrel connectors will do it.

 

[ssssly]

What's the difference or reasoning for using different resistances?

Or does it not really matter?

 

[Grainger49]

Each resistance "draws" a different current.  All sources have a maximum current they can deliver so if you have a resistance that is too low it draws a higher current than the source can supply and the source goes into current limit, not a good thing.

But for a "shorting plug" on inputs you just want to kill any noise there.  

Edit:  As VoltSecond points out, a shorting plug doesn't have to have a short in it, probably shouldn't for safety sake.  Shorting a source will damage the outputs of your source.S

 

[VoltSecond]

I recommend that you never use a dead short in these. Something could get broken by accident.

For digital/ video sources, use 75 ohms because that typically is the impedance the circuit is designed to work with. I'll plug "ins" and "outs" on video/ digital. High speed circuits like to be loaded on inputs and outputs.

For audio "ins" 5K works fine.  75 ohms on an Audio "in" also works great.

I normally don't plug audio outputs. If 5K gets plugged into and audio out, it doesn't overload the circuit like 75 ohms will. 75 ohms on an audio out can stress the circuit.

If you only want to build one type, build 75 ohms and be careful you don't plug it into audio outs. Write the ohms on the connector shell with a marker.

 

[Grainger49]

I have red and black Radio shack cheap RCA plugs.  You could use one color for 75 ohm loads and the other for 5k ohm loads.

 

[tbbenton]

You could use one color for 75 ohm loads and the other for 5k ohm loads.

But then you couldn't tell left and right apart! 

 

[paulw]

Oops, been using a straight bit if wire in mine for "short the input and listen for noise" duty - but that was based on the instructions in the Paramour manual in the Troubleshooting section!

Paul

 

[Grainger49]

Oops, been using a straight bit if wire in mine for "short the input and listen for noise" duty - but that was based on the instructions in the Paramour manual in the Troubleshooting section!

Paul

If that is all you use them for there certainly is no danger.  But, as VoltSecond's site points out, there are a lot of other things they can be used for.  In the other cases a short wouldn't always work.

 

[JeffYoung]

It would seem the original link no longer exists.


Since this topic is pinned, I thought I'd post a link to the last-archived version of the page:


https://web.archive.org/web/20130326014838/http://www.siteswithstyle.com/VoltSecond/Shorting_plug_rca/shorting_plug.html