Preamp Vs Amp: Differences Explained

The terms amplifier and preamplifier might be confusing for you if you’re not updated with all of the audiophile terminologies. It can seem like they’re interchangeable, but they’re in reality they are not. Though preamps and amps serve to amplify your sound or power your speakers, each one has its special use that sets it apart from the other.  

This article gives a thorough discussion of the difference between these two types of equipment, helping you decide which one would be best for your needs.

What Is An Amp?

An amp or amplifier is a device that provides increased power to electrical signals. This is often done with electronic devices where the input signal has a voltage lower than desired output. The amplifier offers additional electronic components to allow for a greater power increase. The increased power of the signal can be used to drive an audio speaker, allowing the user to hear a sound at a higher volume.

What Does An Amp Do?

The main purpose of an amplifier is to amplify electrical signals to be heard over long distances. They can also be used to record audio or in video devices that require huge amounts of power that need to be amplified. Amplifiers are useful devices when you want your electrical signals to be louder than what they would normally be on their own.

In addition, amplifiers are used in many other applications, such as cellular phones, and providing electricity from solar photovoltaic panels. They can also be in-built within some sound systems with subwoofers or speakers without tweeters for increased volume levels.

See our recommendations on the best integrated amplifiers under $1000.

Best stereo amplifiers 2021: best integrated amps, budget to premium | What Hi-Fi?
From Cambridge Audio

What Is A Preamp?

A preamp or preamplifier is a device that amplifies incoming signals, such as from microphones or instrument inputs before an audio system boosts them. They increase the level of signals from low volume to line level that’s connected to a power amplifier. They also help maintain fidelity in old recordings and reduce noise in new recordings when connected to a microphone preamplifier or mixer.

What Does A Preamp Do?

Preamplifiers control the amplitude of an audio signal like the volume of a turntable or CD player, which makes it easier to change the volume with a foot pedal. This type of equipment is also great for pre-amplification, which means that it can boost an input signal before it reaches other kinds of amplifiers like power amplifiers. Preamps provide parameters for changing the dynamic and tonal characteristics of the sounds.

Types Of Preamps

There are various types of preamplifiers that perform different functions and they include:

Vacuum Tube Preamplifier

Tube preamplifiers provide a warmer, fuller, and more dynamic sound. However, they are also expensive compared to solid-state or hybrid preamplifiers. Tube preamplifiers are characterized by using vacuum tubes (valves) to amplify and shape the signal.

Compared with solid-state and hybrid amplifiers, tube amplifiers derive their name from the source of heat power used by vacuum tubes: a tube that uses heated filament.

Vacuum tubes are also known as electron tubes, or thermionic valves. By definition, vacuum tubes utilize electrons to amplify or rectify incoming signals in the form of heat power. They create even-order harmonics, which reduce the distortion and create a superior sound. In addition, the even-order harmonics boost certain frequencies, helping create a fuller tone.

Schiit Freya (From Schiit Audio)

Solid-State Preamps

A solid-state preamplifier is a device that amplifies electrical audio signals before entering other devices such as power amplifiers or digital audio converters. Some solid-state preamplifiers use discrete transistors for each audio output channel, whereas other solid-state preamplifiers use op-amps.

Op-amps provide relatively good audio performance but are more sensitive to temperature and voltage changes, affecting their sound. Most types of recording medium use solid state preamplifiers, including Compact Discs.

Classé Audio Six Mk.II preamplifier | Stereophile.com
Classé Audio Six Mk.II preamplifier (From Classe Audio)

Digital Preamps

Digital preamplifiers use digital audio recording devices, such as hard disk recorders and digital cameras. They convert the analog signal from an analog-to-digital converter to a digital signal and amplify it before entering the digital audio circuitry of the recorder.

Transparent Preamp

Transparent preamplifiers are often used with condenser microphones. Before the signal is amplified, the preamplifier’s circuitry causes the input to equalize the frequency response and counteract those frequencies that would cause noise in an equalized microphone input.

The transparent preamp can be switched between high and low gain modes by a convenient toggle switch. The low gain setting provides a lower noise floor for recording quiet sources and is recommended for high-quality recordings. The high gain setting is best utilized when much background noise is present, such as on stage.

Preamp That Adds Color

The preamp that adds color to the signal is a special type of preamplifier which uses internal equalization to adjust the frequency response of the incoming signal. It is not a transparent preamp because it does not amplify the input signal.

The purpose of the equalizing circuit is to compensate for phase and group delay differences between various parts of an audio system, including microphones, power amplifiers, digital audio converters, and other equipment.

Preamps for Specific Instruments

Some preamplifiers have switches that can be dedicated to a specific instrument. It allows the musician to switch between devices or set up an external instrument from the microphone.

Differences Between Preamp and Amplifier

Splitting

A preamp is a power amplification for the signal that comes from your CD player or turntable. It’s a splitter, which means that it takes the signal you input into your stereo or home theatre receiver and splits it into two paths for amps and speakers. The split creates an inverted output going to one amp, and then another amp takes over after that.

Power Source

Power amplifiers are generally directly powered by the receiver or amplifier thus you don’t need an outside power source as a preamp does. Remember that a preamp affects the sound you hear by splitting the signal and sending it to two different amps. In contrast, power amplifiers are already pre-amplified, so they only receive one signal.

The amp needs its power source when you first connect a preamp or power amplifier to your system. The solution is something called an isolation transformer. The isolation transformer will keep your preamp or amp from showing up on your receiver’s faders. Its job is to isolate you from the amplifier’s power while still allowing you to control the volume.

You can also use an isolation transformer to switch your receiver’s preamp outs – so you can connect an amp and not have it affect the faders on your receiver at all. The isolation transformer also lets your preamp driver send audio signals directly to a power amp without having to go through a splitter.

Output

Power amps generally have a more powerful output than preamps. Their power ratings are more noticeable, and you feel them more. They have a higher wattage rating than preamps do because they have to power the speakers.

Theoretically, a higher wattage rating means that the amplifier can put out more sound than lower-wattage amplifiers. Some people prefer power amps because they don’t split the signal as does a preamp. There’s no inverse signal going back to your receiver, so there’s no asymmetric output when playing music.

Signals

Preamplifiers can only amplify signals, while amplifiers can also change the frequency or phase of a signal. That helps adjust the phase and frequency response of an audio system. Preamps are generally more expensive than amps because they include additional features such as negative feedback, impedance matching, etc., which preamps in amp systems use to compensate for each other’s losses.

Most people use a preamplifier in situations where the amplifier would not be able to deliver enough gain. For example, a microphone or direct box could have very low output and require a preamp with an adjustable increase to receive enough input signal.

Another example is if you are using an instrument with more impedance than the amplifier can handle, i.e. a bass guitar with higher impedance and requires more load than an amplifier can provide.

In summary, preamps are used for increasing gain, impedance matching, and compensating the losses in amplifier systems, while amplifiers are used for changing phase and frequency response.

Do I Need Both a Preamp and Amp?

Many amplifiers have built-in preamps, so you will need to replace the amplifier or the preamp separately. But if you are looking for an extra level of gain, then both may be required. A good rule of thumb is that the more preamp gains an amplifier has, the less likely it will need a separate preamp.

That is because preamplifiers tend to add two different types of gain, one that increases the input impedance and another that increases the output level. The increase in output level will only be necessary if the amplifier’s input is not sufficiently high.

Amplifiers that are very clean with lots of gains will need no effect from a preamp, while amplifiers with less gain will require additional gain through the preamp to get up to spec for recording or live performance.

So, in general, the more gain the amplifier has, the less it needs its preamp. But if the gain from the amplifier is not high enough, then a preamp can provide the boost that might otherwise have been provided by using an external mixer or line driver. That often allows you to use smaller and lighter equipment that will fit more readily into your rig.

Headphone Amp Vs. Preamp

As the name suggests, a headphone amp amplifies sound inside a headphone (or earphones). In contrast, a preamp amplifies audio signals going into an audio-output device like speakers or music system.

Headphone amps and preamps are especially useful when you want to listen to music in solitude without disturbing others. You can also use them in a car without disturbing others as well. If you’re planning to purchase a headphone amp or preamp for the first time, it would be wise to read those reviews before making the final decision of buying one.

People often get confused about the difference between headphone amps and preamps because both amplify audio signals (hence the name). However, the major difference between a headphone amp and a preamp is in their output.

Headphone amplifiers are designed to amplify audio signals that have been sent into the headphone. At the same time, preamps majorly amplify signals coming out of an audio-output device like speakers or music system.

Advantages of Headphone Amp

The main advantage of using a headphone amp is that it is very efficient. Unlike preamps, which amplify the sound coming out of your audio output device, headphone amps’ limit power consumption. That makes it easy for you to save money on your electricity bill without making sacrifices about sound quality or performance.

They are also much smaller than preamps. That means that you can easily carry a headphone amp in your pocket or bag, which isn’t the case for a preamp. In some cases, you might even be able to use a headphone amp as a portable amplifier.

The main advantage of using a preamp is that it improves an audio source’s sound quality and volume more than a headphone amp can. Similar to a headphone amp, preamplifiers are designed to amplify input signals rather than output signals. They’re thus used to boost the sound quality and volume of an audio source.

For best results, make sure that your headphone amp and smartphone or music source are compatible with one another. For example, if you have a low-power smartphone, you might want to consider buying a lower-power headphone amp for it. In most cases, 50 mill watts or less will suffice, depending on how loud the sound you’re listening to is. That might not work with a higher-power smartphone.

Beyerdynamic A2 Headphone Amp (From Beyerdynamic)

What are the Main Differences Between a Headphone Amp and Preamp?

There are three major differences between headphone amps and preamps. First, while headphone amps amplify audio signals sent into the headphone (or earphones), preamps boost audio signals coming out of an audio-output device like speakers or music system.

Headphone amps are designed to limit power consumption; preamps can be quite expensive because of their powerful ability to amplify audio signals.

The main purpose of a headphone amp is to improve the sound quality and volume of an audio source, while the main purpose of a preamp is to boost the sound quality and volume of an audio source. That is why they can perform their specific functions more efficiently and for a longer period.

What Are the Uses of Headphone Amp?

Headphone amps amplify sound from the earphone, ear pads, or headphones for the users. The amplifier contains a circuit that is used to amplify audio signals up to ten times per second. You can use them with smartphones, laptops, or CD players as well.

They are usually designed with amplifiers into small portable boxes and they can do additional functions such as the playback of music for users. They can also work from computers or an external power source through a wall outlet connected to the client device.

Headphone amps are generally used by people who need to hear the sound clearly through earphones or headphones regardless of any noise from the surroundings. The sound amplified is usually clear in both the high and low range. For example, the bass can be amplified to a level where it is felt inside the ears.

These amplifiers contain circuits used to control input volume or sound levels present in the audio signals from external audio devices. You can power some wireless headphone amplifiers for extended periods with rechargeable batteries. These headphones are more widely available than wireless headphone amplifiers because they are less costly to manufacture and take a shorter time to produce.

Uses of Preamp

Preamps majorly boost the sound quality and volume of an audio source. It amplifies the weak audio signals from the music player or any other audio device. It is commonly used with home theatre systems where a large number of speakers are connected and external power sources. These amplifier circuits are designed to reduce impedance and also to improve sound quality.

They work by receiving radio frequency signals that are amplified before being sent back out into the airwaves. They are used in lapel mics, wireless transmitters, and other devices that involve audio signals. They also have different settings and volume controls to allow one to use them in different situations.

Benefits of Using a Preamplifier

  • Improves the sound quality and volume of an audio source.
  • It can be able to perform its specific functions more efficiently than a headphone amp.
  • It is easier to find preamplifiers that will work with high efficiency since they’re made to reduce energy consumption.
  • They can be used for a longer period compared to a headphone amp

Frequently Answered Questions (FAQs)

1) Do You Need Both a Preamp and an Amp?

Your equipment determines whether a preamp is necessary or not. Inputs with poor signal strength need a preamp to boost them. However, if your signal is clean and powerful, you can work without a preamp.

That said, many amps feature a built-in preamp. So, if you have a quality amp that includes a preamp, you’re okay either way.

2) Is Preamp Same as Amp?

Preamps work differently from amps. While the former is typically closer to the start of the playback chain, the latter is toward its end. Whereas preamps split signals, amps don’t.

Moreover, power amps don’t require external power sources like preamps, thanks to their direct powering by the amplifier or receiver.

Also, you enjoy superior output from power amps than preamps. But, power amps require more wattage for the powerful performance.

Then, you get signal amplification plus its frequency and phase adjustment with an amp while a preamp only amplifies.

3) Can I Use Amp as Preamp?

Since the two perform different functions, you can’t swap the preamp with your amp. You shouldn’t have an issue with a high gain amplifier or an amp with a built-in preamp. Otherwise, get a quality preamp to boost your output.

Conclusion

It may be possible to use only one or the other in some cases, but others will require both. Both the preamp and amplifiers serve different functions and are equally important. However, most of the time, an amplifier will be needed for a large number of speakers. And, for most music listening purposes, you will need a preamp for the line-level input of a recording device. The choice will largely depend on your needs and preferences.

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