6 Band Graphic Equaliser Using 741 Op-Amp IC

6 band graphic equaliser using 741 op-amp

6 Band Graphic Equaliser Using 741 Op-Amp IC

With this circuit you can control and blend frequencies and tones as desired.

Essentially, the circuit consists of an IC 741 whose gain at various freguencies is determined by corresponding potentiometer setting.

6 band graphic equaliser circuit using 741 op-amp bass treble control

The audiblefrequency spectrum is covered in six steps: 50Hz, 160Hz, 500Hz, 1.6kHz, 5kHz, 16kHz. All potentiometers are of 100kΩ linear type. The circuit provides adequate boost / cut for normal use.

R1, R2, R3, R4, R5, R6 27kΩ
R7 470kΩ
R8 330kΩ
R9 100kΩ
R10 4.7kΩ
R11 4.7kΩ
VR1, VR2, VR3, VR4, VR5, VR6 100kΩ
C1 100n (104)
C2 33n (333)
C3 10n (103)
C4 3.3n (332)
C5 1n (102)
C6 300pF (301)
C7 100µF 16V
C8 4.7µF 16V
C9 47µF 16V
IC1 741 Op amp

power supply for the circuit can be derived from the amplifier / preamplifier itself. The wide rangeof supply voltage (6V-15V) makes the circuit very versatile. Power consumption is negligible.

Please send your ideas, those are very important for our success…

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20 comments on “6 Band Graphic Equaliser Using 741 Op-Amp IC
  1. myo min aung says:

    [img]tone control circuit[/img]

  2. John says:

    Hi, I’m using this circuit for my 1st year electronic engineering project, however I am picking up a lot of DC noise on my Oscilloscope as the wave produced is not smooth. Has anyone got suggestions how I can solve this problem ?

  3. RacerX says:

    hi john the circuit isnt complete you shuld use like 10uf filer caps in your power seply

  4. John says:

    Hi cheers for the response, just going to try that now.

  5. kyle says:

    the body casing of the potentiometer should be shorted to the ground to reduce noise

  6. rob says:

    hi, is this circuit complete?…thanks rob.

  7. indeewara says:

    good circut thank you.

  8. ndum says:

    hi, am gonna try this now… thanks for the circuit

  9. Grace says:

    Can i know if how these equaler work?

  10. catalin botea says:

    i built it in the stereo configuration and works great except for the last one(high freqwency control)i mean it does not do anything.i even changed the caapacitors of 300pf with 150 pf with no result.all the others are working more than ok.can anybody tell me why?what is going on with this one.thank you in advance and waiting for your replies on my e-mail adress.

  11. Anthony Brown says:

    Have you tried 33pf , 16khz is pretty high in the Audio Spectrum anyway, even 10khz is high enough for music I think. You could try a better IC like the LF351 which will give you better high freguency performance. Good Luck.

  12. Hi, I have been looking extensively for a simple circuit, passive or active.. passive is better where I can achieve a 18db drop of low pass at around 1khz, so I can fade in and out almost all sound above 1khz…

    This is for a guitar/synthesizer effect that will act like an expression pedal so that when its all the way down you just hear the rumble of the synth, and all the way up its sparkles… lol

    So I was wondering if I could easily use this circuit by ignoring the first three controls and making the top three work together….

    I have limited knowledge in these kind of electronics….. 🙂

  13. Bhavin says:

    How to give input from mobile phone can someone please explain me this .

  14. Tony Currier says:

    I have built a very basic Bass/Tone control circuit using LM 386. Input direct to the 386 from MP3 IPod Nano and output to the input of the Bass/Tone circuit. Output from this was to a power amp TEA2025 IC(5Watts). I have excellent results with this and now wish to progress to the 6 Band Equaliser BUT USING THE LM 386. Are there any wiring modifications with the 6 Band Circuit for use with the LM386 ?

    I utilised the LM386 BEFORE the Bass/Tone circuit to boost the signal.

    Look forward to any help and advice.


  15. Samarjyoti Bhagawati says:

    I am going to buy the goods. Is the circuit OK or I have modify ? Please help me.

  16. Samarjyoti Bhagawati says:

    What does the value of capacitors i.e. 33n or 3.3n means. Iam unable to get that. Help me

  17. Alikatek says:

    Works good but generate lot of noise. To repair this problem connect 100k resistor input-ground and output-ground.


    Please tell me how the design of filters is made.

  19. Mounir says:

    How did you design the filters in this circuit

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