[LAU] OT interference / grounding problems

Hi This isn't specifically linux related but maybe I can catch a break. Having recently upgraded some of my gear I've been trying to put the pieces together in order to do some serious audio work. In the process I've noticed some strange (to me) interference problems. As a guitar/bass player, I'm familiar with the kinds of noise you get from proximity to electronic equipment but I don't recall ever hearing snaps and pops and crackling sounds when I touch metal components (the mixer case for example) or the strings. If I put my feet on the floor, the effect is intensified too. I've also noticed that if I connect an RCA cable to my amp input but don't connect the other end, I hear a very loud buzzing sound. Louder than anything recall hearing previously. I've tried using things individually and together but I still have the problem. Does anyone know of an online resource useful for resolving this kind of problem or even some practical suggestions? At the moment the most I can think to do is to move it all to another location to potentially rule out some local weirdness with the mains electricity. (it's a fairly old house with a seemingly deranged circuit setup) It may just be that it took the introduction of better quality gear for me to hear the effects above the usual din but then these static like snapping noises are very distinct. cheers, pete.