Perhaps the only amp you have is a guitar amp, or maybe you want to add some “dirt” to your synth patches. Whatever the reason, running a synth through a guitar amp can be a scary idea if you haven’t tried it before. That’s because you don’t want to put your expensive gear at risk of damage. So let’s talk about this subject, once and for all.
Can you run a synth through a guitar amp?
Short answer, yes. You can definitely run a synthesizer through a guitar amp. It’s an excellent way to get unique synth sounds by tweaking the amp’s gain, EQ, and built-in effects. However, keep the synth’s volume very low and take caution with bass-heavy synth presets because a loud volume and too much bass can damage the amp speakers.
If you want to learn more on how to properly run a synth through a guitar amp without any issues, then keep reading because there is a right and a wrong way to do this.
We’ll take a look at the reasons why you should consider running a synth through a guitar amp, and after that, we’ll talk about the downsides. Right after that, you will learn how to safely run a synth’s signal through the amp to avoid any damage. And then I’ll walk you through the multiple ways of running synths through a guitar amp. Let’s get into it.
Benefits of Running a Synth Through Guitar Amplifier
The primary reason why you would want to run a synth through a guitar amp is for tonal versatility. What do I mean by this?
A guitar amp will give you multiple ways to tweak your synth sounds. You can drastically change how a synth preset sounds with the controls on a guitar amp.
1. To make overdriven/distorted synth sounds.
The first and most common way you can alter a synth sound with a guitar amp is by cranking up the gain. The level of gain you set determines how overdriven or distorted the signal becomes. In essence, the higher the gain on the guitar amp, the more distorted your synth sound becomes.
You can get some killer synth sounds with just the gain on a guitar amp. If you have read my article on using a DI box for synths, then you probably know I do this all the time. I love running bright synth leads through guitar amps and cranking up the gain to get that overdriven tone. Sounds so good.
2. Alter synth with EQ
You can also alter the synth sound with the guitar amp’s EQ controls. Almost every guitar amp has a built-in EQ. They are usually 3-band EQ controls. But there are other options with 5-8 bands graphic EQ.
You can sculpt your synth sound and drastically change how it sounds with the guitar amp’s EQ. Combining overdrive with the EQ alone can also give you something unheard of, depending on the synth preset.
3. Use Guitar Amp’s Built-in Effects
These days, most guitar amps made have built-in effects. You will usually find a reverb, delay, chorus, flanger, or a combination of some of all of them on a guitar amp. Marshall Code 50 (on Amazon), for instance, has 24 effects built into it. And you can use up to 5 effects at the same time in a signal chain.
Running your synth through the amp allows you to use these effects to make your synth presets much more interesting and unique.
Downsides of Running Synths Through a Guitar Amp
The main downside of running a synth through a guitar amp is you can easily damage the guitar amp. But how?
Firstly, guitar amps are designed to receive instrument-level input signals. These are very weak and low-level signals produced by guitars that need to be preamplified. The preamp (or Gain) section of the guitar amp is designed to pre-amplify the weak signal from the guitar for further processing.
Synths, however, output a line-level signal, which is an already preamplified signal. Line level signals are too hot, and running it through a guitar amp can damage the amp or blow the speakers if the necessary precautions are not taken.
Secondly, bass-heavy synth patches can also blow the speakers. Most guitar amp speakers have a frequency range between 70Hz-6kHz and are able to handle the frequencies produced by guitars very well.
Synths, on the other hand, have a much broader frequency range. They can output much lower frequencies, even below 20Hz, which is way below the human hearing range. And they can output much higher frequencies as well.
The lower bass frequencies of a synth at a loud volume can easily damage a guitar amp. That’s because they can’t produce the lower frequencies from a synth, and that puts stress on the speaker’s voice coil and speaker cone. And over time, the speaker parts wear out and breaks.
I explained this concept, in detail, in my article on how bass damages speakers. Feel free to check it out here.
How to Safely Run a Synth through Guitar Amp
Although you risk damaging the amp if you play a synth through it, there are still some precautions you can take to avoid any issues. Follow these steps any time you want to run a synth through a guitar amp, and you will have no issues.
1. Turn down the synth’s volume before you plug it in the amp
It’s very important to turn the synth volume down before you connect it to the amp. As a rule of thumb, turn it all the way down, plug it in the amp, and then gradually increase the volume until it is audible enough in the amp speakers. Why should you do this?
As I mentioned earlier, unlike guitars, synths output a line-level signal, which is an already preamplified signal. But when you plug it in a guitar amplifier, it will go through another stage of preamplification. If the necessary precaution is not taken, the synth can get extremely loud because you are amplifying an already amplified signal.
For this reason, you have to make sure the signal of the synth being fed to the amplifier is very low before it gets amplified again by the guitar amp. Else, the amp speaker or cabinet will be at risk of blowing due to loudness.
2. Avoid Bass-Heavy Synth Patches
Similar to playing bass guitar through a guitar amp, playing a synth bass or bass-heavy synth patch through a guitar amp will break it. So, to run a synth through a guitar amp without any issue, simply stay away from synth bass or bass-oriented patch.
If most of the sounds you’ll play are bass-heavy, you should rather get a bass or a keyboard amp. Both amps have a wider frequency response, and they can play bass-heavy patches without them breaking.
Another way to prevent bass from damaging the guitar amp is to reduce the Lows of the guitar amp with EQ. This is not the best option, but it’ll help protect your amp speakers.
Ways to Run a Synth through a Guitar Amp
Here are the different ways to run a synth through a guitar amp
1. Plug it in the amp’s input
I think this is pretty much self-explanatory. Simply plug a 1/4 inch TRS/TS cable into the synth’s output and plug the other end of the cable into the guitar amp’s input. This will send the synth’s audio out directly to the amp’s gain (preamp) and then further processed by the amp.
2. Run it through guitar pedals first
Another fun way to take your synth sounds to a whole different level is to run it through guitar pedals before the signal is sent to the amp. There are so many guitar pedals to choose from that can drastically change your boring synth patch into something magical. I’m going to walk you through two of my favorite pedals to use on synths.
As a reminder, don’t forget to turn down the synth’s volume before you connect it to the pedals. Once it is plugged in, you can increase the volume gradually until you can hear it clearly. That’s because, similar to amps, these pedals are designed for guitars, and they work well with low-level signals. There are a few advanced guitar pedals, however, that have a line-level switch. If the pedal has one, turn it on.
Eventide Space (on Amazon) is one of the most sought after reverb pedals available today that can give you some incredible results. Fortunately, this pedal was designed with the keyboard player in mind. It has a line-level switch, meaning you can plug your synths directly in it and have no issues at all.
It is a high-end pedal with tons of features and knobs that allows you to dial in just the right type of reverb you need. It also comes with a ton of presets for those who don’t like tweaking pedals. Listen to how Eventide Space sounds on a Korg Minilogue synthesizer.
Another excellent type of pedal you can use for a synth is a chorus, and BOSS CE-2W (on Amazon) is certainly one of the best out there. This has been a classic chorus pedal for years. It’s simple, with two knobs to control the rate and depth of the chorus. And it sounds great. Do well to check it out.
How to Record Synth Running through a Guitar Amp
After plugging your synth in the guitar amp or running it through pedals, you finally have a sound that you like. But how do you record it? Here are two ways to capture your synth sound from a guitar amp.
1. Record through guitar amp’s Line Out
Most guitar amps either have a Line Output (or Line Out) or a headphone jack. If you have any of the two on your guitar amp, it’s quite simple to record the amp’s output.
Simply connect the Line Out or Headphone Jack to a Line Input on your audio interface with an audio cable. This will send the final processed audio from the amp directly to the audio interface. And you can easily record from there.
2. Record Guitar Amp Speakers with a Microphone
This is the most common way to record guitar amps. And it’s been done this way for years for a reason.
Amp speakers (or cabinet) contribute to the overall tone of a guitar amp. There is a noticeable difference between recording a guitar amp through the Line Out and recording the amp speakers with a microphone. For this reason, guitar amp’s are usually recorded with a microphone placed in front of the amp cabinet.
The best microphone for recording guitar amps is the Shure SM-57 Dynamic Microphone (Amazon). It has been the standard mic for recording amps because it prevents mic bleeds, is well built, and can capture loud guitar amps without clipping or distorting.
You can experiment with different mic positions to get different results. For instance, you can place the mic directly facing the speaker cone for a much brighter signal. You can also place it at the sides of the speaker for a different tone.
Alternatively, you can use multiple mics placed in different positions on the speaker and then blend all the recorded signals together for a much unique tone. You can even place the mic farther away from the speaker to record the room to get that room reverb sound. It’s all about experimenting to find something that works for you.
In summary, you can play a synth through a guitar amp. However, don’t play the synth at a high volume, and avoid bass-heavy synth patches to prevent the amp from damaging.