High-Gain 7-Band EQ PUBLIC

7-Band EQ with High-Gain Boost

High-gain 7-band EQ for guitar or bass. Controls Include: Input Gain, Drive, 7 Tone Gain pots, Output Gain, Volume. Center frequencies of each tone pot are shown in the diagram. Maximum gain averages +30 dBV from 100 Hz to 6.3 kHz with all controls at 50%, where lows below 100 Hz fall to 0 dBV @ 20 Hz, and highs above 6.3 kHz fall to 0 dBV @ 80 kHz. Each tone pot provides gain adjustment from cut of -20 dBV to boost of +20 dBV (i.e., +-Vo/Vi = +-11), counted from band center-frequency at +30 dBV. Power-supply not shown. Requires regulated dual-polarity DC supply providing +-9VDC or +-12VDC or +-15VDC at >= 100 mA of current. Note: Op-amp noise is inversely proportional to supply voltage. The specified op-amps were chosen to provide cleanest possible operation. Do not substitute except with op-amp having the same or higher input impedance and the same or better THD+N rating. And while the circuit is simulator verified, treat it as experimental. Breadboard test it before committing to a soldered build.