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no image Sunday, January 07, 2018 by Noel Dillon

Would a 110VAC secondary output from a toroidal transformer suffice for the EPE Dec 2015 Currawong audio amplifier project ?

Hello all,

I am thinking of building the Currawong audio amplifier from the December 2015 edition of EPE magazine but the main toroidal transformer is proving difficult to source.  Its secondary output is 114VAC.  Would a toroidal transformer with a 110VAC output be ok for this project? - it would be a lot easier to find.

Thank you,



  • by  PeterTraneus Anderson
    Yes. Be sure to use a transformer with enough secondary current rating.
  • by  David Ashton
    That's only a 4% difference, I'd be surprised if this didn't work fine.  BIG caveat though - make sure that it is an isolation transformer (completely isolated windings) not an autotransformer which is just one tapped winding and could give you a nasty shock depending on how it is wired.  220-110V autotransformers are very common (for powering US equipment).  So do be careful what you get.  As Peter says above, make sure you get the same or better current rating than the specified one.

    Alan Winstanley - think this is another one where you could get the designer to comment?

  • by  Noel Dillon
    guys, thanks for your comments, I will keep them in mind especially on the isolation characteristic - I would have missed that!


    The one used in the article had 2 x 37VAC + 2 x 15VAC windings + 1 x 12VAC winding (from a second transformer) all connected in series to provide a 116 VAC output (not 114VAC than I mentioned in my initial post).  

    It just seems a little odd that the designer did not use a 110 or 115 VAC output transformer as they are common. 

    Thanks again,


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