Perhaps you are a guitar player looking to learn the keyboard. And you’re wondering if you can use your existing guitar amp for the keyboard. Or maybe you are a keyboard player playing at a venue that only has a guitar amp available instead of a keyboard amp. Whatever the reason, can you use a guitar amp for a keyboard?
You can use a guitar amp for a keyboard. However, guitar amps are not an ideal option for keyboards. That’s mainly because guitar amps don’t have a full-range frequency response like keyboard amps. This means a guitar amp won’t be able to play back keyboard sounds accurately. And also, you can easily damage the guitar amp’s speakers.
But what exactly are the differences between a guitar and a keyboard amp? That’s what we’ll talk about next in this article. I’ll follow that up with all of the reasons why guitar amps are not ideal for keyboards. And then I’ll provide you with some really useful tips on how to use a guitar amp for a keyboard.
If all of this sounds interesting, then let’s get into it.
Keyboard Amps vs Guitar Amps: What’s the Difference?
Guitar and keyboard amps look very similar in many regards. And unless you are someone who is familiar with amps, you may not be able to tell the difference. Although physically, they may look quite similar, there are a few things that differentiate a keyboard amp from a guitar amp. Let’s take a look at them.
1. Keyboard amps have a full-range frequency response
Most keyboard amps that exist today are full-range or have a full-range frequency response. This simply means that they are capable of playing all of the audible frequencies humans can hear.
Keyboard amps usually have a frequency response between 20Hz to 20kHz. And the primary reason why keyboards have such a wide frequency range is that keyboards produce a wide variety of sounds.
As I discussed in my article on using keyboard amps for electronic drums, keyboards produce piano, synthesizer, and organ sounds. And they can also produce the sound of other musical instruments such as flutes, marimba, bass, and even guitar sounds.
Due to this, keyboard amps must have a wide frequency response so that they can reproduce all of these sounds accurately.
2. Keyboard amps have multiple inputs
Most keyboard amps available today have multiple input channels. And all of the inputs will have a dedicated volume knob. This allows you to connect multiple keyboards or other instruments to a single keyboard amp. And because every channel has its own volume knob, these amps can be used as a mixer.
Also, usually, because keyboards are stereo musical instruments, some keyboard amps have stereo input channels. A very popular example is Roland’s KC-990 Keyboard Amp (on Amazon). This is a beast of an amp that provides a total of seven input channels, all in stereo. And it’s a very popular amp used by many live-performing musicians worldwide.
1. Guitar amps have a midrange frequency response
Unlike keyboard amps, guitar amps have a midrange frequency response. Not to get too technical, this simply means guitar amps can’t reproduce all of the audio frequencies in an audio signal.
A typical guitar amp has a frequency range between 300Hz to 11kHz. This means they can playback all of the audio frequencies below 300Hz and above 11kHz. This is because a guitar’s audio signal doesn’t have a lot of low bass frequencies as well as highs.
For this reason, guitar amps can’t play back the deep bass sounds accurately. And similarly, they can’t playback the high frequencies.
2. Guitar amps usually have a single input channel
Most guitar amps have a single input channel, unlike keyboard amps that have multiple inputs. Guitar amps are designed to work with only one guitar at a time. And they have only one set of controls made for a single guitar.
This means two guitar players can’t share the same guitar amp. They will need their own individual amps.
Don’t get me wrong; there are a few multiple-channel guitar amps available in the market. However, they are not as common.
3. Guitar amps have a built-in preamp
Another significant difference between a keyboard and a guitar amp is that guitar amps have a preamp built into them.
Bass and electric guitars output a very weak signal known as instrument-level signal. This audio is usually too weak; it can’t be processed by an amp. For this reason, bass and guitar amp manufacturers add in a preamp.
The preamp basically boosts the weak instrument-level signal into a line-level signal. And that is a strong enough signal which can be further processed. So, on every guitar amp, there is a preamp gain knob. You won’t find a gain knob on a keyboard amp.
Why Guitar Amps are Not Ideal for Keyboards
Here are all of the reasons why guitar amps are not ideal for a keyboard.
1. Guitar amps won’t playback keyboard sounds accurately
As we have already discussed, unlike keyboard amps, guitar amps have a midrange frequency range. They are not capable of playing back all audio frequencies. And this makes them not ideal for keyboards.
Why do I say so?
Keyboards produce a wide range of sounds with different frequencies. Some of these sounds contain low frequencies below 300Hz and high frequencies above 10kHz. And since guitar amps cannot playback most of these low and high frequencies, the output sound you will hear when a keyboard is plugged into a guitar amp won’t be accurate.
There will be a lot of missing sound frequencies that are missing. And you may not enjoy the sound coming from your guitar amp.
This isn’t such a deal breaker though. If you are simply looking to hear yourself play with a band, I wouldn’t worry so much how accurate my keyboard sounds.
2. Guitar amps color the sound
If you are familiar with recording and have used many preamps, you will attest that every preamp sounds different. When a keyboard is run through a guitar amp, the built-in preamp will color the sound differently. And this will change the actual tone of the keyboard’s sound.
This isn’t necessarily a bad thing. For many years, musicians have played Rhodes, and many other keyboard sounds through different preamps to get a slightly different sound from the original sound.
But for someone looking to get a pure tone, this may be a disadvantage. So just keep in mind that when you run a keyboard through a guitar amp, the guitar amp’s preamp will color the sound. And you may either like it or not.
3. Guitar amps can easily distort a keyboard’s sound
Another reason why guitar amps are not ideal for keyboards is that you can easily get an overdriven or distorted keyboard sound.
Guitar amps, in general, have low headroom. This simply means the louder they get, the more distorted the sound becomes. And this is an intentional feature of guitar amps made by manufacturers.
Overdrive and distortion are sound effects desired by guitar players. However, it’s not really a common tone preferred by keyboard players.
Once again, this isn’t necessarily a bad thing. There are many records and songs where keyboard players run their instruments through a guitar amp to get that dirty and gritty tone. And they are commonly used for Rhodes and tonewheel organs, most especially. I even have an article where I talked about using guitar amps for synthesizers. And you should definitely check it out.
However, if you are looking for a clean keyboard tone, running it through a guitar amp isn’t such an ideal thing to do.
4. You can damage easily damage guitar amp’s speakers
Another reason why you should probably not run a keyboard through a guitar amp is that you risk damaging your guitar amp’s speakers. Let me briefly explain why.
Keyboards output an already loud signal known as line-level signal. And when you plug a keyboard into a guitar amp, this signal will be boosted by the guitar amp’s preamp. And this will result in an extremely loud signal.
And depending on how loud this signal becomes, your guitar amp’s speakers or cabinet may not be able to handle it.
Tips for Using Guitar Amps for Keyboards
All hope is not lost. If you have no option other than to use a guitar amp for a keyboard, here are some tips on how to make the most out of it.
1. Keep the keyboard’s volume low
As I mentioned earlier, keyboards output a loud audio signal known as line-level signal. And this signal will be boosted by the guitar amp’s preamp, which can potentially make it too loud for your amp speakers to handle.
For this reason, it’s crucial to keep your keyboard’s volume very low. Ideally, you want to reduce all the way down, plug the keyboard into the guitar amp, and gradually increase the volume to the point where you can hear the keyboard sound clearly without any noticeable overdrive or distortion. Always keep in mind if you don’t want to risk damaging your guitar amp.
2. Avoid bass-heavy keyboard patches
Another thing you want to do to keep your guitar amp safe and prevent the speakers from blowing is to avoid bass-heavy keyboard sounds.
Guitar amp cabinets just can’t handle bass. And it’s even more lethal when it’s loud. Just as I explained in my article on how bass can damage speakers, extremely loud bass can overheat your amp speaker’s voice coil and cause it to blow. And you definitely don’t want that to happen.
What you can do to prevent bass from ruining your guitar amp is to reduce the bass with an EQ. Most keyboard workstations allow you to adjust EQ settings internally on the keyboard. If your keyboard doesn’t have that option, then you may have to use an EQ pedal for your keyboard or use a mixer.
3. Plug the keyboard into the “Effects Return” of the guitar amp.
If the guitar amp you intend to use has an FX Loop, then I highly recommend you plug your keyboard into the Effects Return port.
The Effect return is designed to send the audio signal it receives directly to the power amp and then into the speakers without running it through the preamp. And they are designed to accept line-level signals, which is the output signal of keyboards.
By doing so, you don’t run the risk of blowing your amp’s speakers.
In summary, guitar amps can be used for keyboards. However, don’t expect them to sound great for keyboards. That’s because they are not capable of playing all of the audio frequencies of keyboard sounds.