While sitting here board with IEMs in my head (in ear monitors), and plugged into my tube amp, I accidentally dropped a pen onto one of the tubes. In my right IEM, I could hear a glassy clank. I was like "wtf". So I tapped the right vacuum with the back of my fingernail, and I could hear it in the right
earphone. Tap the left tube, and hear it on the left earphone. This only ...