Yeah it seems to be the amp models that cause it mostly, in terms of 'noise' - but even without those, so everything is quiet, there's some digital artefact noise. It's a bit like there's a very subtle noise gate going on. Like I said though I still think it's fantastic for such a tiny and cheap unit and it's only really noticeable as I'm looking for a perfect HiFi sound, but it's frustrating there's not something better with the same portability and batt power. Hoping the B1 Four is that thing!