8-Band Bass Equalizer Stompbox
Created: Jan 24, 2017
No description available.
This circuit is a bass guitar graphic equalizer composed of 8-bands. This circuit is used to control certain frequencies in your signal by either boosting or cutting it through the use of the slider knobs. Equalizers are used to compensate irregularities in the listening environment or to tailor the sound to a listener’s preferences. The frequencies used in the design are based on the bass graphic equalizer pedals commonly available in the market today.
The circuit is constructed as a stomp box or a pedal effect. It uses a 3PDT footswitch to engage the equalizer “ON” and “OFF”. When the switch is “OFF”, the signal is bypassed directly to the output of the circuit adding no changes to your signal. When the switch is engaged “ON”, the signal through a circuit composed of amplifiers and filters. The signal first goes in a preamp network that can control the overall level of the signal coming in the circuit with a +/- 15dB gain. After this stage, the signal goes into the filter stages of the circuit. In this stage, the user can boost or a cut several frequencies. The frequencies can be controlled around +/- 15dB gain. The band-pass filter circuit is constructed with a simulated inductor. Correct values of the passive components for the filter must be selected to set the desired center frequency. The op amps used in the circuit are the LM4562 and LME49710 op amps. These op amps feature ultra-low distortions, low-noise, high-slew-rate. They are optimized and fully specified for high-performance, high fidelity applications suitable for audio circuits like this project.
An LED is used in the circuit to indicate the 3PDT switch is “ON”. The circuit can be powered through a 9V power supply connected to the DC jack. The circuit design has high input impedance and low output impedance, which are favorable characteristics for a pedal effect.