Low cost effective Bass-Treble circuit using Op-Amp 741

This simple but powerful bass, treble, volume control is made by General Op-Amp IC LM741. The input voltage is 12V, but it will also work with 9V and 6V. This has inbuilt pre-amplifier also.

Left channel is shown. Right channel is same.

Parts List:

  1. IC LM741 x1                                         10/-
  2. T/C 10k,22k,100k   All x1                    27/-
  3. Triansistor BC148/548   x1                 1/-
  4. 220uF/25V   x2                                      6/-
  5. 4.7uF/25V  x2                                        4/-
  6. 2.2uF/10V x1                                         2/-
  7. 10uF/25V x1                                          2/-
  8. Small resistances x12p                         2/-
  9. Small PF    x5p                                      2/-
    TOTAL                                                 56/-

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30 Responses

  1. jay says:

    how this circuit work

  2. imran says:

    have a dual 4440 ic circuit board of dvd player but i want to make it a amplifire the total circuit is complete but i am confuse with bass and volume wiring.

    • premanku kumar nath says:

      Hi Arup

      I have one amplifier having IC LA 4440 double channel in bridge mode. My question is whenever i increase bass in full volume the output is low . Please advise.

  3. Dipak says:

    can you please tell me how it works

    • Arnab says:

      The BC148 transistor is acting as a pre-amplifier, it’s amplified output is fed to the op-amp’s inverting input(pin 2) through a 2 stage RC filter circuit, with some negative feedback from output( pin 6 ).

      The first RC filter stage is around the volume control, and the second stage is around the bass treble control circuit.

      The second stage is doing all the magic, it’s going to be a long theory to explain how bass-treble control is working.

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