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Geddy Lee Jazz makes a hum even though pickups are both on.

MovingPitchers

MovingPitchers

Jun 9, 2013
8,504
12,013
Canada
#1
I see why thought. Neither the pickup cavities and the control cavities are shielded. I recall Geddy Lee signatures being shielded there but apparently this one isn't.

Is it better to grab some shielding paper like copper paper and add it on myself or take it to someone to apply shielding paint inside the cavities?
 
#2
MovingPitchers said:
Is it better to grab some shielding paper like copper paper and add it on myself or take it to someone to apply shielding paint inside the cavities?
Click to expand...

It does sound like it needs shielding added, but I think you'll have to answer that for yourself. Shielding is not difficult, but it does require some level of disassembly to do correctly, and careful attention to detail. In the grand scheme of things, if a difficulty rating of 1 was changing strings, and 10 was building your own bass completely from scratch, I'd put shielding at maybe a 3 or 4. Maybe watch some youtube videos and decide if you want to tackle it yourself?
 
#3
dwizum said:
It does sound like it needs shielding added, but I think you'll have to answer that for yourself. Shielding is not difficult, but it does require some level of disassembly to do correctly, and careful attention to detail. In the grand scheme of things, if a difficulty rating of 1 was changing strings, and 10 was building your own bass completely from scratch, I'd put shielding at maybe a 3 or 4. Maybe watch some youtube videos and decide if you want to tackle it yourself?
Click to expand...

Regarding shielding, I'm gonna use some copper foil. Do I need to just shield the cavities or connect them together somehow? I saw a shielding job done by Dave on Youtube and he had copper foil connect all the cavities on a Jaguar on top of the pickguard.

Also I assume I need to shield the back of the PG, right?
 
#4
Yes, ideally you'd shield the control cavity and the pickup cavities, and any channels that wiring runs through. Shielding the back of the pickguard is basically just shielding the "top" of the cavities. Any shielding needs to be connected to ground - you can embed a screw in the tape and/or solder a stripped wire to the copper. The pickguard shielding can be grounded by contact under one of the mounting screws.

When you're installing the tape, make sure it has good overlap and press it down thoroughly so it doesn't peel back up. If you have a multimeter, you can use it to test the shielding once you're done. Put it on continuity (or resistance) mode, and clamp one probe to the ground lug at the jack. Then touch the other probe to different points across your shielding. You should see a very low resistance reading. If you get anything above a few dozen ohms, check for issues.
 
#5
dwizum said:
Yes, ideally you'd shield the control cavity and the pickup cavities, and any channels that wiring runs through. Shielding the back of the pickguard is basically just shielding the "top" of the cavities. Any shielding needs to be connected to ground - you can embed a screw in the tape and/or solder a stripped wire to the copper. The pickguard shielding can be grounded by contact under one of the mounting screws.

When you're installing the tape, make sure it has good overlap and press it down thoroughly so it doesn't peel back up. If you have a multimeter, you can use it to test the shielding once you're done. Put it on continuity (or resistance) mode, and clamp one probe to the ground lug at the jack. Then touch the other probe to different points across your shielding. You should see a very low resistance reading. If you get anything above a few dozen ohms, check for issues.
Click to expand...

The Geddy Lee body doesn't have an open cavity that connects the neck cavity to the control cavity. The thought of having to solder again is such a stressful time...
 
#6
Skip the soldering then - drive a small screw partway into the bass, right through the copper tape. Then wrap a stripped wire around the screw right under the head, then tighten the screw down. It'll clamp the wire against the foil.

If the wires are passing through a narrow channel from the pickups to the control cavity, you can just skip shielding that channel. Just focus on shielding the control cavity, the pickguard, and the pickup cavities.
 

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