FWIW, I'm running digi-in and this is definitely different than the noise encountered running analog-in to the JB3. As for age of the unit, this was the inaugural run for the JB3 in question - bought it a while (a year?) ago as a backup, but broke it out to run two simultaneous sets of gear this past weekend. And yeah, it's possible I jostled the gear in the timeframe during which the noise occurs. My immediate reaction was "someone's cell phone" or RF interference, but that wouldn't explain the pattern of the noise nor only occuring in a single channel on a single deck. I don't think we're going to resolve this one anytime soon, so I'll just have to monitor my gear performance closely for a while to see if I can nail anything down. All - thanks for the discussion and input, I'll drop a line if I encounter the problem again.