3-Band Active EQ for Guitar PUBLIC

3-Band Active EQ for 6-String Electric Guitar

3-bandpass active EQ for electric guitar using FET-input op-amps. Controls Include: Input Gain, Direct Send, Bass Gain, Mid Gain, Treble Gain, Tone Send, Output Gain, and Volume. The Input and Output Stage are gain stages using one op-amp each. Three op-amps are used for the filters, and one as a summing-amp for the filter output signals. The direct unaltered signal (except for gain boost) and the three summed filter signals are mixed at the Output stage. The direct signal has no tone-controls and ranges from 80 Hz to 16 kHz. The filters are bandpass types with centers at 110 Hz for Bass, 880 Hz for the Mids, and 3.12 kHz for Treble. Thus, the circuit is ideal for 6-string electric-guitar in standard tuning, with emphasis on lows and mids. [Not recommended for 7/8-string guitars or for bass-guitar.] Intended as a rack-mount project only. Max gain = +22 dBV @ 250 Hz with all controls at 50%, or +30.3 dBV with all controls at 100%. Though simulation verified, circuit should be considered experimental. Breadboard test before committing to a soldered build. House completed project in a grounded metal enclosure.