Stacking Op-Amps?

Discussion in 'General Electronics Chat' started by Razor Concepts, Mar 15, 2009.

  1. Razor Concepts

    Thread Starter Active Member

    Oct 7, 2008
    212
    1
    Right now I have one op-amp (TS922) driving a small speaker. It isn't loud enough, so can I stack another TS922 on it for twice the watts? Thanks!
     
  2. bertus

    Administrator

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

    Do you have a schematic of the current configuration ?
    You can try to make a bridge configuration for more power output.

    Greetings,
    Bertus
     
  3. Razor Concepts

    Thread Starter Active Member

    Oct 7, 2008
    212
    1
    Here is the schematic:
    http://ladyada.net/media/wavshield/waveshield10schem.png

    However this is on a PCB, so big changes can't really be made. I just realized a better idea would be to replace it with a more powerful op-amp. Any suggestions? The circuit is being used as an audio player. Thanks!
     
  4. bertus

    Administrator

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

    The output power is also limited by the +5 Volts from the power supply.
    Also the use of standard opamps is power limiting.
    The maximum output current of the tl072 is 60 mA.
    The LMH6672 has a higher output current.
    http://www.national.com/pf/LM/LMH6672.html

    Greetings,
    Bertus
     
  5. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    The minimum supply voltage of a TL072 is 7V, not 5V.
    You do not have its inputs properly biased so it will not work anyway.
    Its minimum load is 2k ohms, not 8 ohms.

    You have two opamps in parallel so they will fight each other and might destroy themselves.

    Use a TDA2822M little power amplifier. With your 5V supply its output at clipping is 850mW into 8 ohms and it does not need the huge output capacitor.
     
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