Wow, I can't believe Valve Art has such a high failure rate on their 2A3 tubes. I'd consider this noise to be a failure mode. I suppose it might be related to method of use, operating point or circuit configuration, but both you and I are getting the same symptoms.What amp(s) and circuit configuration(s) are you running them in? I've got 'em in stock Paramours, and the symptom follows the tube. What I mean is that I can swap the tubes between amps and the symptom follows the tube, not the amp.