Can someone tell me if they are experiencing the same problem? I use an SD Card in my M20d for recording however, I find that I have fluctuations in levels during playback occasionally. I thought it might be attributed to voltage so I bought a voltage regulator (600watt) and put the mixer to feed off it, but the problem continued.
Then I discovered it was my iPad. I use the iPad to mix my levels during performances of the Band. I would walk around the room and mix (very nice! No snake) however, when I turn off the iPad when not in use, that's when the playback level fluctuates. VERY STRANGE!! But I love my M20d.