How does a guitar amplifier work?
It is important to have a basic understanding of how a guitar amplifier works. Only then can you make an informed purchase decision.
Guitar amplifiers were originally developed because the guitar simply couldn’t establish itself in a big band alongside trumpets, trombones and drums. What happens now in an amplifier?
The pick-ups of your electric guitar (the magnets that can be seen under the strings at the bottom of the body) create a magnetic field. If a string vibrates in a certain tone, this magnetic field is interrupted and an electrical voltage is generated.
This voltage is then fed into the amplifier via a cable; there it is amplified and output via boxes. What exactly here on a physical level is unfortunately not that easy to understand. The only important thing is to know that there are different reinforcement designs that generate different results. These are explained further below.
How can you classify guitar amps?
Guitar amplifiers can be classified as follows:
- According to the design (combo or top part)
- According to the intended use (electric guitar, acoustic guitar, bass guitar)
- After using the reinforcing components (tube vs. semiconductor)
- According to the predominant sound characteristics (clean, distorted, British, American)
The good news: the market offer is so extensive that you can find amplifiers in every category. So you can easily find a combo amplifier for acoustic guitar in tube design with British sound characteristics. At the same time, a top part for electric guitars with semiconductor amplification and distorted sound is also no problem.
The disadvantage here: The range of guitar amplifiers is becoming increasingly confusing.
The range and variety of guitar amplifiers is enormous. If you want to make the buying process easier, look for which amplifier your favorite guitarist uses and try to find something in that direction.
According to the design
There are essentially two different types of guitar amplifier.
- Top part with boxes
To do this, one has to understand that an amplifier itself does not reproduce the sound; only the electrical signal is amplified. So that the whole thing can be made audible, an amplifier always needs loudspeakers.
In a combination device, the amplifier and speakers are combined in one element. On the one hand, this is practical because you only have to think about one device. On the other hand, of course, you also give up flexibility.
You can connect a top to different boxes. So you can operate it at home with small speakers, but also conveniently take it with you to the next gig and connect it to significantly larger, louder speakers and still keep your characteristic, familiar sound.
According to the purpose
Also important to know: an electric guitar amplifier does not work for bass guitars and vice versa. At least the result is not optimal. So pay attention to what you want your guitar amplifier to be used for. Do you want to use it on your electric or acoustic guitar? Or are you a bass player? All of these are important when looking for optimal sound.
Because there are actually guitar amplifiers especially for acoustic guitars. If you are looking for an amplifier that is specially tuned to the tonal properties of an acoustic guitar, you will find it in many (online) specialist shops. By the way: There are special pedals with which you can switch between different amplifiers. This gives you maximum flexibility on stage.
After using the reinforcing components
After the electrical voltage has flowed through the guitar cable, it arrives in the amplifier. There are various amplification techniques for what happens to the signal:
- Tube amplifier
- Transistor amplifier
- Modeling amplifier
- Software amplifier
The first guitar amps to hit the market were tube amps. Their sound is often described as warm and full. High-end tube amplifiers are still the best the market has to offer.
Transistor amplifiers were often assumed to sound scratchy and heavy on highs. But this attitude does not do justice to high-quality semiconductor amplifiers. Because good models also offer the best (and versatile) sound here.
Modeling amplifiers are digital machines that can simulate the sound of tubes and transistor amps. When you buy a modeling amplifier, you can choose between different sounds while playing. This makes them incredibly flexible and versatile.
Software amplifiers are loaded as plug-ins in your DAW (digital audio workstation, e.g. Logic or Cubase). They are not really suitable for live operation because of the high input delay. In order to generate high-quality guitar recordings, however, they are highly recommended.
To do this, the guitar is simply plugged into your audio interface and recorded. Advantage: It remains quiet and the signal is picked up cleanly. In addition, you retain maximum flexibility in post-processing.
According to the predominant sound characteristics
Many guitarists see their amplifier as part of the instrument – and not without good reason. Amps have different tonal characteristics, and depending on which genre and style you prefer, you have different options. The following table summarizes the main different sound characteristics:
|Clean||Clear sound without any kind of distortion. Represented at the right place in each genre|
|Distorted||Classic rock sound in ACDC style|
|British||“Fizzy, roasting” – represented in punk genres|
|American||rough and roaring: fuller and warmer than the British sound|
|Crunch||Sounds with moderate distortion|
If you want to hear the American sound in direct comparison to the British sound, take a look here:
After the performance
In addition to the criteria mentioned, there is of course also the amplifier power, which largely determines how loud the amplifier is. Here is important to know:
Double the wattage does not mean double the volume.
Tube amplifiers are also significantly louder than semiconductor amplifiers. In general, volume should not be rated as too important, because on large stages (where high volume is necessary) the guitar amp is picked up with a microphone and amplified via the PA. As with everything, you have to ask yourself where you basically want to use the guitar amplifier. If you play rather small club gigs, a very loud amplifier can be very disadvantageous, as no good sound can be mixed together.
What do you need the guitar amplifier for?
A basic question to ask yourself is what you need the guitar amplifier for. Do you need an amplifier for home practice? Do you want to go on the big stage? Or do you basically just want to get your guitar sound into your PC? Because here applies: There is an optimal guitar amplifier for every application.
For simple practice at home, inexpensive combo systems with a headphone output are often recommended. If you want to go on the big stage, you should make sure that your amplifier has enough power. Attention: Tube amplifiers with 30W can be much louder than transistor amplifiers with 30W.
There are suitable amplifiers for every application. If you need an amplifier for your home, a small combo amplifier will do. If you want to go on the big stage, make sure you perform well.
Which guitar amplifier is the best for the home?
Of course, this is also largely a matter of taste. However, when practicing at home, you tend not to need a very high volume.
Since tube amps nowadays only achieve their best sound at higher volumes, a smaller volume maker is ideal for practicing at home. It is up to you whether you use a combo system or buy a high-quality top part that you connect to small boxes at home and large boxes live.
Tip: For uncomplicated practice at home, smaller all-round transistor amplifiers are often a good choice.
How many watts should my guitar amplifier be?
One should definitely note: the sound of an amplifier is first of all the most important criterion. Because on large stages, the amplifier is amplified and mixed with the help of a microphone over a PA system. Then loud guitar amplifiers can even be disadvantageous because they “pollute” the mix.
If you want to assert yourself against the drummer in the rehearsal room, it is of course important that the amp has the appropriate power. Here you can set the following minimum values with a thumbs-up:
Practice room / at home: 1-20W tube / transistor of any kind
Club gigs: 15-50W tube / at least 50W transistor
Large stages: 30-100W tube / 50-100W transistor
It is best not to use the wattage as a guide, but rather the volume of the amplifier, which is usually given in decibels.
Can I connect headphones to my guitar amplifier?
Playing with headphones is very comfortable, especially at home. But this is not possible with every amp. If this is a criterion for you, make sure that your future amp supports this feature.
How much does a guitar amplifier cost?
Hardly any other product has such wide price ranges. However, one can differentiate a little:
Inexpensive tube amplifier tops start at around € 120. The most expensive variants cost several thousand euros.
In the case of transistor amplifiers, you can find very inexpensive variants from as little as € 80; But here, too, there are variants that cost over two thousand euros. Nevertheless, tube amplifiers are on average more expensive than transistor amplifiers.
Modeling amps are priced in a similar way to semiconductor amplifiers.
Can I connect my guitar amplifier to my audio interface?
Technically, this is possible without any problems. However, you will not get the best results with it. If you want to record good guitar sounds, it is advisable to plug your guitar directly into your audio interface using a jack cable.
An audio interface is a box that is responsible for digitizing analog sound material. It is essential if you want to record something with microphones, for example.
Then you can use software amps such as GuitarRig from NativeInstruments to shape your sound as you like. For this procedure, however, your audio interface should have a direct monitoring function so that the signal can be branched off again before processing in the computer and played back with practically no latency.
Alternatively, you can get a microphone and remove the amp. Dynamic microphones like the Shure SM57 are good variants here. But you can also achieve very good or even better results with condenser microphones such as a Rode NT1A.
How long do the tubes last on a tube amplifier?
Opinions differ as to when a tube sounds bad and worn out. On average, however, something will have to be replaced every two years. Influencing factors here are also how you care for your amplifier: You should let it warm up for 30-60 seconds before playing for the first time and not transport it immediately after switching off, but ideally wait 10-15 minutes. Then of course it also depends on how many hours the amplifier has been in use.
Decision: What types of guitar amps are there and which one is right for me?
In the following, the various advantages and disadvantages of the reinforcing construction are discussed. We differentiate between:
- Tube amplifier
- Transistor amplifier
- Modeling amplifier
What are the advantages and disadvantages of a tube amplifier?
If you love recordings from the 70s and 80s such as Queen or The Who, for better or worse you will end up with a tube amplifier. You not only have to pay more money for the incomparable sound of several large tubes, but also require more maintenance.advantages
- Unmistakable, timeless sound
- Higher volume with the same wattage compared to transistor amplifiers
- Replacing the tubes
- More prone to failure
The amplifier always needs to warm up for about a minute before it can be played, and cooling the tubes is also important. Another disadvantage: the tubes will gradually wear out and have to be replaced (this must be done by a specialist dealer!).
But if you don’t want to compromise on the sound, you will ignore these points and get what you want with a tube amplifier.
What are the pros and cons of a transistor amplifier?
If you do not want to accept the disadvantages of a tube amplifier, a transistor amplifier is probably suitable for you. At this point, one also has to dispel the prejudices against transistor amplifiers; because these have developed enormously in the last 30 years and do not have to hide behind tube amplifiers.advantages
- Sound that doesn’t have to hide
- Comparatively inexpensive
- High-end tubes sound better than high-end transistors
In general, the differences are more likely to be perceived by professional musicians, the audience will normally not see any difference. Ideally, you should try out the amplifiers and form your own opinion.
What are the pros and cons of a modeling amplifier?
What does a modeling amplifier actually do? Modeling amplifiers emerged in the 90s. These are digital devices that mimic the sound of amplifiers. It is practically a software that looks at the sound wave of the electric guitar and compares it with the one that comes out of the tube amp. So you can calculate what is changed and apply it digitally to the raw guitar sound.advantages
- Many amplifiers in one device
- good sound quality
- Opinions about the sound quality differ
The advantage is obvious: when you get a modeling amp, you are not getting a specific sound, but the world of amps is at your feet. Tip: Modeling amplifiers are a good choice, especially for the undecided and people who are still looking for their own sound.
Combo or single device?
When it comes to the question of whether you are buying your amplifier in a combination device in which the amplifier and speakers are combined in one device, or whether you are getting a top that you can easily connect to different speakers, there are various things to consider.
With tops you are more flexible, but you also have the effort to take care of at least two devices. In the case of individual devices, you often also have a price reduction. The more professional solution is certainly a top part; in many situations, however, it can simply be very convenient to only have to deal with a single device.