i've an epiphone les paul 100 and i use it with my spider 4 15w amp.Now i dont know about grounding and stuff but my amp has a 3 pin plug but the switches in my house use 2 pins so i use an adaptor to convert it into 2 pins.I've been plugging my amp in this way for many months now but recently i started hearing some hiss kind of sound not to much but it is there.I checked my gear with the same cables at my friend's house he also has 2 pin switches and the hiss was gone so i think theres nothing wrong with my guitar and amp so it must be the switches i use in my house but one thing i don't understand is why i'm getting this hiss even though i used to plug in the same switch and didn't get any hiss before?

heres a demo:http://www.youtube.com/watch?v=znfcfJ085hY&feature=player_embedded
it could be ground loop hum
My Guitar Rig:
Peavey 6505+ Head
Peavey 6505 slant cab
MXR Smart Gate
MXR Noise Clamp
Ibanez ts-9 tubescreamer
Ibanez RGA72tqm with EMG 81/85

Other Guitar Gear:
Fender Vibro Champ
TTM Guitars Devastator
LTD EC-200
Quote by 14xjake
it could be ground loop hum

how can it be a ground loop i'm not using any pedals just plugging in my guitar to the amp and how can i remove it?