Preparing a Mono Jack With Lead Wire

This is a quick tutorial about soldering a female jack to a lead wire that will accept a mono plug.

Not all jacks are created equal! It is important for you to know whether you're planning on plugging a mono or stereo switch to this jack. In this tutorial, we're intending to plug in a mono switch.

We use the final product of this tutorial to switch-adapt toys, so they will function with external switches that will be plugged into the toy with a 1/8 inch mono plug.

It's important to understand the wiring of a male mono plug to understand what we'll be plugging into our female mono jack.

Look at the image.

Typically, there are two wires extending from the mono plug. Occasionally, there are three wires (as depicted in the image).

The image represents a type of wiring where two wires (black and blue) are connected to the long terminal of the plug (it is also called the "sleeve" or "shield" terminal).

In a typical mono plug, you will see two wires. One is connected to the shield, which is the longer terminal (in the image, this is the blue wire).

The other wire is connected to the "tip" which is the shorter terminal (in the image, this is the red wire).

In the mono plug, the "tip" and the "shield" are insulated from each other. But when the 'red' and 'blue' wires are connected together (through an external mechanism), then the 'tip' and 'shield' close the circuit.

When we're putting together the female mono jack, we have to make sure not to short the terminals that come in contact with the 'tip' and the 'shield'.

Unscrew the insulating black shield from the female jack.

You need to identify the "tip" and the "shield" in the female jack:

You will see a longer terminal and one or two short terminals (the image shows a plug with two short terminals).

Take a multimeter. First, just to demonstrate your use of the multimeter, make sure that the longer terminal and the sleeve are internally connected (by placing the multimeter leads to them and noting there is no resistance).

There are many possible cases, here we will address the three most common ones:

Case 1: If there's just one short terminal, that is your "tip".

If there are two short terminals, you either have a mono jack or a stereo jack.

Case 2: In the mono jack case, either one of the short terminals will be your "tip." You may still want to plug in a mono plug and ascertain that both short terminals are connected to the "tip" of the male mono plug (you do that by placing the multimeter leads, one to the red wire of the male mono plug, the other to the short terminal of the female mono jack, and noting that there is no resistance)

Case 3: In the stereo jack case, one of the short terminals will be "tip" and the other will be "ring." In this instance, it's important to distinguish which one is which, because when wiring the female jack, we want to have the lead extensions extend the "shield" and "tip" (not the "ring"). To make this distinction, plug in a male mono plug into your female jack. Use the multimeter, connect the leads between the red wire of the male mono plug, and the short terminal in the female jack. Whichever short terminal in the jack shows no resistance is the "tip", and is the one to utilize when wiring your female jack.

Make sure you size, trim and pre-tin your lead.

Identify (and label) which of the wires in the extension lead you will connect to the "tip" and the "shield" (if there are only 2-connector cable, there are no hard choices to make).

Take the female jack, and thread the pre-tinned end of the wire from the center of the jack outward, through the terminal holes. Try to bend the wire so its ends lay flush with the terminals, and the insulated parts don't block the male plug (when it's plugged into the female jack).

Solder away!

Crimp the shield terminal onto the lead wire (see picture). This secures it in place.

Visually inspect and test your jack. To test, you can both plug in a mono jack and use a multimeter.

Replace the insulation cap.

You are ready to use your lead female jack!