How to Ground an LM3886 Amp Circuit

Discussion in 'The Projects Forum' started by Eschatonic, Sep 25, 2010.

  1. Eschatonic

    Thread Starter New Member

    Sep 25, 2010
    Hello and thanks for reading this post.

    My project is to buid a hifi amp with the following features:

    National Semiconductor LM3886 power amps
    LM4610 tone/volume controller driven by a PICAXE using grey rotary encoders and digital pots plus an IR decoder.

    I want to put both the LM3886 channels and the power supply on one eurocard and have just set about drawing it using DipTrace freeware 2.1 which I am new to but like so far.

    I am a bit baffled by the two connectors shown in the power supply schematic as +PGND and -PGND. Can anyone tell me how they are supposed to be connected to the common ground shown in the amp schematic?

    Thankyou for any help offered.
  2. Audioguru


    Dec 20, 2007
    Connect the Pos ground and Neg ground together to make the common ground for the circuits.
    The power amplifier draws a fairly high current from the supplies so the pcb design must not have a voltage drop in the wiring to the input ground or input bias that would cause oscillation.
    Eschatonic likes this.
  3. Eschatonic

    Thread Starter New Member

    Sep 25, 2010
    Thankyou so much for your super swift advice.
    All the Best