• Item: Mains DC blocker and RFIEMI filter  
  • Type: The DC Duffer and Mains Filter  
  • Posted: 23 November 2013  
  • Builder: mwhouston  
  • Country: Australia  
  • Comments: 3  

DC Blocker

In Australia our mains supply has gone from clean power to not so clean power. For a number of years now I have built power filters into my power amps but not in media players or preamps. Because DC on the mains can cause many problems with audio gear and particularly audio gear using a toroid transformer a DC mains blocker may improve sonic performance. This simple DC blocker also incorporates an RFIEMI power filter. A choke on the input lead and 10A slow blow fuse round out a simple and neat solution to "dirty" mains power.


  • RJV
  • 23 November 2013 at 03:29AM
  • Impressively simple design. Please give a components list. Thanks.
  • mwhouston
  • 28 January 2014 at 05:00AM
  • The bridge is a 35A 400V type,caps 4700uf 50V and the power filter is just a cheap unit. The rest should be obvious.
  • AmpUtator
  • 4 March 2018 at 04:47PM
  • I Love it.

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