Hello,\nI have a 1Mii bluetooth receiver and a WiiM Mini wifi streamer connected to the same HTD audio system, located in my basement. When I connect both devices directly to the HTD controller, all is well. However, when I put the 1Mii bluetooth receiver upstairs, powered by a wall outlet, and connected to the HTD controller through CAT6 ethernet with a pair of audio baluns, there's a noticeable buzz through the speakers from the moment I turn on the amplifier until I start playing music, at which point the buzz disappears completely. Suspecting I'd created a ground loop by connecting the 1Mii bluetooth device to an outlet different from the one the HTD controller is connected to, I purchased the BESIGN ground loop isolator from Amazon, but it seemed to have no effect, leading me to wonder whether the issue could be something other than a ground loop. Note that the buzzing stops immediately when I begin playing music and returns a few seconds after the music stops, as though the DAC in the 1Mii device disables its outputs when not in use, allowing something else to drive that buzzing frequency. But what is the source of the buzzing? If it's A\/C currents from the power supply induced in the ground loop why do they not persist when the DAC is active?\n\nI'm assuming the BESIGN ground loop isolator uses some sort of transformer to perform the isolation, but if the induced currents are A\/C, how does this work exactly? Wouldn't the transformer pass the A\/C ground loop currents? Is there an easy way to try disconnecting the shield in one of the cables from the 1Mii bluetooth device? (I'm assuming the RCA cables are make-before-break, preventing me from simply plugging in part way...)\n\nThanks in advance,\nBrett S.