3 band tone control design

The tone control i posted last time was simple with only bass and treble control. it is also a mono circuit, you need to build two pcb to make it stereo. Now let’s build a little more complicated, a stereo tone control with mid control. If you haven’t tried building any PCB, I suggest try first the more simple tone control circuit. I will also include the simulation file just in case you want to change the response of the circuit.

It is easy to change the response of the circuit by just running the simulation file. More on that later.


About the Circuit

The circuit uses 2 op-amps. The first one is used as a buffer. You can remove this one provided that the circuit connected at the output will be on the same PCB. The numbering on the simulation file and PCB is not the same(R1 on sim file is not R1 on PCB), so for the sake of discussion, let’s refer on the sim file.


C2 determines the center frequency of the Bass, C3 for the mid and C6 for the treble. If you want more treble boost, increase the value of C6. You may want to increase C2 and decrease C1 to decrease the rumble on the bass. Lowering C1 to 1uf will give a roll off on frequency below 20Hz. This is good if you have low power system. Take note that you need to higher output power for low frequencies. The lower the frequency, the higher the power it requires.


Final Circuit

The circuit has 2 channels for stereo.

PCB Design

It is a bit challenging to design a single layer PCB of a complex circuit without using jumpers. I had successfully designed a PCB without any jumpers but the result is that the PCB becomes a little bigger than it is. You can download the PCB file and edit it with your own preference of you can just use my design.



Download the PCB, Schematic and simulation file here:


Download Page

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