Odd bass grounding problem - tapewound related

[Beer of the Bass]

I've just stuck some nylon tapewounds on my bass, and they've brought to light a grounding issue which was probably already there, but I never noticed it with ordinary strings. The bass has single coil alnico J pickups, the bridge is grounded and the cavities thoroughly screened with copper foil, all of which is grounded too.
The problem is, if I touch the polepieces on either pickup when playing (easily done with my playing style), it hums. It's not as loud a hum as if I was touching the live side of a jack, but it's still enough to be irritating. If I don't touch the polepieces, there is no issue with hum, whether I'm touching the bridge or not. As these are typical fender-ish pickups, the polepieces aren't connected to anything, and I've verified this with a multimeter. I've also checked that the strings are grounding OK at the ball ends. I'm presuming that due to the non-conductive surface of the strings I'm not grounded when I play, and I'm acting as an antenna when I touch the polepieces.
Rather than coming up with some Heath-Robinson contraption to ground my body, I suspect I'd be better off either grounding the polepieces by running copper tape across the backs of the pickups or covering the poles with something to insulate them (nail varnish?). Any thoughts on which to go for?

[BOD2]

Have a look at this -

[url="http://www.audereaudio.com/FAQ_PUMag_Gnd.htm"]http://www.audereaudio.com/FAQ_PUMag_Gnd.htm[/url]

Alternatively you could put some insulating tape over the pole pieces to see how well that works.

[gjones]

[quote name='Beer of the Bass' timestamp='1348224811' post='1811030']
I've just stuck some nylon tapewounds on my bass, and they've brought to light a grounding issue which was probably already there, but I never noticed it with ordinary strings. The bass has single coil alnico J pickups, the bridge is grounded and the cavities thoroughly screened with copper foil, all of which is grounded too.
The problem is, if I touch the polepieces on either pickup when playing (easily done with my playing style), it hums. It's not as loud a hum as if I was touching the live side of a jack, but it's still enough to be irritating. If I don't touch the polepieces, there is no issue with hum, whether I'm touching the bridge or not. As these are typical fender-ish pickups, the polepieces aren't connected to anything, and I've verified this with a multimeter. I've also checked that the strings are grounding OK at the ball ends. I'm presuming that due to the non-conductive surface of the strings I'm not grounded when I play, and I'm acting as an antenna when I touch the polepieces.
Rather than coming up with some Heath-Robinson contraption to ground my body, I suspect I'd be better off either grounding the polepieces by running copper tape across the backs of the pickups or covering the poles with something to insulate them (nail varnish?). Any thoughts on which to go for?
[/quote]


Hmmmmmm....I had this issue and ended up putting masking tape on the E polepiece (which was the one I tended to touch when playing). I recently bought a set of DiMarzios which have adjustable polepieces, which you can sink below the pickup cover and that also solves the problem.
Alternatively, I notice some pickups have pickup covers that have no holes for the polepieces. a set of those covers fitted to your pickup would do the trick.

These are the pickup covers [url="http://www.ebay.co.uk/itm/PICKUP-COVERS-SET-FOR-JAZZ-BASS-BLACK-CLOSED-/380453874696?pt=UK_Guitar_Accessories&hash=item5894d16c08&_uhb=1#ht_1335wt_864"]http://www.ebay.co.u...1#ht_1335wt_864[/url]

Edited September 21, 2012 by gjones

[mcnach]

[quote name='Beer of the Bass' timestamp='1348224811' post='1811030']
I've just stuck some nylon tapewounds on my bass, and they've brought to light a grounding issue which was probably already there, but I never noticed it with ordinary strings. The bass has single coil alnico J pickups, the bridge is grounded and the cavities thoroughly screened with copper foil, all of which is grounded too.
The problem is, if I touch the polepieces on either pickup when playing (easily done with my playing style), it hums. It's not as loud a hum as if I was touching the live side of a jack, but it's still enough to be irritating. If I don't touch the polepieces, there is no issue with hum, whether I'm touching the bridge or not. As these are typical fender-ish pickups, the polepieces aren't connected to anything, and I've verified this with a multimeter. I've also checked that the strings are grounding OK at the ball ends. I'm presuming that due to the non-conductive surface of the strings I'm not grounded when I play, and I'm acting as an antenna when I touch the polepieces.
Rather than coming up with some Heath-Robinson contraption to ground my body, I suspect I'd be better off either grounding the polepieces by running copper tape across the backs of the pickups or covering the poles with something to insulate them (nail varnish?). Any thoughts on which to go for?
[/quote]


extra hum is a common issue with tapewounds... or rather an issue that tapewounds brings out...

if you only have issues touching th epolepieces, I would try to ground them. Depending on the actual pickup design that may not be easy. If you can access the bottom of the polepieces, a simple strip of copper foil, grounded, and you are laughing. Otherwise, nail varnish works very well. I have used the Rimmel 60 secnd one (stop sniggering) which dries very quickly and you can apply a few coats in no time... and that's the problem sorted.

[Beer of the Bass]

Grounding the polepieces shouldn't be too hard, as the poles stick out of the bottom of the pickup. I'll have to stick masking tape over the top of the poles for tomorrow's gig though, as I haven't got any conductive backed copper in the house at the minute and I play right over the bridge pickup on a couple of songs. I notice Herbie Flowers has tape over his pickups in some photos, which makes me think it must be a common problem with tapes. The strings sound good though, so I think it'll be worth the extra faff.

[Beer of the Bass]

I experimented with insulating the poles with some tape, and while it reduces the noise, there's still a little hum when my fingers are on top of the poles, so I think grounding them will be my best option. Copper foil is in the post, but the gaffa tape on top of the poles should get me through tonights gig.