Intermittent Guitar Hum

Question

I've been dealing with an issue for weeks now and have yet to fix it, so I'm hoping someone has an idea.

This problem is happening with both single-coils (tele, strat), humbuckers (les paul), and also a tele with noiseless PUs. It's less extreme on the HBs, but still very noticeable.

The problem is that every few minutes I'm getting a loud buzzing sound for about 15 seconds. This isn't normal 60-cycle hum, it's like a weird interference. I'm using Logic to record, and this happens even when logic isn't running - I can hear it when direct monitoring my interface. It does go away if the volume on the guitar is turned all the way down. Here's what I've tried so far:

1) Different computer (macbook pro vs. mac mini) 2) Different audio interface (apogee duet vs. apollo twin) 3) Unplugged everything in the room except the computer/monitor/interface 4) New cables, new power supply (pedal power 2 vs. MXR Iso Brick) 5) Plugged everything into a Furman power conditioner rack 6) Turned off all lights/fans in my house 7) Turned off any type of cell/bluetooth device 8) Watched activity monitor on the Mac to see if there were any processes running intermittently that might be doing something funky.

This isn't improved by moving the guitars around in the room, or by touching the strings (aka a grounding issue).

It seems pretty obvious to me that it's some sort of electrical issue, I just can't figure out what it could be given everything I've tried so far.

Any help is greatly appreciated!

Answer 1

Have you tried playing the guitar through a different amp in a different location? This would help distinguish between a guitar problem and a system (amp, computer, etc) problem. The idea is to isolate the parts to see where the problem is.

It could be a grounding issue, but that 15 second pulse makes me wonder if there is some radio-frequency interference from something powerful outside your space.

Answer 2

insufficient points to comment but two causes of noise interference are: 1) bad power: until you get into the models with SMP for Furman it really doesn't "condition" the power. M 2) guitar electronics. Try grounding on the volume / tone pickup selector.

Are you sending out from a DI on the amp or recording with a Mic? Or are you even going DI straight from the pedals!