Ahh I see. I don't think I'll be using IEM's at this stage. Would there be the same cause for concern for the DT1990's? And would you recommend doing the same for them?Make sure that the volume is not full blast when you switch from speakers to headphones . It's always good to turn the volume back down when you turn it off at night and before connecting your IEM. So far, my DX3 pro is behaving nicely but I intend to check the inside very soon for a cleanup and soldering inspection. The serial is 19025930xx