Question Powering two devices with one power supply

[Paul68]

Would I be right in saying that as long as both devices are the same voltage and the amperage doesn't exceed the rating of the power supply, that it's safe to do so.
If so what cables would be required, would any dc splitter (2 way) do.
Power supply 5v 3A
Device 1 5v 500 mA
Device 2 5v 130 mA

 

[rabski]

No problem technically with doing that. The only thing to watch is to ensure the polarity is correct for both devices. Any suitable splitter will be fine.

 

[Phyztech]

If those 2 devices are also connected with the cable you may create a ground loop which often deteriorates sound quality to some extent

 

[rabski]

If those 2 devices are also connected with the cable you may create a ground loop which often deteriorates sound quality to some extent

You won't create a ground loop with two low-voltage DC supplies.

 

[Paul68]

No problem technically with doing that. The only thing to watch is to ensure the polarity is correct for both devices. Any suitable splitter will be fine.

Thank you very much, all devices are centre pin positive.

 

[rabski]

To expand on the above comment. A ground loop requires a small differential voltage to be created in signal ground connections. The usual troublesome case for this is turntable to phono stage connections, where the signal level is extremely low.

Two separate low voltage DC powered items powered this way will have a common negative and positive supply, but these will be isolated from mains earth. Assuming they are not a phono stage and head amp (extremely unlikely) the negative DC supply side could potentially be common to the signal ground, but even coupling this through the power supply and then coupling the negatives also through signal cables will not introduce a differential voltage.

 

[Paul68]

To expand on the above comment. A ground loop requires a small differential voltage to be created in signal ground connections. The usual troublesome case for this is turntable to phono stage connections, where the signal level is extremely low.

Two separate low voltage DC powered items powered this way will have a common negative and positive supply, but these will be isolated from mains earth. Assuming they are not a phono stage and head amp (extremely unlikely) the negative DC supply side could potentially be common to the signal ground, but even coupling this through the power supply and then coupling the negatives also through signal cables will not introduce a differential voltage.

The devices are an ifi spdif ipurifier and a usb to spdif converter.
Thanks for explaining that it's much appreciated.

 

[rabski]

The devices are an ifi spdif ipurifier and a usb to spdif converter.
Thanks for explaining that it's much appreciated.

I have used a very, very similar digital conversion setup in the past. Both powered directly from my own built 5V supply. That will not cause any issues whatsoever. It's anyway in the digital line, not even an analogue signal path.