Boss Pro GE-21 Graphic EQ Equalizer w/ Power Supply

The BOSS GE-21 is a great example of the brand’s more serious side: a Japanese-made, half-rack professional graphic EQ designed for guitar, bass, recording, PA, and studio applications. With 21 individual frequency bands spanning 22 Hz to 22 kHz and up to ±15 dB of boost or cut per band, it offers far more precise tone shaping than a typical stompbox EQ. This is the kind of piece of gear you can use to surgically carve frequencies, shape an instrument in a recording chain, fine-tune a PA or room, or completely rethink the character of a guitar rig. The GE-21 is also built to professional specifications, with exceptionally low noise and distortion for its era.

BOSS has been a major force in effects and signal processing since its beginnings in Japan in the 1970s. The company introduced the CE-1 Chorus Ensemble in 1976 and followed it with the OD-1, PH-1, and SP-1 compact pedals in 1977, helping establish the rugged, practical pedal format that became an industry standard. BOSS gear has been used by generations of major players, including Andy Summers, Steve Hackett, Pat Metheny, Jeff “Skunk” Baxter, and Eddie Van Halen—the latter famously used the earlier GE-10 graphic EQ.

This GE-21 includes a correct BOSS AC power adapter, making it a particularly nice setup for anyone interested in vintage Japanese signal-processing gear. It’s an unusually versatile piece of BOSS history and a great addition to a guitar rig, recording setup, or collection of classic rack and studio equipment. If you appreciate gear that gives you real control rather than simply adding another effect, the GE-21 is worth a closer look. These older BOSS pro-audio pieces don't turn up nearly as often as the company's ubiquitous stompboxes, so if you've been looking for one, this is a good opportunity to add a genuinely useful piece of BOSS history to your setup.