Negative Feedback loop on a Power Amp. circuit

Discussion in 'The Projects Forum' started by i r flipflop, Feb 3, 2010.

  1. i r flipflop

    Thread Starter New Member

    Feb 3, 2010
    So, I'm making a small radio-reciever that will eventually connect to a loudspeaker.

    I'm using 2 741 op-amps, one of which has a variable resistor on the negative feedback loop acting as a volume control.

    I then have output (pin 6) of the second 741 connected thohg a capacitor to a push-pull circuit using one P and one N channel MOSFET.

    I've looked around on the internet, but can't find any circuit diagrams as to where to connect the negative feedback to,

    I've been told that it connects to somewhere around the MOSFET's, but that's all the info. i've been given.
  2. SgtWookie


    Jul 17, 2007
    The 741 opamp is really not a great choice. You'd be far better off using a TL071 or TL072 (single and dual opamps, respectively).

    The TL071/72 has far greater bandwidth and far lower noise.

    Usually, the opamps are configured for a set amount of gain, and a pot (10k audio taper) is used to attenuate the input signal. One end of the pot is connected to ground, the other end to the input signal, and the wiper is attached to the input of the amplifier.

    If you're using a single-ended supply, you will need to use a cap between the wiper of the pot and the input of the opamp.