I just recently moved Kunming and brought a bunch of DJ equipment with me. I also brought a voltage stabilizer and converter. For some reason I'm still getting a buzzing/electrical current type of feeling from my laptop, which it did last time I was here with no stabilizer or converter. Since my mixer explicitly says it must be grounded or earthed I'm scared to plug it in.
Anyone here, musicians, djs that have dealt with this issue? There has to be a solution., there are plenty of mixers set up in bars and clubs. Thanks for the help!
I'm just a computer nerd but I can tell you a lot of the earth points are not connected. The first and most frequent culprit is any extension cord (power board) that you have plugged in. Often they give you an earth plug socket (ie. 3 pins) but don't plug earth in to the wall (ie. 2 pins to the wall only)! This would be illegal in the west but is super common in Asia. Failing that, it's quite likely that some wall sockets are similarly not properly wired for earth. The way to check is to try many different sockets and see if some eliminate the humming. If so, you have found your problem and can probably investigate connecting to your local wall socket via an earthing plug (which must exist on Taobao) to manually ground the system through something else ... an outside metal drainpipe or similar. Good luck. Worst case, you can probably run an audio filter... even my video editing package, lightworks, incorporates an audio filter aimed at mains hum suppression so the means to filter digitally must be pretty widespread. This will place no load on your CPU as the DSP (digital signal processor) in your sound card can achieve this 'for free'. If that fails, the interference is analog against your speaker cable between your system and your ears - try to buy headphones or speakers with a stronger shielding on the cable, or run your cables along a different route.
Not sure your laptop is the best measure to go by. It probably doesn't need the converter and laptops all deteriorate somewhat overtime so it might be the hum from the cheap china made power brick or the bearings and oil drying out from your internal fan. Get a multimeter and if the voltage both before and after the converter seem stable that's the best you can hope for. If you need extension cords pay more for the Philips ones from C4 or Walmart, not just from neighborhood hardware shop.
Walter is right, ground wires are often not properly connected or not connected at all. As an electrical engineer I would recommend using a isolating transformer to cut of any connection to the ground. This way you create an isolated electrical circuit. However, for your own protection you have to use a residual current circuit breaker (RCCB)or ground fault circuit interrupter (GFCI) on the secondary side of your transformer. Use one with a low release current e.g. 5mA and a quick release time. Having said this, I am not too sure if that was available in Kunming.
indosailor good advice. I lived in a newer apartment 2013-2014, in the bathroom there was an outlet with a reset button. I took this to possibly be a ground fault device but I wouldn't bet my life on it. The danger is always improper installation and screwed up wiring. You might be able to find it but the rest of us don't have a clue.