I've been having a problem with my rDAC recently which is getting progressively worse. Often, during normal listening, the sound will drop-out momentarily. When the music is stopped, the rDAC emits an intermittent clicking sound, exactly like the sound of switching input modes on the rDAC. These clicks appear very random. Sometimes they occur in isolation, othertimes they occur in rapid succession so that it sounds like a machine gun. This clicking also occurs during the sound dropouts, but can't always be heard during the brief pauses in music. The green light indicating USB input is selected stays on, i.e. it does not flicker, turn to red or move to indicate another input has been selected. As I indicated, this seems to be happening more frequently, and this behaviour is the same no matter which USB port on my Mac mini is used to connect the rDAC. The rDAC is the only USB device connected to the Mac mini. The rest of my system is composed of: Mac Mini > 0.75m Furutech Formula 2 USB > rDAC > Atlas Equator Superior interconnects > Denon AVR 3310. The rDAC was purchased new around 6 months ago and did not exhibit this behaviour until about a month ago. By-passing the DAC and outputting the audio via hdmi to the amp works without any issues. Has anyone else experienced such an issue, or heard of anything similar? I think I will take it back to my dealer at the weekend and see what they think.