"Ground Loop Isolator". Sounds scary and technical, doesn't it? But don't worry, it's not the crucial component Scottie needs to repair the warp drive in this weeks episode. So what, then, is it?
First of all, I'm going to explain why you need one.
This is a standard UK plug. Your plug may vary, but I'm going to keep this UK-specific.
Each plug has three wires - one for each prong. The live wire - which carries the electricity for your appliance, the neutral terminal, which isn't actually used, and the earth (or ground). You can see the terminals on the diagram.
Now if you look at your laptop power supply, where the laptop plugs into the power supply, you'll notice that it seems that only one wire fits into your laptop. This wire is actually split into two terminals - live and neutral.But there is no ground terminal or wire. So your laptop is not properly grounded.
Yes Dave, you're saying, but so what? What does all this mean for my DJing setup? Well, it means that the little amount of excess electricity on your laptop has only one place to go, through the lead to your soundcard into the club mixer or PA that you plug it into!
This manifests itself as the light hissing and screeching when you plug in your ungrounded laptop into your amplifer/PA/mixer. So that's why you need a ground loop isolator. It stop this excess electricity leaking into your audio channel, by making sure your laptop doesn't ground itself on your playout system.
You can pick up a basic GLI from Maplin.co.uk for about £10. This is what I use, and really I have had no problems with it at all. You can get better quality GLI by searching around but to be honest, I'm not sure whether you need to pay extra as it seems to do exactly the same thing.
So if you're experiencing hissing and screetching on your club playout system, get a ground loop isolator first, and see if it fixes it.
Scottie would be proud.
