I just rewired and shielded my SX jazz, and I'm still getting some hum. The pickups and pots work fine though. I'd like to use a multimeter to check the solder joints and makes sure everything is grounded properly, but I'm not sure what reading I should be looking for. Can anyone help me out?
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Multimeter and Shielding
- Thread starter mremic01
- Start date
Don't think that you can accurately measure these minor variances in resistance with a multimeter unless the solder joints are very bad.
Would also take horrible solder joints to induce hum IME, IMO.
Would also take horrible solder joints to induce hum IME, IMO.
the reading you should get is 0Ω, but in reality your meter will show .1 or .2 Ω. you cant really measure a bad solder joint with a multimeter unless it is really really bad. the easiest way to make sure the joint is good is to melt the solder and add just a small amount of new solder to the joint.
Shielding does not work miracles...
If you have shielded the bass properly, that's about as much as it's going to do for your hum problems.
What I like to do is get a multimeter with a continuity buzzer.
Whenever the leads make contact with each other, the meter makes a buzzing sound.
Place one lead to a piece of shielding, then go through and touch the other lead to each other piece and make sure you hear the buzz for every grounded point.
When you use an ohm meter, check the resistance at various points and make sure that it is low.
Ideally, you want 0 ohms, but it may be higher.
The most resistance you should have would be maybe 2 or 3 ohms from neck pickup cavity through to bridge pickup cavity.
If you have shielded the bass properly, that's about as much as it's going to do for your hum problems.
What I like to do is get a multimeter with a continuity buzzer.
Whenever the leads make contact with each other, the meter makes a buzzing sound.
Place one lead to a piece of shielding, then go through and touch the other lead to each other piece and make sure you hear the buzz for every grounded point.
When you use an ohm meter, check the resistance at various points and make sure that it is low.
Ideally, you want 0 ohms, but it may be higher.
The most resistance you should have would be maybe 2 or 3 ohms from neck pickup cavity through to bridge pickup cavity.
Rick Auricchio
Registered Bass Offender
If the bass has single-coil pups, remember that you will still get some hum directly through the tops of the pups. You can mount them in a solid metal guitar body, but you can't shield the tops of the pups!
Thanks guys. It looks like it's all grounded right then. It turns out I've got a continuity buzzer, it was just labeled with a buzzer symbol so I didn't know what it was for.
This might be obvious but be sure to test all the shielding back to the ground side of the output jack. It should be close to 0 ohms to there as well. I am amazed at how many times people have done the shielding and then don't realize they need to connect it to the instrument ground!!
