Here’s an improve tone control with 12dB boost on 80Hz for better super bass experience.
About the Circuit
The circuit is made up of 2 opamps TL072. This can be changed to other general purpose opamps like LM358. First stage opamp gain is set to 1, if you need more gain, you will need to decrease R2. If you want to use it for Mic, use 1k for R2.
Take note that there is no capacitor in series with the output, this is only for simulation, in reality you will need to add capacitor at the output to cancel out the DC offset on the output.
Want more Bass?
This circuit can already deliver +12dB boost at 80Hz but if that is not enough for you, you may want to decrease value of R3 and R4 for higher bass boost. Decreasing it to 3.3k will give you a bass boost of around 17dB at 80Hz! That would be too much and take note that you may need more power for that.
Simulation
Flat response ( bass and treble set to 50%)
there is roll off at both ends but it is only around -1dB which is fine. The roll off on the 20kHz is intended to reduce AM interference. This can be reduced by reducing C7 value. While the roll off at the lower end is needed to reduce subwoofer excessive movement. For music listening, the 20Hz to around 50Hz frequency is not important because almost no instrument is playing on that range of frequency. You can further decrease that roll off at 20Hz by decreasing value of C1.
100% Bass and Treble
0% Bass and 0% Treble Vs Set to both maximum
PCB Design
Please do take note that the simulation part numbering is not the same on the PCB part numbering. In example R1 on the simetrix simulation file is not the same R1 on the PCB file.
For PCB design, I used only single layer PCB so it will be easy to build for anyone. But in order to do this, I needed to add some 0 ohm resistors as jumpers. Just use wires for these 0 ohm resistors, these are R13, R14 and R20 on the schematic.
3D Render from Kicad Software
Downloads
You can download the kicad project file and simetrix simulation file here: