Headphone amps and preamps are terms that are often lumped together and can seem confusing to musicians and recording engineers. in reality, these devices perform useful and individual functions.
headphone amp vs. preamp: what’s the difference?
Reading: Headphone amp and preamp
Preamplifiers are used for three main purposes: to select a sound source, to control dynamics, and to add gain. on the other hand, a headphone amp is specifically designed to power headphones. they are essentially volume controls.
These are the main differences between the two, but when we take a closer look, it becomes apparent that headphone amps and preamps vary in many other ways.
Their power requirements, compatibility, and the effect they have on tone coloration are some of the distinguishing differences. After reading this comprehensive guide, you’ll know exactly what purposes both devices are best suited for and how they differ from each other.
the main differences between headphone amplifiers and preamplifier headphone amplifiers
To understand the difference between headphone amplifiers and preamplifiers, we must first consider their purposes. Headphone amplifiers are used specifically to boost the signal from a sound source so that it is ideal for playback through a pair of headphones.
preamplifiers are more complex. Preamps are primarily used to select a certain sound source using the onboard controls and significantly boost the sound signal to be compatible with a power amp or mixing controller. Preamps also offer various adjustable parameters to adjust the characteristics of the sound.
Technically speaking, preamps and headphone amps differ greatly in their power requirements and the load they are capable of handling.
Preamp outputs are typically required to drive a much higher impedance load than headphone amps, because they are used with more powerful devices like monitors, mixers, and interfaces.
The following table shows an example of the differences in power requirements between headphone amplifiers and preamplifiers.
As you can see from this table, there are significant differences in the way headphone amps and preamps work.
This is mainly due to the devices preamps are commonly used with, which require some impedance strength. The electronic requirements for headphone amplifiers may vary depending on the type of headphone they are used with, but these figures are accurate in most cases.
These two devices are essentially used to control volume levels. When a musician is recording with headphones, it is very important that the levels are set to the optimum level for their preferences. it’s common for headphone amps to allow the musician to adjust the dynamics of their instrument or backing track.
preamplifiers go a step further and allow you to select from multiple sound sources.
Each sound source can be adjusted using the volume controls, and some preamps also provide the ability to add gain. by doing so, they can alter the coloration of the instrument or other sound sources to suit their preferences.
I’ve written an article that looks at expensive headphones and whether they’re worth it. you can read it here.
what is a headphone amplifier used for?
In the next section, we’ll take a closer look at headphone amplifiers and their purposes.
a headphone amp works in combination with a dac (digital audio converter). These devices are responsible for converting the signal produced by a sound source into analog so that it can be received by the headphones. here’s an excellent example of a reliable headphone amp.
An example of this would be if you were to plug a headset directly into your phone or computer and then play an audio file, the signal would be sent digitally, in the form of zeros and ones. a dac then converts this into an analog format that headphones can play.
so where do headphone amps come into the equation?
well, by itself, a dac doesn’t boost the output signal enough for it to be received by headphones. needs an extra boost, which is provided by a headphone amp.
At this point, it’s easy to see why people often confuse headphone amps with preamps, since technically the headphone amp amplifies the signal before sending it to the output device.
see my article on headphone preamps here
combining dac and headphone amps
The main difference between a preamplifier and a headphone amplifier becomes apparent when we consider the sound card in a computer or laptop. In most cases, sound cards combine the headphone amp with the dac, so you can plug right in and hear the audio file instantly.
virtually all computers produced today will have some combination of headphone amps and dacs built in. they may provide headphone ports or dedicated outputs especially for speakers, but no matter what medium you’re listening to, a headphone amp and daw will almost certainly be used.
in some cases it may be necessary to use external standalone dacs. however, this alone would not provide enough amplification to the signal to play through headphones, so a headphone amplifier would also be needed.
an excellent sound card to start with is the focusrite scarlett solo.
check out this popular audio interface here on amazon.
what is a preamplifier used for?
We’ve established the purpose of a headphone amp, so now it’s time to compare it to that of a preamp. This video explains very well the basic concepts of a preamplifier.
Preamps play a critical role in any recording or live audio setup.
- these devices basically shape the sonic characteristics of a particular signal, enhance, refine and define it before the signal is amplified and output through speakers, monitors or speakers. any other audio equipment.
Sounds pretty simple, doesn’t it? In reality, preamplifiers are quite complex devices. not only do they serve the function of preparing the audio to be projected through an output, but they also provide parameters that can be used to adjust the tonal and dynamic characteristics of sounds.
That brings us to the next point of discussion. If all preamps perform the same basic function of boosting the signal to prepare it for speakers or monitors, is there a difference between the multitude of preamps available on the market?
The answer to this question is yes. while it’s true that the function of a preamplifier remains the same no matter which one you choose, where there is a lot of variation is in the color they add to the audio.
When I use the term color, I am referring to the effect a preamp has on the timbre and tonality of the audio signal they are boosting. In the same way that a guitar effects pedal adds color to the clean guitar signal, preamps are also used to add color to the dry audio signal.
This is a good example of a preamplifier that adds natural color to the signal.
This is where the main difference between preamps and headphone amps becomes apparent. Headphone amps sometimes offer a volume control, but don’t add any color to the original audio. they are used exclusively to boost the signal and interact with the dac so that it can be heard in the headphones, while the preamps, as we have mentioned, are capable of not only altering the dynamics but also the general sound.
I have written an article about preamplifiers and integrated amplifiers. you can find it here.
headphone amp specifications
Unlike preamps, headphone amps are rated by the amount of output voltage they are capable of producing. preamps, on the other hand, are rated based on their power, converting watts to 8 ohms. This is partly for convenience, and also because headphone amps don’t rely as much on the impedance of actual headphones, while preamps rely on the impedance of your speaker, monitors, or a mixing console.
another notable difference between the two is that headphone amps have a maximum current limit they can produce. this is the attribute that indicates how much power headphone amps can deliver directly to the load low impedance, for example around 50 ohms or less.
Headphone amplifiers are often limited by the maximum current they are capable of drawing before distortion sets in. distortion is commonly used with headphone amplifiers that exceed their dynamic limits. makes the audio clip and sound unpleasant to the ear.
It is important to note that too much amplification when using headphones can cause hearing damage. this is more apparent than with preamps because the headphones are closer to the ear and the volume is less intense because you don’t physically feel the vibrations of the audio like you would with a powerful PA system or set of studio monitors.
the different types of preamplifiers
Another clear difference between headphone amps and preamps is that there are many varieties of preamps that produce different results.
Virtually all headphone amps perform the same function, and the only contrast from one model to another is in their capabilities and the quality of amplification they are capable of producing.
Preamplifiers come in a variety of forms. the most common are:
- transparent preamps
- preamps that add color
- tube preamps
- digital preamps
- solid state preamps
- preamps for specific instruments
Unlike headphone amps, preamps can be tailored specifically for a purpose. This explains why recording studios often have multiple preamp devices. each one is used for a particular sound, instrument, or to achieve a certain result.
Although preamps are versatile, choosing one that is well suited to your sound source, output, or recording purpose will certainly produce the best results. In the next section, I’ll discuss the details behind each type of preamplifier and explain exactly why they’re suited for that particular purpose.
Audio purists are likely to prefer transparent preamps to ones that add color to the dry signal. these preamps reproduce the sound of the instrument, song, audio file, or voice as close to the original as possible.
The advantage of this is that it allows more room for retroactive processing. the cleaner the preamp output, the more impact the post effects will have on your tone.
In musical genres such as jazz, classical, or blues, the engineer is likely to use a transparent preamp because they want to preserve the intimate human elements of the performance without adding gain or tonal shift.
It is worth noting that no matter how transparent a preamplifier claims to be, any electronic signal path will always cause the original audio to be altered at some level.
Once audio is played through a speaker or headphones, it has already been affected, so there is no way to play it completely “pure” other than to experience it live with your own ears.
preamplifiers that add color
As I said earlier, one of the main differences between headphone amps and preamps is that preamps are capable of changing the tone of an audio source. they do this by affecting the frequency response.
Preamplifiers that add color are useful for the following purposes:
- improve audio that sounds flat or thin
- tailor audio to fit specific speakers or monitors
- add bass, mids, and treble to audio
- enhance transients within audio
Unlike preamps, headphone amps do not change the timbre or tonal aspects of the audio source in any noticeable way.
Headphone amps never use valves, but preamps often do. these types of preamps are sometimes called vacuum tubes or valve preamps. Like their purpose in guitar amps, tubes are used to produce gain in the audio signal.
The tube preamps create a distinctly warm tone, caused by the slight levels of distortion they produce. as the signal level increases, the tube begins to overload, thus causing clipping. this adds warmth to the audio signal, making it sound authentic and vintage.
tube preamps also affect the harmonics of the audio source.
On the one hand, we have headphone amplifiers that aim to limit distortion and simply amplify the signal without affecting the harmonics of the audio. conversely, some preamps are actually intended to have an effect on the transient response of the loudspeaker, monitors, or other output devices they’re connected to.
A tube preamp creates what are known as even-order harmonics. this means that they produce harmonics that fall in the ideal range, which reinforces the fundamental tone. this is similar to the common double tracking effect, which is used to thicken vocal tracks or remove pitch inconsistencies.
Digital head amps are another popular variety of these useful devices. these are similar in nature to headphone amps, but work in the opposite way. they convert the audio signal and make it suitable to be played by a daw, an interface or speakers.
Digital preamplifiers are also very similar to interfaces. Digital preamplifiers work by converting an analog signal to digital so that it can be processed by recording software. digital preamps are rarely used to boost the signal and send it to a power amp or set of monitors.
solid state preamplifiers
As a result of advances in music technology, solid-state preamps are now capable of producing gain without the distortion that comes with digital preamps.
This is a very important capability for recording music, as it allows you to add more gain to the audio signal while keeping the output constant and not clipping too much.
Solid-state preamps are used in some of the world’s most prestigious recording studios. Revered for their pristine audio quality and overall warm tone, they’re used to record everything from drums, guitars, basses, keyboards, and vocals.
the different types of preamplifiers summarized
Clearly, the main difference between headphone amps and preamps is that headphone amps are generally used for a single purpose: to boost an audio signal, convert it from digital to analog, and make it audible in headphones.
preamplifiers, on the other hand, can be used for multiple purposes. The following table summarizes the different types of preamplifiers and what they are used for:
Can a headphone amp be used as a preamp?
In some cases, it is possible to use a headphone amplifier as a preamplifier. to do so, the headphone amp would have to be able to go down to around 16 ohms, or preferably even less.
Should I use a headphone amp with internal monitors?
In-ear monitoring systems have built-in DACs and headphone amplifiers, so there’s no need to use a separate one. the built-in headphone amplifier boosts the signal so it can be heard through the internal monitors.
what is the difference between a preamplifier and a volume controller?
Preamps and volume controls perform a very similar function, but volume controls are less versatile. they simply adjust the dynamics of an audio source, while preamps amplify the signal and affect its tone.
I hope this article answers the question “what is the difference between a headphone amp and a preamp?” and help you on your musical journey.