Pickup coating/shielding/???

Muaguana · #1 07-06-2010, 03:50 PM

I recently swapped out the Duncan Designed pickups in my Squier VM fretless for a pair of used Basslines I got at a local music shop. Something that struck me as odd is that three of the four pickups have some kind of black material wrapped around the copper wiring - on the DD's it looks and feels like electrical tape, while one of the Basslines has what looks like nylon or some other synthetic fabric.

What function does this serve for the pickup? Is it to help reduce noise? The reason I ask is because, ever since I installed the Basslines, the bass has been noisy even when both pickups are at full (which, at least with the DD's, canceled out the noise.) When soloed, the bridge pickup - the one without any material covering the winding - seems to have white noise in addition to the single coil hum exhibited by the neck pickup when soloed.

Would it make sense for a pickup with exposed copper wire to be noisier than one that is covered? And if this is causing the problem, what can I do to solve it?

**line6man** · #2 07-06-2010, 03:52 PM

The tape has no effect on sound, as it's not conductive.

Muaguana · #3 07-06-2010, 04:35 PM

Quote:

Originally Posted by line6man

The tape has no effect on sound, as it's not conductive.

That's what was so baffling to me; logically it shouldn't do anything to affect the sound, but that's the only thing that sets it apart from the other pickups. I guess I'll try replacing all the wires on the control plate and see where that gets me.

Are there any other factors that might introduce white noise into the signal, in addition to the single coil hum?

**line6man** · #4 07-06-2010, 04:43 PM

Quote:

Originally Posted by Muaguana

That's what was so baffling to me; logically it shouldn't do anything to affect the sound, but that's the only thing that sets it apart from the other pickups. I guess I'll try replacing all the wires on the control plate and see where that gets me.

Are there any other factors that might introduce white noise into the signal, in addition to the single coil hum?

What do you mean by white noise?

Are you getting 60Hz hum?
Microphonic coils by any chance?

Muaguana · #5 07-06-2010, 08:24 PM

Quote:

Originally Posted by line6man

What do you mean by white noise?

Are you getting 60Hz hum?
Microphonic coils by any chance?

There's a 60Hz hum with both pickups, but the bridge pickup has additional overtones that give it a somewhat harsher tone. I don't know if the coils are microphonic; I was in my backyard with a practice amp and headphones and it was still going on as it was laying on my work bench. Though I suppose that's a possibility given that the bridge pickup isn't potted; I'm not sure.

Also, since I got these pickups used from a local music store, they could be an unmatched pair. They both have stickers on the bottom with SJB-2 on them, but the material covering the wires is different, and only one has a cover that says "Basslines" on it. Would unmatched pickups cause noise issues?

**line6man** · #6 07-06-2010, 08:27 PM

Quote:

Originally Posted by Muaguana

There's a 60Hz hum with both pickups, but the bridge pickup has additional overtones that give it a somewhat harsher tone. I don't know if the coils are microphonic; I was in my backyard with a practice amp and headphones and it was still going on as it was laying on my work bench. Though I suppose that's a possibility given that the bridge pickup isn't potted; I'm not sure.

Also, since I got these pickups used from a local music store, they could be an unmatched pair. They both have stickers on the bottom with SJB-2 on them, but the material covering the wires is different, and only one has a cover that says "Basslines" on it. Would unmatched pickups cause noise issues?

When the pickups are at an equal volume, they should humcancel.
If they are out of phase, you would hear a thin nasally sound.

Muaguana · #7 07-06-2010, 09:50 PM

It doesn't sound nasally, as it still retains the low frequencies, it's just sounds noisy. It's not debilitating, but annoying nonetheless, especially since I've gone over all the ground connections and re-soldered them several times, and even replaced a wire that could have been bad, but wasn't likely.

Muaguana · #8 07-09-2010, 07:19 PM

So I replaced the bridge pickup with the DD, and now the noise is gone. The single coil hum cancels out, as well, so something's wrong with that Bassline. I'll try my hand at potting it one of these days. In the meantime I'll just order a Tesla VR-B4 and see how that sounds. Thanks for the help.