Am i right in thinking that unplugging a guitar whilst the amp is on is bad for it? is it bad for the guitar or the amp or both, and how? and why? also if my amp is off and my preamp is on standby (its not true bypass) can i unplug my guitar? also, does anyone know why amps sometimes make an odd popping noise when yu switch off? it happens at my guitar teachers house, and it did so on my jcm 800 t'other day.