EarthQuaker Devices Acapulco Gold Power Amp Distortion Effects Pedal ControlsBig Knob: The big knob sets the output level, sometimes known as Volume. PLEASE BE CAREFUL! The Acapulco Gold is extremely loud! Measures4 5/8 x 2 1/2 x 2.25 with knob Power Our pedals take a standard 9 volt DC power supply with a 2.1mm negative center barrel. Current draw is 30 mA.