For every musician who plays string instruments, the amplifier is an indispensable element that defines a large part of the sound, printing to your notes and chords the desired tone and power.
It is very likely that, on more than one occasion, you have wondered how to choose an amplifier and, for this, it is important that you know its components, types and in what aspects to look at when making the decision.
Basically, the amplifier is used for electrical instruments – such as guitars or bass – to project their sound, something for which a series of elements is necessary, so – to make an intelligent decision – it is best to know in detail how these teams are formed
Elements of an amplifier
An amplifier is a device that amplifies sound waves, allowing you to adjust different variables to achieve the sound that the player wants. Broadly speaking, there are three essential elements for these devices to work: preamp, power stage and speaker or speaker.
Not all amplifiers have all three elements: some only have the preamp stage and the power stage, so an external speaker must be connected to be heard.
The teams that have all three elements are called combos. If you only have the first two, it is called a head. The combo mode integrates the three functions, while -if you have a head and speaker separately- the sum of both is known as the stack mode. There is a third modality: rack, which consists of having the three stages separately (something usually used by the most fussy professional musicians).
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Each modality has its advantages and disadvantages. While the combo is easier to transport and you don’t have to complicate with the connections, the stack and rack modes allow you to have a finer sound, in addition to being able to alter the elements to obtain different results.
Now, every amplifier has three stages in terms of sound processing and projection:
• Preamp: it is the first stage of the amplifier, where the input sound (the one that comes from the guitar or bass) is processed to result in the final tone.
• Power stage: this is where the previous signal rises and acquires the necessary power to project through the speaker.
• Speaker : also known as speaker, it is the element that outputs the audio processed in the previous stages. The final audio depends largely on its quality, so it is just as important as the first two stages.
Channels
As a musician, you will always have the need to experiment, so you should think about the way you will use the amplifier.
A common amplifier consists of a single input -processing and audio output-, but there are stereo amplifiers that incorporate more. But what is a stereo amplifier? It is a type of equipment with two or more channels instead of one, so it has two or more audio inputs and independent volume controls for each.
The advantage of having a stereo amplifier over a mono one is the versatility: while in one channel you can have a clean sound, in another you can have an overdrive sound, with other effects or reinforced at certain frequencies (depending on the equipment).
Now that you know what a stereo amplifier is and the difference with a mono one, you can get an idea of the type of equipment you need. But that’s not all: there are more variants that you should know.
Types of amplifiers
The amplifiers are divided into two basic types: valves and transistors, and both differ in the power and fidelity of the final sound.
Valve or tube amplifiers
The valvular amplifiers work processing the input signal through the filaments of vacuum tubes (also known as tubing), which -to generate sound- must be at temperatures above 100 ° C.
When amplifying an instrument with a tube device, the sound obtained is of high quality and the power is considerably greater than that of transistor amplifiers with the same watts. Therefore, a 30 watt tube amplifier can easily “devour” a transistorized one of 100 watts.
The problem is that these devices are more expensive, heavy and delicate, so they require more maintenance, and they must always be heated before starting to use them (turn them on a couple of minutes before touching).
Transistor amplifiers
In transistor amplifiers the final sound is more flat and less powerful than that of a valve amplifier, although thanks to technological advances, today transistor amplifiers are capable of emulating in an acceptable way those of valves.
Transistor amplifiers have the quality of being cheaper and more resistant, and they can integrate effects into the same amplifier.
Hybrid amplifiers
There is a third type: hybrid amplifiers . In them, the preamp stage works with valves, while the power stage is based on transistors.
Characteristics of an amplifier
Other aspects you should know about amplifiers are the following:
Power
How to know the power of an amplifier and which one do you require? The amplifier specifications will indicate the number of watts it offers (usually on the back panel), which will depend on where you are going to play. It is important to remember that a valve amplifier has much more power than one of transistors with the same watts. In other words, the tube amplifier sounds louder than one transistorized in relation to the same number of watts.
If you plan to play in a small rehearsal room, 20 watts in transistors will be enough. However, to play in a large or open space, you will need a device above 60 watts in transistors, or one with tubes of at least 15 watts.
Tone
Every amplifier includes a series of knobs thanks to which certain frequencies can be altered. These are divided into bass, middle and high, or bass, medium and treble respectively. In general, every amplifier comes with independent controls for each of these, being able to model the final tone to suit the musician.
How to choose an amplifier? The budget is the key
If you want to know how to choose an amplifier for electric bass or for guitar, after knowing all the previous points, you should evaluate your budget. In that sense, you should consider your needs as a musician: the spaces in which you will play, the sound you want, the effects you plan to use and your mobility needs.
A transistor combo amplifier will fit limited budgets, in addition to being able to transport it with relative ease. On the other hand, a stack amplifier or valve rack will give you great power and sound control, although you require a larger budget, as well as being more difficult to handle and transport due to the weight and the multiple connections involved.