Grounding issue on outputs?

Fuse MiniFuse
#1

Although I’ve had a great run with the Minifuse 4 the last couple months, a couple weeks ago I had a weird problem where one of my speakers suddenly stopped having any output. It was just a soft fuzz sound instead. Thinking it was their time, as I’ve had them almost 10 years, I decided to at least try out different cables and plugs. I swapped the speakers and suddenly everything was fine. Weird!

Now, today, it happened again and didn’t go away. On unplugging the audio cable, a pop like a sudden grounding problem was heard and, curiously, as soon as I put my hand on the box, the problem stopped. I thought it was me touching the cable, so I swapped to an entirely new cable. Further testing, though, showed that I could “fix” it by resting my hand on the Minifuse box, although it only lasted about 5 seconds. Lifting my hand and the fuzz returned.

I should’ve realized something was up with the Minifuse itself once I swapped the L/R speakers, but didn’t try outputs 3/4 to see if it was the actual device. I had a Novation interface for 8 years without any issues at all, so it’s a little discouraging for the Minifuse to have a hardware problem after only two months.

Has anyone else encountered weird grounding or interference like this before? Did I just get a bad unit?

#2

I also filed this to Arturia support, and they said it was highly likely to be a ground loop. Actually, after going through some of the steps suggested, I also tried running it off only USB power (the one similarity to the Focusrite interface, which didn’t have ground loop problems but also didn’t have its own power supply).

This appears to have addressed the issue, which makes me happy. For others who come across this in the future, test it out first by disconnecting the power supply and running on USB power only. If it fixes it, then a clear indicator of a ground loop problem.