Buzz persists after thorough shielding

Ah, so Wet Wet Wet would love that:

 

Just start over and do it right . You can’t may chicken salad with chicken poop.

 

I was also going to mention checking the bridge grounding. In a lot of cases the ground wire from the controls, etc., comes up through the body, some insulation is stripped, and the wire is “sandwiched “ between the bridge and body when it is assembled. Might not hurt to check and make sure this is correct. Just an idea.

 

no, No, NO!
the bridge is already grounded or the noise wouldn't reduce when touching strings

 

Buzz persists after thorough shielding

you know … I would just remove the pots, the jack and all of the wires and start from scratch … 2 pots, a jack and a capacitor, and some wires … not much of an investment … keep the pickup and the pickup wires.

 

Aluminum tape has issues. Yes, you may rub the overlap with marker or something and get it to show continuity with your meter - but it won't stay that way over time. It will lose conductivity as the surfaces oxidize. Besides ... if you use Aluminum tape in the pickup cavity, the only way to connect that to ground is with a mechanical connection (a screw pressing the ground wire tight against the foil) because you can't solder it. And besides, the surface of the aluminum is oxidizing over time so that mechanical connection won't last. Copper works much better and easier and isn't expensive if you buy it somewhere besides StewMac.

 

Bridge isn't grounded... so Strings are not grounded when you touch the strings on a ungrounded bridge you Become the ground soaking up any RF . Strings being so close to the pickup need to be grounded.
the coil in a pickup naturally wants to receive signal ...
ungrounded strings with a close proximity to a pickup, the strings act as antenna the space between is a capacitance, the coil is the receiver .

Might try to turn off all lights and appliances in the house

 

2 questions. Did you buy copper tape with conductive adhesive? Also, wouldn't it be easier for the pots to be touching the copper tape instead of relying on a jumper wire from the pickguard to the pot?

Edit: It seems my questions have been answered by actually reading the thread lol!

 

I went crazy trying to solve a hum in a passive P bass. (As stated above, its not shielding which prevents induced noise from nearby electrical interference, lights.). It turned out to be a ground loop somewhere in my home wiring that this bass was susceptible to. Touching it stopped the bass hum. The key insight was taking the bass to other locations and it sounded fine. In my house, it hums up like crazy. I had a Lakland Glaub and Fender P that did this, only when plugged into gear plugged into my home AC power. I have another Fender P and J that work just fine. My active basses behave, as well. My homes previous owner had a garage stall converted to a den, which is now my bass space. I suspect the electricians adding the new circuits to the house did something wrong, creating a ground loop. So, if you have not done so, try your bass at someone else's house or venue.

 

I’ve got dimmers that cause huge problems. Check your dimmers and check your LED lights. Try playing with all the lights off and see if it’s better. If so it may be that you need an AC filter, or better dimmers. Or glow-in-the-dark fretmarkers.

 

This is entirely wrong. You are the source of the noise. If the bridge is grounded your noise gets drained to ground when you touch the strings or any other part of the bass that is grounded. If you read the post above you will see that the noise increased when he put his hand over the pickup. The noise from his body was being picked up by the bass.

 

This thread has been bombed with people weighing in with incorrect information, so I can see how you'd be confused.
If you won't trust me, at least trust Turnaround, he does this for a living.

 

Quote from OPs original post
"I had buzz that went away when I placed my hands on the strings. "


Capacitance happining between string and coil , hence noise , RF has no path to ground , persons nor amp ...

 

If the noise decreases when touching the strings, the bridge is connected to chassis-ground.
This is a fact & not even debatable.

It's not just radio-frequency:

(Radio-Frequency Interference) RFI vs. EMI (ElectroMagnetic Interference)

 

Exactly! When the strings are touched the person is grounded and that drains the noise from the person's body to ground. No more noise.

 

You can solder to aluminum tape, it is just a lot more difficult. While it may degrade over time, I have used aluminum tape for years without any issue. That being said, the reason I moved away from tape in general is because the adhesive can lose grip over time. Although I have never seen that occur either, I didn't want to worry about it. I do all my job with conductive paint now. It is much easier to work with as well.

 

These threads would be hilarious if it weren't so SAD how they boggle the mind of the person seeking help.
I'm not going to count how many times "bridge ground" has incorrectly been brought up, or false statements about shielding tape. Get the REAL thing, don't be too cheap to do it correctly! (it's not expensive, except from Stew-Mac).

What boggles my mind is how the ill-informed want to spread this "information" they have, and even when it's explained to them (in detail) that it's incorrect they go on to argue how it is as they say, LMAO!

 

You asked a few questions:

It could have been an issue in the electrical supply to the outlet in that room, or an issue with other equipment in/near that room (LED lights, dimmers, the furnace in the room next door, the pump on the fish tank in the other end of the room, etc.). It's hard to say without trying process of elimination, but the lesson is, lots of things can produce "noise" that a magnetic pickup will respond to.

Typically (I'm sure someone will come along shortly and try to skewer me for suggesting "typical" scenarios), active basses are less susceptible to noise. Some types of pickup (humbucker vs single coil, hot vs low output, etc etc) are a little more susceptible, too. And not all shielding is equivalent - an instrument with a metal pickguard and thick shielding in the cavities will respond to noise differently than one with spotty conductive paint or thin metal foil shielding. So - it's really no surprise that some instruments will be noisier than others.

Noise is really a spectrum - rather than think of one instrument as silent and another as noisy, it's probably more correct to think of one instrument rejecting more noise than the other. And it's most correct to think of that relative noise as a percentage of noise in a given environment that an instrument will reject. Some rooms/houses/stages are noisier than others. If you took your three instruments to a really noisy room, you might find that they all buzz a bit. Or if you took them to a room without a lot of background noise, you might find that they all seemed quiet, or even silent.

As others have explained - your body is giving off noise. Some of this is due to the fact that you're a living human with biological processes happening inside you, and some of it is due to the fact that you're basically acting as a big reflector for other noise sources nearby. When you touch something that's grounded, the minute electrical signals that cause that noise are given a place to go (to ground) and the amount of noise you radiate or reflect is significantly reduced. Hence, touching a ground reduces the amount of noise hitting your pickup, and makes your instrument quieter - because, instead of being a source of noise, your body is now basically an extension of the shielding on your instrument.

 

You'll need a multimeter to really check it, make sure all the things that are supposed to be grounded have continuity (Zero Ohms Ω) back to the sleeve side of the output jack.
Did you try switching the pickup wires?
Some pickups will have their own shielding & one of the wires will be connected to that shielding. If the wrong wire from the pickup is going to ground, that shielding will not be effective.

One possibility is just that the pickup halves are not well-balanced and/or they're just more sensitive to higher-frequency noise than your other instruments.
Does this instrument have a lot of high-frequency output?