Line outputs and headphone outputs are two similar audio connections that are frequently confused with one another.
An audio connection port for a line-level out signal is the line out. Headphone outs are used to drive headphones, whereas line outs are used to connect to external amplifiers.
A line output generates an audio signal that can be amplified further by an external amplifier, whereas a headphone out amplifies the signal before sending it.
What Is Line Out?
An audio connection port that can produce a line-level audio stream is known as a line-out (or Line Output). Signals at the line level are steady enough to be sent between multiple devices without causing significant signal fluctuations.
To go a bit further, line out refers to an audio output port or point of connection on a source device where external devices such as speakers, headphones, or other output devices connect. Line out allows the audio devices to receive line-level audio signals from the source device.
Some other devices with a line out include guitars, bass amps, keyboards, mixers, and many more. The machines, therefore, send audio signals through the line out to other devices for processing.
For instance, you can send an audio signal from a mixer into a keyboard amp using the line out of the mixer.
What Is Line In?
Also known as sound in, audio in, or mic in, line in is an audio jack used to connect to another audio output device or microphone. It can either be analog or digital and serves the primary purpose of manipulating the incoming audio or audio recording.
Line-in can be found on most audio devices and computers. They bear electrical audio signals, and you can connect microphones, portable music players, or other audio devices to them.
What Is A Headphone Out?
Generally speaking, a headphone out is an output that carries enough amplification to drive headphones.
Remember, headphones are passive speakers and mainly depend on external amplification to be able to produce perceivable sound. Therefore, the keyword in “Headphone Out” is “Amplification.”
To go further, the technology used to replace/substitute line-level output is known as headphone line out. Headphones, external speakers, and other output devices can all be linked to your speaker via a headphone line-out.
A pure line output will deliver greater sound quality than a headphone line out when it comes to sound quality. However, in recent years, the disparity has become almost insignificant.
As a result, headphone line-outs can drive both headphones and line-level output loads.
Difference Between Line Out And Headphone Out
Most people can’t tell the difference between Line Outs and Headphone Outs since they’re so identical. The Headphone out is used to boost line-level signals so that headphones can be driven.
Line-Outs are audio ports that connect two audio devices and send line-level audio signals. The major differences between the line-out and headphone-out audio connection ports are outlined below.
From the description we already gave, line out, and headphone out seem to be pretty similar. There are, however, some striking differences between them. Let’s look at some of the differences below.
Output Signal Quality
From the discussion so far, you understand that headphone outs have built-in amplifiers, while line outs do not. It is, therefore, valid that the amplifier creates some level of distortion in the sound as the signal is amplified.
Depending on the quality of the amplifier used in your headphone out, the level of distortion may be high or low.
Some high-quality amplifiers will deliver pristine sound, and even if they have some slight noise, it may be pretty hard to notice as opposed to those created by low-quality amps.
Since line-level outs do not have amplifiers, the sound they deliver is usually very pure.
Generally, line-level outputs have 50 to a few hundred ohms source impedance. They are mainly intended to drive high-impedance inputs up to 5k ohms or more. Also, they are highly optimized for low noise and low distortion, mainly when used with high-impedance loads.
On the other hand, headphone outs are generally built with source impedance more diminutive than a hundred ohms.
They are meant to drive impedances in the range of 16 ohms to 300 ohms typically found in headphones. Besides, they are adequately optimized to deliver low noise and reasonable distortion with low impedance loads.
It is, therefore, very clear that headphone outs are optimized for lower impedance loads while line outs are optimized for higher impedance loads.
The source resistance of the line out signals is in the range of 100 ohms and higher. They’re designed to drive signal loads with a high input impedance. Headphone outs, unlike line outs possess a very reduced signal intensity.
They have impedances ranging from 16 to 600 ohms. The purpose of headphone outs is to reduce the resistance created by headphones. With low impedance loads, headphone outs are tailored to drive high current with minimal signal degradation and noise production.
A headphone output, on the other hand, is built expressly for lower impedance loads and is capable of transmitting more power to them. A line-out, on the other hand, is designed to drive loads with higher impedance ratings.
Amplification And Volume Regulation
Generally, line outs are not meant to drive headphones. This is because they are not made with amplifiers in them. On the other hand, headphones out are incorporated with amplifiers that make them suitable for driving headphones.
If you use a device with a line out and an in-built amplifier, the line out will, in many cases, bypass the amp. However, if the device has a headphone out and an amp, the amp will help drive the headphone by amplifying the audio signal transmitted through it.
Also, you cannot control the volume of audio coming through the line outs. This is because line outs are designed to connect to external amplifiers from which you can do volume controls. On the other hand, headphone-outs allow volume controls because they have inbuilt amplifiers to help with that.
• Output Signal Purity
Line-level signals are amplified and sent to the headphones. As a result, audio signals sent through a headphone jack will go through more than one stage of amplification, potentially distorting or adding noise to the signal.
As a result, headphone outputs are typically muted in comparison to the clear sound from the line out. However, depending on the strength of the headphone out’s built-in amp, this noise may be difficult to detect. Line-level output signals, on the other hand, are extremely pure.
They’ve been tweaked to create almost little noise and distortion. Line-out transmissions are less likely to be corrupted in theory because they have a low audio signal intensity.
• Volume Control and Amplification
Line outs do not have built-in amplifiers and are therefore unsuitable for driving headphones. A headphone out, on the other hand, was developed with built-in amplifiers. As a result, headphone outputs may deliver greater power with less distortion.
When you use the line out of a gadget with an inbuilt amp, the device’s amp is bypassed. Line outs also have a fixed volume on the device they’re connected to. You can, on the other hand, control the volume of a headphone output.
Can I Use A Headphone Out As Line Out?
Line outs are built to drive high-impedance loads, while headphone outs drive low-impedance loads.
As a result, interchanging them may not give you pretty good results. However, you can easily use the headphone out as a line out without damaging your equipment.
Besides, some modern devices, such as keyboards, may not have separate line out and headphone out ports. If your device only comes with a headphone out, for instance, you can use it as a line out as well.
However, keep the volume down to prevent any damage to your device or ensure you are getting good audio with little noise or distortion.
So the bottom line is that you may use your device’s headphone output as a line out. This will not cause any significant distortion or reduce signal quality intensity.
Line outs can be used with headphone outs. Although headphone outputs are not as clean as line output signals, they can be used as line-outs without sacrificing sound quality.
It’s a good idea to keep the volume down as a general rule. This is because, when compared to a Line Out signal, a headphone out signal offers a substantially louder audio output. This will decrease noise and prevent signal distortion.
Despite the fact of the matter is that using a headphone-out as a line-out is a conceivable possibility.
Audio professionals with expertise advise against making such connections.
Can I Plug Headphones Into Line Out?
Since line-level outs are generally low signal carries, they will have minimal effect on the headphone.
Therefore, the headphone may be able to work on the line out, but the sound will be shallow. This is because line outs do not have amplifiers to augment the sound signal before sending it to the headphone.
On the other hand, the experience you get with this kind of connection will vary depending on the type of headphones you use and their electrical impedance.
Remember, the headphones use a coil that must be supplied with enough signal strength in the form of electrical power to be able to vibrate and reproduce the sound. The line out signal is usually very low, and you may end up with very little or no sound at all.
The bottom line is that headphones can be plugged into a Line Out. If the audio output is detectable at all through the headphones, it will be feeble. Because the audio signal from the line out is frequently insufficient to drive headphones, this is the case.
This means that if you plug a headphone into a Line Out, you will almost certainly hear nothing. Even if you do, you will barely be able to hear anything. The bass will be much diminished, even if the audio is loud enough.
All of these difficulties will, of course, vary depending on the headphones you’re using and the line Out of the device you’re connected into.
It is very well worth noting that the Line Out feature does not include the needed signal amplification that your headphones require to function.
What Does Headphone Line Out Mean?
Modern devices are built with headphone line output systems. These are technically output lines that use a combination of line out and headphone out.
They are more flexible and user-friendly as you can effectively use them to power line-level devices as well as headphones without facing any challenges.
What Does Line Out Mean On An Amplifier?
The working principle of the amplifier is an audio connection technology that is simple and easy to grasp. The line out sends line-level audio signals from one device to another, and the line-ins are connected to the line outs. The signal is received through the port’s line.
On a final note, there are a few things to keep in mind when it comes to line outs and headphone outs.
Line outs are designed to drive signals into external amplifiers, while headphone outs have built-in amps that boost the signal before transmitting to the headphone. You should therefore restrict each port to its intended use for the best results.
Norvan Martin is the founder of BoomSpeaker.com. He is a professional Electronics Engineer and is passionate about home theater systems and AV electronics. BoomSpeaker was created as an online hub to share his knowledge and experiences as it relates to home theaters and home audio electronics.