Fixing Hum - Adding a ground to the UM2 Mic Preamp

Описание: The UM2 is an inexpensive USB interface for microphone and other line level devices (guitars, keyboards, etc), but for the ipad to use it, it needs to go through a USB powered hub, where it picks up a bit of hum due to the leaky power supply - here I add a ground to the signal sleeve directly to the third pin of the AC wiring to help dissipate this noise