LINE NOISE PLAGUES ME and it's the single leading reason I have not uploaded podcasts during the past three months. I have to solve this problem and it's helpful to read Dennis Gray's suggestion. He was "recording analog audio from the laptop's soundcard headphone jack into a mixer. PCs use a derived ground, so ground loops are inevitable, and so you hear the hum and CPU noise. Plugging all the gear into one outlet point doesn't always fix the problem. The only good way I found of killing the trash in the audio was with a "Rolls Buzz-Off". I use the model HE18 stereo flavor". I'm looking for this connector, both in County Tipperary and around Dublin.
As it stands, I'm not getting any line noise from my new Sony ICD-MX20. I do get noise when recording audio via analogue line-out leads. I want to eliminate all the noise and I think I'm on the home stretch.