What Are Class A/B Guitar Amps

If you’re a guitar player, you’ve probably heard about guitar amp classes and wondered what they mean.

In simple terms, Class A/B refers to the way in which the power section of the amplifier operates. It’s related to the time period of the amplifier passing current.

There are different types of tube amp classes and in this beginner’s guide, I will explain guitar amps with Class A/B.

Understanding this concept is important if you want to choose the right amp for your needs.

How Class A/B Guitar Amp Works

class A/B amp circuit diagram

Class A/B amplifiers are the most common type of power amplifier used in guitar amps, and they are known for their smooth, warm tone and low distortion.

This is achieved by using a combination of Class A and Class B amplification. Class A amplification uses a continuous flow of current to produce the output signal, while Class B amplification uses a more efficient, but slightly less linear method.

The Class A portion of the amplifier produces a warm, smooth tone with low distortion, while the Class B portion provides more power and increased efficiency.

The result is a guitar amp that can produce a clean, clear sound at low volumes and still deliver high power and sustain when you need it.

Another advantage of Class A/B amplifiers is their versatility. They can be used for a wide range of music genres and playing styles.

I love Class A/B amps for classic rock, blues, and smooth and warm guitar solos. But there are Class A/B amps to dial in a good metal tone.

However, when choosing a guitar amp, keep in mind that there are other factors to consider besides classes like speakers, tubes, etc.

How Class A/B Tube Guitar Amp Sounds

class a/b combo

Class A/B guitar amps are known for their rich, warm tone and low distortion which is great for many styles.

The Class A stage of the amplifier contributes to a more linear, distortion-free output, resulting in a smooth and transparent tone. This stage is often described as having a “creamy” or “round” sound, with a pronounced mid-range and good sustain.

And Class B stage, on the other hand, provides increased power and efficiency. It’s responsible for delivering high volume and headroom and is often described as having a more aggressive and punchy tone.

When combined, these two stages produce an amp that has a well-rounded sound with a good balance between clarity and warmth. These factors make Class A/B tube amps very versatile.

You can use Class A/B amps or combos in any genre but I like them for more distorted tones and they are also great amps for metal.

Famous Class A/B Guitar Amps

Tube amplifiers have a unique character that has made them popular among guitar players for decades.

Class A/B amps are used by many famous guitarists and in every style of music because they are very versatile.

Here are some of the most famous Class A/B guitar amps:

  • Mesa Boogie Dual Rectifier – The Mesa Boogie Dual Rectifier is a versatile Class A/B amp that can deliver a wide range of sounds, from clean and crisp to heavy and distorted.
  • Vox AC30 – The Vox AC30 is a classic British Class A/B amp that is often associated with the “British Invasion” sound of the 1960s. Its bright and chimey tone has been used by countless players, from The Beatles to U2.
  • Orange Rockerverb – The Orange Rockerverb is a modern Class A/B amp that has become popular among alternative and hard rock players. It’s known for its warm, fat tone and high gain.

These are just a few examples of the many Class A/B tube guitar amps that are available. However, there are Class A/B modeling amps, for example, Boss Katana Artist which is a very versatile modeling amp.


Class A/B guitar amps, particularly those powered by tubes, offer a warm, rich, balanced, and versatile tone that is popular among guitar players. From the classic Vox AC30 to modern designs like the Orange Rockerverb, there are many notable examples to choose from, each with its own unique sonic characteristics.