Not only have electric guitars become so widespread, but you can also record high-quality stuff at home. There are plenty of fairly cheap solutions for this, and with some experience, you can sound like a pro. But there’s one thing that often comes to mind with this topic: can you plug a guitar into line level input?

For those who are not familiar, the line level input is often found on mixing boards and audio interfaces. You’ll also see it on regular hi-fi devices, marked as “aux” or “phono,” but that’s a different story. These line inputs have their purpose, and so do other types of inputs. In simple terms, it’s all about pairing different input levels with appropriate sources. The whole thing also involves different impedance levels, but we’ll get to that.

So can you plug a guitar into line level input? Well, you can, but the results won’t be that good. In fact, I doubt that you’ll enjoy the tone that comes out of such a combination. You’d need the proper gear to make it all work.

So is there a solution for this if you don’t have any other options? Yeah, there are, but they require different solutions. In this guide, we’ll explore different audio signal level inputs and whether you can plug your guitar into a line level input.

Table of Contents

Types of Audio Signal Level

When it comes to audio equipment, there are four basic types of audio signal levels. According to their strength, going from the weakest to the strongest, they are:

  • Microphone level
  • Instrument level
  • Line level
  • Speaker level

Of course, when we’re talking about the “strength” here, it refers to the voltage. In some cases, we’ll also have to think about the impedance, especially if we’re talking about guitars. Here, we’ll tackle them one by one and explain what makes them so special.

Additionally, it’s also important to know how microphone and instrument levels are properly taken to the line level. Safely assuming that you’re here because of finding ways to plug your guitar into line level input, we’ll also share a few practical solutions for this problem.

Microphone Level

Microphone level inputs are designed for (you’ve guessed it) microphones. For this purpose, we usually have XLR jacks, which can be seen with any standard equipment designed for mics. They are, in almost all cases, balanced.

Anyhow, microphone level signals are pretty weak and delicate. Because of this, microphones require additional power to get them to the line signal level. For this purpose, we have microphone preamps. In most cases, these preamps are integrated within mixers and other devices.

For instance, a mixing board will feature a channel that has an XLR input for microphones and a regular 1/4-inch TRS jack. The XLR inputs are actually connected to a microphone preamplifier, which then goes into the line level input. The same could be said about audio interfaces with microphone inputs these days.

But if a mixing board or an audio interface comes without a specialized mic preamp, then you can use a standalone device. They also come in handy for other applications, and you can even use them for getting better sound quality. If you prefer to go this way, then we’d advise you to plug the standalone preamp into a line level input. These are available on your mixing board or an audio interface.

Instrument Level

The instrument level is what we’re interested in the most here. It’s stronger than the mic level, but still not strong enough for the line level input. Electric guitars, bass guitars, and acoustic guitars with piezo pickups are at the instrument level. It’s also important to note that they produce unbalanced high-impedance signals.

So if they have this high impedance, this means that they need to go into a high-impedance device. The line level has lower impedance. And if you plug your guitar into it, it results in a very quiet output. Not to mention that your tone will be awful due to a significant loss of high-ends and higher mids.

As mentioned, having a source with a high-impedance output requires its equivalent in the form of a high-impedance input. These are only found on specialized devices, like guitar amplifiers.

What’s also tricky about the instrument signal is that it’s unbalanced. In the practical sense, this means that it will lose its quality if you use longer cables. This is why in some settings musicians have to use DI boxes. They can help you convert the unbalanced instrument level signal into a balanced low-impedance signal. On one side, they have a high-impedance input, while the output is an XLR one that produces a low-impedance signal.

There are also solutions for bringing the instrument signal to line level. However, we’ll get this covered later below.

Line Level

To put it simply, the line level signal is the “standard” for live or studio settings. Basically, anything that goes through a mixing board needs to be taken to the line level. In a practical setting, this is pretty much any instrument. And one way or another, your guitar, microphones, or any other device will be taken to the line level.

But without proper signal amplification, it will all just sound too weak. Additionally, all of the studio and live rack equipment is designed to work with the line level signal. On the other hand, feeding line level signal into a device designed for mics or instruments will result in excessive distortion. This is something that you should avoid as you can potentially damage your speakers.

Some electronic instruments, like keyboards, come with a line level output. At the same time, they can also feature an instrument level output.

However, there are two types of line level signal. These are:

  • Consumer level: These are common with consumer hi-fi devices, like CD players. Their nominal level is −10 dBV (decibel volts).
  • Professional level: This signal level is common with pro audio gear and the nominal level here is +4 dBu (decibels unloaded). A lot of pro audio gear pieces have a toggle switch that lets you choose between consumer and pro type of signal.

You can also plug consumer devices into pro ones and vice-versa. However, you’ll need to adjust the appropriate output and input levels. But that’s usually not a common practice.

Bear in mind that one of the most common causes of unwanted distortion and noise in a studio is mismatched gain. Always make sure that you check this first.

A man and a studio mixing board

Speaker Level

Finally, the speaker level signal is the strongest one. It’s essentially an amplifier line level signal. Some devices, like power amplifiers, have outputs for passive speakers. Active speakers have integrated amplifiers that take this signal to the required level. Technically, you wouldn’t be able to make passive speakers work without this signal level.

It’s absolutely important to know that you shouldn’t ever connect a speaker level output to a weaker input (line, instrument, or microphone levels). This way, you’re risking serious damage.

Balanced vs. Unbalanced Audio

We’ve talked about balanced and unbalanced audio. Balanced audio requires three conductors to carry the signal. Two are for negative and positive signals, while the third one is for grounding. Unbalanced audio requires only two conductors, one for the positive signal and the other for the negative signal and grounding.

Balanced has a few advantages. The ground is separated from the negative signal, it can take longer cable runs without quality loss, and there’s far less chance that you’ll experience interference from various radio signals.

Can You Plug a Guitar Into Line Level Input? Will It Work?

So can you plug a guitar into line level input? Yes, you can, but you’d need proper gear in order to make it all work. In fact, a lot of guitar players these days are going directly into PA systems. It makes things much simpler than using microphones to capture the tone of a guitar amp.

We’ve also discussed plugging electric guitars directly into power amps. You can read more about it here.

There are a few things you can use to make guitars work at the line level. These are:

  • Specialized guitar preamps (often in the pedal form)
  • DI boxes
  • Multi-effects processing and amp modeling units
  • Audio interfaces

Specialized guitar preamps, which are usually in the form of pedals, are not that common but are useful. You can simply plug in directly to a mixing board with it.

Multi-effects processors and advanced amp modeling units can let you replicate entire rigs. You can have a very convincing tone without even using an actual amplifier.

DI boxes are usually common in studio settings. Although simple, it’s becoming less popular with all the digital modeling amps and other specialized devices. It’s useful if you rely completely on rack-mounted studio devices and digital plugins.

Finally, many audio interfaces these days are intended especially for guitars, basses, or generally anything with an instrument level output. This is more than useful for home studios or even some semi-professional and professional settings. Simply plug your guitar into an audio interface and use various plugins in your DAW to shape your tone.