How to Solder Banana Plugs
How to solder banana plugs depends on the type of banana plug and the thickness of the wire.
Banana plug is a cylindrical, single-wire, male connector used for joining wires to electrical equipment.
It is typically used for audio or video connection such as to connect speaker, amplifier, or other electronic devices. A banana plug has a similar shape to an RCA plug.
In addition, banana plugs connected to high-voltage cables can be used on test equipment.
The banana plug has a stronger grip on the mating banana jack and is preferable for heavier wires or in high voltage uses where safety is a concern.
A banana plug can be a stackable plug with a 4 mm hole either on the side or on the back. This allows multiple connections at a single point.
The majority of banana plugs come in red and black color. Red banana plugs are typically used for connecting positive electrical signals while black banana plugs are used as ground connections.
There are many different types of banana plugs. In this guide, we will solder the following model: stackable, 4mm, four-leaf banana plug.
The first step is to prepare wire which will be soldered to a banana plug. Stranded wires are more flexible than solid wires. If you are soldering a thin solid wire (22 AWG or thinner wire) to a banana plug, it may easily break especially if it is bent a few times.
Remove 3/8” (9.5 mm) of wire insulation with wire strippers.
It is easier to prepare the wire correctly for soldering if you strip insulation longer than needed, and then, after tinning, cut off the excess of the inner conductor.
Take wire strippers with one hand and hold the wire with the other hand.
Run the wire through the proper gauge slot on wire strippers. By doing this you will avoid any risk of nicking or scratching bare wire.
Press down the handles of wire strippers to cut into the insulation. Keep the jaws of the wire strippers perpendicularly to the wire. Once the jaws are positioned to the correct point move them towards the end of the wire.
In this guide we are using 18 AWG stranded wire, so we need to run it through the 18 AWG gauge slot on the wire strippers.
Twist the strands of stranded wire together so they will stay in place during soldering.
Banana plugs are big metal connectors, so for heating them you will need to use a bigger iron tip. In this guide, we will use a screwdriver tip 3/32” (2.38 mm). Replace the iron tip and then turn on the soldering iron.
Soldering banana plugs requires a lot of heat. When soldering banana plugs, you should set soldering iron to a higher temperature than when soldering circuit boards. Set temperature of soldering iron to 750 F (400 C).
Mount wire in the third-hand tool to hold wire (you can use a small vise or another holder).
Apply a small quantity of rosin flux to the top surface of the exposed wire while you are waiting for the soldering iron to heat up.
Place the tip of the soldering iron to the wire.
Molten flux will flow from the top to bottom surface of the wire caused by gravity.
Add solder to the wire at the area where iron touches the wire.
Make sure that solder flows into the strands of the stranded wire and not just on the surface.
Solder Banana Plugs
Before you start to solder banana plugs, you need to take apart banana plugs
Unscrew the barrel of the banana plug from the metal body.
Different types of banana plugs come with different barrels (metal or plastic).
Slide the barrel on the wire to be soldered.
This is a very important step – if you forget it, you have to de-solder wire from the banana plug, run the wire through the barrel and again solder the wire to the banana plug.
Insert wire into the cup of the banana connector to measure the proper length of the wire.
Insulation of wire should be flush with the end of the banana plug when the wire is fully inserted.
Cut the excess of the wire with wire cutters.
Place the metal body of the banana plug in a small vise.
Start heating the banana plug with the soldering iron.
It will take some time to heat this big metal connector.
After 5 seconds feed solder into the cup of banana plug – not to the iron tip. Sooner or later solder will start to melt filling the cup.
Don’t feed too much solder since it will spill once you insert the wire.
Use soldering wire with a diameter of 0.031” (0.8 mm) or with a bigger diameter.
Quickly insert the wire when the most of cup is filled with molten solder.
Remove soldering iron and place it on the iron stand.
Continue holding the wire with your hand until the solder solidifies. Part of the wire close to the solder joint will get hot during soldering so hold the wire at the point that is at least 4” (10.16 cm) from the solder joint. You can use small pliers to hold the wire as well.
Insulation of wire may shrink a little bit during soldering.
The banana plug is very hot at this point. After you solder banana plugs, wait at least a couple of minutes to allow banana plugs to cool down.
Screw the barrel back to the body of the banana plug to cover the solder joint.
Connect banana plugs without soldering
Soldering is the best way of connecting wires to banana plugs. It provides an excellent electrical and mechanical connection.
A decent connection between wire and banana plug can be done without soldering as well.
For this connection, you can use either the stranded or solid wire.
The following is one sample of connecting a wire to a banana plug without soldering:
Remove 1 inch (25.4 mm) of wire insulation from wire ends with wire strippers.
Twist the wire with fingers if you are using stranded wire.
Run the wire through the hole in the metal body of the banana plug
Fold the wire as shown in the picture.
Slide the sleeve on the metal body of the banana plug.
There is a groove inside the sleeve left to run wire.
Pay attention to proper sleeve orientation.
Now, you need to push the metal body of the banana plug inside the sleeve.
For this operation, you may use the tool shown on the image.
Push the metal body inside the sleeve all the way until you hear a click.
That means that sleeve has been locked to the metal body of the banana plug.
Updated: April 22, 2021