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TPA3122D2 Class D Amp ticking sound and produces no music

Discussion in 'Audio' started by Phae, Nov 22, 2018.

  1. Phae

    Phae

    4
    0
    Nov 22, 2018
    Hi, i recently made a class d amp using tpa3122d2 according to the instructions by afrotechmods on youtube, just as a simple project. When i plugged 12V supply to the amp, the speakers starts to produce ticking sound and continue ticking even when i plug the amp to my phone. Can anyone help?

    Here's the link to the video


    Here's the schematic diagram of the amp
    MITAXQ5.jpg
     
  2. Harald Kapp

    Harald Kapp Moderator Moderator

    9,055
    1,818
    Nov 17, 2011
    What type of inductor did you use for the 33µH filter on the output lines? It needs to be able to carry the output current for the speaker. Using too small an inductor (even at 33µH) can lead to saturation of teh inductor's core. It will then loose its inductance and the filter will not work.
     
  3. Phae

    Phae

    4
    0
    Nov 22, 2018
    Thanks for spending your time to help out~ I'm using Bourns SRN1060-330M inductor.
     
  4. Harald Kapp

    Harald Kapp Moderator Moderator

    9,055
    1,818
    Nov 17, 2011
    That one is good for 3A, should not be a problem here.
    In the datasheet the polarization of the input capacitors is inverse to the one shown in your schemativ. Probably not an issue but should be corrected.
    You should also make a clear distinction between AGND (pins 7, 8) and PGND (pins 11, 20). Make separate nets (use separate wires) for each and connect them at a single point whre the power supply enters your board. This link shows details for analog and digital ground, but the technique can be applied to analog and power ground as well.
    Do the same for analog and power ground. Read also the chapter on power supply decoupling on page 13 of the datasheet.
     
  5. kellys_eye

    kellys_eye

    4,286
    1,146
    Jun 25, 2010
    What PSU are you using?

    Show your component layout.
     
  6. Phae

    Phae

    4
    0
    Nov 22, 2018
    I did connect analog and power ground altogether at one place, but next to each other as a hole on the board cannot fit so many wires, is that ok? And i connected the analog grounds to the same wire since they are next to each other on the TPA3122D2, does ur "make a clear distinction" mean i should give them separate wires even they are close?

    In case u need to know, im using 2 SP500104-1 speakers, 1 for each output, are those suitable?

    Picture of my project
    46662688_577303272691045_1937356028060368896_n.jpg 46510414_342891076264525_506071778829795328_n.jpg
     
  7. Audioguru

    Audioguru

    2,495
    553
    Sep 24, 2016
    Your problems are probably caused by your very messy tangle of wires.
    The parts should be close together and connected with short, straight wires. Buy the kit with its pcb instead.
    I agree that your input capacitors have backwards polarity, but since your tiny speakers (squeakers) produce no bass then non-polarized 0.33uF film capacitors should be used.
     
  8. Phae

    Phae

    4
    0
    Nov 22, 2018
    I rebuilt the circuit on a breadboard, now the speakers play music with a low volume and high distortion.
     
  9. Audioguru

    Audioguru

    2,495
    553
    Sep 24, 2016
    It is still a messy tangle of wires that are much too long. It should have neat short wires or a pcb.
     
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