[sdiy] Quick Question about Grounding Power Supplies

Michael E Caloroso mec.forumreader at gmail.com
Fri Jul 3 21:53:10 CEST 2020

Never connect earth to the CT of a transformer.

At least here in the US, earth of a three prong AC plug should be
connected to the metal chassis.  Local circuit ground should be
coupled to earth through a low resistance (IE 10ohm at least 1/2 watt)
with a cap in parallel.  That would be a better solution to reducing


On 7/3/20, Shawn Rakestraw <shawnrakestraw at gmail.com> wrote:
> Some of you may remember helping me learn how to design some PCBs a few
> months back. I have been using one of my homemade eurorack cases for a
> while now. To refresh the idea, it is essentially an electronotes design
> where a 24V center tapped transformer is regulated down to +12V and -12V.
> My question is this - Should the ground pin of the power cord be connected
> to the center tap of the transformer? Currently, I have it connected to the
> "Earth" terminal of the power switch and it is also connected to the "Body"
> of the transformer, but I have left the center tap "Floating".
> After putting a Make Noise Pressure Points module into the case and
> noticing what looks like a lot of noise on the signal, I think that maybe
> the earth ground should connect to the center tap and floating ground.
> Thanks for your advice.
> - Shawn

More information about the Synth-diy mailing list