. I cannot stress more firmly than this. I'm sorry for this my next response! Please do not use these external power supplies. If you do you maybe risking seriously damaging your Chord units and it will be on our shoulders to repair the mess they've caused. Companies that make these products are often not capable of analysing what they trying to achieve. Also the Companies producing these units will often propose that their power supplies can improve the performance of chords designs which is total nonsense. Therefore we strongly recomend you save your money and disregard the complete twaddle put about by these companies. After all had their engineering capabilities been good enough they would be producing complete products rather than just parisitising ours. I'm sorry if it sounds like I'm annoyed it's because I am!