Building a DC-blocker

Ever heard your transformers buzzing? Maybe during the day, maybe when a (modern) hairdryer is used somewhere in the house? Chances are that a DC-component is present on your mains voltage and that your powertransformers do not like this. Especially cheap modern household devices have power supply solutions that might place a DC-component on the mains voltage. Older and toroid transformers most of the time can not handle DC well and start to buzz.. I'd like to think that this is common knowledge but time after time I hear that this knowledge is not so common at all..
So maybe worth building one and hear if it has a positive effect on the stereo gear.

Lots of articles can be found on the net about this, so I see no point in doing that again. Instead I just link to the site of John Broskie, Tubecad.com, where he describes a failsafe suggestion which I use for many years now. It is hidden somewhere in the middle of a post about linestages from 2018. Really worth reading as it contains many other tips and tricks. He also describes why this might affect stereo gear. You can find the article here but you can click as well on the screenshot I made of the dc-blocker part (I do hope John does not mind me doing doing this..)

Taken from Tubecad.com, click the image for original blogpost by John Broskie

So this is about building the thing into a wall wart enclosure. The end product is safe for usage in living rooms and practical as well as it sits between wall outlet and mains plug.

The components for this project. All good available, nothing special. I used 16AWG wire..


Glueing the capacitors into the wall wart, laid out for short wiring


Soldering the only resistor and 'cold' wire, the neutral, and safety earth..


The 'hot' input wire, the phase, soldered into place..


Diodes and 'hot' output wire installed..


Close up..


And output outlet installed. Ready to place the lid on the enclosure.


..and ready for use!