PS: We should keep in mind that it's very important how the gear is designed, what components are used. Some legal mains jacks don't provide grounding. https://en.wikipedia.org/wiki/File:Euro-Flachstecker_2.jpg Gear signed with this logo https://en.wikipedia.org/wiki/File:Double_insulation_symbol.svg usually is not connected to ground. Attention, _at least it's not allowed to connect ground to the case of a class II device_! Metal case, build in power supply, Europlug http://www2.yamaha.co.jp/manual/pdf/pa/english/mixers/RM602E.pdf _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user