I've had a DAC1 USB for about two years and have it well integrated into a Win7 system, using JRiver Mediacenter as the database/player combination.

I was recently given a set of Bose QC3 noise-cancelling headphones that I would hope would work well with the phone jack on the DAC.  Unfortunately, I get a series of unpleasant tones (even without music playing) when I jack in.  It is not digital noise, much more analog.  Probably in the 100-200Hz zone.  I've used other non-powered earbuds, and in-ear phones without difficulty.

Has anybody else had this issue, or have insights into its cause?  Perhaps the noise cancelling? 

Thanks in advance.