Are Guitar & Bass Amplifiers Mono Or Stereo Devices?

Electric guitars and basses are naturally mono instruments, but the music they're used in is most often in stereo. So then, it makes sense that there would be some confusion as to whether guitar/bass amplifiers are mono or stereo.

Are guitar amplifiers mono or stereo devices? Electric guitars and bass guitars are naturally mono instruments, so most guitar/bass amplifiers are mono as well, even if they drive more than one loudspeaker. However, some amplifiers are designed with stereo outputs to accommodate common stereo guitar/bass effects (chorus, delay, reverb, etc.).

In this article, we'll discuss why guitar and bass amplifiers are typically mono devices while also considering stereo examples. Additionally, we'll go over common stereo effects for guitar and bass, as well as the process of using two mono amplifiers to achieve stereo results.

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• Top 11 Benefits Of Learning & Playing Guitar
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• Top 11 Benefits Of Learning & Playing Bass Guitar
• Top 11 Best Online Resources To Learn How To Play Bass Guitar

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Are Guitar And Bass Amplifiers Mono Of Stereo?

As discussed in the introductory paragraphs, the vast majority of guitar and bass amplifiers are mono. This is largely due to the fact that electric guitars and basses output mono signals, so they only really need a mono amplifier.

The guitar or bass output sends a single channel of mono audio to the amplifier's input. The monoblock preamplifier and power amplifier bring the signal level up to effectively drive the loudspeaker(s) of the separate cabinet or integrated cabinet in the case of combo amplifiers.

Note that some cabinets have multiple speakers, though this does not necessarily mean they are wired for stereo. These speakers are often connected in series and/or parallel and are designed to reproduce sound from the single-channel mono output from the guitar/bass amplifier output.

Furthermore, if we did happen to have a set of speakers wired for stereo in a single amplifier cabinet. In that case, they'd likely be too close together to produce a meaningful stereo image. We'll discuss such a design (the Roland JC-40) in an upcoming section.

To produce a distinctive stereo image, a stereo amplifier could be used to drive two separate cabinets/speakers spaced apart from one another.

Going a different route, a stereo signal could be split to drive two individual mono amplifiers to produce a stereo effect, as we'll discuss in the section Using Two Mono Guitar/Bass Amplifiers In A Stereo Setup.

With all that said, if we consider music recordings, much of modern music is done in stereo.

The bass guitar (and other bass elements having low frequencies) are typically panned to the centre, which is effectively mono (same signal in the left and right channels). Low frequencies are naturally omnidirectional, so keeping them mono or panned centre keeps things sounding natural.

For this reason, many bass amps are mono. Of course, there are stereo bass effects, but for the most part, the bass is mono, especially in the low end.

Guitars are often panned off-centre in a stereo mix, though often captured in mono. That being said, many guitar effects can produce stereo results, as we'll discuss in the section Common Stereo Effects For Guitar & Bass.

So, to recap, electric guitars and basses are mono instruments that output mono signals. Even if they're panned within a stereo mix, they're most often mono sources. This means that pure amplification should also be in mono. The need for stereo arises with stereo guitar and bass effects, which produce variations in the left and right channels to widen the mix.

For more info on mono and stereo audio, check out my article Is Stereo Or Mono Audio Better? (Applications For Both).

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What About Multi-Channel Guitar & Bass Amplifiers?

There are plenty of multi-channel guitar amplifiers on the market and quite a few multi-channel bass amps, too. Let's break down what “multi-channel” means.

First off, multi-channel can be confusing because stereo audio is technically dual-channel audio (left and right-channel audio). However, many multi-channel amplifiers are mono, so what's the deal?

A common multi-channel channel guitar amplifier design features a clean channel and a distorted channel. The amp's input is directed to one of the two channels before the output, and these channels can often be toggled between via a footswitch (or via a hand switch on the amplifier).

Dual-channel amps may also have “high gain” and “low gain” channels, “normal” and “bright” channels, or some other selection. This concept can be stretched to amp designs with more than two channels.

With these multi-channel amps, we can effectively switch between mono channels for a variety of different tones (each channel can be set to have its own tone).

The Hughes & Kettner GrandMeister Deluxe 40 is an example of a 4-channel guitar amplifier. The four channels are clean, crunch, lead, and ultra.

The Fender Super Bassman Head is a 2-channel bass amplifier with foot-switchable vintage and overdrive channels.

We notice that the Super Bassman has two inputs labelled Input 1 and Input 2. This is fairly common on bass amplifiers.

The two inputs do not apply to their own individual channels (remember how we can switch between the channels via a foot or hand switch rather than unplugging from one input and plugging into the other). Rather, both “inputs” technically feed into the same input, which is then sent to whatever channel is selected (in this case, the vintage or overdrive channel).

On bass amps, the first input is generally designed for passive electronics (pickups), which tend to output weaker signals than active electronics (pickups). The second input is designed for active electronics (pickups) and has a 6-15 dB pad (passive attenuation device), and may have a different impedance rating to best serve the intended “active pickup” signal.

Read the user manual of your specific dual-input amp to see if it's safe to use both inputs at once.

To recap, multi-channel amps are not necessarily stereo. The two concepts are mutually exclusive. That stated, some multi-channel amps, like the 4-channel Revv Generator 120 MKIII, do offer stereo processing and stereo outputs.

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Stereo Guitar And Bass Amplifier Examples

The majority of guitar and bass amplifiers are mono, and there are plenty of examples on the market. Unless otherwise noted, it's likely a safe bet to assume that an amplifier (and even a multi-channel amplifier) is mono.

So then, in this section, we should consider stereo amplifier examples.

The Magnatone Panoramic Stereo 12+12-watt is a stereo tube amp head with stereo vibrato/tremolo and tube-driven spring reverb effects (controlled via an external footswitch).

It is a single-channel amp with a high sensitivity input at input 1 and a low sensitivity input (-6dB) at input 2. Note that the input is mono, while the effects and outputs can be stereo.

As for the stereo output, the Panoramic Stereo 12+12-watt features a line output and a speaker output (rated 8Ω) for its left and right output channels. As per usual, plugging into the left output only will effectively output a mono signal.

The Roland JC-40 Jazz Chorus is a stereo-input/output guitar combo amplifier. It features a single channel with left and right input jacks for stereo inputs from stereo guitar effects, though it can also be used in mono by plugging only into the left input.

The JC-40 features a 3-band EQ with a bright switch along with distortion. It also has built-in stereo reverb and vibrato/chorus effects, which affect mono and stereo inputs alike to produce a stereo output. All effects can be toggled on and off via connected footswitches.

The JC-40 has stereo line outputs (left and right) along with a stereo headphone jack. The effects loop features a mono send and stereo (left and right-channel) return.

Note that this combo amp has two 10″ speakers: one for each of the stereo channels. As mentioned previously, the amp will produce a stereo field by itself. Still, this stereo field may not be wide enough for our listening pleasure, especially if we're not directly in front of the combo amp.

The Yamaha THR10 II 2×3″ 20-watt is a single-channel modelling amp with a single 1/4″ input jack, USB and Bluetooth connectivity. The amp also features an auxiliary input and can play music through a dedicated channel along with the guitar channel.

It offers 5 amp digital models with 10 additional models available via the proprietary THR Remote App. The amp features a 3-band EQ, compressor and noise gate along with stereo effects such as chorus, flanger, phaser, tremolo, echo and ever (spring and hall).

The THR10 II has two 3″ speakers: one for each of the stereo channels. It can send digital stereo audio via USB or Bluetooth, though this particular model doesn't have any stereo line or speaker outputs for analog audio.

The Wayne Jones Audio WJBA2 1000-watt bass amplifier is a single-channel bass amp with a single mono/stereo 1/4″ input and a stereo Class D power amp module with 500 watts per side.

The output can deliver 500W into 4Ω or 8Ω loads, and the output can be bridged (by plugging only into the left channel output) to drive 1000W into 4Ω or 8Ω loads.

The effects loop features stereo (left/right) sends and stereo (left/right) returns. In addition to stereo functionality, the WJBA2 offers a -10 dB input pad for active electronics (pickups), an optical compressor stage, and a 6-band EQ with a selectable 30 Hz boost.

Related article: Can You Play A Synthesizer Or Keyboard Through A Guitar Amp?

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Common Stereo Effects For Guitar & Bass

Let's consider a few popular stereo effects for guitar and bass, namely:

• Chorus
• Delay
• Reverb

Stereo Chorus Effects

What is the chorus effect? Chorus is an effect that produces copies of a signal (the original signal and each of its copies has its own “voice”) and detunes each voice to produce a widening and thickening of the sound. Each voice interacts with the other voices to produce slight modulation and an overall larger-than-life sound.

The modulated signal copies of a chorus effect can be panned within the stereo field for further widening.

Let's consider a few chorus effects units for guitar and bass.

The versatile TC Electronic Stereo Chorus + is one of the most famous chorus pedals ever. It has a mono input and two outputs. Plugging into the left output will produce a mono effect, while plugging into both outputs produces a stereo effect.

Like many chorus units, the Stereo Chorus+ is also capable of flanger and vibrato.

The Boss CEB-3 Bass Chorus is another top-level chorus pedal. This time, it's for bass guitar. This pedal has a mono input. When output A is the only output jack connected, the output is mono.

When outputs A and B are connected, output A outputs the modulated signal while output B outputs the dry/unprocessed signal. In doing so, the stereo effect is based on the “space synthesis system,” where the depth of the effect is largely dependent on the space between the A speaker(s) and B speaker(s).

For more information on the chorus effect, check out the following My New Microphone articles:
• What Are Chorus Pedals (Guitar/Bass FX) & How Do They Work?
• Top 11 Best Chorus Pedals For Guitar & Bass
• Top 11 Best Chorus Modulation Plugins For Your DAW

Stereo Delay Effects

What is the delay effect? Delay is a time-based effect where an input signal is recorded for a relatively short amount of time and is played back after a set period of time after the initial recording. There are many ways to achieve delay and different styles/types of the effect.

The delayed copies of the signal can be panned within the stereo field for further widening and realism.

Let's consider a few delay effects units for guitar and bass.

The Boss DD-8 is the 2019 version of the company's beloved DD Digital Delay line of pedals. It features dual-mono/stereo inputs (inputs A and B) along with dual-mono/stereo outputs (outputs A and B). As per usual with Boss pedals, plugging solely into the A input or output will make the input or output mono while plugging into A and B will make the input or output stereo.

Depending on the mode (the type of delay selected), the DD-8's true stereo I/O will produce one of three output modes between outputs A and B:

• Independent: parallel delays on the left and right channels, allowing you to maintain the true balance of stereo input sources in the effect (standard mode).
• Panning: for “ping-pong delay” effects (tape, warm, reverse, +reverb, shimmer, modulation, warp and GLT modes).
• Wide stereo: for enhanced spatial depth (analog mode).

The Strymon TimeLine is another digital delay with stereo inputs and outputs (left and right channels). It offers 12 unique delay machines and 200 presets.

For more information on the delay effect, check out the following My New Microphone articles:
• What Are Delay Pedals (Guitar Effects) & How Do They Work?
• Top 13 Best Delay Pedals For Guitar & Bass
• Top 10 Best Digital Delay Plugins For Your DAW
• Top 10 Best Analog Delay Emulation Plugins For Your DAW
• Top 10 Best Tape Delay Emulation Plugins For Your DAW

Stereo Reverb Effects

What is the reverb effect? The reverb effect recreates the natural effect of Reverberation, which happens when a sound wave hits a surface (or multiple surfaces). It reflects back to the listener at varying times and amplitudes. This creates a complex echo that holds information about the physical space.

The delayed copies of the signal can be panned within the stereo field for further widening and realism.

Let's consider a few reverb effects units for guitar and bass.

The MXR M300 Reverb is a reverb pedal with 6 different reverb modes (Plate, Spring, Epic, Mod, Room, and Pad). Though it only has a single 1/4″ output jack, this TRS jack can be split into left and right-channel mono signals with a proper Y-splitter cable.

The big bad Boss RV-500 is a fantastic reverb unit with 12 Reverb Modes and 297 preset locations. It features true stereo I/O (left and right channels at the input and output), though it's mono-compatible if only the left channel is plugged into.

For more information on the reverb effect, check out the following My New Microphone articles:
• What Are Reverb Pedals (Guitar Effects) & How Do They Work?
• Top 13 Best Reverb Pedals For Guitar & Bass
• 12 Best Reverb Plugins (Spring, Plate, Algorithmic, Convolution)

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Using Two Mono Guitar/Bass Amplifiers In A Stereo Setup

If we remember our earlier discussion on the Roland JC-40 Jazz Chorus, we had a single combo amp with dual-mono inputs (individual inputs for the left and right stereo channels). This amp could effectively accept the dual-mono/stereo output from a stereo (or dual-output) guitar or bass effect.

The same principle can be applied to two separate amplifiers with even greater results.

We can take two amplifiers (ideally identical for improved tone similarity between the left and right channels) and use each of them as its own channel.

For example, we could have a chorus, delay or reverb pedal at the end of our pedal chain. We can send the left output of the pedal to the input of the left amplifier and the right output of the pedal to the input of the right amplifier. Each amplifier would be tasked with amplifying its own stereo channel.

It would then be up to us to position the two amps in such a way that the listener could experience the stereo field optimally. This typically means spacing the two amps apart from each other (much more than a single combo amp housing could provide).

Additionally, when it comes to miking these amps, there will be less channel crosstalk bleed between the two channels (compared to if the two channels were reproduced in the same amp unit).

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Related Questions

Do microphones output mono or stereo signals? Microphones convert sound waves to audio signals via mic capsules. Most mics have one capsule that outputs one signal, making them mono devices. Some mics have multiple capsules and output multiple mono signals (which could be mixed in stereo). However, “stereo mics” are truly multiple-mono devices.

Related article: Do Microphones Output Mono Or Stereo Signals?

What is a monoblock amplifier? A monoblock amplifier is a single unit (“block”) responsible for amplifying a single channel (“mono”). The components of a monoblock amplifier amplify a single channel rather than being shared between multiple channels. Monoblocks, therefore, are larger, heavier and more expensive (per channel).

Related article: What Is A Monoblock Amplifier? (Monoblock Vs. Stereo Amps)