My onboard bass guitar preamp design

Discussion in 'The Projects Forum' started by nemuikuma, Apr 6, 2012.

  1. nemuikuma

    Thread Starter New Member

    Apr 4, 2012
    I'm trying to make a preamp for my bass!
    I admit i am kind of a beginner, but i couldn't find any schematics that would satisfy my needs.
    The idea of the preamp that when i'm playing a song i don't really have time to set the tone knob to the desired value, so this provides me the option to set the pots before playing, and when the filter is needed, i just have to turn a switch and i have the right cutoff.

    In TINA-TI everything seems good , but i did not built it yet, but i hope everything will work as it works in the simulation.

    The pot in the 1st opamp's feedback loop is a trimmer, to set it for the pickups output.
    In the filter section the the pots set the cut off point for the lopass and hipass filters, the switches are 2 circuit type that turn of/on the filters, and connects the the parallel resistor in the feedback loop of the second opamp thus giving a recovery for the filters.
    If both switches turned of, it will give a bandpass filter with level boost.
    The last pot is to control the output volume.

    I would appreciate any feedback, is you find any errors or unnecessary components, wrong values, etc.
  2. #12


    Nov 30, 2010
    I'd change VF4 to about 50K. That will stop the next (output) cable from affecting the highpass frequency.