ac transformer for power amplifier?

Discussion in 'General Electronics Chat' started by morphemes, Jan 28, 2014.

  1. morphemes

    Thread Starter New Member

    Jan 27, 2014
    4
    0
    Say I need an AC transformer that outputs something like 20-0-20 (give or take a few volts). Toroidal transformers are quite expensive. Laminated steel core transformers are affordable, but I can't find any that have a 0v line. Can I just wire the zero volt to earth?

    I've been eyeing these "DIY" 2.1 Channel TDA7294 2x80W+160W power amplifier kits. I have a 19.0V - 0v - 19.0V toroidal, but a match there is not. So, I'm trying to figure out what I need & I've been banging my head against the wall for about a week now.

    Any recommendations, other than therapy? :)
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,520
    2,369
    What is meant can't find a 0V line? This is just a centre tap of a 40v continuous winding.
    What is the problem with the 19-0-19? If it measures 38v across the outer ends then it is centre tapped.
    Max.
     
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  3. MrChips

    Moderator

    Oct 2, 2009
    12,435
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    Many power transformers come with C.T. (center tap) secondaries. That is what the 20-0-20 means.

    The center tap is simply your 0V reference or common.
     
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  4. morphemes

    Thread Starter New Member

    Jan 27, 2014
    4
    0
    Center-Tapped! Thank you both! For this most arcane of jargons, I am forever in your debt.
     
  5. MrChips

    Moderator

    Oct 2, 2009
    12,435
    3,360
    You're welcome. You just have to ask. Someone here will have an answer.
    Welcome to AAC!
     
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