Two observations:
1) I would like to hear from someone that they disconnected the battery and the Mojo runs without coil whine without further, complex interventions, additions, modifications. Otherwise why is this thing recommended as a solution for running it as a desktop unit?
2) My battery is back in and I am running the Mojo continously charged. No problem. I will say that the build quality is amazing and opening it, then closing it was a pleasure. Now, according to Rob Watts, once the battery is full, it should not continue to charge when running the unit as a desktop amp. The power coming from the USB cable should power the current use and the battery charge should stop. This is not what I am getting. I fully, fully charged the battery with the unit off. I then started running it as a desktop amp with power from my USB port (good cable, good USB port, etc.). And the charging light? Off for 15 minutes, then back on. And the unit is hot, suggesting the battery is now being charged as the unit runs, despite it being connected to the USB power. As I am writing this, the nearly fully charged buzzing has started. Therefore I am delaying my posting. ... And here I am, 45 min later and the buzzing is still there. When the unit is off and charging, this final charge buzzing goes on for max 10 minutes and I understand it. The fact that now it has been going on for 45 min suggests to me that the unit is drawing some battery power despite being connected to the perfectly working USB charge port.
My current conclusion: the Mojo does not work as a desktop unit. It appears to have been designed to run as a battery powered unit and that is it.
I do like the Mojo. But I can only laugh thinking that somewhere in this thread it was stated that there is no need for a Mojo 2, that Rob Watts said the Mojo is perfect as it is.