Guitar Amps: The Ultimate Buying Guide (2021)

Guitar Amplifier Guide

Without amplifiers, an electric guitar would kind of been useless back in the day. Now, they’re not quite as necessary. Virtual amps are all the rage at the moment and are getting better at realistically reflecting the authentic tones and feel you get from using hardware.

Quite a few artists have made well-regarded albums without using a guitar amplifier at all – Filosofem by Burzum created a raw, lo-fi tone by plugging an electric guitar into a pedal, and then a stereo amp.

But what about for live audiences? What about if you aren’t a black metal artist where awful quality isn’t actually the goal, and is in fact, rather undesirable? What about for a jam session?

Yes, it’s true, electric guitars don’t necessarily need to be paired with expensive guitar amps anymore. The digital revolution has seen to that. Technically, you could even play live without using a guitar amp by running a cable into an interface, through a digital amp VST, then back out to a monstrous PA system.

So, even though you can avoid using an amplifier and still get a lot out of your electric guitar, you have to ask yourself a vital question:

Should you?

What is an Amplifier?

Guitar Amp

An amplifier is actually a broad spectrum rather than a device used to make guitars sound good for metal or turn reverb up/down. Many amplifiers are configured differently, depending on their prime purpose.

In a general sense, an amplifier is an electronic circuit that strengthens the power of a signal.

An amplifier can be an independent piece of gear, or an electronic network part separate to the device (like an audio interface’s pre-amp).

How Does an Amplifier Work?

Ahh. Welcome back my friends. It’s time for your favorite segment of my articles — the largely irrelevant, complex and boring physics sections.

What’s that? Do I hear the scratching of your finger as it tickles the scroll wheel of your mouse; the catalyst for your escape? Not so fast — you never know when you might need to explain the fundamental intricacies of an amplifier.

As I mentioned earlier, it is the amplifier circuit’s sole duty to take a signal (electrical current, voltage, and others) and make it BIGGER. How does it do this? There are a few ways.

TransformerTransistorValve/tube

Transformer – some amplifiers use an electromagnetic device to manipulate low-voltage currents into becoming larger. There are often two transformers in an average electric guitar amp.

And no, it has nothing to do with those movies.

Transistor – a large number of amplifiers use a different electromagnetic device known as a transistor, which mutates the input signal into a greater output signal using three wires known as the base, emitter and collector.

Valve/tube – a weird-looking device that somewhat resembles a lightbulb. Vacuum tubes control and increase the signal of an electric current.

Beyond these popular methods of amplification, there are further sub-categories we need to split amplification techniques into. Lucky for you, I have decided to spare you from that pain and instead briskly introduce the only one we need to worry about.

Instrument Amplifier: Instrument amplifiers are typified by being suited for, well, instruments…like a guitar, or microphone. They often come embedded with equalization devices, in-built reverbs and the like.

Although these amplifiers will be the focus of the article, it’s worth noting different amps will use different amplification methods to achieve their goal.

What Can I Use an Amplifier For?

Electric Guitar Amp Stack

The functions of an amplifier are incredibly broad. Much of what you can use an amplifier for will depend on its intended functionality.  Certain amplifiers are equipped with certain capabilities, especially when it comes to working with particular frequencies or signals.

For example, a guitar amplifier is probably going to work between 0 and 20kHz frequencies, whereas a radio amp might stretch all the way to 300GHz.

But hey, we wouldn’t be musicians if we didn’t thrive on taking things intended for one thing and bastardizing it for something else. Why don’t we just take a dreadful laptop and use the amp in its speakers to record our next radio-ready hit?

As to avoid losing all touch with reality, I will refrain from listing all the things you can do with amplifiers, but let’s take a brief (yeah, right) look at the most popular applications for guitar amplifiers.


Live performance

Rock Guitarist

Naturally, live performance is probably the first thing that comes to mind when thinking about guitar amps. Huge cabinets, insane light shows, roaring audiences.

What’s not to like?

Live guitarists will often use a variety of pedals, amplifiers and guitars to replicate a meticulously crafted tone, though beginner performers may find it better to keep things simple.


Jamming

Jamming guitarist

Whether with a band, a backing track, or home alone, an amplifier can make playing a guitar so much more fun. It’s a bit of a buzzkill trying to rock out to ‘Battery‘ by Metallica without being able to hear your own playing over Lars Ulrich’s drumming.


Recording

Mic

Though digital amps are soaring in popularity and guitarists are experimenting with directly inputting their instruments into interfaces (think Bon Iver, Bon Iver by Bon Iver) the vast majority of recording artists still prefer to mic up their amps.

There is still a level of authenticity and musicality, even through feedback and imperfections, that makes recording actual amplifiers the preferred option.


Speaker

Speaker

Quite a lot of amplifiers will operate as a speaker for mobile devices. Most are equipped with some sort of ‘AUX IN‘ jack so you can just plug your phone in and voila, you have a multi-purpose portable speaker (though maybe not the best sounding one, considering the frequency range limitations guitar amplifiers often have)!


Reamping

Going off the theme of using a guitar amplifier as a speaker, a popular recording technique used by artists and engineers is ‘reamping’. This involves routing a pre-recorded track – usually clean – out to an amplifier, which can then be recorded using a microphone (or even sent directly back into an audio interface).

Guitar Reamper

This process wields a lot of creative power, as it can be used to completely alter and liven the tone of a stale guitar tone. Some artists even run their entire mixes through mediocre guitar amps — The Radio Dept. are known for doing this on some of their albums.


Annoying your neighbours, family, partner and pets

Especially your pets. Trust me, if they could, they’d do it to you too.

What are the Different Types of Guitar Amplifier?

Guitar amp types

You might have read this title and groaned to yourself. Didn’t we already cover this!? That’s where reading comprehension comes into play my loyal audience — we learned about the different types of amplifiers, not guitar amplifiers. So, without a further ado…

There are five main types of guitar amps.


Tube (valve) amps

Tube valve guitar amps

You may remember tube amps from such segments as the one you read a couple of minutes ago. Tube amps are old-school technology — they were invented over 100 years ago in 1906.

Back then, there were naturally growing pains — signal amplification came at the cost of significant distortion. Though that may be a desirable effect nowadays, remember that in the early 1900s if someone created a ‘metal’ song they’d likely be whisked off to a mental institution.

Eventually, tube amps were phased out of popular applications (radios, portable speakers, etc.) in favor of transistor-based circuits. In spite of their age, tube amps are still the most popular amplifiers for electric and bass guitarists. They are a bit rough around the edges, but their tone is noted for being of inimitable warmth and musicality.

That said, this doesn’t mean you should limit your search to exclusively valve amps. You may not like the tone at all! Never take the word of someone else (like me, for example) without doing your own research when it comes to music and creative-related decisions.

The Vox AC30 is an example of a prominent valve amp.


Solid-state amps

Solid-state guitar amps

The solid-state amp was the natural follow-up to tube amps and incorporated the newly invented transistor to decrease distortion, and improve durability. Though transistors took over most amplification devices, solid-state guitar amps were never exclusively preferred over tube amps.

Solid-state amps have a reputation for being a bit cold and mechanical, perfect for genres that required attention to detail and cleanliness (think jazz, some progressive music, pop).

Though modern technology has diversified these amplifiers to incorporate a wide variety of tones — some indiscernible from a tube amp — solid-state amps aren’t popular among professional guitarists.

That said, solid-state amplifiers still have their place in the musical world. They’re much less likely to break, lighter and cheaper than a tube amp, which are all parameters worth considering for beginners, amateurs and even certain pros.

The Roland Jazz Chorus is an example of a well-renowned solid-state amp.


Hybrid amps

Hybrid guitar amps

Hybrid amplifiers are a bit weird but are no less worthy of mention than any other type of amplifier. As their name suggests, hybrid amps involve a combination of both tube and solid-state technology, with one powering the other’s output.

As you might expect, the point of hybrid amps is to morph the warm, sought-after tone of tube amps with the versatility and durability of solid-state amps. Like with any product, there are some good and bad, but overall hybrid amps haven’t been hugely successful.

Best-of-both-worlds solutions often end up actually being too-good-to-be-true scenarios, and hybrid amps are no exception. Many of them sacrifice the authentic, musical, voice of a tube amp making their entire purpose redundant (or vice versa).

That said, this is only the opinion of some guitarists. Many will have owned and used a hybrid amp throughout their career to great accomplishment. How you personally react, enjoy and mesh with the sound of any given amp is much more important than what someone 1000 miles away says about the virtues of a specific electrical component — the name of which you can’t even pronounce.


Modeling amps

Modeling digital guitar amps

Modeling amps are a bit like amp simulator VSTs you might download onto your DAW. They are a relative newcomer to the music industry (with Line 6 often credited as one of the first adopters) and utilize microprocessors instead of transistors, transformers or valves. This makes them nearly always digital.

Modeling amps present a compromise between the issues of amp simulators (frigid tones and inaccurate reflection of playing on a real amp) and the creative playground they provide with their huge range of tones. Because they’re digital, modeling amps will often contain software within the device that allows the guitarist to switch between all sorts of sounds based on vintage amps.

For example, you might be playing around on a Fender Reverb for one song, only to completely switch up the sound with a classic Marshall the next. Many modeling amps also contain simulated pedals and diverse effects, making them a good bet for interesting… genres like post-rock, shoegaze, and progressive.

Many purists find modeling amps to be a disgusting entry in the market. Okay, disgusting might be a little harsh, but the tones of a model amp are just that — models of the real thing. Some are really, really close, but there is certainly a stigma against modeling amps from certain camps in the guitar community.

But really, who cares? A modeling amp has a certain power and functionality that many valve amps could only dream of and is suited to all sorts of musicians, no matter the genre or proficiency with which they play guitar.

The Line 6 Spider is an example of a popular modeling amp.


Acoustic amps

Acoustic guitar amps

And now, the guitar amplifier will take upon its final form: the acoustic amp. While electric/bass guitars are functional (and encouraged) to be used with the aforementioned amp types, electric-acoustic guitars are a different beast altogether.

There’s some good news though — new electric-acoustic owners may not have to rush out and purchase an independent amp at all. Not to be presumptuous, but no doubt many of my faithful readers are piano players — given the name of the website and all.

Acoustic amps operate very similarly to a keyboard amp, or a PA, and are generally interchangeable. They produce a flat, uncolored tone, in contrast to the other types of guitar amps that distort and mutate the signal.

Acoustic guitar amps are still worth considering even if you do already own a keyboard amp, as they will have controls and functionality unique to guitars, including equalizers, reverbs, compressors, and more.

What to Consider When Buying a Guitar Amplifier

Ah, it’s about that time of the article again, when I put on my holier-than-thou hat and lecture you about needing to ‘try before you buy’ and that ‘one’s trash is another’s treasure’.

All of these cliches still apply, yes. The tone of a guitar is a very personal thing and what you enjoy listening to and playing around with will probably dictate you purchase more than any other element.

But, let’s not waste any more time on something you probably know, hey? For once, let’s dive right in.

Amplifier controls effects


Amplifier controls and jacks

This will be one of the biggest elements to consider before buying a guitar amplifier.

There are a few controls that are pretty universal to amplifiers, and it’s good to get your head around them so you understand any functionality that an amp boasts (e.g. a certain amount of clean volume, parametric EQ, AUX inputs, and so on).

GainVolumeODTreble and BassFXCable jacks

Gain – No doubt the most important control on any amplifier, the gain knob is largely responsible for altering the guitar’s tone. While it may seem as though it is in charge of the amp’s volume, this is not strictly true (albeit functionally so).

Gain is actually a mathematical sum — the ratio between the volume of an input and output signal. In simple terms, messing with the gain controls results in the input of a channel being made louder, ultimately distorting the signal.

Volume – Many will confuse gain for volume and vice versa, but the volume knob is pretty much exactly what it seems like. It affects the volume of the amplifier’s output, and has no impact on tonality.

OD – This won’t actually be a knob and often takes the form of a little button. It has a number of different names, but it’ll usually be something like O.D., or distortion.

Again, this function works exactly as advertised — it further distorts the signal (without impacting volume too much) to create a crunchy, sometimes wild tone, perfect for rock and metal. Not every amp will have this feature.

Treble and Bass – These are essentially shelf equalizers, which can drastically affect a guitar amp’s sound. Turning the bass knob up will make the guitar sound thicker and deeper (by amplifying lower frequencies), while the treble knob will give you extra clarity, detail and sharpness (through amplifying higher frequencies).

Some guitar amps will also have Hi-mids, Lo-mids and other options, which just represent various portions of a typical equalization spectrum.

FX – Not every amp will have this knob. Some might only have one, whereas others can boast up to, or in excess of 10. What the effect will be entirely depends on the product.

Reverb, delay and tremolo are probably the three most widely found.

Cable jacks – Again, what input and output jacks are available will vary from amp-to-amp. Most, actually all, will possess an ‘Input‘, which is where you put in your guitar or microphone. From there, some may have auxiliary inputs for reamping, headphone jacks or even input for a foot-switch pedal.

Many will also have ‘Line Out‘ jacks where you can send the signal from your amp somewhere else, like a PA system, or back into an audio interface (if you don’t want to record your amp with a microphone).



Cabinets and head stacks

To be completely honest, it’s probably been a bit remiss of me to not mention stacks until this deep into the article. Amplifiers are actually a bit more complex than I’ve made out to be.

Look, if you’re a beginner making hit songs from your bedroom, you’re probably going to stick to a combo amp anyway so it won’t matter. But it’s worth learning about what a stack actually is. Stacks are divided into two components — the head, and the cabinet.

A head is essentially an amplifier without any friends a speaker. So, all the lovely knobs and effects are available on the amp head, and it’s what you plug your guitar into, but using a head on its own would be rather ridiculous. This is because, there’d be no sound.

Enter the cabinet. To put it bluntly, the cabinet is essentially a big, bad speaker. Unfortunately, this speaker lacks the ability to manipulate the tonality of a guitar. Plugging a guitar directly into it would be a bit like jamming your instrument into a PA system. It’d work, but it’d sound awful.

However, when you combine a cabinet with a head, well, suddenly you’re cooking with gas.

The prime purpose of a stack is for live performance, creating a penetrating, powerful sound that can overpower even the biggest of open fields packed to the brim with screaming — and I mean really screaming – adolescents.

Amp stack types combo

There are three basic configurations of a stack: full-stack, half-stack and combo.

A full-stack is an amp head and two cabinets (or more). This is only really relevant to gigging artists, because cabinets can be really bloody heavy. Like, back-breaking heavy.

Think about a band with a lead guitar, rhythm guitar and bassist. That is at least SIX cabinets needing to be transported, and that’s operating on the assumption the band forces their drummer to carry their kit through the streets unassisted. Yeah, you might want a van for that task.

A half-stack is a bit more manageable for the recording/bedroom artist, though may also be a step too far for some. A half-stack is basically just a head and a cabinet. It’s less powerful, but also less strain on the legs (and wallet).

Finally, you have combo amps, which essentially contain both the head and cabinet in one convenient location. Generally, most lower-tier amplifiers are combo amps, though there are many excellent options in the higher price ranges too.

Amp manufacturers will often release a combo version of popular head and cabinets (sometimes the other way around) for those that need a more portable option for their guitar-playing.


Wattage

A common misconception is that higher wattage means more volume. While this is technically true for the most part, wattage doesn’t actually relate to the volume — it is responsible for power.

This is only one element of how loud a guitar amplifier will be (speaker and compression the other two major ones), though it does act as a pretty decent guide.

What type of amp size and wattage you are looking for will really depend on your purpose as a guitarist. If you’re a heavy metal artist playing bone-shredding riffs in front of crowds in excess of 10k, yeah, you’re gonna be after a pretty damn large 100+ wattage amp.

Smaller indie artists that still want to gig but don’t particularly want to lug about a 100 lbs behemoth can probably get away with 50-100 watts. Rehearsal amps can be found in the 30-50 watt range, and bedroom amps are typically around 15 watts.

Remember, wattage and size are only general guidelines when it comes to the volume, and there are other parameters that can affect what might work best for you. Just because an amp goes up to 60-watts doesn’t mean it isn’t suitable for bedroom practice.

It’s also worth mentioning that wattage and size have relatively minimal effect on the amp’s tone. Price range is honestly a better indicator of an amp’s quality, and that is much less reliable than my favorite indicator — whatever you prefer!


Other bits and pieces

We’re nearly at the end, but just quickly, here’s a couple of more things to quickly consider before jumping into your car and barging into the local music store.

Don’t forget accessories! Amplifiers will require at least one instrument cable, and sometimes more if you want to re-amp, or record direct into an audio interface. You can read more on cables here.

Guitar cables

What style of music you play will likely dictate which direction you take in your search for a suitable guitar amplifier. While most popular amps are so versatile that they can be dragged, kicking and screaming, through any genre and perform well, there may be certain functions that a metal player should keep an eye out for (overdrive and distortion) that an indie-pop guitarist may ignore.

It should go without saying that you’re going to buy an amp for your particular instrument. Don’t buy an electric guitar amp if you’re a bass player. Buy a bass amp. I will say no more on this matter.

Though I encouraged the irritation of those closest to you by blasting Smoke on the Water at 3 am on your new-purchased amp, if those situated nearby aren’t so accommodating (selfish, right?) you might want to consider a pair of studio headphones that will plug into your amp. One good idea beyond that might also be ensuring that the amp you buy actually supports plugging in headphones.

Conclusion

guitar amp cable illustration

Alright! We’ve made it. You should now be well-equipped to enter into arguments with strangers on the internet about the merits of electric guitar amplifiers. With this knowledge you shall have the power to spread your opinion with confidence and vigor.

Of course, if you’re anything like me, you will have been perpetuating your ideas pig-headedly regardless of if you actually have any clue what you’re talking about, but it’s nice to know you’re well-informed every now and then.

Jokes aside, guitar amplifiers are a huge part of becoming a guitarist. Not only would live performances be completely different without them, an amplifier can completely change your relationship with a guitar.

Finding a tone you love and then applying it to your guitar-work can take you in a musical direction you’d never actually considered. It’s an enchanting and exciting time. The creative world is at your fingertips, ready to quiver under the sheer artistic power you are about to wield.

Stay tuned for the next part of this article where I walk you through some of the most popular guitar amplifiers on the market today.

Until then!

About the Author – Ben Knight

Hailing from the depths of the world — aka Australia — Ben Knight is a passionate pianist, cellist, songwriter and engineer.

With a Master’s in Writing and Editing, he combines his love for music with his knowledge of the written word to make sure he has the funds to keep buying unnecessary pieces of musical equipment for his home studio.

You can check out his band Mellow Daze on all the major streaming services.

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