The Boss GE-7 Equalizer pedal adjusts the harmonic contents of an instrument in 7 separate bands ranging from 100Hz to 6.4kHz, with a boost/cut 15dB per band. The additional Level control knob helps you to set a different volume for normal and effect sound (or to use the pedal only as a gain booster).
Fig. 1: Boss GE-7 Equalizer guitar pedal schematic diagram
Fig. 2: GE-7 circuit board - foil and component side