You know how in Sesame Street Big Bird has a friend called the Snuffleupagus that only he ever sees? Well, I've got a problem that's rather similar. My bass developed an electrical crackling noise, slightly similar to the sound you get when turning a dirty volume control, when I played certain notes. So I took it to a luthier and he replaced the electronics, but a while later I noticed I was again getting the crackling noise, but now on different notes, namely the open G string and, to a lesser extent, the open D string. I took it back and the luthier said that the problem was fret buzz and that was to be expected from an inexpensive bass. But the problem is definitely not fret buzz. The sound is the kind of sound you get with poor electrical contacts, as if the G of the open G string makes some electronic components vibrate. Eventually I gave up and decided to cut my losses and go to another shop where I wouldn't be talked down to like I was an idiot. But, while I was treated like an adult, the person I spoke at the second shop couldn't reproduce the sound, even though he plugged the bass into an amp and tried it out in front of me, so I could see he was doing what ought to have caused the sound. So I took the bass home, and the same crackling sound came back. I swapped every other possible source of the noise — cable, audio interface, computer, amp, headphones — but I still was getting the noise. Today I took the bass back to the same shop and spoke to someone else, but he couldn't reproduce the crackling either. So I went home again, plugged in the bass, and found that there was no crackling … at least for a while. After playing for some time, the crackling came back. Does anyone have an idea what is going on? Why might this crackling only happen sometimes, but not at other times? Is there a way I can either get rid of the crackling myself, or find out how to be sure to be able to trigger it so that I can make sure that the luthier actually sees the problem?