P-Bass hum when hands near pup

[Nashrakh]

Hey guys,

I have a minor issue with my 2008 MiM P. Great instrument, recently swapped the old pups for 62 RI and damn they totally cop the vintage sound...

Anyway, here's a weird one for ya that's been a minor annoyance with the old pup as well; the bass starts to hum when I move any of my hands towards the pickup.

When not touching anything at all, it's dead silent.

I have pickup and bridge covers installed, but I found that removing the pickup cover didn't help. At all, which is a bummer since I thought that was the culprit... solder joints under the PG all look okay.

Search function gave me nothing as usually it's the other way around. When I touch the strings with the left hand while the right one is near the pickup, it's silent again.

Shielding inside the cavities is minimal but I'm not even sure if it's a shielding and/or ground issue as I seem to be the source of the hum (gotta have someone else play it to test)

I notice that this is worse on some days than on others. Static electricity in my fingers maybe? Wild guess.

Anyone else ever had this? As said it's only a minor issue and you don't even hear it during rehearsal or gigs, but I'm a**l like that...

[Bobster]

If it stops humming when you touch the strings, that's "normal" but it also means you need more shielding. Some folks use foam under the pickup that's wrapped with copper to ground the pole pieces in the pickup to the body. That's a pretty easy DIY fix.

If it hums when you touch it, that's a ground issue.

Is there a computer, TV, florescent lighting in the immediate vicinity of the bass? If so try moving away from it and see if that helps.

All the best,

Bob

[Nashrakh]

Hey Bob,

I usually play in front of the computer when woodshedding.

Tried to record the hum, but it was gone... went into the pc via line in to guitar rig 5.

Nothing. Really weird... gotta wait and see.

Concerning your first point about shielding, the 62 RI came on a metal base plate, with a wire going from the pup to it. I thought that was for grounding, but I saw the jazz bass shield fixes and I'll try something like that. Can't hurt, can it.

[dmusic148]

By any chance does your computer have an old-school CRT monitor? Those are big hum generators.

[Nashrakh]

Thanks for chipping in.

Tossed the CRTs years ago. It's a flatscreen, old but can't say if LCD or Plasma.

I'm suspecting the speakers hooked up to the computer, had them turned off during recording and no hum. But I was across the room to test if it was the PC with the speakers on and the hum was there. They hiss like crazy on their own though, maybe I should test that some more. (It would certainly explain why I never noticed it in the rehearsal room too)

[dave_bass5]

Subscribing to this thread as i have a issue with the same pup. No buzzing/RF noise at all unless i touch the pole pieces. I thought it was a P-Retro issue so took that out and re wired the bass back to passive. Its still there.
I used the brass plate under the pup, and although i hear it when sitting in front of my PC (LCD monitor, headphones) i also hear it at gigs using a radio system.

[Cadfael]

Hi Dave,

watch this thread: '57RI problem?
That's normal ...

The brass plate is under the foam?
Put grounded copper (or brass) foil directly under the magnets and humming won't occur when you touch the magnets.

[E.J. T.N.T.]

I also have had a similar issue. I believe this is a very common issue with passive pickups, especially older ones. I believe it has to do with the shielding of the pickup.

Under normal circumstances the wax potting should be enough. But over time, due to the sweat from your hands part of it will go away and it will make the pickups buzz when you touch them. This occures most commonly on the pole pieces. So here are some quick fixes:

-Don't touch the pickups while playing.

-Never play fingerstyle again. See above why.

-Wear gloves while playing.

-Put some electrical tape on the pickup covers. A lot of people do this to also eliminite the clacking noise when the strings touch the pickup's pole pieces when playing with either a very aggresive style or with very low action or a combination of both.

-Have your pickup rewaxed (never tried it, should work though)

-Use nail polish to shield the pickup polepieces or even the entire top of the pickup cover.(That's what I did on my p-bass after playing the pickup for almost 10 years and helped a lot)

[bassdude51]

Originally Posted by Cadfael

Hi Dave,

watch this thread: '57RI problem?
That's normal ...

The brass plate is under the foam?
Put grounded copper (or brass) foil directly under the magnets and humming won't occur when you touch the magnets.

Putting some clear finger nail polish on the top of each magnet pole also stops contact hum.

[dave_bass5]

Originally Posted by Cadfael

Hi Dave,

watch this thread: '57RI problem?
That's normal ...

The brass plate is under the foam?
Put grounded copper (or brass) foil directly under the magnets and humming won't occur when you touch the magnets.

Thanks, interesting thread. Ill have a read through it tonight with the bass in hand.
Im not sure where the brass plate is, ill need to check that. I "think" its under the foam at the bottom.

This is the first P bass ive had that has done this, and it was definitely ok with previous pups in it, i wonder if the Fender pup has gone bad.

[Cadfael]

Hi Dave,

maybe the previous P PUs had the other coil humming and you never touched them.

The humming is normal as long as you don't touch the strings (or other grounded parts). There is a good chance you simply never recognized it! And now that you recognized it at you bass, you tuouch the pole pieces without other grounded parts much more often than you normally would.

[dave_bass5]

Thanks for the replay. I know they didnt do this before because i normally tap or touch the pole pieces when im installing a new pup, just to make sure they are working before putting the strings back on etc. Ive never heard anything other than a thud when using a screwdriver, yet now i get the buzzing if i do the same thing.
I also do touch the pole pieces by accident sometimes so i know its not something ive suffered from before.