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Are Aux (Auxiliary) Connectors & Headphone Jacks the Same?

We often get asked are aux (auxiliary) connectors & headphone jacks the same? If you took them at face value, you would say yes, they are the same. But you probably didn’t realize they are two different cables that share many similarities.

Aux connectors look the same as headphones connectors sharing a 3.5mm (1/8”) TRS plug. The definition of an aux connector is a cable for universal audio. While a ‘headphone jack’ is more suited to headphones, they do come in many different sizes.

So, let’s take a more in-depth look at the similarities and differences.

What Are Headphone Jacks?

Headphone jacks send audio signals to your headphones. The jack that goes into the headphones is the female connector, while the jack at the end of the cable is the male connector. The output impedance of headphone jacks is 24 Ω, while the impedance of actual headphones is usually between 8 Ω and 600 Ω. However, 32V is becoming a standardized level.

The differences in headphone jack impedance in comparison to headphones impedance can sometimes cause issues. For instance, headphone jacks can’t handle the high-impedance of professional headphones or audiophile models.

If this is the case, you will need a headphone amplifier to boost the voltage. Bridging the impedance between the headphones jack and high-end headphones is essential.

The best headphone amplifiers…

 best headphone amplifiers

If you do need a headphone amplifier to boost the signals to your headphones, check out these highly recommended products.

Neoteck 3.5mm Headphone Amplifier

This mid-range product is an affordable portable HiFi headset amplifier that has a two-way gain switch. This is a great entry-level product if you have new pro headphones.

Fosi Audio Q4 Headphone Amplifier

This high-end headset amp booster is also a digital to analog converter that would be ideal for those with a professional studio setup.

Creative Sound BlasterX G5

This is another high-quality market-leading headphone amplifier for pro setups. This is the ideal headset amp to use with Windows, PS4, or Mac.

Here are some examples of headphone jack sizes:

  • 2.5mm (3/32”)
  • 3.5mm (1/8”)
  • 4.4mm
  • 6.5mm (1/4”)

Headphone jacks use what are referred to as tip, ring, and sleeve connections. They are usually denoted by their abbreviations. These are often described as ‘poles,’ and each one has a connection that carries audio signals. However, these types of jacks can also be equipped with many poles. Here are some examples of the most common.

  • TS (tip-sleeve)
  • TRS (tip-ring-sleeve)
  • TRRS (tip-ring-ring-sleeve)
  • TRRS (tip-ring-ring-ring-sleeve)

The most common headphone jack is the 3.5mm TRRS connection. This is the variety you will usually need for a laptop, older smartphones, or a tablet. This type of connector can also work as a TRS or TS plug.

What are Aux (Auxiliary) Connections?

Now we have learned the basics about headphone jacks; we need to learn more about aux. What is an aux (auxiliary) connection? Auxiliary cables are designed to connect numerous devices to a universal jack. That’s the idea anyway. But there is so much more to learn about this type of connection.

best car stereos

Ever see a car stereo input in the 2000s? If so, you have already seen an aux connection but didn’t realize it at the time. It’s these types of aux inputs that allowed us to connect smartphones, MP3 players, and laptops directly to the car stereo system. This was before USB connections changed everything forever.

Understanding aux inputs…

The impedance of the auxiliary inputs is over 10 kΩ but can usually deal with nominal voltage levels of -10 dBV (0.300 V RMS). But this voltage level will largely be determined by the audio device’s volume control functions.

The standard size of aux inputs is always 3.5mm, with no exception. The types of devices that use aux inputs for audio are old car stereos, active loudspeakers, clock radios, audio amps, and stereo receiver systems.

Here are some great examples of the best car stereos with aux inputs that are currently available to purchase.

Aigoss Bluetooth Car Stereo with Aux Inputs

This very affordable car stereo is Bluetooth-enabled with a choice of aux and USB connections.

Boss Audio Systems Multimedia Care Stereo

This impressive product has both USB and aux connections and is the perfect choice for high-level audio.

Camecho Single-Din Bluetooth Car Radio

This is a classy car stereo/radio that looks great and performs better. There are inputs for aux, USB, and even for an SD card.

Mixing Consoles with Auxiliary Outputs

Aux outputs, on the other hand, can only be found on just a few devices. But the most common is on a mixing desk or mixing console used for professional recording. Auxiliary inputs, however, are used across the board and are compatible with most audio sources. This is why 3.5mm headphone jacks can be used as auxiliary inputs, even though they are not “aux outputs.”

The impedance of auxiliary outputs is usually 75 Ω to 150 Ω, but you will find that the nominal voltage level is also -10 dBV (0.300 V RMS). But again, this voltage level is usually determined by the device’s volume settings. Auxiliary outputs can also be compared directly to “line outs” and often link from an amplifier to a recording device or a mixing console.

Check out these highly recommended mixing consoles with both headphones and auxiliary outputs.

Depusheng DX8 Professional Mixer

This affordable mixing console is ideal for home audio, or entry-level studio builds. It has lots of aux input and output channels and ports.

XTUGA Pro Audio Mixing Console

This compact mixing desk represents great value for money. It comes with aux inputs and outputs, alongside 7-channels and digital effects mixers.

Sound Compact 4-Channel Audio Mixer

This is a great value for money mixing console with 4-channels and both aux and headphones outputs. If you are looking for something cheap and easy to use, this is the perfect budget mixing consoles.

The Similarities Between Aux Connectors & Headphone Jacks

The Similarities

Now that we can answer, “Are Aux (Auxiliary) Connectors & Headphone Jacks the Same?” we need to go more in-depth. What are the similarities between aux connectors & headphone jacks? What sort of features do they share? And why are aux and headphone jacks often considered the same product? Keep reading, and I will tell you.

It’s always easy in life to talk about our differences, but why don’t we focus more on our similarities? It’s a rhetorical question. There are numerous similarities between headphone jacks and aux connectors. For starters, they are both analog cables, which essentially means that the audio signals are transported through wires via AC voltages.

Analog-to-digital converters…

With so many digital devices now in use, there are several analog-to-digital converters currently on the market. These converters are positioned at the jack ends on both the auxiliary and headphone ports. Their main function is to convert digital audio to analog audio.

A good example would be the digital audio played on a smartphone. This digital audio is then converted to analog before being outputted to your headphones.

Another example would be when an analog signal is sent to a device such as a car stereo. At the aux input port, you will use an analog-to-digital converter that will convert the audio back to a digital format that can be played from the car stereo. However, the audio is then converted back to analog in the amplifier so it can be played out of your car’s speakers.

More similarities between aux and headphone jacks…

The size, wiring, and aesthetics are major similarities between aux connectors and headphone jacks. This is why the untrained eye cannot tell the difference between the two. They look so similar. Take a quick look at headphone output jacks that you would use with a laptop and aux input cables side-by-side. Can you see any differences? Not likely.

That’s because the auxiliary input is designed to be a universal plug for numerous audio sources and devices. And you will quickly realize that the 3.5mm TRS connector is one of the most compatible you will find. The most commonly sized headphone jacks are also 3.5mm TRS and TRRS connectors. This is why it can be so confusing to distinguish the two.

What does this mean?

The simple truth is that a 3.5mm male-to-male TRS or TRRS auxiliary wire is highly compatible. It can be used with almost all audio devices to aux inputs. This is why the cable is often referred to as a universal connection. And although it’s not exactly true, it’s true enough.

In this age of consumerism, there are countless amounts of 3.5mm TRS and TRRS auxiliary cables that are available to buy. Check out some of the best 3.5mm TRS aux cables that come highly recommended, not only by myself but by other sound professionals and audiophiles.

The Differences Between Aux Connectors & Headphone Jacks

Aux connectors and headphone jacks have lots of similarities, but what are the major differences between the two? They look the same, but why aren’t they the same thing?

Auxiliary outputs are generally known for having low-level signals that are better suited to high impedance loads. Standard consumer headphones, however, handle much lower impedance. This makes them better suited to listening to audio than using aux connectors.

Aux to jack or jack to Aux?

Sending audio signals from aux to headphones can be problematic. You will need the help of a headphone amplifier to bridge the gap between the two. In fact, one of the major differences between headphone jacks and aux connectors is that you will have trouble sending audio signals from aux to headphone jacks.

In comparison, a headphone output can effectively send audio signals to an auxiliary input. We already discussed the differences between aux and headphone jack impedance levels earlier. The contrasting impedance and voltages between the two are the reason why headphone output to aux input is more effective.

Size does matter…

One of the major differences between aux connectors and headphone jacks is size and wiring. We already know that the standard size of aux connectors is 3.5mm. But things are not that simple with headphone jacks/plugs.

Headphone jacks can be 2.5mm, 3.5mm, 4.4mm, and even 6.35mm. And we’ve not even talked about the various wiring types of headphone jacks.

Aux 3.5mm connectors are unbalanced TRS but do also have some TRRS capabilities. It’s important to remember that aux outputs can be either unbalanced stereo or balanced mono. But if we are discussing ‘aux send line’ outputs, they usually have a single TRS connection, which then can be wired in stereo or mono, although stereo is more commonplace.

Understanding aux send line outputs…

You can also separately connect both the L and R channels with aux send line outputs. And therefore manually control the balance. In this instance, the two channels are added together so they can be used for the headphone output.

This is also true in regards to monitors or loudspeakers. This is in stark contrast to 3.5mm headphones connectors that are generally unbalanced stereo.

The Differences in Aux and Headphone Jack Wiring

The Differences

We are now getting down to the business end of this subject. Since we answered, “Are Aux (Auxiliary) Connectors & Headphone Jacks the Same?” it’s time to get technical. But not too technical, of course, so stop worrying. You are in safe hands.

One of the major differences between these two types of cable is the wiring. Let’s take a look at the different wiring that you will find in both aux connectors and headphone jacks.

Auxiliary Input Wiring Protocols

We have already talked about the 3.5mm TRS (tip-ring-sleeve) aux input. But what do these initials mean? 3.5mm aux connectors can accept unbalanced audio from both TRS and TRRS connectors.

Aux input wiring standards

  • Tip – left channel audio.
  • Ring – right channel audio.
  • Sleeve – common ground.

This wiring system makes it easier to receive signals from many other devices. It’s important to mention that TRRS signals from headphones and headsets can also connect to a TRS aux input, which gives you more compatibility.

The tip and the ring wires in the TRRS will connect the right and left audio channels. The microphone part of the wiring is positioned on the second ring, so the sleeve, which makes this aux input compatible with laptops, smartphones, and tablets.

Aux Output Wiring Protocols

There are only two main wiring standards with aux outputs on a mixing console or amp. Here is a rundown of the aux wiring standards.

Unbalanced Stereo TRS

  • Tip – left channel audio.
  • Ring – right channel audio.
  • Sleeve – common ground.

This type of connection is used for a stereo line-in or to drive headphones. But you can use a “Y cable” to split the connector into two unbalanced signals by RCA cables.

Balanced Mono TRS

  • Tip – audio signal (positive pole).
  • Ring – audio signal (negative pole).
  • Sleeve – common ground.

These types of aux inputs are balanced and come in pairs for the left channel aux and the right channel aux output. From there, they are usually sent to stereo speakers or monitors. It’s important to note that aux outputs use 6.35mm jacks.

Headphone Jacks Wiring Protocols

Now we understand aux wiring standards; we need to look into headphone jack wiring types.

Mono Unbalanced TS Headphone Jack

  • Tip – audio.
  • Ring – return path + ground.

These TS connectors are unbalanced mono, which is a very simple 2.5mm headphone jack/plug. The TS headphone jack plug is 6.35mm in size and is also used for musical instruments such as electric guitars. You might know this cable as a “jack cord.” Headphone amplifiers also use 6.35mm jacks.

Unbalanced Stereo TRS Headphone Jack

  • Tip – left channel audio.
  • Ring – right channel audio.
  • Sleeve – common ground.

This wiring setup is the most common when sending unbalanced stereo audio to headphones. At the Y-tip of the headphones, the tip part goes into the left driver. The ring goes into the right driver. But the sleeve is split into both. This action creates the unbalanced mono signal in each of the drivers but culminates in stereo for the headphones.

TRRS Wiring (AHJ) Standard

  • Tip – left channel audio.
  • Ring – right channel audio.
  • Ring – common ground.
  • Sleeve – microphone.

This TRRS wiring setup is one of the most commonly used for headphones and headsets. This is the AHJ (American Headphone Jack) standard that has been used by all headphone producers since 2015. Most manufacturers of smartphones, laptops, and tablets use this standard. Meaning this is now a universal headphone-to-device connector.

TRRRS Headphone Jacks Wiring Standard

  • Tip – left channel audio (positive pole).
  • Ring – left channel audio (negative pole).
  • Ring – right channel audio (positive pole).
  • Ring – left channel audio (negative pole).
  • Sleeve – ground/shield.

This TRRRS (tip-ring-ring-ring-sleeve) connector is one of the newer headphone jack varieties. This type is generally used with a 4.4mm Pentaconn jack/plug. If you want perfect stereo sound, this is a great option.

This wiring standard sends balanced audio to the left and right headphone driver for amazing stereo. This type of connection offers more protection against electromagnetic signals.

Need More Great Audio or Headphones Advice?

Our experts can help you find the answers, so check out our handy guides on How to Fix Echo in HeadphonesHow to Use Two or More Headphones On PC or MacHow To Clean HeadphonesHow to Remove a Broken Headphone JackHow to Fix a Loose Headphone Jack, and How to Disable a Headphone Jack for PC and Phones for more useful information.

Also, have a look at our in-depth articles on How do noise-cancelling headphones workUsing Headphone Jack as MicrophoneWhy Are My Headphones So QuietWhat Is a Good Driver Size for HeadphonesHow to Fix Headphones When Only One Side Works, and Open Back vs Closed Back Headphones for more helpful hints and tips.

Are Aux (Auxiliary) Connectors & Headphone Jacks the Same?

The short answer is they are, in fact, very similar unless you delve a little deeper. They look the same to the untrained eye, but their functionality sets them apart. Of course, you can interchange them in most cases, but we wouldn’t recommend it.

Same but different…

Headphone outputs and aux line outputs are different even though they have some similarities. The main differences are in terms of how they receive audio signals and handle impedance.

Aux inputs have an impedance of 10 K Ω, while aux outputs have an impedance level of 75 Ω to 150 Ω. Alternatively, headphone inputs have an impedance level of 8 Ω to 600 Ω. Headphone jack outputs have an impedance of 0.1 Ω to 24 Ω.

However, the main difference between the two is their wiring. The standard aux connector size is 3.5mm, while headphone jack sizes vary from 2.5mm to 6.35. You can use a headphone jack for an aux-in, but not the other way around. Auxiliary cables are essentially used for mixing consoles.

Until next time, happy listening.

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