The guitar amp market is undeniably huge. While you probably have a good idea of the sound you want, there are more ways of getting it than ever before. Whether you’re looking for a gigging amp, a home-use practice amp, or anything in between, it can be difficult to know where to start. One of the most important questions you’ll likely encounter is: combo amp or head & cab?
What’s the difference between a combo amp and a head & cab?
Let’s start with the basics. To make the right choice, you need to know the difference between a combo and a head & cab setup.
How does a head & cab work?
As you may have guessed, a guitar head & cab is a two-piece rig. The head part determines your guitar tone and the amount of power you can deliver to your output. The cab (cabinet) is simply a passive speaker or set of speakers designed to receive the powered signal from an amplifier.
As with any musical gear, there are plenty of types of guitar heads and cabinets to choose from. Different heads offer different tones, levels of control, power outputs (wattage) and connectivity options. Guitar cabs also come in different shapes and sizes; different speaker varieties, number of speakers, even wood types.
Guitar amp heads generally connect to cabinets using speaker cables. Speaker cables have 1/4” jack connections and are built to carry stronger signals than regular jack cables (like your guitar lead). Heads and cabs are matched up by impedance, measured in ohms. Impedance is the level of resistance a speaker offers to an input signal; amp impedance is generally 4, 8 or 16 ohms.
Reasons to buy an amp head & cab
- It looks cool
A head and cab setup is versatile in that it can be switched around easily. You can generally use your head with any cab (as long as the impedance matches up), and vice versa. This makes gigging, recording, rehearsing with a band and even upgrading your rig super easy. You’ll also be transporting both components separately, which can make gigging and soundchecking a whole lot easier.
Because of the compatibility bonus, you’ve got more choice with heads and cabs. If you want a guitar head that’s great for metal, you’ll want a cab that matches it. You have the freedom to choose whatever brand or variety of cab that you want. Head and cab rigs also tend to pump out more volume. This isn’t always the case, but heads tend to have a better power capacity (wattage) and larger cabs naturally make more noise. Finally, heads & cabs look super cool on stage – there’s no denying that!
What is a combo amp?
As the term ‘combo’ may suggest, this is the combination of the head and cab components into an all-in-one amplifier. It’s essentially an identical setup to a head & cab, but both parts are built in to each other.
The ‘head’ part still determines the tone and controls, and the cab still makes the noise – but they come pre-wired and ready to go. This means less setting up and worrying about ohms, as the work has already been done for you.
Reasons to buy a combo amp
- Minimal setup required
- They sound good straight away
- They’re good for monitoring
- You can expand if you need to
As mentioned above, the fact that combo amps combine the necessary components means that you don’t need to worry about setting up. No matching up cabinets, no worrying about impedance – it’s all been done. You can rock up to any show, rehearsal or session with a guarantee that you’ll have exactly the sound that you need.
(below) The Fender Hot Rod Deluxe is among the most popular gigging amps in the world, but it’s undeniably heavy.
Further to this, the speakers in combo amps have been matched to the amplifier by the manufacturer. This means that the cabinet is already voiced in a way that suits the amp’s tone, so you’ll have a great sound right away.
Combos are also popular for on-stage monitoring. If you don’t have wedge or in-ear monitors on stage, you can simply tilt your combo amp slightly so that it’s pointing towards you. This allows you to hear yourself clearly without affecting sound. It’d be difficult to tilt a head & cab in the same way. Finally, combo amps can often be expanded with extra cabs if you need more volume or a broader sound. This is dependent on the output/connectivity options on your amp, but it’s a useful thing to bear in mind!
Guitar amp FAQs
Now that we’ve covered the basics, there are a few extra things to consider. You may be feeling more confident with your choice by now, but these questions may further influence your decision. Check it out:
Full Stack vs Half Stack
Stack is another term for a guitar head & cab rig – the two components being stacked on-top of each other. A half stack refers to a head with a single cabinet, while a full stack is a head with a vertical column of two cabinets.
The stack was made popular by the rockstars of old; Jimi Hendrix, Pete Townshend, Slash and the like. Players who wanted more volume and a more imposing stage presence, and they got it. A half stack will often deliver more than enough volume for any application – even stadium shows – but if you really want to tip over the edge into full-blown rockstar territory, a full stack is always an option!
(below) Marshall cabinet stacks are iconic stage-pieces. This setup belonged to the late Jeff Hanneman of thrash metallers Slayer.
How Do Guitar Cabinets Work?
As mentioned earlier, a guitar cabinet is just a passive speaker designed to take a signal from an amplifier. Different cabinets have different numbers of speakers (transducers), different speaker sizes, different speaker varieties & materials, different woods – the list goes on.
The loudspeaker cones range from 6” to 15” in size depending on the cabinet, and are generally made of alnico, ceramic or neodymium. Popular speaker manufactures include Celestion, Jensen and Eminence among others.
If you want to know more about the variety of guitar cabs on the market, check out this groovy article: What is the best guitar cab?
Can You Use an Amp Head With a Combo Amp?
In short, yes. Combo amps have a speaker cabinet built-in, but many manufactures leave the connection visible on the back panel of the amp. This allows you to disconnect the speaker from the built-in amplifier and connect your own if you wish. Again, make sure the impedance matches!
Does Guitar Head & Cab Impedance Have To Match?
Ideally yes. Amps are given these ratings for a reason; generally speaking, matching head & cab impedance means that your amp sounds the best it can. It’s also safer – you don’t want to risk overcooking your amp and ruining the tubes or circuitry.
That having been said, many players believe that mismatching can be ok provided your amp is built well. Generally speaking, if you’re going to mismatch, it’s considered safer to use a cab with a lower impedance than your head (i.e. 16 ohm head into 8 ohm cab). In the case of solid-state amps, however, it’s the opposite; only mismatch with a higher-impedance cab (i.e. 4 ohm head into 8 ohm cab).
Bass Amp Combo or Head and Cab
We’ve explored the recommendations for guitar amps, but what about bass? For the most part, the same principles apply. There are a few extra things to consider though.
Firstly, it’s far more common to find a solid-state bass amp than a valve bass amp. This means that bass amps (heads in particular) tend to be a little lighter and more compact than many guitar amp heads. As a bassist, you also have the option of DI-ing straight from your amp, which in some cases negates the need for a speaker cabinet at all. It simply depends on your tonal preference and your circumstances.
Many gigging basses opt for a compact head and cabinet, often travelling with just the head. If you mostly play at home or in the studio, a combo provides adequate volume and tone without you having to worry about transport!
Can I Use a Cab With a Combo Amp?
Yes. Provided your combo amp has enough outputs, you can easily connect extra speakers to your combo. Speaker outputs on any amp should always be labelled with the correct impedance depending on number of speakers connected.
Connecting extra speakers can alter your sound in a number of ways. First of all, it can provide a notable volume boost. Secondly, if the extension cabinet uses a different speaker type, you may notice a different tone entirely. In addition to this, having another cab can help with projection and hearing yourself on stage. You could set your other cab up on the other side of the stage, or tilt it slightly for monitoring purposes. It simply makes your setup that little bit more versatile.
How do Guitar Cab Simulators Work?
As you may have guessed, cabinet simulators aim to replicate the response of a guitar cabinet. If you’ve ever heard the raw sound of a preamp or distortion pedal going directly into a desk or interface, you’ll notice that it leaves a lot to be desired. A guitar cabinet is half the tonal battle.
With this in mind, a cab simulator can take your (sometimes unattractive) raw preamp sound and add shape and colour to it. This can be extremely handy for any scenario, in that it saves you worrying about setting up / transporting a cabinet.
Don’t be mistaken though; you cannot replace a guitar cabinet with a cab sim. Cab sims usually come in the form of a guitar pedal for your board, designed to interact with your signal chain – not your amp. As mentioned earlier, amplifiers require a certain amount of resistance to operate safely and sound their best. If you connect an amp head to a cab sim, the lack of resistance will likely fry your amp – nobody wins.
That’s where a loadbox comes in. A loadbox provides the same amount of resistance as a speaker cabinet, then converts the signal into an output that can be easily connected to a mixing desk or interface. As far as your amplifier is concerned, it’s connected to a speaker with matching impedance. If you pair a loadbox with a cab sim, you’re looking at an extremely handy & compact gigging solution. Some manufacturers like Two Notes & Universal Audio combine these functionalities into single units for maximum practicality.
That’s a wrap, folks. Hope you’re feeling a little more confident about the differences between combos and head & cab rigs. In a band? Solo recording artist? Bedroom rocker? Consider your circumstances and you’ll make the right choice. There’s no right or wrong answer – it depends entirely on your needs!
If you want to learn more about the weird and wonderful world of musical gear, check out the rest of our Learn articles while you’re here. And if you’d like to browse our full guitar amplifier range, click here – enjoy!