Hello, I need a little help diagnosing a problem with my Orange Rockerverb amp. So the problem is very specific. I have to use my Gibson Les Paul in the neck position and reverb has to be on. Every time I hit a F note there is a weird metallic noise that slowly tapers off to what sounds like someone do a slow pick slide down the E string. It's really irritating and really loud. I tried a different reverb tank, no dice. I tried seeing if a tube was loose, or any loose screws around the speakers or reverb tank and that also didn't work. I can't tell 100% where the noise is coming from, but it sounds like it's somewhere in the chassis. Any ideas as to what's causing this?