Drum machine idle noise

Discussion in 'The Projects Forum' started by MarFene, Apr 13, 2015.

  1. MarFene

    Thread Starter Member

    Feb 27, 2014
    39
    3
    i am currently working on a project i started in my free time. i am trying to construct a drum machine , which is going better than expected. something which is giving me nightmares is the ammount of noise i am getting when the device is started


    This can be noted int he first seconds of this video




    any suggestions on how i can pull down this noise is highly appreciated.


    I was noting that a 555 timer working on the same power supply can be clearly heard in the noise.



    also this video shows a partial of the circuit from above since the other video does not show much.






    i know you are going to ask for schematics , but these are unfortunately not available since the breadboard is ongoing various impromptu changes.


    This circuit is of my design , and it is much simpler than it looks.
     
  2. Veracohr

    Well-Known Member

    Jan 3, 2011
    550
    75
    Do you have power supply decoupling?
     
  3. bertus

    Administrator

    Apr 5, 2008
    15,647
    2,346
  4. MarFene

    Thread Starter Member

    Feb 27, 2014
    39
    3
    since there are several timers on the same power rail , does that mean that i have to add capacitance to my voltage rails as a whole? i am actually blaiming the cheap chinese mb102 power supply i am using
     
  5. bertus

    Administrator

    Apr 5, 2008
    15,647
    2,346
    Hello,

    Each NE555 will need to be decoupled by an 1-10 μF tantalium and a 0.1 μF ceramic capacitor.

    Bertus
     
  6. MarFene

    Thread Starter Member

    Feb 27, 2014
    39
    3
    that'll have to wait till this weekend then gotta get some tantalums hah . how about paper?
     
  7. MarFene

    Thread Starter Member

    Feb 27, 2014
    39
    3
    didnt really work with paper caps just tried it with 1 uf and 0.47 uf in parallel. had no difference on the noise
     
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