3 Band Equalizer


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 and is 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 are henceforth not connected in the ground.

Circuit diagram

Circuit diagram

Part list

  • 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