The BOSS SD-1 Super Overdrive is a true classic. It’s been around for a long time, since 1981 in fact, and I got mine way back in 1982.
It’s a beautiful pedal that furnishes a smooth, warm, classic overdrive sound although it can be used as a pre-amp or booster. Like its cousin, the DS-1 Distortion, the SD-1 only has 3 controls: level, tone and drive. At high drive settings the SD-1 provides a valve-like overdriven sound but by dropping the drive and raising the level you can use the SD-1 to boost your guitar’s signal to induce overdrive in the amp. The SD-1 was brought in to replace the original BOSS overdrive, the OD-1, which lacked a tone control.
The SD-1 is another pedal that lends itself to modification and a number of well known modifiers such as Robert Keeley offer modified SD-1s. Mine is still in stock condition.
The clip below shows off the SD-1’s overdriven sound. I’ve routed my Ibanez JEM 777FP through the pedal and into the Line 6 POD XT Pro which is set to a very clean sound. The overdriven tone you hear is all SD-1. The JEM is being played on the neck pickup.