How Does a Guitar Amp Work? Everything You Need to Know

An amplifier is one of the first and most important pieces of gear most guitarists get. There are many types of amplifiers, all of which work with different components. Knowing how your guitar amp works will help you modify it while improving your skill set.

A guitar amp works by using transistors or tubes to convert digital signals into sound waves. These sound waves go through internal speakers or through external headphones, speakers, and computers. There’s a preamp and a power amp in each amplifier that receive and send signals.

Throughout this post, I’ll explain how each type of guitar amp works and how you can use them to the best of their abilities.

How Do Different Types of Guitar Amps Work?

All guitar amps send signals through speakers, but they don’t work nearly the same way. Some amps require a lot more maintenance, while others are as plug-and-play as it gets. Additionally, it’s important to note that you might not have the same number of inputs and outputs on different styles of amps.

Without further ado, let’s dive into the way each of the four types of guitar amps work.

Solid-State Amplifiers

Solid-state amps are some of the world’s most common amplifiers. They use transistors to form circuits, repeatedly pulling and sending audio signals.

Here’s the process a transistor amp uses to amplify sounds:

1. The amp’s transistor receives a digital signal from your guitar’s pickup.
2. The transistor sends the signal from the preamp to the power amp to produce sound through the speaker.
3. Onboard modifications happen in the middle of the circuit before it completes (gain, volume, reverb, etc.).
4. When the audio wave goes through the speakers, the next signal goes into the transistor circuit.

This process happens so quickly that it’s almost impossible to notice the time it takes for the circuit to complete.

Tube Amplifiers

Tube amps have small tubes (also known as valves or bulbs) on top of the amp. These tubes are vacuum-sealed, and they contain filaments and other components to heat and amplify the incoming audio signals.

Positive-charged and negative-charged terminals have a grid between them that connects to the guitar pickup. When audio signals are sent through the pickup, the aforementioned filament heats up, and the anode (the positive terminal) amplifies the sound.

Guitar Player explains that the harder you strum the guitar and the louder you set the amp’s volume, the more heat is created. This is the main reason tube amps can heat up a room simply by playing the guitar.

Hybrid Amplifiers

A hybrid amp combines the tube preamp used in a tube amp and the power amp used in a solid-state amplifier to create a modern take on music production. As sound waves go into the aforementioned grid between the positive and negative terminals, they heat up and go into the power amp to produce audio waves.

Hybrid amps are becoming very popular because they’re low-maintenance (like a solid-state amp) and naturally pleasing to the ear (like tube amps). You don’t have to worry about breaking the exposed valves, nor do you have to sacrifice audio quality.

Another benefit of choosing hybrid amplifiers is that they typically don’t weigh as much as tube amps. They also don’t get nearly as hot because they only have a preamp tube rather than two sets of tubes. Additionally, hybrid amps boast the well-known power and kickback found in most solid-state amps.

Modeling Amplifiers

Modeling amps are quite complicated, but they have a lot more effects to use. You can change all sorts of settings with effects knobs and switches on the amp because there’s a built-in computer.

So, how does this process work?

1. Your guitar pickup sends a digital signal into the modeling amp.
2. The amp’s computer picks up the signal and converts it into a readable code, which then uses all of the input modifications to alter the signal.
3. The modified signal converts into audio waves after they finish changing, then they go through the built-in speakers (or through the connected output channel).

Modeling amps are constantly changing as technology advances. New-age computers allow modeling amps to sound closer to traditional amps (solid-state and tube amps) without the price tag.

Read Also: What is a Modeling Amp?

Where Does the Tone Come From in a Guitar Amp?

The tone from a guitar amp comes from multiple sources, including the pickup going into the amp, the amp’s ‘tone’ effect, and the style of amp. Many external factors influence the tone, including guitar strings and speakers. All of your guitar equipment can alter the tone in one way or another.

Let’s take a deeper look at how an amp gets its tone below.

• Your guitar’s pickup and amp cables affect the tone. The pickup is the bridge between the amp and the guitar. If you don’t have a good pickup, your amp won’t have the tone you’re looking for. There are many types of pickups, including P90 pickups, humbuckers, and more.
• Many guitar pedals and knobs have ‘tone’ effects. Check your amplifier to see if you can alter the tone without swapping out any of your gear. Most modeling amps have multiple effects knobs onboard. You can also plug pedals into the guitar amp’s inputs to change the tone, chorus, distortion, and more.
• Solid-state amps and hybrid amps have much more modern, pop-rock tones compared to the vintage, natural tone of tube amps. Also known as valve amps, tube amps sound rounded and smooth because they don’t produce artificial buzzing sounds. Additionally, they’re much more efficient with their signal conversion processes.
• Your guitar strings have a massive impact on the amplifier’s tone. Thick strings provide more resonance, which means they hold their tone and sound production much longer when going through an amplifier. Changing your guitar strings can help you change your amp’s tone without altering its settings.
• The amp’s built-in speakers will inevitably change the tone. It’s very difficult to change an amp’s internal speakers. The good news is that you can plug most amplifiers into external speakers, which lets you alter the tone. You can also do the same thing by plugging high-quality headphones into an amplifier.

Keep in mind that many parts of an electric guitar affect tone, including the materials, shape, fretboard width, and more. If you notice intonation issues, it’s likely due to problems with the guitar, not the amp. Turn off the amp and listen to the guitar unplugged to see if there’s still a tone problem.

What Makes a Guitar Amp Sound Different?

Guitar amps sound different based on their style or quality. Additional factors include the onboard effects loops, pedals you add to the amp, and the size of the amp. An amp’s wattage often affects how loud it can be, which can influence the distortion (especially on tube amps).

So, why do some amps sound so much better than others?

Effects and Pedals

Most amps can use most pedals. A modeling amp can also use various effects loops without using external equipment, though they’re still compatible. If you want your amp to sound different, you can use pedals to change the chorus, reverb, ambiance, and many other effects. Pedals are the main way that musicians alter and improve their amps.

Wattage and Volume

Wattage and volume go hand in hand when it comes to amps. However, tube amps don’t need as many amps as solid-state amps to produce the same volume. Most amps require between 15 amps to 100 amps. Additionally, tube amps don’t sound nearly as good if you use them at reduced volume levels (or if you don’t let the tubes heat up).

Quality

An amplifier is only as good as its quality. You can use all the pedals in the world, but it won’t make a low-end amp sound professional. If you’re looking for reliable brands, try BOSS, Yamaha, or Fender. They make high-quality amps for a variety of budgets. If you don’t want to spend too much but you want more sound alterations, try a modeling amp.

Internal Speakers

Your amp’s internal speakers can make it sound different, which isn’t always a bad thing. You can use 100-watt amps for incredibly louder speakers or 30-watt amps for low-noise speakers. 

Furthermore, Fuel Rocks explains that a 12-inch (30.5cm) speaker will sound fuller than a 10-inch (25.4cm) speaker. An amp speaker’s shape and size are essential parts of sound production.

Amp Style

Tube amps are known for their unique sound output. It’s often said that no two types of tube amps sound the same. On the other hand, most solid-state amps are only affected by the quality and size of their speakers, transistors, and onboard effects. Choosing an amp is much more than the way it looks or functions.

Tone is only a fraction of an amp’s total sound output. You also have to consider the distortion, resonance, and how well it translates sound signals into audio waves. All of these factors are best determined by messing around with multiple amps. If you’ve never used them, you’ll have more luck with a solid-state amp because it’s easier to change the sound.

Why Do Some Guitar Amps Have Two Inputs?

Some guitar amps have two inputs because they can use multiple pedals or two guitars. You can also plug a mic into the open input, though this isn’t recommended because it’s often drowned out by the guitar. Check your amp’s input cable requirements to know which equipment can be used.

Here’s what you should know about guitar amps with multiple inputs:

• They usually have low and high inputs that affect the overpowering guitar. If you plug a guitar into the high input, it’s usually a bit quieter than the other input. You can use this info to your advantage, especially if you only have one amp to use with your vocals and guitar.
• The piece of equipment with higher gain should go into the lower input. If you have a guitar that uses a low-gain pickup, plug it into the high input. A guitar with a high-gain pickup can go in the low input because there’s a higher sound ceiling. This layout prevents a high-gain pickup from clipping when it goes through an amp.
• Some pedals work better when they go through the ‘effect loop’ area on a modeling amp. If you have ‘effect loop’ inputs, you should always use your pedals there instead of in the regular front inputs. Reserve the main inputs for guitars or vocals for the best results. You’ll be able to swap through the pedals much easier, too.
• The number of inputs doesn’t correspond to the number of outputs on an amp. You might notice two inputs and only one output. This is because the outputs go to speakers, computers, or headphones. All of the inputs will go through the desired output. For example, you could have two guitar inputs going through one pair of headphones.
• Some amps have 48v ‘phantom power’ inputs. Phantom power is necessary for instruments and other audio devices that require more voltage than usual. This issue is quite common with cardioid microphones, but it can also be the case with some electric guitars. Note: Always plug in the instrument prior to activating the amp’s 48v input.

Many beginners make the mistake of thinking they can plug their guitars into either input on an amp. Unfortunately, this error affects the way a guitar sounds. Check the labels above the inputs or review the owner’s manual to know which input you should plug your guitar into.

How Many Guitars Can You Plug Into an Amp?

You can plug as many guitars into an amp as there are inputs. If you have an amp with two inputs, you can use two guitars. That being said, you can use a Y-splitter to plug two guitars into an amp with one input. The cable’s quality directly influences the clarity and tone coming through the amp.

Fuel Rocks reports that using a Y-splitter to use two guitars on one amp input will halve the signal, which means you need to increase the gain and volume. It’s also a good idea to mess around with the amp’s settings after plugging in both guitars since they will inevitably sound different from one another. Your stock amp settings won’t work for both of them.

The Icespring ¼” Splitter Cable (available on Amazon.com) lets you connect two guitars into one amp input. Customer reviews explains that this cable works wonderfully for connecting headphones and guitars into the same input, or plugging it into the amp’s output for two speakers or headphones.

Unfortunately, you can’t split the outgoing audio from an amp to have one side be one guitar and another side be the other. You can hook up multiple speakers, but there’s no way to choose where the input guitars split.

Do Amps Matter More Than the Guitar?

Amps don’t matter more than the guitar, but a low-quality amp can make a great guitar sound awful. Additionally, a top-notch amp isn’t going to make a bad guitar sound too much better. It’s important to have the same quality throughout your equipment setup if you want your amp to sound better.

Getting a better amp will definitely make your guitar sound slightly more professional, but it’s essential that you focus on all of the gear. If you’re determined to only replace the amp or the guitar, I suggest swapping the amp. You can change the effects and the tone with an amp, which can mask some of the guitar’s downfalls.

Consider these variables when you’re trying to make your amp sound better:

Pickups

You can change your pickups to alter how your amp and guitar sounds. Pickups are often seen as the most important part of the connection process, though the cables shouldn’t be overlooked. Swapping out the pickups immediately changes the way your guitar sounds, which is why an amp doesn’t always matter more than the guitar.

Gain and Volume

Some guitars have gain and volume knobs, but they’re much more common on amplifiers. Gain refers to the sound level of the signals going into the amp. However, volume refers to the sound level of the audio waves coming out of the amp. You can increase the gain if you want to help the amp receive the signals much easier (too much gain can be detrimental).

Combo and Stack Speakers

A combo speaker is a speaker and an amplifier combined into one unit. On the other hand, an amp stack is an amplifier with a speaker stacked on top. Andertons shows that an amp stack is easier to modify because you can remove the speaker from the top of the amp. This means that you can alter the audio waves without touching the guitar.

Final Thoughts

While guitar amps might seem complicated, they’re really just boxes with receivers that send audio waves through speakers. Some of them use vacuum suction, while others rely on transistor circuits. Amps can be simplified to a series of inputs and outputs that control where the signals convert into noises.