BOSS SD-1-4A Super Overdrive 40th Anniversary

Released for 2021 production only, the Limited Edition 40th Anniversary SD-1 Super Overdrive pedal celebrates 40 years of continuous SD-1 production. This commemorative pedal features a black body with yellow lettering, gold-capped knobs, and a vintage silver thumbscrew for the battery compartment. It comes packaged in a unique box with a special 40th Anniversary logo.

The Limited Edition 40th Anniversary SD-1-4A Super Overdrive is now available from Merchant City Music, Glasgow’s longest-established guitar specialist. We ship fast to the UK, Europe and Worldwide.

BOSS SD-1-4A Super Overdrive 40th Anniversary

Since its release in 1981, the workhorse SD-1 Super Overdrive has been the core gain pedal for a swathe of players across musical genres. Based around the revolutionary asymmetrical clipping circuit from the OD-1 Overdrive—one of the three original BOSS compact pedals from 1977—the SD-1 delivers rich, smooth, and highly musical overdrive tones that continue to inspire guitarists everywhere.

In 1977, BOSS created an entirely new stompbox category with the OD-1, bringing natural overdrive in pedal form to guitarists for the very first time. Producing a signal rich in even-order harmonics, its unique asymmetric clipping circuit replicated the pleasing sound and feel of a driven tube amp—but at controllable volume levels. Four years later, this breakthrough design evolved into the more versatile SD-1, which added an active tone control for shaping the treble response and subtle enhancements for more low-end body.

The SD-1 allows players from beginner to pro to get inspiring sounds right away, thanks to its natural behavior and the subtle mid boost that's part of its design. It gives your tone a push where it matters most, ensuring your guitar always sits perfectly in the mix with warmth, clarity, and rich presence. Lower drive settings are great for rhythm parts, while higher settings are ideal for fat, singing leads. The SD-1 is also very sensitive to input gain, letting you dial in different shades of overdrive simply by adjusting your guitar's volume control.

BOSS SD-1-4A Super Overdrive 40th Anniversary Features

• Classic BOSS overdrive sound
• Unique asymmetrical clipping circuit produces tube-like overdrive characteristics
• Mild-to-moderate drive tones with focused midrange and tight low end
• Ideal for use with clean and slightly driven amps
• Also works great for bringing tightness and definition to high-gain amp tones
• Stacks well with boost, overdrive, and distortion pedals
• BOSS five-year warranty