[sdiy] MIDI phantom power...over 5 pin MIDI connector ?

[Roman Sowa]

There is no ground loop in MIDI-line-powered device! There's only one 
input and one output. No 3rd lead that will cause ground loop. It's just 
like the cable - there's shield on pin 2 going from one end of the cable 
to the other. Both sides of transmission don't care if there is a cable 
in between DIN plugs, or a black box. There's no current path anywhere 
outside one end of the cable or the other.
So using one IN/OUT MIDI-powered black box is exactly like using a 
cable. No need for optocouplers or any other isolation methods in the 
black box.

Roman

W dniu 2015-09-11 o 21:55, rsdio at audiobanshee.com pisze:
> By the way, the second caveat of this approach is that you will have
> a ground loop between input and output, making your MIDI device fail
> the usual MIDI guarantee that there won't be any ground loops.
>
> You can solve this by filtering your pin 2 output so that it's
> connected to ground through a high impedance, but that means you
> cannot chain more than one MIDI phantom-powered device.
>
> Brian
>