Guitar Amps Explained

If you’ve recently begun playing the guitar you’re probably being introduced to lot of different concepts from chords to tab and effects pedals to string gauges. Another source of confusion for beginner can be amplifiers, more commonly referred to as amps. This post, Guitar Amps Explained, will introduce you to amplifiers. We’ll talk about the different types of amp available and look at their features. We’ll also look at what you should consider when thinking about buying an amp. Ready? Let’s get started.

What is an Amplifier?

At it’s heart an amplifier is an electronic circuit, which takes the signal from your guitar and boosts it. The circuit is combined with a loud speaker, which produces the amplified sound. Ok, that was kind of a dry explanation, but it’s the very basic function that all amps carry out. The concept of amplifiers was invented in 1908 by Lee De Forest, whose idea was readily used in radio receivers.

Talk to any guitarist and one of the first things they’ll talk about when comparing amps is wattage. The wattage of the amp is effectively the amount of power it can output. Wattage comes in all shapes and sizes, from 3 watt micro amps right up to 100 watt plus amps suitable for gigging. We’ll talk a little more about wattage in the next section.


The first amps were tube or valve amps. They used what looked like a light-bulb crammed with electronics. The bulb was actually a vacuum. Unfortunately, like light bulbs, the tubes need replacing as the tone deteriorates. In fact, just like a light bulb the tubes can go pop! It’s no straight forward job to replace them.

Solid state amps were the next incarnation. These use analogue or digital circuitry to produce their tone. Digital circuitry is comparatively new and allows manufacturers to incorporate on-board effects into their amps. There’s a lot of debate about analogue versus digital. Some guitarists think that digital amps sound fake. Technology is improving all the time and modern digital amps sound much better than their distant relatives.

Some guitarists are dead against solid state amps, citing the lack of punch in comparison to the valve amps. There’s also a debate about whether or not the harshness of the tones of solid state amps is a good or a bad thing. It’s certainly good for heavier styles like hard rock and metal.

Digital amps are usually feature heavy. Usually they come with in-built voices, or styles. These voices produce the classic tones associated with classic amps. The VOX Cambridge 50 for example models the sound of the classic VOX AC30 used by The Beatles among others.

Digital amps can also feature a range of on-board effects, memory banks and the ability to connect directly to a computer. Digital amps can produce a large and dynamic sound from a small box. The Boss Katana 50 for example delivers a series of styles, on-board effects and memory banks. Digital amps tend to be good value for money too, due to the range of tones they can produce and their range of features.

You might also come across the term combo when looking at amps. All that means is the the pre-amp and power-amp are built into the same unit. If you just had a pre-amp you’d need to connect to a speaker cabinet.

Another term you might hear is “head”. A head contains the pre-amp and power-amp but has no built in speaker. That’s where you need a speaker cabinet. Think of the walls of speakers you sometimes see at rock festivals.

The power output of an amp is measured in watts. That’s not the same as volume. You can turn a 10 watt amp up and get noise complaints. The higher the wattage, the more volume you can add without the tone breaking down or getting lost.

A practice amp (anything up to about 15 watts) is perfectly suitable for most guitarists. If you’re looking to start gigging, you’ll want at least 50 watts, maybe even 100 watts for larger venues. Be warned – 50 watts turned up is very loud!

What to Think About When Choosing an Amp

There are a few things to think about when considering an amp. The most ubiquitous question is what will you use it for? Are you just going to use it to practice in your bedroom or with a few friends? Or are you going to need to keep up with a drummer or play venues? If you’re using it for practice you can get away with a practice amp. If you need something that’ll keep up with a drummer you’ll need at least 50 watts of power.

The next questions is what sort of style do you play? If you like classic tones, then going for something solid state or even a valve amp might suit you best. If you want something that’ll create a wide range of tones it’s best to go for a digital amp.

Another prudent question is whether or not you’re planning to connect to speaker cabinets or other external speakers. If so you need to make sure the amp will support external speakers. That tends to be in the 50 watt plus range. It’s rare for practice amps to connect externally, except maybe to a PC or mixing desk.

Speaking of connecting externally, do you want to be able to configure the amp from a computer or mobile device? Some digital amps allow you to manipulate and save your settings in an app. Subsequently you can dial in your settings if you’re using someone else’s amp (of the same make of course).

Do you want on-board effects, or do you have a pedal board already? Do you want looper functionality? Yes, some modern amps now even have loopers built in as well as a whole host of modulation type effects. Control of these effects is best achieved by foot-switch. You’ll need to make sure that your amp of choice will support a foot-switch, and they’re usually sold separately so factor that in to your thinking.

How important is control of the EQ to you? Broadly speaking EQ covers bass, middle and treble. Although with all too many amps the middle control is missing. That’s always surprising to me. As guitarists we live in the middle range, so not having control over the middle is baffling. Some practice amps have full EQ but it’s more commonly found on large amps.

Think about the answers to those questions and you’ll have a much better idea of what sort of amp might suit your needs. It’s better than landing on a sales page and being completely confused by the features list!

Final Thoughts

It can be a little intimidating when you first start looking a amps. There are a so many brands, so many types and so many features to get your head around. With improvements in technology has come improvements in quality and available features. I remember when I bought my first solid state amp. It was a 50 watt Marshall bought for around $450. When I compare it to what’s available today it feels pretty antiquated.

Not only was it much more expensive than good quality 50 watt amps available today, it’s very basic and has few features. But it does make a lot of noise! The morale of the story? You can get some amazing amps these days. One of my favorites is the Boss Katana 50. So much dynamism for such a good price and loaded with Boss quality effects. I hope you’ve found this post useful. Feel free to leave any comments or questions below. Alternatively you can get in touch using my contact page. Choose your amp and go make some noise!

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