Wiring Schematic Diagram

Here is the circuit of 3 band tone control using a single op-amp IC and few components. The IC used here is LF 351 which is a wide bandwidth single JFET operational amplifier.

The high input impedance of the IC makes this circuit compatible with most of the audio signal sources. The op-amp is wired as an inverting amplifier. The input signal is fed to the inverting input of the opamp via the filter network. The filter network can produce a +/- 20 dB enhancement or cut on the three frequency bands 50Hz,1KHz and 10KHz.POTs R1, R2 and R3 can be used for adjusting the gain of the different bands