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Intermitten Hum

Technotitclan

Lurking TB from work
Mar 1, 2012
1,028
204
Rochester, NY
Hey all, I tried searching for this one but can't find an answer.

I'm getting this odd hum in one of my three basses (the only one I've modded) and I'm not going to avoid blame on this but I feel my wiring is decent. The situation is that while i do have a tiny tiny amount of 60 cycle hum that is completely gone when touching the strings (only audible when volume is jacked up) I am getting what sounds like very loud 60 cycle hum that lasts for about 15-20 seconds then goes away for about 2 minutes then will return.

I've re wired a couple times and it is all much better now but the sounds stills occurs, just not as loud anymore and is mostly inaudible if I'm playing and I'm sure in a mix will be non existent but I would still like to get rid of it as I can still hear it when practicing alone.

Thoughts?
 
Some sort of electrical motor or generator nearby is cycling on and off every 2 minutes. A refrigerator, or air conditioner.

Hmmmmmm.....

Sounds like fridge for sure but it is clear on the other side of the house. Is this something that could emanate through the ground connection through the whole house? My house has pretty bad electrical so this doesn't shock me.
 
Yeah, it sure can. I just moved out of an apartment that had this problem. The wiring was so old there were no ground pins on any of the electrical sockets. 3-prong cords had to use an adapter, but there was nothing for the ground pin to connect to, unless I wanted to wire all ground pins myself to the plumbing or something. Even the neighbors' appliances could be heard cycling on and off through my bass.

The new place is not an apartment but a standalone residence. 3-prong outlets. No appliance noise.

But even with good electrical grounding, a single-coil pickup can still receive electromagnetic energy from motors and generators and other devices. Humbuckers, of course, are wired so that external signals cancel out.

You might want to try an EHX Hum Debugger pedal. For me, it works very well to silence single-coil hum. You must plug it into a wall socket, however, ideally on the same circuit as your amp. It doesn't work with a 9V battery.