Jp1208 may have a point; however, polarity of A/C line and the configurations inside a particular electronic device may be very confusing too. Xindak's design is not really wrong. I already checked with Xindak US distributor (www.LotusAudioImport.com). They pointed out a very informative page for everyone's reference:
http://www.gcaudio.com/resources/howtos/acpolarity.html
I believe that should help.
http://www.gcaudio.com/resources/howtos/acpolarity.html
I believe that should help.