Amps, Effects and Modeling – oh my!

Every guitarist reaches a point in his playing life when he begins to come across terms like “Combo Amp”, “Rack mount”, “Stompbox” and the like. This may happen early in his guitar journey, or much later – particularly if he has played acoustic for many years before venturing into the realm of the electric.

That was me. I played acoustic guitar for over 10 years before I ever picked up an electric. I never paid much attention to terms like “amp head” and “rack mount”. But after receiving my first electric guitar for Christmas one year, I quickly found myself immersed in a world of terminology completely foreign to my otherwise knowledgeable self.

Today, I am going to provide some detail on these terms. (since I was unable to find any decent info on the Internet that wasn’t loaded with too much info).

E n j o y.

What is a Amp Head?

An amp head (sometimes referred to as simply a “head”) is the base amplifier. In it’s simplest definition, the head is the box that receives the signal from the electric guitar, and routes it out to the speaker(s), P.A. system or headphones.

The 50w Marshall JVM205H Guitar Amplifier Head.

It may be solid state (i.e. using integrated circuits and a digital processor to carry the electronic signal) or tube (i.e. Using Vacuum tubes to carry the signal). Tube amps are also sometimes referred to as valve amps.

It is called the head because it historically sits on the top, or at the head, of a speaker stack or cabinet.

The amp head is usually rated by power consumption, ex.: 15w or 30w, meaning it consumes 15 or 30 watts of power while in use. The higher the wattage, the more muscle. Amps today range anywhere from less than 1w to over 400w.

A final word of caution on amplifier wattage: more watts does not always mean louder sound. It’s only a measure of potential power, the ultimate sound quality and decibel level is also a factor of the input and the speaker(s).

What is a Combo Amp?

So, if the amp head is the amplifier itself, what is a combo amp?

The Fender '65 Twin Reverb combo amp

Put simply, a combo amp is both the amplifier and the speakers in a single unit. Combo amps are ideal for learning to play and for practicing, whether solo or in a band. Everything you need to produce sound (outside of the actual instrument) is in a single, self contained unit.

Combo Amps vs. Amp Heads

So which is better, an amp head or a combo amp?

That depends on your desired use. Each has it’s benefits and drawbacks.

Amplifier heads are typically better amplifiers than combo amps. This is because you’re paying top dollar for just the head. Many combo amps have very good amp heads and good speakers, but generally speaking you get a better amplifier for your money when you buy an amp head.

Combos are ideal for practice and learning, but the speaker(s) in a combo amp cannot compete with stand alone cabinets for concerts or live shows.

Most hobbyists will do just fine with a combo amp, while most professionals favor the stand alone amp head with speaker cabinet set up.

What are Effects?

OK, with me so far?


Now that we know what gets the sound from the electric guitar out through the speakers we can turn our attention to sound effects.

There’s no definitive list of effects, but the most common types include:

  • distortion
  • modulation
  • dynamics
  • filter
  • time-based
  • pitch/frequency
  • feedback/sustain

Much of a guitarist’s sound is the result of their choice of effects.

Effects should be viewed as an added layer of sound put on top of the base sound from the guitar. It’s for this reason that the most important aspect of an amp is it’s ability to deliver good, clean tone without any (unintended) distortion or sound degradation. After all, if you start with a muddy sound, you’re only going to end up with a muddy sound at the heart of whatever effect you’re applying.

Effects can be applied to that sound a number of ways. Here are the 3 most common.


A Stompbox is an effects pedal, designed to lay on the floor and be turned on or off by the player stomping it with his foot. The stompbox may have 1 or more effects, and a multitude of controls affecting volume, signal, etc..

The Fulltone OCD Obsessive Compulsive Drive Overdrive Guitar Effects Pedal.

The instrument cable is connected from the guitar to the stompbox, and another cable is connected from the stompbox to the amplifier. Sometimes, multiple stompboxes may be chained together, creating a more complex sound as the signal is modified by each box on its way to the amp.

Common pedal effects include:

  • compression
  • wah
  • overdrive
  • chorus
  • flanger
  • phase shifter
  • delay
  • echo
  • reverb


Lexicon MX400 Dual Stereo/Surround Reverb Effects Processor

Rackmounts get their name from the fact that they are larger than stompboxes and require that they be mounted in a rack, like the kind used in telecommunications and networking.

Rackmounts are larger and usually offer more control over the signal, making for a more complex sound. Since they are not as easily toggled on/off as stompboxes, rackmounts are favored in recording studios or sometimes used in live sound mixing, whereas the stompbox is used by the guitarist at home and on stage.

Some of this separation has disappeared as modern rackmounts can now be controlled by foot switches, much like a stompbox. However, they are still less portable than their stompbox cousins.

Modeling Amps

Fender Mustang III modeling amp

Lastly, some amplifiers provide sound effect features on-board, eliminating the need for the stompbox or rackmount. These are usually called “Modeling amps” as they model the stompbox or rackmount capabilities.

Some newer amps take modeling to a new level, modeling other amplifiers themselves. These amplifier modeling amps make it possible to emulate vintage amps that are often too expensive for the beginner, which makes them great amps for the hobbyist.


The world of electric guitar is much broader than that of the acoustic, at least in terms of gear and equipment available. But that’s part of the allure. After all, who doesn’t love to roll up their sleeves and play around with a different sound now and then?

It may seem like a lot of info, but it can open up whole new worlds of sound to explore.

Happy exploring!

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