Boss GE-7B Bass Equalizer pedal schematic diagram

The Boss GE-7B pedal is a 7 band (62Hz - 4kHz) equalizer with a boost/cut of 15dB per band, designed specifically for bass guitars. The schematic is similar to the GE-7.

Schematic diagram of GE-7B Bass Equalizer pedal
Fig. 1: Boss GE-7B Bass Equalizer guitar pedal schematic diagram
GE-7B Bass Equalizer circuit board (component side) Fig. 2: GE-7B PCB - component side
Boss GE-7B Bass Equalizer pedal


  • Residual Noise Level: less than -100dBm (IHF-A Weighted, Typ.)
  • Equalizer Control: 7 bands, +/- 15dB
  • 7 band EQ: 62Hz, 125Hz, 250Hz, 500Hz, 1kHz, 2kHz and 4kHz
  • Level Control: +/- 15 dB
  • Input Impedance: 470kΩ
  • Output Load Impedance: more than 10kΩ
  • Connectors: Input Jack, Output Jack, AC Adaptor Jack
  • Power Supply: DC 9V dry battery, AC Adaptor
  • Current Draw: 12mA (DC 9V)
  • AC Adaptor: ACA-Series
  • Width: 70 mm
  • Depth: 125 mm
  • Height: 55 mm
  • Weight: 450g

ICs, transistors and diodes used in the Boss GE-7B Bass Equalizer:

  • IC1-IC4: M5218P (dual operational amplifiers)
  • IC5: HA1457W or HA12017 (low noise preamplifier)
  • Q1: 2SC2240GR (NPN silicon transistor)
  • Q2, Q3: 2SC945-P or 2SC1685 (NPN silicon transistors)
  • Q4, Q5: 2SK30ATM-Y (N-channel JFET transistor)
  • D1, D2, D3: 1S2473 (switching diodes)
  • D4: RD5.6EB3 (500mW 5.6V Zener diode)
  • D5: 1OE2 or S5500G (400V/1A diode)