Amplifier PSU & Oscilloscope Advise

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  • Nevillet
    Badcaps Veteran
    • Sep 2019
    • 272
    • United Kingdom
    #1

    Amplifier PSU & Oscilloscope Advise

    Hi All,

    I have been trying to do some measurements on a a small TDA2030 chip amp using a Siglent scope.
    I've been powering the amp with a cheap Chinese HANMATEK HM305 bench power supply.
    The problem is high frequency noise on the output of the amp when powered with the the bench supply.
    If I power it using 2x 9V batteries the noise goes away.



    So my question is what can I do to reduce the noise from the PSU?
    Is there a filter circuit I can use to help this situation?

    Many thanks.
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    • petehall347
      Badcaps Legend
      • Jan 2015
      • 4426
      • United Kingdom
      #2
      Re: Amplifier PSU & Oscilloscope Advise

      could try bypass capacitors . or even better filters .. i can't see the power supply from here never mind what's inside it ..

        Comment

        • stj
          Great Sage 齊天大聖
          • Dec 2009
          • 30985
          • Albion
          #3
          Re: Amplifier PSU & Oscilloscope Advise

          put ceramic or film capacitors across the power rail at the amp

            Comment

            • Nevillet
              Badcaps Veteran
              • Sep 2019
              • 272
              • United Kingdom
              #4
              Re: Amplifier PSU & Oscilloscope Advise

              Thanks guys.

              Pete: what kind of filter? could you direct me to a circuit or product?

              STJ: What kind of cap values are we talking about?

              This is the PSU: https://www.amazon.co.uk/gp/product/B0855N2FGY

              Thanks for your help.

              Neville

                Comment

                • stj
                  Great Sage 齊天大聖
                  • Dec 2009
                  • 30985
                  • Albion
                  #5
                  Re: Amplifier PSU & Oscilloscope Advise

                  try 100nF ceramic or film
                  AND 220uf electrolytic in parallel

                  ceramic/film deal with very short high frequency noise, the electrolytic deals with general stuff

                    Comment

                    • petehall347
                      Badcaps Legend
                      • Jan 2015
                      • 4426
                      • United Kingdom
                      #6
                      Re: Amplifier PSU & Oscilloscope Advise

                      filter capacitor like already suggested

                        Comment

                        • Nevillet
                          Badcaps Veteran
                          • Sep 2019
                          • 272
                          • United Kingdom
                          #7
                          Re: Amplifier PSU & Oscilloscope Advise

                          Many thanks. I'll report back..

                            Comment

                            • petehall347
                              Badcaps Legend
                              • Jan 2015
                              • 4426
                              • United Kingdom
                              #8
                              Re: Amplifier PSU & Oscilloscope Advise

                              wondering about adding a choke if needed later .

                                Comment

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