A Summary of the Basics on Line Selector and AB Box Effects Pedals

Hello everyone! It’s Kaoru the composer!

This time, I would like to talk about the basics of effect pedals, specifically Line Selectors/AB Boxes. Strictly speaking, it might not be considered to be an effects pedal, but since it’s used in pedalboards, I’m introducing it here!

A line selector is not something that adds effects to the sound, but it’s rather a handy tool used to increase flexibility. It's a must-have for people who use a lot of effect pedals or those who want to make their live performances more convenient!

■ What is a Line Selector?

A line selector is a pedal-type effects unit that switches signal paths. The footswitch allows you to switch between signals instantly, making it very convenient to use during a performance.

There are three main types:

• AB Box: A device that allows you to switch between two signal paths.
• Line Selector: A device that allows you to switch between three or more signal paths.
• Switching System: A more complex unit that can switch between even more intricate circuits (this article doesn’t cover this type).

These are the three main categories of line selectors.

■ What is a Line Selector?

A line selector refers to a pedal-type effects unit that includes send and return terminals. The signal exits from the send terminal and returns through the return terminal in a simple structure.

Typically, the line selector is used to manage multiple connected effects, allowing you to switch them all on or off simultaneously while the signal is returning from send to return. For example, if you want to use both a booster and a distortion effect simultaneously during a guitar solo, this would be an ideal scenario for using a line selector. It's a highly versatile tool that allows you to customize your setup based on your needs.

Some models also include a buffer, which helps to prevent the "signal loss" (sound thinning) that often occurs with large pedalboards. By using these features creatively, you can execute tasks that would normally be a hassle in just an instant, making the line selector a very interesting and useful item.

Additionally, some models are equipped with a tuner-out terminal. Due to its simple internal structure, many people choose to build their own line selectors. However, given the abundance of affordable ready-made options available these days, unless you have specific requirements, it’s generally better to go for a pre-built one!

■ What is an AB Box?

Structurally and functionally, the AB box is quite similar to a line selector. You use the footswitch to switch the signal, just like with a line selector.
However, the key difference is that the AB box can be used for both input and output.

For example:
・You can switch between the two amps instantly by connecting a Roland JC amp to the A terminal and a Marshall amp to the B terminal. This is useful for switching amps based on the genre of music you’re playing, making it a handy tool for live performances.

And,
・Switching between guitars becomes hassle-free if you connect a Les Paul to the A terminal and a Stratocaster to the B terminal. This is also very practical for live performances.

It’s important to note that the AB box only handles one-way signal processing.

With a standard line selector, you can also split the output into two and use it as an AB box. Personally, I would recommend using a line selector for more flexibility!

Now, let's take a look at some of the recommended products available at Sound House.

BOSS / LS-2

The LS-2 is a classic line selector model that has been a long-time favorite. Despite its compact body, it offers six different selection modes, making it a versatile tool.

Not only can it switch between signal circuits, but the VOLUME knob allows you to control the volume for guitar solos or backing, giving you more flexibility in your performance. Additionally, it can supply power to BOSS’s compact effect pedals, making it an ideal choice for building a compact pedalboard! (Note: A separate parallel cable PCS20A is required for power supply).

If nothing is connected to the send/return, you can also use it as a clean booster—a nifty trick!

The large footswitch is another great feature that makes it easy to operate, and it’s of course suitable for use with bass guitars as well!
Having one of these in your gear collection will definitely prove to be very useful!

VOCU / Magic Switching & Loops

The VOCU Magic Switching & Loops is a switching system that features two effect loops, allowing you to control it with various switching methods. It also includes a line selector function and an external footswitch functionality.

One personal highlight is that both effect loop terminals are placed on the same side, which simplifies the wiring—a common challenge when using multifunctional line selectors!

The VOCU's unique toggle switching mechanism allows you to swap the on/off of the two loops with just one action, making it quite efficient.

Additionally, because it doesn’t use any electronic parts such as variable resistors in its circuitry, there is no impact on the sound quality, ensuring that your tone remains unchanged.

VOCU / Magic Blend Room Spec.B

The VOCU Magic Blend Room Spec.B is a multifunctional model that comes with two parallel effect loops and a variety of assist functions such as a splitter, booster, and buffer.

It offers the following features:

• 2 parallel effect loops
• Frequency splitter
• Low booster
• Treble booster
• Level booster
• Buffer amplifier
• 3-channel parallel box
• 3-channel mixer
• Phase inverter
• Line selector

With all these features, this unit will definitely be a valuable tool. It also includes a mute switch.

I recommend this product not only for those who use many effects but also for anyone who wants to create a compact pedalboard. The fact that it's priced under 20,000 yen is very surprising!

This concludes my summary and recommendation of Line Selectors and AB Boxes. These are versatile items, and their usage varies from person to person, making them fun to explore. How about experimenting with your own unique ways of using them?

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