I'm playing a G&L ASAT Special, with the jumbo MFD pickups. I do much(*) of my playing in my office. Recently I've become increasingly annoyed with single coil hum. Before I go getting a noise gate or some kind of active device, I was wondering if there's any chance I'll be able to track down the actual cause? Some observations: I recently used copper tape to completely line the back of the pickguard, pickup and control cavities. I verified continuity of all the tape to ground, I'm confident it's reasonably well shielded now. I have another identical ASAT Special that is NOT shielded, but there doesn't appear to be any difference in this particular hum between the two guitars. It's virtually non-existent with a clean amp, at least at the bedroom volumes I'm using. The hum is slightly worse, but still bearable, with my overdrive pedal (Boss OD-3). It's unbearable with my Rat. As long as the pedal volume stays below roughly 11:00, it's not too bad... But (outside the hum), the pedal sounds better with the volume up a bit! There's no hum with humbucker pickups (or with my ASAT on the middle position, i.e. both pickups (presumably in series, like a humbucker)). The hum doesn't change if I touch the strings or any metal part of the guitar. The hum does go down as I roll the guitar volume down (and no sound at all with the volume control all the way down). If I spin my body around, it does get a little better at a couple positions. But it's a very narrow band where the hum is minimized. I also tried holding the guitar parallel to the floor (perpendicular to my body), both with the pickups pointing up, and also pointing down, and spinning around 360 degrees. With the guitar like this, I could not find any position where the hum went away. I tried shutting off everything in my office - PC, monitor, stereo amp, printer, etc. Basically anything I could turn off (except for the amp), I did turn off. No change. My understanding is that AC wiring is typically the most common cause of this kind of hum. But in theory, all my in-wall AC wiring should be shielded with steel conduit. My house is only a few years old, and code in my area requires AC lines to be run in steel conduit. The outlets in my office are all on a dedicated circuit (i.e. don't share a circuit with anything like a refrigerator or furnace motor). So I guess the easiest solution is to just turn down the Rat pedal volume, but I'd be really interested to track down exactly what's causing the hum. Something must be causing some kind of EM field, but I can't figure out what that would be. I suppose I could methodically start killing breakers in the house until the hum goes away. That might annoy my family though, anyone have any ideas for a less invasive way to track this down? Thanks! (*) With the social distancing, I'm now doing all my playing in my office. Band is on hiatus for the time being.