Guitar effect dynamic overdrive has been designed out of a need for a super touch sensitive overdrive that could exactly follow the playing of the guitarist without having to turn any knob during songs. The design goal we wanted to achieve was to create an extremely easy to use yet still dramatic and versatile overdrive. Controls for Volume, Gain, Bass and Treble. The Volume control acts as a master output level control. The Bass and Treble controls manage the frequency responses of the pedal. With both set 'at noon' the Sparkle creates a totally flat frequency response, covering the entire spectrum of guitar frequencies. When adjusting the tone controls, the sound always stays full and well-defined without ever getting muddy or gloomy. These tone controls let the Sparkle deliver the best tone quality with every guitar and amp. The 9 V/18 V switch allows the guitarist to choose which voltage the circuit would be supplied with, still using the same external power supply. In 18 V mode, the pedal offers a lot more headroom than the standard 9 V, which is extremely useful for guitars with more powerful pickups.