With a simple modification,  you can totally change the sound of this pedal from its trademark thin and fizzy sounding distortion, to full and rich sounding. Here's what I did. First , take off the back plate and locate diodes D4 and D5 on the circuit board. (They are marked). Then simply snip the ends off of both of them disconnecting them. It's the most popular and effective mod for this DS1. There are many videos on YouTube about this simple great mod. It turned my Boss DS1 distortion into a fantastic, way more expensive sounding pedal. Have fun!