TDA2009A Hi-Fi audio amplifier not producing output

Discussion in 'The Projects Forum' started by bhaskarauvsp, Jun 28, 2015.

  1. bhaskarauvsp

    Thread Starter New Member

    Jun 28, 2015
    4
    0
    Dear Members,
    I built a new TDA2009A Hi-Fi audio amplifier for 5.1 surround system. I prepared three TDA2009A PCB boards for driving 6 speakers. Each board is supplied by individual power supply made of 30V step-down transformer, KBP206G bridge rectifier, 2nos. of 2200MicroF capacitors in parallel, L7824CT 24V positive voltage regulator. And also attaching schematic diagram for your reference and this is different from PCB layout shown in TDA2009A datasheet. Now the problem is that sometimes i am getting output from single channel and most of the time I am not getting output from amplifier boards. Please look into the schematic and provide your suggestions and i spent lot of time to debug the circuit but in vain not able to get the sound from amplifier boards. Also note that complete circuit is made by me due to this circuit is not functioning properly.

    Thanks.
    Bhaskar
     
  2. GopherT

    AAC Fanatic!

    Nov 23, 2012
    6,069
    3,840
    What is your 5.1 audio input source? Is it already separated into 5 channels? If not, you need a device that can do that. Also, your schematic is impossible to read. Take a picture directly above and keep the camera very steady and use your flash.
     
  3. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,809
    1,105
    Welcome to AAC!
    Your schematic is too small to see all the details. We need a larger image (but preferably similar file size).
     
  4. bertus

    Administrator

    Apr 5, 2008
    15,649
    2,348
    Hello,

    Your drawing is not clear to me.
    The feedback lines are not completed.

    Have a look at the example schematic from the datasheet:

    TDA2009_example_schematic.png

    I have also attached the full datasheet.
    It also contains a PCB for this circuit.

    Bertus
     
  5. bhaskarauvsp

    Thread Starter New Member

    Jun 28, 2015
    4
    0
    Dear Members,
    Please find the clear schematic and in PCB those feedback lines are already connected but same is not shown in schematic. IMG_20150629_230200_1.png
     
  6. bertus

    Administrator

    Apr 5, 2008
    15,649
    2,348
    Hello,

    What kind of speakers do you use?
    Are those 4Ω or 8Ω types?

    Keep in mind that the efficiency is about 60 % at 24 Volts supply.
    It can well be that the 24 Volts regulator shuts down due to overload.
    You could try to replace the regulator by an 78S24, wich can deliver 2A continu and 3 A peak.
    Cooling of the regulator is essential.

    Bertus
     
  7. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,809
    1,105
    Shouldn't the floating 'wire' connect to the negative of the 24V supply?
     
  8. bhaskarauvsp

    Thread Starter New Member

    Jun 28, 2015
    4
    0
    I am using 4 Ohm speaker at the output. There is no problem with 24V regulator because when I check the output of DC it is showing perfect 23.6V but there is no output at amplifier.
     
  9. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,809
    1,105
    Near the top right corner of your schematic there is a missing connection from the negative of the supply.
     
  10. bhaskarauvsp

    Thread Starter New Member

    Jun 28, 2015
    4
    0
    Disconnection in schematic is for testing purpose only and in actual PCB it was shorted. Please provide the alternate solutions because I am unable to proceed further without knowing the actual problem.
     
  11. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,809
    1,105
    Pins 2 and 4 of the TDA2009 should not be open-circuit. See the datasheet for a typical amp circuit.
     
Loading...