A History of the Headphone Jack

By Tim Maninger, Features Writer

Apple has for decades been the arbiter to the demise of old technological standards. They were the first to abandon the floppy disk, the optical drive, and now, the 3.5mm headphone jack. The decision to remove the headphone jack is a curious one to most, especially since in early iPod ads, headphone wires attached to iPod were the focal point in Apple and iTunes’ carefree and spirited branding. There are reasons that this effort can be a good thing and reasons that it will not completely abolish the age old analog plug.

You may be surprised to find out that the simple, but effective TRS plug has been around in some form or another since the late 1800’s. It was originally developed for some of the first telephone switchboards and subsequently, it became the standard for most consumer grade audio equipment. The smaller 3.5mm jack came about as portable transistor radios, becoming more common in the 60’s and in turn, the demand rose for personal headphones. Portable cassette players and CD players only expanded this market and the introduction of the iPod caused the market to explode. Up until this point, headphones had largely been a luxury product for people who could afford the player and the listening device, but once cell phones were capable of digital audio playback and everyone had a cell phone, headphones almost became a commodity. These days everyone seems to have at least one pair, if not more.

Such a long history begs the question: why has nobody tried to replaced the plug before now? The answer lies in the way that audio playback works. With physical media the sound is stored either physically in the grooves of a record, magnetically on a tape, or digitally on a CD. Playing back the physically or magnetically stored audio is fairly simple, the sound is not encoded or compressed, you just need the right sensor and you can feed the signal directly to an amplifier or a listening devices. Digital audio is used by CD’s, phones, and computers and is slightly more complicated. You need the stored media, a sensor or processor capable of reading in the digital information, and a dedicated piece of hardware called a Digital to Analog Converter. This translates the digitally stored audio into an analog signal that resembles the originally recorded sound, only then can it be sent to an amplifier or a listening device. The end goal of all of these processes is the same: to generate an analog signal that can be amplified for listening and because all of these methods produce the same signal, there has been no reason to replace the plug that was designed specifically for it. So what purpose does replacing it now serve?

In the case of cell phones, replacing the analog headphone jack with a digital plug like Apple’s lightning port or the USB Type-C that modern Android phones use means that phone manufacturers have a relatively large amount of space freed up. They can use this space for extra battery or to make the overall size of the phone smaller; however, anyone wanting to output audio from these devices will need to purchase either new headphones or an adapter for their old ones. There is an upside to this insanity as well though. Up until this point headphones with features like active noise cancelling or other features requiring power in addition to audio signal needed annoying batteries to function, but with a lightning port or USB Type-C connection, they will be able to draw power and audio signal from the same port. These features would also be accessible to both phone/tablet users and computer users since they would use the same ports, making the overall headphone market more feature rich. In areas where these features aren’t particularly relevant or desirable, like high end audio, the standard headphone jack will likely live on among purists or possibly be replaced by more professional grade balanced outputs.

While moving to a new standard is almost always met with some resistance initially, in the end, it usually ends up being a change for the better and at the very least, it is an excuse to learn about how this stuff works. In this particular case, the technology being replaced is so ubiquitous and simple that there will likely still be inexpensive hardware manufactured for it for decades.