I (also) wonder: Are some XP's /JV's worse than others? (Different production batches maybe?) My XP-60 is not bad at all. I really have to turn up the volume of the amp to max as the sound decays to hear it at all; on normal levels I have never heard it. I would not have noticed it at all if I had not read about it and decided to listen for it. I do not have "symptoms" anywhere near those described by some other users.