Hi, can anyone suggest what may be the cause or can suggest what I need to look at first. I'm running a Yamaha AW16G through a Samson amp and into monitor speakers. I'm getting a crackling noise from both speakers which can go away for maybe 20 - 30 seconds then returns for 10 seconds or so.This happens regardless of what I'm doing. Sliders don't seem to cause it or knob turning either. It still crackles when I'm doing nothing although the master fader has to be up for anything to come through the speaker. This has just started out of the blue after having worked perfectly for several years. Any help or ideas gratefully received. Thank you.