I designed a 6 band audio equalizer using Sallen-Key active filters and an audio amplifier. The filters were designed using the UA741 and the amplifier was designed using the LM386. I used Eagle Cad to design the PCB and JLC to manufacture.

The LM386 is designed for audio amplification and it doesn't need a dual power supply while the UA741 is not a good amplifier for audio without an external current source.

Song: "Pillars of the Dawn" Zombi
UA741 Datasheet: https://www.ti.com/lit/ds/symlink/ua741.pdf?ts=1605452646478&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FUA741
LM368 Datasheet: https://www.ti.com/lit/ds/symlink/lm386.pdf
Video of equalizer: https://youtu.be/7KhZvftxPuY