amplifier to speaker power issue

Discussion in 'The Projects Forum' started by babb27, Jun 30, 2011.

  1. babb27

    Thread Starter New Member

    Mar 16, 2011
    21
    1
    so I purchased a small 10W car audio amplifier PCB setup to be used in a talk box. it uses the TDA2003 IC and i have checked the datasheet for information.

    unfortunately in my ignorance i purchased a 8 ohm speaker rated at 40W max. the datasheet only rates the TDA2003 for a maximum of 4 ohm load resistances. and even at highest supply voltages the output power is less than 5W

    so at low frequencies the speaker is distorting. in the higher range the response is fine. from what i understand this is because the speaker is not receiving enough power. so i need to increase the output power.

    another problem is the company did not give me the schematic for the PCB. so I am looking to use my small knowledge to try to increase the power by using another amplifying stage. I understand I could use a lower impedance speaker but i would rather amplify the signal and use the 8 ohm speaker.

    any suggestions on what topology to use between the PCB and speaker to amplify it to proper levels? I was going to use a simple non inverting op amp.

    any and all help is appreciated
     
  2. #12

    Expert

    Nov 30, 2010
    16,278
    6,789
    An opamp will not fix this. They don't have the current driving ability to do the job. You will have to drop that amplifier in the parts box and buy a bridged amplifier to get 10 watts into an 8 ohm speaker from a 12 volt supply. It's either discard the amplifier or discard the speaker.

    Oh...you've already decided. OK. See you at the amplifier store.
     
    babb27 likes this.
  3. babb27

    Thread Starter New Member

    Mar 16, 2011
    21
    1
    thanks for the quick reply. i have reconsidered my decision and will be looking into a lower impedance speaker. thanks
     
    #12 likes this.
  4. #12

    Expert

    Nov 30, 2010
    16,278
    6,789
    Nice! It's refreshing to deal with somebody that can understand the answer, and more importantly, is willing to accept reality. So many people just go on whining that helpers on the site must be smarter than that and could we please try again to violate the laws of physics.

    babb27, you just made my day :)
     
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