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P bass constant buzz


Rayman
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I have a buzz on my P bass. Recently fitted KiOgon loom is fitted correctly, no problem there, it's great, ground wire is good, cleaned and attached as it should be, but there an albeit quiet ish buzz constantly. It doesn't go if you touch metal parts, it's constant, and only disappears if I physically move the bass around the room.

 

None of my other basses do this, they're silent.

 

Is this a normal P bass thing? Or could there be an issue with the old, affordable pickup?

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If it comes and goes as you move the bass around it is some external interference being picked up by the bass' wiring.

As rmorris asks, is the bass screened?  If not, screen the pickup and control cavities with copper tape/foil and connect it to the basses ground.

It is 'normal' with unscreened instruments to pick up interference. 

 

The other approach is to find the source of the buzz, in the house, and if possible eliminate it. This can be any electrical kit - mains transformer in the amp, wireless routers, networking over mains units, mobiles and chargers, HVAC, light dimmers and even ring mains wiring.

 

As it's a constant buzz it's probably the mains wiring - if it's the amp getting closer makes the buzz worse and most of the other sources are intermittent or pulsed.

 

Best approach is to screen the bass - it will then be good wherever you take it...  😉

 

https://www.allparts.uk.com/products/shielding-copper-tape-1-inch-x-5-feet-25mm-x-1-5m  or similar

 

 

 

 

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45 minutes ago, NancyJohnson said:

By way of an alternative, search on Amazon for adhesive copper slug repellent tape.  Same thing, fraction of the price.

The only difference is conductive glue. WIthout conductive glue you manually have to connect all the strips together with e.g. wire and solder to get the faraday cage effect. That said, I haven't tried it so maybe it's sufficient?!

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4 minutes ago, bloke_zero said:

The only difference is conductive glue. WIthout conductive glue you manually have to connect all the strips together with e.g. wire and solder to get the faraday cage effect. That said, I haven't tried it so maybe it's sufficient?!

 

The idea of the shielding is to stop/reduce interference from outside sources (dimmer switches/electronic anomalies); the slug tape alternative was suggested to me by John East.  I'm not certain that it's necessary to connect the strips together; any adhesive overlap should have sufficient conductive properties to create a sealed enclosure, plus the pots will also be in contact with it as well.

 

This is the first time I've ever seen the words conductive and glue in the same sentence!

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2 hours ago, NancyJohnson said:

 

The idea of the shielding is to stop/reduce interference from outside sources (dimmer switches/electronic anomalies); the slug tape alternative was suggested to me by John East.  I'm not certain that it's necessary to connect the strips together; any adhesive overlap should have sufficient conductive properties to create a sealed enclosure, plus the pots will also be in contact with it as well.

 

This is the first time I've ever seen the words conductive and glue in the same sentence!

 

Conductive adhesive on the tape is definitely needed unless seams are made by solder or pressure. If the "slug tape" adhesive is reasonably conductive then fine but if it's not it will not shield effectively. And there is definitely adhesive copper tape that has non-conductive adhesive. It's a source of frustration / amusement in the world of EMC testing when a "non-technical" customer doesn't understand why they are having problems despite wrapping stuff with copper tape. 

Test with DMM shows it's not electrically connected as it has non-conductive adhesive.

And put good pressure on the adhesive join to get a good connection.

(You generally need to rely on pressure for screening 'detatchable' bits eg control cavity covers / scratchplates.

Connecting scratchplates / pickguards to the screen will also help avoid 'static' noises caused by rubbing the scratchplate / screws.

Edited by rmorris
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31 minutes ago, Rayman said:

Slug tape ordered. It’s just odd that 4 other basses don’t make a sound, and I’m pretty sure two of them are also unsheilded. 

 

Different electronics can easily have differing susceptibility to interference.

wrt the pickups - yes they can make a big difference - type / construction / resistance / inductance all relevant.

And pot / cap values and the wiring. Larger pot values will be more easily affected.

 

It's still advisable to shield the other basses. Even though you may not hear interference through whatever setup you are using it may show up in a different system (typically one with more high frequency response eg cab with tweeters or in a studio environment.

 

Also, they may be shielded with conductive paint ? - It usually black. imo not as good as metal but can be effective if properly applied.

 

Hope you get it sorted.

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I’ve just shielded a recent build with that slug tape and can confirm that the glue is indeed conductive enough (resistance test with multimeter) to not need to solder each join. Mind I did solder leads to each pickup cavity and feed those back to the control cavity shield before connecting that and the bridge earth to the ground on the output jack. Result is the quietest passive bass I’ve ever owned. 

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On 25/02/2022 at 13:03, Jean-Luc Pickguard said:

I used copper slug tape from amazon.co.uk to shield my squier jaguar shortscale and can confirm that no slugs have been found in or near the bass since.

 

Seems I got it wrong then. I used it to tape slugs to my bass. It's s bit slimy now 😳

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  • 1 month later...
On 23/02/2022 at 18:30, JPJ said:

I’ve just shielded a recent build with that slug tape and can confirm that the glue is indeed conductive enough (resistance test with multimeter) to not need to solder each join. Mind I did solder leads to each pickup cavity and feed those back to the control cavity shield before connecting that and the bridge earth to the ground on the output jack. Result is the quietest passive bass I’ve ever owned. 

Both products are probably the same stuff, can't imagine a slug tape  factory and a (higher volume) EMI shielding tape factory.

Edited by pfretrock
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