STACKED MOD!!! Two TI RC455P IC ICs stacked inside for clarity, noise reduction, and a mini-toggle for TONS OF TONE options.

The SD1 5 Star Ge mod includes a two way gain switch that allows you to select between two different diodes for the clipping/distortion section of the pedal. The “down” position selects a germanium diode (the “Ge” part of the name). The Ge diode clips the signal more than a standard silicone diode, providing a more saturated, compressed, and smoother sound with more distortion available. The “up” position selects an LED for the clipping section, which clips less, allowing a clearer, more “open” sound, with less compression, more dynamic response, and more output available. Both are asymmetrical and both are an attempt to make the pedal more ‘tube-like’ since tubes and transformers rarely produce a symmetrical distortion.

NOTE, this is not just a switch to make it like a TS9 as some folks do. This makes it MUCH fatter, cleaner, and more defined, AS WELL AS gives it another mode to increase the gain beyond what a stock SD-1 offers!

BETTER BYPASS! Keeley has improved the BOSS switching making it even closer to true-bypass! In stock form these units may suffer a bit of bleed through when off if the level and gain are set very high. No longer! Keeley now has the best sound pedal both on and OFF!

As of January, 2005, Keeley Electronics made the BOSS SD-1 effect pedal better! Now with a unique twist, the Diode Switch is a standard feature instead of an option. This allows players to get a really heavy sound for pushing a Marshall amp, etc., or to use it as a really fat sounding tube amp simulator! Perfect for both single coil and humbucker guitars!