Boss GE-7 Equalizer pedal schematic diagram

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. 2: GE-7 circuit board - foil and component side

• Residual Noise Level: -100dBm (IHF-A Weighted, Typ.)
• Equalizer Control: +/- 15dB
• 7 band EQ: 100Hz, 200Hz, 400Hz, 800Hz, 1.6kHz, 3.2kHz, 6.4kHz
• Level Control: +/- 15 dB
• Connectors: INPUT Jack, OUTPUT Jack, AC Adaptor Jack (DC 9V)
• Power Supply: DC 9V Dry Battery (6F22/9V), AC Adaptor
• Current Draw: 7mA (DC 9V)
• AC Adaptor: ACA-Series or PSA-Series (new models with silver label)
• Width: 70 mm
• Depth: 125 mm
• Height: 55 mm
• Weight: 450g

ICs, transistors and diodes used in the Boss GE-7 equalizer:

• IC1, IC2,IC3: TL022CP dual operational amplifiers
• IC4: uPC4558C dual operational amplifier
• IC5: HA1457W preamplifier
• Q1: 2SC732TM-GR NPN silicon transistor
• Q2, Q3: 2SC945-P NPN silicon transistor
• Q4, Q5: 2SK30ATM-Y N-channel JFET transistor
• D1, D2, D3: 1S2473 diodes
• D4: RD5.6EB3 500mW 5.6V Zener diode
• D5: 1OE2 diode