I haven't seen this on my N3 with my box. But, a lot of times, random USB disconnects isn't caused by cables or connectors - it's the port isn't capable of sustaining the current required by the device. There's quite a few motherboards with "weak" USB ports, weak power supplies, or poor design that has caused this, not just with DACs, but other devices such as external hard disks or USB wireless dongles.
On my box, the on-board USBs are only used for lower powered devices, such as my keyboard, Wacom tablet, card readers, scanner, and label printer. All of my high power devices are connected to an add-on NEC chipset card that has it's own internal Molex for additional power to prevent dropouts. Before I added the cards, I would get an occasional dropout when I had 4 or more bus-powered USB external disks attached to the onboard ports.