Korg Poly800/EX800 Users

> Interesting but potentially dangerous if somebody else grabs that
> midi feed not knowing there's power on it.  You could also provide it
> from the audio cable on TRS I suppose, since you may not always need
> a MIDI cable plugged in, but you will always need the audio out
> cable...

    There are two pins which are not used in the MIDI specification. You can 
feed 9VDC there and supply the Poly.