thanks for the quick reply Nick.
Point taken-but- if a factory supply @ approx 1amp rating drops from 15V to 9V under load, then a 3rd party device rated @500ma will most likely easily drop from 12V to 9V under load.
I'm only pursuing this like everyone else to find a more compact – and safer solution for my new pedal board.
Having 240AC floating around with AC plugs, sockets etc doesn't seem to me to be as optimal as an integrated, sealed tank for the time that guy drops the glass of beer on my board.
Yeah I know- I need to play in more classy venues!!!