I've had the 901 for a couple of weeks now and was concerned with the left channel cutting out when I slowly rotated the volume wheel. I arranged to have mine sent in to Hifiman for them to look at. Then I noticed some posts earlier in this thread that said that this was normal because the volume control is a step attenuator - this symptom will occur between the discrete steps? After reading this I'm thinking that there's no need to send the 901 in. Just looking for some confirmation. Thanks!