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Switching power supplies and Earth


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Hey guys, I have recently realised... Since the power supply for my bass amplifier is essentially just a single 48v power supply, I seem to get electric shocks when I touch the rear of my amplifier! (The case is "grounded" and metal). So what I was wondering, can I connect the metal case to earth to stop the shocks? Because since I am using two switching power supplies in this fashion, my bass is at 24v potential to earth since it is also grounded which may cause a few problems!

The power supplies are wired up in Series to create a 48v power supply. Essentially, its just

-  +-  +
0 24 48

Can I earth the supply at the 24v point?

Thanks, Haz

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It's probably more likely to be -24V 0 +24V.

My guess is that the electric shock is caused by leakage from the mains to DC side via the RF suppression capacitors inside the SMPS. It should be a fialry low current and safe but when lots of appliances are connected together the currents add together making the situation worse.

I wouldn't like to say, my guess is yes you can as neither power supply seems to be connected to earth but to be on the safe side, you could try connecting it to earth via a 1

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  • 3 weeks later...

Just to answer incase anybody is looking for the future :)

I used two 4.7uF 63v capacitors on each of the positive terminals of the power supply and connected them to the earth terminal on the power supply. The electric shocks have now gone and the noise has been reduced too! Thank you hero :)

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