When starting playing guitar you may not be aware of the wide variety of options you have but if you dig into this instrument’s world you will find a lot of interesting gears for sure.
Some of them are amp heads, hugely used by experienced players.
This statement could raise a lot of confusing questions but don’t worry, we are here to answer each of them.
What is an amp head? Can I use it without a cab? Or is a speaker strictly required?
Tube amp heads, which include the preamp and power section will require to be connected to a speaker cabinet to not be damaged. Although, there are exceptions where some have a switch that shuts off their output if no load is connected. Solid-state and digital amp heads can be used without cabs with no risks.
I know this may be overwhelming but let’s dive deeper into this topic to clarify your doubts.
In this article, I will show you the most important aspects of using an amp head without a cab, in the end, you will be aware of everything needed regarding this issue.
Can you use a tube amp head without a cab?
In most cases, tube amp heads need to be plugged into a speaker or a dummy load, but before we continue, I would like to clarify what a dummy load is.
A dummy load is a device used to test’s an amplifier capability and diagnose possible problems but without producing high, intense sound.
Having said that, you need to know that tube amp heads use an output transformer that produces high voltage peaks.
If the secondary winding (a cab or speaker) is not connected, the power from the head has no place to go so it will come back again to the place where the tubes are connected, which could cause the tubes to blow, damage the transformer, or even both.
Of course, is not something that immediately occurs, the tubes or the transformer won’t be instantly damaged but it may take a while until things get bad.
Nevertheless, there are some modern tube amps that are protected about being used without an output, they have an automatic switch that prevents this from happening.
Can you use a solid-state amp head without a cab?
In opposition to their counterpart, solid-state amp heads don’t have an output transformer plus they can be perfectly loaded by the speaker cabinet.
Without a speaker or cabinet, the amp will see an infinite load which also powers it properly so, if there is no cabinet, the amp can be run fine anyways.
However, there are some exceptions of older solid-state amps that require a load to be powered.
Fortunately, this does not apply to modern solid-state equipment but is a remarkable aspect to bear in mind.
Last but not least, you need to know that, like what happens with tube amps, solid-state may be damaged.
This could occur if there is too low resistance or the load goes below the minimum,(maybe if a cable shorts) the amp will overload causing it to blow up.
Can you plug the output of an amp head into a mixer, PA, or audio interface?
This is a common question among players, would it work safely or would something get immediately destroyed? If the latter occurs, how can avoid it?
In short, if the head has a line out, you could do it but there are some aspects that you have to consider.
Firstly, you won’t get an amazing sound without a cab, by plugging your amp head in a mixer or a PA system you won’t get the full experience at all.
Although is a good option or alternative to the speaker, in most cases your sound will suck.
What is more, you need to be aware of the device in which you are plugging in your amp, if not using a line output, because it could be blown.
That’s because a line-level input is designed to receive a signal that is 1V or even less, consequently, as the output of the amp is higher (between 25V and 75V), it could destroy any device you plug the speaker output into.
Finally, I would advise you to check with your amp’s manufacturer if plugging something to the line output of your amp bypasses the speaker out.
Only this way you would be sure that using it without a speaker load will be safe when going out at line level.
Why you should ALWAYS plug your tube amp head into a speaker cabinet
As we discussed before, tube amps will require a speaker or cab because of the output transformer which sends high voltage peaks.
When in doubt, always go and plug a speaker cabinet without a second thought, otherwise, you will ruin your amp.
That’s because if a tube amp head doesn’t have a way to output the signal, that power comes back to the tubes which will overload them.
Tube amps need to see a load, the speaker cabinet is the most common but you can use a dummy load instead.
Furthermore, is not safe to use a valve amp head without connecting a speaker.
Take this into account when playing, you won’t want to risk damaging your valuable tube amp
Do all guitar amp heads require to be plugged into a speaker to work?
As a general rule, you won’t be able to play just through a guitar amp head because it doesn’t provide output sound at all.
What instead does is to output a signal but the one in charge of translating that signal into sound is the speaker cabinet.
As you already know, for all-tube amp heads a speaker or load is definitely required whereas solid-state counterparts should be ok to turn on without a cabinet connected.
The clue is to check the amp’s power section, if it is a tube amp, don’t run it without a load attached, in the case of solid-state amps you can run them without a load but to be sure, always check the manual before using your amp head without a secondary winding.
In addition, although in most cases you will need a cab, there are some exceptions.
Some amp head models come with an inbuilt speaker which allows you to play without anything connected or even digital heads provide the same feature.
The Boss Katana Head is a perfect example of this, a gear with a speaker built into it, intended for home practice, excellent to play at low levels.
By using this equipment you could play without the need for a cabinet.
Nevertheless, although you have other alternatives, you must remember that outputs might not work for line-level inputs.
The best way is always to connect a speaker to the amp head, in that way, you won’t worry about it.
Can you plug any speaker or speaker cabinet into any guitar head?
This is something pretty usual among musicians, as each of them builds their own style and sound, mixing and matching amp heads and cabinets is a common practice.
What is more, some players use two different speakers not only to have a varied sound but also to play a bit with the panning.
A remarkable aspect to bear in mind is that you need to make sure about the output impedance that requires to match the cabinet.
However, nowadays everything is pretty standardized and there are not plenty of options.
Is it safe to unplug the speaker cabinet when your guitar amp is in standby mode?
In general terms, it is safe to do it because the amp is not working itself.
For most amps putting it on standby will be fine, but you have to know how it works.
What standby generally does is heat up the tubes but not all standby circuits work the same.
In some cases, mainly in old Silverstone and Danelectro amps, the standby switch just shorts the drive but does not actually power down the output stage of the amp so, on those occasions, it will be better to fully power down the amp.
Is there a way of using only the preamp of your guitar head and skipping the power section?
The most usual way to do it is bypassing the power section with the FX loop out or the line outs as well.
Nevertheless, the tone you will get is strongly influenced by the amp’s power section and also due to the speaker cabinet.
By skipping that amp’s section you could get a harsh sound, quite uncomfortable or even small.
Although there are some alternatives to make it work, it might not be so useful because the available possibilities will function as filters to simulate a cabinet’s effect on tone.
Hello there, my name is Ramiro and I’ve been playing guitar for almost 20 years. I’m obsessed with everything gear-related and I thought it might be worth sharing it. From guitars, pedals, amps, and synths to studio gear and production tips, I hope you find what I post here useful, and I’ll try my best to keep it entertaining also.