Hi Everyone! I recently bought an Tascam Midistudio 644 and i love it. But an random pop noise is coming from no where? I can’t figure out what to do about it. I have tried in different electrical outlets but it still appears. I have tried using group out 1-2 as a monitor but the sound comes there too even though it is shown on group out 3-4? I also thought it was channel 7-8, but when I "disconnect them" from the groups, it is still heard. I recorded the problem with my phone camera so you can hear it in action. any help or suggestions is much welcome!