I think it is the noise from the MDAC as it switches in/out resistors. I know the Rowland Synergy also had this effect. I had the 380 and have the 32 and using balanced connections, can barely hear it when I put my ear right up to the ribbon tweeters in my Piegas. But it's so quiet that it took quite a few turns up and down to ascertain its existence. Do you have the same noise from both RCA and XLR outputs and it out loud?
