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Regulated 12v Supply, Hum reduction

Discussion in 'General Electronics Discussion' started by bigkim100, Jul 9, 2021.

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  1. bigkim100

    bigkim100

    196
    19
    Apr 17, 2013
    Ok, so I have my old 12Vdc 6 amp power supply, with TONs of fresh electrolytic capacitors, but Im still getting a bit of 60cycle hum. I doubt that I will ever be pulling more than 2 amps from it, but it is rated at 6 amps.
    Can someone suggest a choke, capacitor combo that will finish off the last bit of hum...something I can get from EBAY.
    I remember back in the 70s when I had a power supply for my Radio Shack CB Radio with a bit of hum, I pulled a random choke out of a box of military surplus components from POLY PACKS (remember them). I had no idea of its rating, but I had zero hum from then on.
    15 years later I sold it, and it was still perfect, and I never knew what the hell the choke was.
     
  2. Audioguru

    Audioguru

    3,617
    763
    Sep 24, 2016
    Most power supplies use a full wave rectifier bridge that produces 120Hz, not 60Hz. Then one or two of your rectifier diodes do not work.
     
  3. bigkim100

    bigkim100

    196
    19
    Apr 17, 2013
    Its only a slight hum, but noticeable. I did not realize that the bridge rectifier changed it to something other than 60 hz.
    This does use a big, chunky full wave diode bridge module, mounted to the case for heat dissipation, I can only guess.
    This is all followed by several high value electrolytics.
    I changed the electrolytics to fresh ones, since I had them kicking around.
     
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