5.1 Audio Amplifier power supply assistance with schematic.

Discussion in 'Power Electronics' started by adagger, Jun 4, 2016.

  1. adagger

    Thread Starter New Member

    Jun 3, 2016
    Hi All,

    I'm putting together a 5.1 Audio Amp with built in pre amp and needing assistance with what supply voltages are required and whether i can just throw on a toroidal transformer or i need a proper protected power supply. To my knowledge i need to supply 15v and a 24v from what i can gather off the website and schematic but i am unsure.

    I've attached the website from purchase (has broken english description but worth a look) and the the schematic that came with it.

    Can i please have some assistance with what supply voltages i need and what power supply would you use.

    thanks for the knowledge and wisdom,


  2. #12


    Nov 30, 2010
    The power amplifier chips prefer to have as much as +/- 50 VDC
    The pre-amp board wants an AC power supply of 15-0-15 volts at 20 watts rated.
    One regulator chip is LM7824 designed to provide 24VDC but I haven't found what uses 24VDC. The LM7824 is a 1 amp chip so it couldn't be the power amplifier chips using 24 volts.
    Maybe that's being derived from the VCC of the 500 watt transformer.

    One transformer seems to be rated at 28-0-28 at 500 watts for a VCC of 38 volts, unregulated.
    The broken English seems to indicate that the 500 watt transformer can be rated anywhere from 36 VAC center tapped to 60 VAC center tapped. That would make VCC options from 24VDC to 41 VDC after rectifying and filtering.

    I'm seeing at least 2 transformers.
    Anybody else is welcome to help. The best information seems to be in the PDF of post #1

    That's a quickie look at it.
    Last edited: Jun 4, 2016
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  3. Veracohr

    Distinguished Member

    Jan 3, 2011
    i think +24V is used for the relays.
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  4. crutschow


    Mar 14, 2008
    That would appear to be true.
    I would change to 15V relays so a separate supply is not needed.
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  5. #12


    Nov 30, 2010
    Good idea. It reduces unnecessary complication and you probably can't buy a 15-0-15 rated at exactly 20 watts so you're going to have some extra power available, anyway.
    adagger likes this.