Here is a project that I designed in 2020. It is a 3 Band Equalizer and a low wattage amplifier. I had a pair of clean bookshelf speakers but the low frequencies were lacking so I decided to build an equalizer that could boost the low end. It is meant to drive the input of a power amplifier or low power headphones or earbuds. It could be useful to someone who uses book shelf speakers as a main system or someone who just wants a low power 2 channel 3 band equalizer. It does have a noticeable pop at turn on because the TL084s that I used have a non-linear startup condition. It does work fine for me and maybe it will work fine for another DIY builder. The roll off frequencies are 400 Hz and 5000 Hz as designed but can be changed to what ever some one wants. It can use a 3v to 15v DC power supply but I usually run it at 12v. The parts are labelled on the circuit board and I sent the Gerber files in case someone wants to give it a try. The surface mount resistors are 1206 in size. The schematic shows one channel of the design.
