fa001
Posts: 84
Joined: Wed Jan 02, 2013 8:25 pm

radio build power ?

Thu Sep 17, 2015 8:50 pm

I am in the process of building a Pi based radio project. I have a 12v power supply for the amp and I was going to connect a DC-DC 3A Buck Converter Adjustable Step-Down Power Supply Module to that to power the Pi. However reading another person's construction notes I find the following note, "Do not try to tap off power from the Power supply or transformer used by the speaker’s amplifier. This won’t work (earth loops) and can cause damage to the PI and peripherals."
Can someone explain this or tell me how to avoid such problems?

drgeoff
Posts: 9762
Joined: Wed Jan 25, 2012 6:39 pm

Re: radio build power ?

Fri Sep 18, 2015 10:25 am

The warning of damage is about using the speaker supply directly, without the DC-DC converter to 5 volts.

Earth/ground loops do not cause damage. They can introduce a background noise but that is unlikely in your case and can often be eliminated or reduced to acceptable level by appropriate wiring of signal and power ground connections.

Try it and see.

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