I am having issues both with an analog and microprocessor based circuit where power line noise causes a microprocessor to reset. The same noise causes popping in my tube amp speakers.
The popping comes from the switching of large inductive loads (motors, fluorescent light ballasts, arcing, etc) that kick noise back into the line. The switching regulator (off of a transformer secondary) for the processor does not stop the noise nor does the pi filter in my tube amp work. I have tried inductor/capacitor combinations, metal oxide varistors, and even a voltage suppressor diode in an attempt to filter the noise. None seems to help. The noise when displayed on my scope is arbitrary in amplitude, frequency, and duration. Any ideas on how to stop this? I am not experienced in designing filters to combat such problems.