Mad Professor ROYAL BLUE Overdrive Guitar Effects PedalRoyal Blue Overdrive offers a wide range of tones from light overdrive into distortion and at lowest Distortion knob setting works as an EQ. It can also be used to create tube amp like crunchy strike hard for distortion effect. There is not much filtering on the overdrive, to provide a transparent tone that you can tailor with both the Treble and Bass controls. Like the best boutique amps, the Royal Blue OD lets you determine the amount of breakup by