One band EQ, Can be stack for multiband Eq need +/- 12V  

on first module, dont put R2 and C4, and bypass C4.


On last module, dont put R1 and C3, and bypass C3.


On every other module (betwin the first and the last) dont put R1,R2,C3 and C4, bypass C4.


R, C1 and C2's capacity/resistance are in image Gallery.