What Does A Preamp Do And Why Do You Need One?

Preamplifiers are one of the most important pieces of kit in a recording studio. If you use a microphone, then you’ll need a PreAmp. They’re also very useful for record players and audio systems. 

But what does a preamp do? 

Many musicians ask this question but don’t get a good answer. The main thing to remember is that preamps increase signal gain. They improve your sound by taking a weak signal and boosting it to a line-level signal. 

Let’s break down this essential equipment in all of its glory. 

Microphone Preamps

Microphones record their signals at the mic level. 

However, when you’re in a recording studio, you need a line-level signal. This has a stronger voltage and a much louder volume. Recording equipment like compressors, equalizers all require this type of signal. 

Usually, microphones require a lot of gain. Often this is between 30-60dB. Meanwhile, instruments like guitars need about 20-30dB. 

There are several types of preamps. These include cheaper built-in systems and external preamp modules. The former are typically more powerful and effective. 

Turntable Preamps

Many turntables already contain internal preamps called a phono stage. If you don’t have one, then you may need an external preamp. 

Many new vinyl users complain that their turntable produces a very quiet sound. The reason behind this is a weak signal. A preamp provides a boost so that your sound system will receive the signal from the turntable. 

Benefits of External Preamps

It doesn’t matter if you’re recording or playing music; preamps provide several benefits. Let’s look at these now. 

Improved Sound

The first thing you need to know is that a preamp won’t automatically improve your recording audio. You should invest in a high-quality microphone first. 

However, it is like the cherry on top. It filters out electronic static and removes harmonic distortion. This allows for additional processing and cleaner output. 

As you connect more sources, the preamp becomes more valuable as it enhances optimal performance. 


Preamps are great for turntables because they keep a consistent sound. 

As well as boosting the signal, preamps apply the RIAA equalization curve to the signal. This means that the sound doesn’t change at all. 

Without a preamp, the shape of the RIAA curve can fluctuate and distort the overall sound quality of your listening. 

Additional Sound Character

Preamps can change the quality of your sound when you’re recording music. 

Built-in preamps are clean and transparent. But you can use an external preamp to mix it up and produce the dirty or vintage sounds. 

Types of Preamps

Color Preamps

These preamps enrich the overall sound by adding color. This type of preamp disguises thin, dry signals by leaving them unrecognizable. You could have an intimate sound or a very strong and lively one. 

Transparent Preamps

If you want to reproduce the sound of the instruments or microphone without changing it, a transparent preamp will do the job. 

It’s fundamentally different from a color preamp because it has a transparent signal. Basically, this is about keeping it true to the original voice or tone. That’s why they are more popularly used by classical orchestras. 

Digital Preamps

Digital preamps convert analog signals to digital signals. Next, they add their sonic signature in the processing before the signal is sent to a DAW. 

Some people regard these as more of a digital interface, but they serve the same function as standard preamps. Usually, audio interfaces have inferior converters. That’s where the digital preamp comes in and works its magic. 

Tube Preamps

As their name suggests, tube preamps use thermionic tubes to color your sound, adding warmth and depth to the music. 

When the signal level increases, the tube produces mild distortion. That’s what creates the warmth and added body. Another function of tubes is that they smoothen out distortions and reduce high-frequency content. 

Solid-State Preamps

Transistor preamps create gain without additional heat. As gain increases, they maintain low distortion up to their maximum levels. 

They’re able to accept higher gain levels without distortion. 

Additional Features

Not every preamp has the same characteristics. Let’s look at what sets them apart. 

Multiple Channels

Most preamps come with multiple channels. 

These allow users to process and record multiple inputs at the same time. If you intend to record different sounds and instruments simultaneously, it’s important to get your hands on one of these. 

Gain/Saturation Control

It’s likely that your preamp has many knobs. 

At least a couple will be dedicated to gain and saturation control. These will enable you to create different effects by attenuating the signal. 

USB/Firewire Connections

Many preamps are DAW-friendly. 

As a result, they’ll have some kind of attachment port like USB or firewire connections. If you’re planning on doing a lot of recording, make sure your preamp has this feature. 

Multiple Preamps

Maybe you’re not sure what preamp to buy. Or perhaps your needs have evolved as you experiment with different types of music. 

There’s nothing wrong with this because many musicians and sound engineers find themselves in the same position. Everybody wants the best gear possible because it allows for more opportunities. 

If you can’t afford to drop hundreds of dollars on multiple preamps, try and get a versatile system. Preamps with multiple channels and different tone signatures are more flexible to use. 

Final Thoughts

It doesn’t matter if you’re producing music or simply enjoying listening to it. Preamps enhance both of these functions. In short, a preamp is like a control station. 

It will ensure that the sound quality stays strong and consistent after the signal leaves the microphone, instrument, or record player.

You may prefer color or a transparent preamp, but the reality is that many musicians will use both. This offers more flexibility depending on the circumstances and the desired sound. 

But remember that a preamp can’t do the job by itself. It’s not a magic solution. You need to invest in good equipment to ensure the best overall experience.