what is a preamp

PreAmp Types? EVERYTHING You Need To Know!

Did you know Preamps are widely used with both acoustic and electric guitars? This is important because certain preamps are designed for each guitar!

Preamp Types? There are two main types of preamps these include solid-state and tube amps.

If you are seeking the most suitable type of preamp for your very own setup? Then in this article, we will be covering the essentials by looking at (in detail):

  1. What is a pre-amp?
  2. What will you need to consider before purchasing a preamp?
  3. What are the different types of preamps?
  4. Aesthetic purpose
  5. Circuit design
  6. Format

So, let us jump right in!

1. WHAT is a PREAMP?

A preamp is a device that boosts the original output signal from your guitar. This is important because if your guitar is sending a really weak signal then a preamp will boost the volume without adding fuzz or hiss to your tone. In addition,  your tone will appear fuller and crisp as it comes out of the speakers.  

At the beginning of this article, I have given a basic description of what a preamp is for people that just want a quick answer. If you would like a more in-depth description then please keep reading.

So, a preamp is a type of amplifier that is designed to take really weak signals and make them louder. 

This essentially boosts the true volume which we call a line-level signal.

A line-level signal is the specified strength of an audio signal used to transmit analog sound between audio components. Whereby, it boosts the volume of the frequencies that we want to hear such as the guitar tone. Without, boosting the noise that surrounds our tone (such as unwanted electrical interference). 

2. Why is Preamp Important for guitar?

If you boost a guitar signal without a preamp you will hear fuzz and distortion as a regular amp will boost all frequencies that pass through it.  This is because, with any audio signal, it contains the guitar’s signal as well as electrical interference.

Unfortunately, electrical interference is unavoidable. It is present simply because of the transducer which originally captured the audio signal, to begin with. 

The transducer is basically a microphone or pickup and it is a device made from copper coils and a magnet that essentially converts the vibrations from plucking your instrument into an electrical signal. However, transducers capture other unwanted frequencies that are in the surrounding area.

This makes preamps truly important because we are able to boost the signal of our guitar without boosting the electrical interference that surrounds it. This basically means a stronger well-rounded signal, whereby all quieter frequencies of the guitar are boosted at a level at which people can hear easily, and the unwanted noise is not boosted.

Thus, by applying a preamp, it will reduce electrical interference. As a result, it will shape your amp’s voice and character by adding warmth and dimension to your sound, thereby ensuring a more audible and dynamic guitar output that is not noisy. 

3. How Does a Preamp Work?

Preamp’s fundamental purpose is to convert a mic-level or instrument-level signal into a line-level signal. This is why they are highly most commonly amongst acoustic players.

A microphone records the signal at mic-level. The thing is, this is a very weak signal, or at least there will be levels of the frequency that are not loud enough to be heard. 

A preamp is the very first part of an amplifier that your guitar actually interacts with. An ideal preamp would be linear enough, which means that it has to have constant gain in its operating range. It would also have high input impedance (requiring a little amount of current to sense the input signal) and low output impedance (minimal change in output voltage when the current is drawn from the output).

4. Built-in Preamp On Mixers?

If already have a mixer or interface, do you really have to spend money on a separate one?

You may wonder. Well, even the best mixer and interfaces cannot deliver a more quality sound than a dedicated preamp, that’s the truth.

Mixers and interfaces are limited in their ability to deliver exceptional sound quality, and there is also no room in them to place the components of an excellent external preamp. However, if you have a really tight budget, an interface or mixer that includes a preamp’s function may satisfy your needs, but obviously now you cannot expect it to deliver top-notch sound quality.

5. WHAT will you need to consider BEFORE purchasing a PREAMP?

You will easily get bombarded with lots of technical terms regarding the preamp and its functions which very much likely don’t mean a thing. You may sometimes find yourself wondering “What in the world is the SNR ratio?” (which basically means signal-to-noise ratio). But don’t worry, since most experts don’t really pay attention to it. What you really need to look for when considering a preamp are the following things.

First, the type of preamp. There are tube preamps, there are also solid-state preamps. The first one tends to be more colorful while the latter is cleaner in its sound. Find the one that suits your purpose.

Second, identify the number of channels. One, two, or multi channels? Identify it before you make the decision.

Next thing is the inline processing. You may somehow end up wanting the EQ and compression from the channel strip, consider that.

Another factor is the maximum gain, which appears to also be the last one. Condenser mics require gain at 30dB-50dB while ribbon mics and old dynamics usually require 50dB-70dB, a lot of gain.

6. WHAT are DIFFERENT TYPES of PREAMPS?

First and foremost, let’s group different types of preamps according to their aesthetic purpose: transparent preamps and coloured preamps. AESTHETIC PURPOSE

Transparent Pre-amps

Some preamps are designed with the purpose of reproducing the sound and doing it as truly and cleanly as possible, without altering the tone or timbre of the guitar’s sound throughout the process. Transparent preamps, with the purpose as mentioned, take the signal, converting it to line-level volume with little or no distortion. They perfectly reproduce the sound, in short.

Now how do they do that? Solid state electronics are the answer, they help create transparency. Unfortunately, old preamps on the market tend to use tube technology, which is less favoured for transparent preamps.

Who may prefer transparent preamps? Musicians or recording engineers who are in charge of jazz music and classical performances would be the ones who prefer this kind of preamp since they need the sound as true as it is.

Coloured Pre-amps

In contrast to the preference of maintaining the sound’s pureness throughout the signal chain, coloured preamps, on the other hand, introduce another way of altering the sound quality, which is to add a specific colour to it. In short, coloured preamps boost your signal’s volume while introducing a harmonic distortion. The harmonic distortion is based on the signal itself, at a lower volume and frequency, thereby offering a sense of “warmth” to the sound, making it more sophisticated. This is especially useful when the sound itself is thin and dry. Use a coloured preamp in this case, and the result you get is a much richer sound and timbre.

So what is the underlying mechanism behind this? Coloured preamps can add flavor to your signal thanks to the use of vacuum tubes or transformers. However, these coloured preamps can make your signals over the top if not properly used, so beware of that.

Some recording engineers and producers prioritize transparency while others prefer sound that is rich in itself. There is no right or wrong, it is just personal preference. Transparency does not mean dry, and color does not take away your true timbre. You can even combine both types of preamps to achieve a unique sounding tune.

CIRCUIT DESIGN

Instead of grouping preamplifiers according to their aesthetic purposes, another way is to categorize them into groups of circuit designs. Here we have tube preamps and solid state preamps.

Tube Pre-amps

Tube preamps are usually made of thermotic tubes, or the so-called “valves”, to create gain. Tube preamps are the type of preamp that will add significant colour/flavour to your signal with deep bass and airy, open highs. Warmth is also present here, since as the signal volume gets higher, the tube will experience mild distortion, which in turn provides more depth to the sound, especially in the midrange. The distortion happens gradually and in a reasonable amount, and that’s the reason the sound you get will, most of the time, be ear-pleasing.

And not just by distortion, tube preamps are also able to add colour thanks to its tube circuit design. The design specifically provides the preamp with natural compression features. It can be very subtle for normal ears, but producers and engineers would wish to spend their money on the high quality tube compression. You can imagine it as the glue that connects everything together, the one that brings the feeling of “completeness” to your sound.

In addition, tube preamps can also serve as low-pass filters which smoothes out high distortion and reduces high frequency content. This function of tube preamps is desirable for warm vocal tone but unfortunately, undesirable for percussion where it is essential to have attack information.

Solid State Pre-amps

Solid state preamps, on the other hand, provide more transparency than tube preamps. It is mainly because of their capability to accept higher gain levels without producing distortion. In solid state preamps, when gain increases, the transistors operate in a more consistent manner, thereby producing very little distortion up to their maximum level.

In contrast to tube preamps which produce even harmonics that are pleasing to the ears, solid state preamps have a tendency to produce odd harmonics, a much less pleasing sound. With that being said, solid state preamps have more transparency and less colouration in its sound compared to tube preamps. Hence, it is more preferable for instruments that have quick attack as well as powerful transients. The conclusion here is, if you want to capture the natural tone of your sound, a solid state preamp would be a great choice.

FORMAT

That’s it for classifying preamps according to its circuit design. Another way to categorize preamps is to think of its shape or format. Come to think of it, preamps can be categorized into three types: 500 series preamp, desktop preamp, and racked preamp, in which the 500 series one is the most popular.

500 SERIES PREAMPS

The 500 series preamp is a format which includes individual signal processing units housed in a powered enclosure. It is probably the best option for those seeking high quality equipment but having a tight budget.  Most of the 500 series preamps are single-channel. Still, channel strips are also available for preamps with added compression or EQ.  It’s worth your investment and the two main benefits below are the reason.

First, 500 series preamps come with relatively small sizes. Small size, as a matter of fact, will reduce manufacturing cost and distribution cost, which eventually significantly reduces the price you have to pay. In a user’s perspective, smaller size means you have more space to place other recording units and signal processing equipment since these 500 series preamps take a lot less space than their full size siblings.

Second, flexibility is what the 500 series offer. Mix and match the units whatever you want to create your self-designed custom signal path. For example, you can create a high end guitar chain, a vocal chain with vintage sound or an analog mastering chain. These are a few possibilities, and there are even more for you to discover once you own this 500 series. Furthermore, you can even add the modules whenever you need, which is cool because you have the ability to actually “grow” your recording friends.

Desktop Preamps

If you are among those musicians that require only one high quality channel for your vocal, desktop preamps are the ultimate choice. In other words, those do not need a lot of equipment. Powerful gain function with enhanced bass along with custom audio sound, desktop preamps provide “enough” functions like any other preamps, plus the fact that they come with a compact size, leaving space for your desktop.

Racked Pre-amps

Rackmount preamps have somehow become lost in this world of modern equipment ever since the 90s. Yet it remains great for people who value the preset tone’s programmability and components being interchanging. With the chassis and the holes’ width being standardized for 19-inch rack rails, rackmount preamps make enough space for your preference of studio gear.

Digital Pre-amps

Digital preamps are a different world. The purpose of this kind of preamp is to convert an analog signal into a digital signal. Digital preamps make sure to add the signal’s sonic signature along the process before outputting it to a digital audio workstation (DAW). Some digital preamps even have a digital output sound card installed in the computer. Others, on the other hand, have the conversion and processing which is directly built into the preamp.

Digital preamps can also be considered as digital interfaces since their function of converting the analog signal to a digital signal is the same. Nevertheless, the units are designed just like the preamp while the conversion of the audio signal can be seen as a byproduct of the primary preamp function.

CONCLUSION

As Almost all of our gear expects a line-level signal to get the BEST results. 

After reading this ultimate guide to preamps and their different types, we hope you gain a basic understanding of how different types of preamps can have a varying effects on the overall signal chain. The question of choosing the right preamp now comes down to deciding what you want. Basically,for example, if you are seeking a colourful, rich and warm vocal tone, tube preamps are the answer. Contrastingly, a solid state preamp would be a perfect choice if you want to capture the sound as true as it is without adding any colour.

As time goes by, when you gain more experience and take on more projects, you will eventually have the need to purchase more than just one type of preamps because of varying purposes. Read this article again that time if you are still not sure which one is the right one. Hope this helps, and thank you for reading.

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