by 51 Relic » 13 May 2011, 08:52
Hi found this on the internet may be of help
The first and most important matter is safety. Discard any cables, particularly mains cables, that have any nicks or look generally tatty - damp grass makes an excellent earth. Tighten up all the connections on plugs and distribution boards. And make sure you take (and use) a Residual Current Detector (RCD) - a little box built like a two-way mains plug adaptor. An RCD detects any current leaks to earth, and cuts off the mains supply before (hopefully) you get a nasty dose of electric shock treatment. It's not a total guarantee of safety but it is a step in the right direction. Insist on some form of staging, even if it's just some boards laid on the ground - it's amazing how much earth hum is generated by having to stand your gear on that aforementioned damp grass.
Try to find out even before you accept the gig what sort of power supply you'll have. Will the organisers be providing mains electricity, or will a generator be used? If the latter, check that it will provide enough current to meet your requirements. As a rough guideline, a 1K rig will draw something like five amps at full price. It's also worth asking if there's going to be adequate earthing - there's not much you can do if there isn't, but you may just stimulate the organiser into checking with his/her electrical bods. You'll almost certainly need a mains filter if you use any computer-based equipment on generator power.
You'll need more poke from your kit in the open than you do inside - the sound literally disappears into thin air. You may already have loads of headroom on your gear, but if you're already pushing it to the limit indoors, then you should consider begging, borrowing or even hiring a more powerful system. Even on the sunniest and driest days, damp can be a real problem in marquees