Humming buzz

[bigbassman75]

Greeting Gentlemen.

Since the world has shut down around us, I've been playing a lot more bass. What I have noticed is that my Jazz Bass is constantly buzzing a 120hz buzz. I've tried all the usual techniques, changing the batteries, spraying compressed air into the tone knobs from the back, changing cords. It is constantly there in active or passive mode. My pbass does the same but the buzz stops as soon as you touch the strings or knobs or amp which leads me to believe that is a grounding issue but the Jazz bass keeps on buzzing.
I spoke to the guys at the music store but they were not letting anyone in before they closed up shop and he said it could be dirty power I have running in the house. In that case I would need a ground loop oscillator. It could be the pre amp in the Bass. It could be wiring issues inside both basses. They are not accepting repairs for minimum 2 weeks until this virus blows over so I've come here to ask the experts. Any ideas on what it could be and how to fix it?

 

[Warpeg]

This is a long-known characteristic of single coil instruments. It is specifically what humbucking pickups were designed to mitigate. Having both pickups turned on should lessen the hum. If not, look into humbucking Jazz Bass pickups and some shielding.

 

[BasEd]

Greeting Gentlemen.

Since the world has shut down around us, I've been playing a lot more bass. What I have noticed is that my Jazz Bass is constantly buzzing a 120hz buzz. I've tried all the usual techniques, changing the batteries, spraying compressed air into the tone knobs from the back, changing cords. It is constantly there in active or passive mode. My pbass does the same but the buzz stops as soon as you touch the strings or knobs or amp which leads me to believe that is a grounding issue but the Jazz bass keeps on buzzing.
I spoke to the guys at the music store but they were not letting anyone in before they closed up shop and he said it could be dirty power I have running in the house. In that case I would need a ground loop oscillator. It could be the pre amp in the Bass. It could be wiring issues inside both basses. They are not accepting repairs for minimum 2 weeks until this virus blows over so I've come here to ask the experts. Any ideas on what it could be and how to fix it?

If the buzz stops when you touch the stings it's a shielding issue. If it gets louder it's an earthing issue.

Electro magnetic interface comes from various sources including dimmer switches on house lights. Passive pickups and electrics (volume and tone controls) are particularly susceptible to it. Shielding creates a faraday cage. You need to shield the pickup and control cavities with copper foil. Sticky back foil is cheap and conducts on both sides. After shielding, attach a wire to all cavities using the sticky foil and attach these, along with the bridge ground wire, to the earth pole on the output jack. Make sure the body of all the pots is connected to earth as well.

I've done this to a few basses. Did it tonight (Coronavirus indoor activity!) to a Lakland with two single coil pickups which buzzed whenever the landing light was on (dimmer switches) and the buzz has completely gone. Before doing this I had to touch the strings to stop the buzzing.