Simple 3 Band Graphic Equalizer with BC548

This is a simple 3band graphic equalizer for audio amplifiers. There are three controls for three ranges, low frequency,mid frequency,and high; or simply for Bass, Treble and Mid range.

This circuit consists of a mini amplifier made by two BC548 transistors and the input-output differential feedback network is coupled with those controls as input.

Though this unit has own amplifier unit, it doesn’t omits the need of preamplifier(if any). Only one channel is shown, if you need to use in stereo, add another clone.

Parts list:

  1. Q1, Q2= BC548, or BC547, or BC549 NPN transistor
  2. VR1,VR2,VR3= 47K linear T/C
  3. R1=33K
  4. R2=33K
  5. R3=22k
  6. R4=22K
  7. R5=33K
  8. R6=1K
  9. R7=100K
  10. R8=4.7K
  11. R9=470
  12. C1,C2,C3=0.047µF, or 472
  13. C4=470pF
  14. C5=1µF
  15. C6=4.7µF
  16. C7=47pF
  17. C8=100pF


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5 Responses

  1. Rashmi Ranjan Rout says:

    Hiii ,i also love electronics,but i don’t find the best ckt diagram,i have one apm (ic-LA5408) & i want to make a bass & treble ckt for me easly.

  2. jayu says:

    hi sir ARUP
    in my house so much bill 1500/- per month what i am do
    please help me i cant understand in electricity please tell me properly

    thanks reply me

  3. shubham says:

    arup sir
    you mentioned a website for identifying
    base emitter nd collector of a transistor
    i forgot that link
    please tell me that link again
    it was like ……… .uk
    thanks in advance

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