BOSS introduces the EX-4 Effects Expander with 120 effects

BOSS has introduced the EX-4 Effects Expander, a compact effects processor designed to add versatility to any pedalboard, shipping in October 2026 for $299, according to No Treble.

The unit runs up to four effects at once, drawn from a library of 120. Every major category is covered, including overdrive and distortion, modulation, delay and reverb, along with bass-tuned effects and BOSS favorites such as Slow Gear and Slicer. Utility blocks can be placed anywhere in the effect chain: foot volume, two noise suppressors, send/return and a divider/mixer. A global EQ handles overall tone shaping.

The EX-4 has a 2.4-inch color display showing the signal chain, effect blocks, options and menus. Four dedicated buttons switch each block on or off with a single press, and holding one opens the editing parameters for that effect. Each button is color-coded to match the screen.

Other features include dual-function footswitches, mono or stereo inputs and outputs, an expression pedal input and MIDI in and out. Nate Navarro presents a full rundown of the unit.