3 Band Graphics Eq.

A classic circuit of regulation of tone of three way, with which we can regulate low, mid and high frequencies, of acoustic signal. The boost/cut can be regulated in the range of ± 18 dB/oct. In the circuit the supply is ± 15V, but can be also supplied with alone supply + 9 until + 30V, it is enough it is connected pin the 4 IC1, in the 0V andis connected the circuit with as it appears in fig. 2, giving half the supply in the not inverting entry of IC1, in the 5 and 3 equivalents, which arehenceforth not connected in the ground.

R1-2= 47Kohms
R3-4-5-12-13= 10Kohms
R6-7= 3.3Kohms
R8-9= 1.8Kohms
R10= 270ohms
R11= 22Kohms
C1-11= 10uF 25V
C2= 33pF ceramic
C3= 2.2uF 63V MKT
C4= 47nF 63V MKT
C5-7= 4.7nF 63V MKT
C6= 22nF 63V MKT
C8= 1.2nF 63V MKT
C9-10= 100nF 63V MKT
C12=47uF 25V
RV1-2= 100Kohms Lin.
RV3= 470Kohms Lin.
IC1= TL072, NE5532

Source : Sam Electronic Circuits