Can You Plug a Keyboard or a Synth Into a Guitar Amp?

We, guitar players, are very curious animals. If we are given the chance of borrowing a synth or keyboard we would not turn it down.

Maybe this is your current situation, or maybe things happened differently. The thing is you have a keyboard at home and you are itching to play it.

But, wait…

Would it be ok if you just plugged it into your guitar amp or would it blow up?

If you want a short answer to this question, here it is:

You can plug a keyboard or synth into a guitar amp if you get a 1/4 inch jack to 3.5 mm adapter and use the line or headphone output if the instrument doesn’t have a 1/4 inch out. There is, however, a risk of damaging the guitar amp speaker and component with the rattling generated by the lower frequencies.

If you want to stick around with me for a bit longer, in this article I will go in-depth into the differences between keyboard and guitar amps, and what would happen if you plug yours into your only available amp.

Also, I will give you alternatives and advice on what could work better for you if you want to play a keyboard or synth at home.

Are you ready to get started? Let’s go!

Why are keyboard and guitar amps different?

Keyboard or synth amps and guitar amps are different because these instruments have pretty dissimilar outputs. Guitars have a narrower range, centered around what’s considered the mid-range while keyboards and synths cover a broader specter of pitches, from the lowest lows to the highest highs.

How are keyboard and guitar amps different?

Amps are designed to serve specific instruments most of the time. In particular, guitar amps tend to be voiced and tuned to deliver sounds within a guitar’s range.

On the other side, speakers or amps intended to be used with a keyboard, electric piano or synth are often what’s called full-range units, a definition that refers to their ability to generate a broader scope of tones.

Do guitar and keyboard use the same cables?

All guitars use ¼ inch line-level cables since they all share the same input jack. However, keyboards and synths have different output jacks depending on brand, model, and price point. The most usual connectors these instruments will have are 3.5mm stereo line out, midi out, and USB out.

The good news is that your keyboard or synth has a line-out jack, you could use a guitar cable with an adapter with it. However, you should note that if that output is stereo you might face some issues because instrument cables are mono.

What are the risks of playing keyboard through a guitar amp?

Risk of pluging a keyboard into a gutiar amp

The risks of playing a keyboard or synth through a guitar amp are damaging the speaker or some internal components of the amp. This is because guitar speakers are designed to serve mid-range frequencies, and a keyboard can go well below that range. The rattling generated could also damage internal components.

How to know if an amp is for guitar or keyboard

The fast method is by looking up the model name on google.

If you are stranded on an island without internet connectivity. I would recommend you check for any mention of the amp being a full range one, this would mean that it’s designed to take a wider spectrum of frequencies.

Also, keyboard amps or PA systems tend to look more like audio speakers. Guitar amps, on the other hand, have a pretty distinctive look.

What kinds of guitar amps are ok to use with a keyboard?

There is actually not an industry standard or a golden rule to answer this question, however, in my experience, I would only use entry-level guitar amps with a keyboard or synth.

To give you a more specific list:

  • Cheap guitar amps
  • Solid-state guitar amps
  • Combo amps
  • Digital amps
  • Guitar preamps that don’t have a speaker attached
  • Hybrid guitar and bass amps like the Peavey Vypyr

What kinds of guitar amps are NOT ok to use with a keyboard?

Any reasonable player would refrain from plugging anything but a guitar into an expensive amp. I would argue that a guitar player with a valve amp would probably know better than sending a synth signal through it.

However, maybe you are a friend or relative of that player, and you have their beloved amp at your disposal and home.

Please be extra careful.

As I mentioned earlier, even if the speakers take the beating, the rattling of the lower frequencies might break internal components such as connections or even tubes.

A specific list of where not to plug your keyboard or synth in would be:

  • Expensive guitar amps
  • Tube guitar amps
  • Half stack amps
  • Vintage guitar amps
  • High output guitar amps
  • Any guitar amp you don’t want to risk breaking

How to protect your guitar amp if you are plugging a keyboard into it

There are a few things you can do to minimize the chances of damaging a guitar amp when plugging a keyboard into it. The main thing I would recommend is to always play at low volumes, to don’t ever push the speaker. I would also turn down the bass control all the way to try and cut those resonant low frequencies.

Another thing I would recommend is using the amp’s clean channel and, if your instrument has any kind of EQ control I would also cut lows and highest highs there.

Can you play a keyboard gig with a guitar amp?

I would not recommend playing keyboards through a guitar amp at gigging volumes. You will be risking damaging the amp’s speakers and their internal components due to the rattling. If there is a PA system, the wiser choice would be to send your signal through it.

Can you play a keyboard gig without an amp?

You can gig with a keyboard without an amp. The common practice is to send the signal to a  mixer and then through the house speakers. Most venues and events nowadays will have this kind of setup available.

Can you get good keyboard tones with a guitar amp?

Guitar amps are tuned to make guitars sound great. The closer your keyboard or synth tone sounds to a guitar the better the amp would make it sound. If you are planning on getting clean piano sounds or high-fidelity tones, this would not be a great experience.

Are there amps that work well for both guitar and keyboard?

There are amps such as the Peavy Vypyr designed for both bass and guitar which would make for acceptable practice keyboard amps, however, the needs from a synth and a guitar are pretty different. A full-range speaker will output dull guitar sounds unless you process your guitar signal beforehand.

The main problem here is that the tone of a guitar is partly shaped by the amp while the tone of a keyboard or synth is outputted “ready to be served” and only needs a speaker with a flat response to give it volume.

Cheap keyboard amps to practice at home

If you are afraid to damage your guitar amp and you are considering getting an exclusive amp for your keyboard or synth, here are 3 cheap alternatives that would work great for home use:

Peavey KB1

Peavey KB

The Peavey KB1 is designed exclusively for keyboards. It’s an entry-level piece of gear, but it would serve you as a great practice tool to take your first steps with this new instrument. It is built like a tank and outputs 20 watts of power.

Laney AH150

Laney AH

The Laney AH150 is a bit more expensive and generalistic full-range amp. It is designed to be used with just any instrument, however, it would not color a guitar tone in the way a guitar amp would. For keyboard and synth is just what you need, and you get extra input channels to jam with your friends, or even plug in a mic and sing along.

Roland Mobile Cube

Roland mobile cube

The Roland Mobile Cube, as its name implies is a portable 5-watt amp prepared to serve a broad range of frequencies. However, their small speakers might have a limited response on the low end. It is battery-powered, and for room volumes, it would work just fine. Something to have in mind is that the AC adapter is sold separately.

Do all keyboards need an amp?

Not all keyboards need an amp. Most entry-level ones, those intended for home practice, and particularly digital pianos have built-in speakers that are intended for home use. If this is the case, an amp is an alternative but not a must-have.

Alternatives for practicing keyboard at home without an amp

If you can’t or don’t want to afford an extra amp to play your keyboard or synth at home, there are some alternatives you could go for.


Headphones e

Almost every keyboard you could get will have a headphone out or a line out. In this jack, you could plug a pair of headphones and listen to your practice jams quietly. This is one of the best alternatives to practice at home.

Bluetooth speakers with a line-in jack

Bluetooth speaker

If you happen to have a Bluetooth speaker that you use to listen to music streamed from your phone and that small speaker has a line-in jack, you could get an auxiliary cable that has two 3.5 mm male jacks and send your keyboard signal to the small speaker.

Computer speakers

Computer speakers

Keyboards nowadays have USB outs that could let you play them through your computer and its speakers. You could also use an audio cable and go into an audio interface if you prefer the analog way.

Bass amp

Ashdown studio

Bass amps are preferred over guitar amps for keyboard and synth since they tend to be cleaner sounding and have a better response to lower frequencies, of course. The tone you will be getting might not be as great as with a dedicated keyboard amp or PA system, but the risk of damaging the gear would be way lower.