What is a Headphone Jack? | A Complete Guide

AA headphone jack is an electrical connector used to transmit audio signals from a device to headphones.

Headphone jacks come in different sizes, including 6.35mm, 2.5mm, and 3.5mm, which is the most versatile of the three jacks.

The 3.5mm jack allows you to perform various operations, such as transferring videos and connecting a game system to a television. 

This article covers everything you need to know about headphone jacks, the various types that exist, how they work, and how to replace faulty jacks.

What is a headphone jack?

Also referred to as a phone jack, audio jack, or jack plug, a headphone jack is a pin-shaped phone connector that allows you to connect your smartphone to a pair of stereo headphones.

a headphone jack
A headphone jack

They are also used to establish a connection between your smartphone and other equipment like a TV or home theater.

Types of headphone jacks

Headphone jacks are available in three different sizes, each with its unique set of features. 

These are the three sizes of the headphone jack:

  • 6.35mm headphone jack
  • 3.5mm headphone jack, and
  • 2.5mm headphone jack

6.35mm headphone jack

A 6.35mm headphone jack, popularly known as a quarter-inch jack, is used to play mono and stereo audio. 

It was initially designed to connect handsets, headsets, and microphones to communication circuits.

The 6.35mm headphone jacks are widely used for audio areas, and they remain the standard of music studios and musical equipment. 

This headphone jack is more durable and solid compared to other jack plugs.

Despite its versatility, this audio jack may be too large for most portable devices. 

What is the 6.35mm headphone jack used for? 

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Amplifiers or AV Receivers

The 6.35mm jack plugs are commonly used to connect earphones to amplifiers and television sets.

Musical Equipment

This plug’s mono function makes working with musical instruments such as guitars and keyboards easy.

Stereo Usage

The stereo version of the 6.35mm jack plug can be used as a stereo cord, allowing for a more natural and dynamic audio transmission.

3.5mm headphone jack – The standard audio jack size

Also referred to as a mini-jack, the 3.5mm headphone jack is the most widely used and standard type of jack plug. 

It is a smaller version of the 6.5mm headphone jack and supports mono and stereo audio and a microphone for making phone calls.

Unlike the 6.5mm headphone jack, the 3.5mm jack plug is suitable for portable electronic devices. 

What is the 3.5mm headphone jack used for? 

Smartphones

Most smartphones come with audio ports that can accommodate 3.5mm headphones.

Laptops and PC

3.5mm is the standard audio jack for PCs and laptops.

Digital Audio Players

Audio devices, such as cassette players, are well-suited to the 3.5mm jack connector.

Phone calls

The microphone function of this audio jack allows you to make calls with ease.

2.5mm headphone jack

Also referred to as a sub-miniature jack, the 2.5mm headphone jack is the smallest type of audio connector.

Although some headphones still use this connector, it is not as common as the 6.5mm and 3.5mm jack plug.

Like other headphone jacks, the 2.5mm connector also supports microphone and speaker audio, and they are commonly found on communication devices such as wireless phones and two-way radios.

How does a headphone jack work?

Now you know the types of the headphone jack, let’s move on to how they work and the different formations.

The plug, which is the main point of an earphone jack, transfers audio sources from electronic devices to headphones.

Once a functioning plug is inserted into your smartphone’s audio port, sound will automatically be transmitted to your earphones.

Headphone jacks have three formations which include TS, TRS, and TRRS. Let’s look at the different forms of headphone jacks and how they work.

TS headphone jack

The term TS stands for Tip and Sleeve, which refers to the actual construction of the plug’s contact points. 

The Tip manages the left audio channel, while the Sleeve controls the ground. The TS is a mono headphone jack because it has a single audio channel.

When you cut open your headphone cable, you’ll discover that the jack consists entirely of wired circuits. 

A TS audio jack is designed with a copper wire ground sheath wrapped by one blue wire. The blue wires are usually the left audio channel, while the other wires you’ll find serve as the ground wire.

TRS headphone jack

A TRS headphone jack is divided into three parts- Tip, Ring, and Sleeve. 

TRS jacks are common in 3.5mm headphone jacks and are always found on standard headphones that offer stereo sound but do not feature a microphone.

On the TRS audio jackshaft, there are two colored rings, with the ring located in the middle. The Tip is in charge of the left audio channel, while the ring is in charge of the right channel. Lastly, the Sleeve, located at the end of the plug, serves as the ground.

TRRS Headphone Jack

TRRS stands for Tip, Ring, Ring, and Sleeve. TRRS jacks are commonly found on 3.5mm headphone jacks, and they support stereo, sound, and microphone functions. 

The TRRS headphone jack supports microphone function because of its extra ring, serving as a microphone signal.

Here’s how the TRRS construction works; 

The Tip receives the mixed stereo signal, while the ring receives the signal from the microphone. 

The TRRS headphone jack has three wire connections; red, green, and copper wire connections.

The copper wire is located inside the sheath, and it receives the microphone signal. 

The red and green wires, on the other hand, are located on the outside sheath, and they serve as the microphone ground.

How To Replace A Headphone Jack

Note that this task requires you to have some soldering skills. 

If you’re new to soldering or haven’t done it in a while, you can watch some videos to see how it’s done.

Before replacing your damaged headphone jack, ensure you have the following items. You will need them in the replacement process.

Steps 

Step 1: Cut out the old jack

  • Grab your old jack plug and wire-cutter, and then cut through the wire as close to the plug as possible. 

If your faulty jack plug is molded, you can dispose of it as you will no longer be able to use it.

  • If you use a standard pair of headphones and need to replace the jack plug, you need a 3.5mm stereo replacement jack plug. 

You can get this connector from any electronic store nearby or order one online. 

Moreso, ensure your new jack is a stereo one as mono plugs are usually very similar in appearance.

Step 2: Cut your cables

A headphone has two cables inside it. You’ll find several colored wires running through your headphone when you cut the cables. 

One of the cables runs through the left earbud and the other through the right. They are usually red and green colors.

  • Carefully strip the colored wires back to create space between the colored wires and the shiny bare wires. 
  • Separate the colored wires from the copper wires by twisting the two copper wires together. Once you are done, you should have three sets of wires instead of four.

Note that some headphones are wired differently. Usually, you’ll find one red wire, one green wire, and a set of copper wires. 

At times, the copper wires may come in striped colors, and it may be confusing. 

The stripped wire is equivalent to the shiny copper wire in other cables. So, don’t get confused.

Step 3: Remove the insulation

  • Next, take your lighter or matches and heat the ends of all three wires for a few seconds to burn off the insulating covering. 

Note that if you skip this step, you won’t be able to solder the wires to the jack properly, which means the jack won’t work. 

Ensure you don’t burn off too much of the wires while doing this. (If the wires turn out to be black and brittle, it means you’ve damaged them.)

  • Unpack your jack plug to reveal the three terminals and then pass the cable through the plug’s top plastic part (also known as the cover). 

If you fail to do this before you solder the wires, you may have to unscrew everything and start over.

Step 4: Check the jack again

  • Tin the bare wires to create strong joints. 

It is necessary to have a strong mechanical connection between the wires and the terminals before soldering. 

Do this by sticking the wires through the holes and wrapping them around a couple of times.

  • Double-check the wiring and make sure the connections are firm. Once you have done this, plug in the headphone to your phone to see if it works. 

You made all the connections correctly if the headphone gives you crack sounds when you jiggle the wire. 

There’s nothing to worry about; the crackly sound will disappear when you solder the wires. 

If you don’t hear any sound, confirm that you made all the connections correctly.

Step 5: Solder the wires

  • Solder the shiny copper wire to the large outer terminal, the one with the cable clamp on top. 
  • Solder the green wire to the left terminal and the red wire to the right terminal.
  • Use your bulldog clips or vise to hold the jack plug while soldering. If you hold the plug with your bare hands, you may burn your fingers. 

Also, ensure the jack plug is completely secure and motionless before soldering the wires; you’ll end up with a poor and unreliable connection if the jack plug moves as you solder.

If you mix up your colored wires, the headphone will still produce sound, but the left and right channels will be switched over.

  • Once you’ve soldered the wires, carefully place them inside the clamp. The clamp is located at the top of the jack plug. 
  • Now tighten the wires with a plier to create a strong unbreakable connection. 

Holding the wires with a plier ensures that they don’t break when you pull on the cable.

Step 6: Push all of your soldered wires toward the center, ensuring that they will fit snugly when you finally screw the jack. 

Also, make sure all your wires are clear of one another once you are done soldering and pushing them in. 

If they come in contact, you may lose sound in one or both of your headphones.

Step 7: Secure the wires with insulating tape

This is so that they don’t create an electrical connection even if they touch each other. 

Screw the top of the jack and test the headphone. If you don’t get any sound, you may have to check your connections again.

Conclusion

Headphones aren’t built to last for long, and their jack plugs can fail at any time. 

If you notice that your headphone jack plug is malfunctioning, you can purchase a new one and replace it yourself.

Carefully follow all the steps listed in this guide, and you’ll get your headphones working properly again.

Jude is a music and headphone lover. He has tested and reviewed several audio listening devices and enjoys writing helpful tips and information for readers like you.