The Aftermath of 4.4mm Balanced Headphone Connections: From Rare New Terminal to Practical Standard

How many years has it been since headphone jacks started disappearing from smartphones? Many people must have thought that wired connections would quietly fade away.

However, that prediction is half right and half wrong. The jacks have disappeared from the smartphone body itself, but wired connections are still alive. In fact, they continue to evolve on the "outside" of the device. The leading role in this is the "4.4mm balanced connection."

I previously wrote an explanatory article about this terminal. It covered how the 4.4mm is not just an intermediate-sized plug, but a 5-pole balanced connection terminal based on the JEITA RC-8141C standard. It avoids the weakness of the 3.5mm stereo jack, which is the structure of sharing a return path for left and right channels. It also discussed how its adoption is progressing in the world of DAPs, DACs, and headphone amplifiers. That was the gist of it.

So, what happened after that?

Let me start with the conclusion. The 4.4mm is no longer a "rare terminal used only by a few high-end audio enthusiasts." Of course, this doesn't mean that 4.4mm jacks have started appearing on standard smartphones. On the contrary, the trend of headphone jacks disappearing from smartphones themselves continues. However, in the world of small DACs, Bluetooth DACs, portable amplifiers, and DAPs that connect to the outside of those devices, the 4.4mm has become a quite natural choice.

This is the biggest change since the previous article.

4.4mm is no longer a "special terminal"

Previously, when people heard "4.4mm balanced terminal," many thought of high-end DAPs, desktop headphone amplifiers, and full-scale audio equipment. Both the terminals and cables were a bit special, and it was a world that required a certain level of commitment to enter.

But now, even USB Type-C DACs small enough to fit in the palm of your hand come with 4.4mm jacks as a matter of course.

This may seem like a small change, but it is a big one. It means that 4.4mm balanced connections are no longer just for enthusiasts who buy dedicated players, but are now open to ordinary listeners who use small DACs plugged into their smartphones or PCs.

Instead of seeking high sound quality from the smartphone itself, the output of the sound is left to an external small DAC. That DAC is equipped with both 3.5mm and 4.4mm jacks. When this happens, the 4.4mm is no longer a "special additional feature," but a "normal option provided from the start for those who want to listen with better sound."

3.5mm will not disappear. They will coexist

However, just because the 4.4mm has spread, it doesn't mean the 3.5mm will disappear anytime soon. The current trend is rather the coexistence of both.

The strength of the 3.5mm lies in its overwhelming compatibility. Old earphones, headphones, speakers, game consoles, and PC peripherals. Whether plugging in existing earphones or connecting a headset for calls, the 3.5mm is more than just "convenient"; it is "essential." This will not disappear easily.

On the other hand, the 4.4mm is a terminal used when you want to drive with higher output, when you want to increase left-right separation, or when you want to utilize balanced-compatible cables.

In other words, the two are not competitors, but have a relationship of shared roles.

• 3.5mm as a daily general-purpose terminal.
• 4.4mm for sound quality and driving power.

This dual approach has become the most realistic compromise.

2.5mm balanced is quietly retiring

In the past, when it came to balanced terminals for portable audio, the 2.5mm 4-pole was also frequently used. While its small size was an advantage, it was thin and delicate, and many people worried that it might break someday.

In that regard, the 4.4mm connector is thicker than the 2.5mm one, providing a greater sense of physical stability. Yet, it is not as cumbersome as the 6.35mm connector. It is a perfect size that is easy to incorporate into portable devices while also fitting well with desktop equipment. As a result, if you are starting with balanced connections now, it has become more natural to choose 4.4mm over 2.5mm.

Of course, those who already own 2.5mm cables or equipment do not need to rush to replace them. However, if you are planning to purchase new cables, a DAC, or a headphone amplifier, I believe we have reached a stage where you can safely make 4.4mm compatibility your standard for selection.

The intrigue of 4.4mm on Bluetooth DACs

A recent trend that I personally find interesting is the inclusion of 4.4mm balanced outputs even on Bluetooth DACs.

At first glance, this might seem contradictory. After all, you are connecting wirelessly, yet you end up plugging in wired earphones or headphones. However, when you actually use it, this configuration makes a lot of sense.

・Connect to your smartphone wirelessly
・Let the compact DAC in your hand handle the audio output
・Drive your favorite wired headphones from that DAC using a 4.4mm connection

By doing this, your wired headphones can be fully utilized even if your smartphone lacks a headphone jack. Furthermore, you can keep your phone in your pocket or bag while controlling the volume via the DAC in your hand.

This is not just a trick to extend the life of old wired equipment. It is a concept that captures both the sound quality of wired connections and the convenience of wireless in a single device.

While true wireless earphones are convenient, one might sometimes feel dissatisfied with battery life, sound quality, latency, or connection stability. Considering that, this method of driving wired headphones with a small Bluetooth DAC is quite a realistic compromise.

A note of caution: "4.4mm" does not automatically mean "high sound quality"

However, there are some points to keep in mind.

Just because a device has a 4.4mm terminal does not guarantee it will produce good sound. Sound quality is determined not by the shape of the terminal, but by the DAC chip, amplifier circuit, power supply design, output impedance, noise suppression, and compatibility with your headphones.

Moreover, even if they look the same, the internal circuitry of 4.4mm terminals can vary drastically between products. Some are truly engineered as left-right independent balanced outputs, while others prioritize compatibility or terminal convenience. Therefore, when purchasing, do not judge based solely on the "4.4mm terminal included" line; it is better to check specifications such as "balanced," "output power," "supported impedance," and "crosstalk."

And one more thing: avoid using simple conversion adapters to plug standard 3.5mm cables into a 4.4mm balanced output. Because balanced outputs handle the positive and negative signals for left and right independently, using a conversion that does not match the wiring can not only degrade sound quality but also potentially put a strain on your equipment.

If you are going to use 4.4mm, ensure your headphones are capable of being recabled and that you are using a cable designed for 4.4mm balanced use. This is a point you should definitely keep in mind.

How to think about it when buying from now on

So, if you are planning to buy a DAC or headphone amplifier, is 4.4mm compatibility necessary?

My view is this: if you care even a little about sound quality or future-proofing, it is well worth choosing a device that supports 4.4mm.

Especially for those who listen to music, play games, watch videos, do editing work, or wear headphones for long periods on a PC, the benefits of an external DAC or headphone amplifier are easy to notice. In that case, choosing a model that features both 3.5mm and 4.4mm ports rather than just 3.5mm will give you more flexibility when you upgrade your peripheral equipment later.

Conversely, if you are already fully satisfied with 3.5mm, your current earphones do not support recabling, or you do not feel a lack of volume, then there is no need to rush into switching to 4.4mm. The 4.4mm connector is not a magic wand. It is a standard that only shows its true potential when combined with compatible equipment.

It is not something to jump on immediately. However, for those who are just starting to set up their environment, it has become too valuable to ignore.

Summary

The history of earphone/headphone jacks is not just a single path from 6.35mm to 3.5mm, and then to wireless. Alongside that, the 4.4mm jack is quietly evolving as a new standard for improving wired connections.

Even as jacks disappear from smartphones, the appeal of wired connections has not faded. In fact, with the 4.4mm standard now settling in, the future of wired audio has become interesting once again. I think it is safe to say that.