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 Post subject: Bad electronic humming problem!
 Post Posted: Wed Sep 29, 2010 6:14 am 
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Joined: Sat Jun 26, 2010 11:35 am
Posts: 25
Location: Louisville, KY
So today I put a single coil pickup (strat pickup) in the spot of the foam mutes of my Rickenbacker 4001. I have noticed a weird buzzing before, but now it's more noticeable with a high output pickup.

What the problem is I am getting a constant buzz/hum/ When I touch either the neck or bridge pickup(or bridge pickup harness) the buzz goes away. Touching the strings or bridge does not make the buzz go away. I checked all of the grounding and everything seems to be attached well, as well as the ground wire attached to the bridge. (Thus why touching the bridge and strings does not stop the buzzing)

I assume one of the pickups is wired wrong or something which is why touching the pickups stops the buzz.

Any help??

I also noticed that when I touch the input jack, any of the pots, or the pickup selector, the humming stops as well.

HELP!!


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 Post subject: Re: Bad electronic humming problem!
 Post Posted: Wed Sep 29, 2010 7:52 am 
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Joined: Sun Oct 08, 2006 6:07 am
Posts: 3830
Unfortunately, with a pickup that is a bare coil with nothing but a plastic cover, that is exactly what you will get. The noise goes away when you touch the strings because you become the ground.

If you want a mute compartment pickup, the standard choice is the Bartolini made for such. Yes, people have shaved the bobbins and shoehorned in everything, including a J pickup, but the polepieces, even for a neck version, are too wide. If you must have a mute cavity pickup, do it right: drop the bucks, and get the purpose made Bart. Convert one of the tone controls to a volume control for the pickup, rewire your bass for the remaining tone control to be a master tone, and run the output of the Bart straight to the output jack so it can be dialed in as desired.

But think about it: the reason this pickup was developed was before rounds became commonplace, so it was an attempt to get as much treble as possible out of flats (this pickup has been on the market for around 40 years, and yes, Rotosound rounds are older, but they hadn't made it into general circulation in the USA at that point. The first one I ever saw was when I was in high school in the mid '70's, before there was a 4003!).

You really don't "need" this pickup now with stainless rounds.


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 Post subject: Re: Bad electronic humming problem!
 Post Posted: Wed Sep 29, 2010 8:53 am 
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Joined: Sat Jun 26, 2010 11:35 am
Posts: 25
Location: Louisville, KY
I get what you are saying here, but when I touch the strings the buzz does not go away. The buzz only goes away when I touch any of the pickups. Not the bridge or strings.

This problem was also here before I put in the new pickup in the bridge. The bass and treble pickup are both original. The only new thing I added is the pickup inside the mute-area. But the problem was around before I did this mod.


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 Post subject: Re: Bad electronic humming problem!
 Post Posted: Wed Sep 29, 2010 8:59 am 
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Joined: Sat Jun 26, 2010 11:35 am
Posts: 25
Location: Louisville, KY
When the ground wire is soldered to the mute bar, it creates the ground. I never used the mute bar, so why can't I just attach the ground wire to the bridge itself and create the ground?


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 Post subject: Re: Bad electronic humming problem!
 Post Posted: Wed Sep 29, 2010 9:38 am 
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Joined: Mon Mar 05, 2007 12:33 am
Posts: 3403
Location: Denver
Quote:
When the ground wire is soldered to the mute bar, it creates the ground. I never used the mute bar, so why can't I just attach the ground wire to the bridge itself and create the ground?


The bridge and mute bar are electrically continuous. And the tailpiece and the strings and so on.

If touching the strings doesn't do the trick then you need to resolder/rejoin the mute wire to ground (the back of a pot casing). If you still have problems I find a single plane of shielding surrounding all of the pots and the switch (on the pickguard) shores up any discontinuities and often quiets the bass. As much as shielding can seem silly, my fully shielded 4003FL really is my quietest bass--much quieter than my non-shielded 4003 with HB-1s, which as a really nasty buzz when I'm not touching the strings.


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 Post subject: Re: Bad electronic humming problem!
 Post Posted: Wed Sep 29, 2010 5:52 pm 
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Joined: Wed Nov 16, 2005 2:00 pm
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Location: Scotland
Quote:
When the ground wire is soldered to the mute bar, it creates the ground. I never used the mute bar, so why can't I just attach the ground wire to the bridge itself and create the ground?
You can. That's exactly why your bass is buzzing - no bridge ground. You don't need to (and probably can't) actually solder the wire to the bridge, you just need to strip back some of the insulation and trap it between the bridge and the body.

That will cure 90% of the buzz when you *are* touching the strings. To make any significant difference when you're *not* touching them (and the other 10% when you are) you will need to fully shield the control cavity, and probably the back and sides of the bridge pickup cavity (and maybe the mute cavity if you're still going to use the pickup in there), as cassius said.

Bear in mind that this will only eliminate electrostatic buzz too, you can still get some forms of electromagnetic interference that sound like buzz rather than hum (typically from switch-mode power supplies) which are picked up directly by the single coil pickups... but you probably knew that.


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 Post subject: Re: Bad electronic humming problem!
 Post Posted: Thu Sep 30, 2010 2:27 am 
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Joined: Sat Jun 26, 2010 11:35 am
Posts: 25
Location: Louisville, KY
Quote:
Quote:
When the ground wire is soldered to the mute bar, it creates the ground. I never used the mute bar, so why can't I just attach the ground wire to the bridge itself and create the ground?
You can. That's exactly why your bass is buzzing - no bridge ground. You don't need to (and probably can't) actually solder the wire to the bridge, you just need to strip back some of the insulation and trap it between the bridge and the body.

That will cure 90% of the buzz when you *are* touching the strings. To make any significant difference when you're *not* touching them (and the other 10% when you are) you will need to fully shield the control cavity, and probably the back and sides of the bridge pickup cavity (and maybe the mute cavity if you're still going to use the pickup in there), as cassius said.

Bear in mind that this will only eliminate electrostatic buzz too, you can still get some forms of electromagnetic interference that sound like buzz rather than hum (typically from switch-mode power supplies) which are picked up directly by the single coil pickups... but you probably knew that.


I have all the problems solved so far except for one left. I have everything grounded now, and all sounds great. but I have noticed that the new single coil pickup in the bridge mute space is causing a great amount of hum, like you said. Is there anyway to stop this buzz?


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 Post subject: Re: Bad electronic humming problem!
 Post Posted: Thu Sep 30, 2010 3:06 am 
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Joined: Sat Jun 26, 2010 11:35 am
Posts: 25
Location: Louisville, KY
Actually. Never mind. I ended up re-soldering the pickup ground wire and all the buzz is gone! So I'm good to go.

Thanks everyone!


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