The MS-3 from BOSS is a multi-effects switcher designed for electric guitar and bass. It combines the switching aspects of a multi-pedal switcher (so that you can turn whole effects-chains on and off with one footswitch) with a multi-effects engine equipped with BOSS processing, such as distortion, chorus, flanging, and more. With this pedal, you can activate and control six built-in pedal effects alongside—and woven between—three external pedals.

If you utilize a dual-amp setup on stage, the pedal will let you select between your amplifiers or run them in stereo. Also provided is a MIDI output jack, so you can send tempo, CC, and PC messages to compatible devices.

The MS-3 offers three different loop paths, each with its own send/return I/O. You’ll also note the TRS control I/O, which lets you integrate outboard switches and expression pedals for deeper modulation of onboard effects parameters. Two different modes are provided on the pedal: Memory and Manual. Memory mode allows you to use the four footswitches to select among patches and banks, while Manual mode gives you the ability to switch various loops on and off, and provides some control of processing parameters to boot.

Measuring 9.7 x 3.8 x 2.7', the MS-3 is a relatively compact solution for sporting the feature-set it carries; you could place this pedal on a conventional board and still have room for three or more stompboxes. The unit ships with an AC adapter and four rubber feet.