Buzzing Hollowbody (caused by P90?)

JezWynd

Picked up an ES-225. Nice guitar except for the buzz. It seemed to originate from the neck pickup area so I removed the pickup and wound some material around the braided wire from pu. Still buzzing. Then I noticed that if I have the pickup not touching the guitar body at all, then the buzzing stops. There doesn't appear to be anything loose on the pu so I'm thinking it must be where it touches the body. I've tried putting pieces of card under the screw flanges to act as washers but it still buzzes. The only cure is to not have the pickup secured to the guitar. Any ideas on how to cure this? It's a loud buzz that transfers through the pickup and gets amplified and makes playing acoustically impossible.

Funkfingers

Looking at your photograph, the edge of the P90 baseplate is very close to the edge of the pickup cutout in the arched top of the guitar. It might be worth attaching something to damp any vibration between those two surfaces. (i.e. something self-adhesive along the edge of the pickup baseplate.)

How tightly do the mounting screws fit into the pickup cover, baseplate and the guitar wood? Any slop could allow unwanted resonances. 

How well does the P90 cover sit over the screw lugs on the pickup baseplate? If the cover fouls the angled edges of the lugs, this will have some effect on the tightness of fit against the guitar body.

Other than that, the only other possibility that springs to mind is a split in the wood somewhere. 

JezWynd

I don't think it can be a split as holding the pickup clear of touching the body cures the buzz. I did initially try putting a piece of material in between the pickup and body on the side that had the tightest fit but that didn't cure it. I like your idea of some tape all around the pickup to cushion it against the body.

The screws (with the cover removed) screw down tight so the pickup cannot move and I did try some card as a washer without any change.

It's a frustrating thing to troubleshoot as to get good access you need to remove the strings, which means you can't then test your fix.

Winny_Pooh

V annoying. Wish I could offer some proper advice but it's only an issue you can figure out in person. Look at where the plastics are perhaps uneven in contact w the body. 

JezWynd

Having done a bit more fiddling about it seems that a downward pressure on the clear plastic top of the P90 stops the vibration/buzzing completely.

The pickup bobbins appear to be seated on a small wooden plank. There is very little free movement when the top bobbin is pressed downwards but I'm wondering if the vibration might be between the bottom bobbin and the wood plank.

How easy is it to disassemble the pickup? I see on the underside there are two screws, would undoing these release the bobbins as a complete unit or do I risk the whole thing falling apart (eek!)?

I have some epoxy and also superglue, so I could feasibly attach the bobbin to the wood more firmly and perhaps cushion the bottom of the wood from the metal tray. Any advice/options very gratefully received, I'm a bit out of my depth here.

ICBM

Be careful - if you undo the screws the magnets will be able to fall out. They will most likely try to flip so that the unlike poles are facing each other - the pickup with only work properly when the *same* poles are in contact with the polepieces.

My guess would be that one or both of the magnets is loose - that would not only make an acoustic buzz, it would be drastically amplified. One of them appears to have slipped out of position already, it shouldn't be that far out from under the bobbin. That would also explain why pressing on the bobbin stops it.

I would first try gently *tightening* the screws, if they will.

Corvus

Those two screws seem to attach the baseplate, if hold that at the ends does the bobbin move at all, rock slightly? If so praps one or both need a little nipping up. Undo them slightly first just a quarter turn say, then you can feel them bite when tightened.

Or is that clear cover moving at all vs the bobbin, if glued maybe one end can buzz. Can't really see what holds that down.

JezWynd

Thanks for your replies @ICBM & @Corvus. You'll have to excuse me a bit here, I'm a complete dunce when it comes to pickups.  I've been looking at some exploded views of P90's and it seems I've been using the wrong terms and misidentifying parts. When I referred to the pickup sitting on a wooden plank, I think this is actually the magnet. When I referred to the top bobbin I was meaning the top clear plastic cover.

@ICBM, when you refer to undoing the screws and the magnets will be able to fall out, are you referring to the two bottom screws? I have tried tightening the two baseplate screws, I was able to turn each approx 45 degrees, nothing more.

@Corvus, if I hold the baseplate, the bobbin is unable to move save for a minute fraction. There is nothing that's obviously loose but given that the noise stops when the pickup is not touching the body I think it must definitely be the pickup that's causing the problem.

ICBM

JezWynd said:

@ICBM, when you refer to undoing the screws and the magnets will be able to fall out, are you referring to the two bottom screws? I have tried tightening the two baseplate screws, I was able to turn each approx 45 degrees, nothing more.

Yes - don’t undo those screws unless you know what you’re doing, or prepare properly.

Do the magnets move if you push them? If so they’re too loose.

If you do want to take it apart, mark the ends of the magnets first so you know which way round they go.

JezWynd

ICBM said:

Do the magnets move if you push them? If so they’re too loose.

Yes the magnet that shows in the picture was loose, I think gravity moved it to the end of the tray, I was able to push it back quite easily so that explains where the buzzing originated.

I followed @Corvus's advice and loosened the two base screws before tightening them back up, having moved the magnet back into position.

Everything now fully secured, I restrung and voila!, no more buzzing!

Thank you so much guys for your tips and advice, it now sounds fabulous.

ICBM

Great!

I've always loved this model - it's one of the most under-rated of all old Gibsons. Many have lost their original trapeze bridge, which is a pity - I think people sometimes have trouble with them moving or buzzing against the top, but if so then put a small piece of double-sided tape under each of the feet. (Make sure the intonation is correct first.)

I had a blonde '57 single-pickup one a long time ago - it had lost its long tailpiece and been fitted with a cheap standard one and a normal rosewood bridge, so I put a Bigsby on it. I loved the sound and look of it, but the middle pickup got right in the way for playing and was very frustrating, so I eventually sold it. I still miss it a bit though...

JezWynd

ICBM said:

I had a blonde '57 single-pickup one a long time ago - it had lost its long tailpiece and been fitted with a cheap standard one and a normal rosewood bridge, so I put a Bigsby on it. I loved the sound and look of it, but the middle pickup got right in the way for playing and was very frustrating, so I eventually sold it. I still miss it a bit though...

The single pu model was the one that initially sparked my interest, I've always loved single pu guitars but after doing some research and looking at YouTube it did seem that the pickup was poorly placed - it would have been better at the neck position.

I particularly wanted to try one with the original long tailpiece but I think I might follow your tip to put tape under the feet as the upright threaded pole can screw into the face of the guitar if you're not careful when adjusting the height. It's the perfect upgrade to my 125T with the cutaway and extra pickup being sensible improvements on the original design.

This '59 has its original frets in excellent condition as well as the original tailpiece but with 60's (?) pickups and replaced electrics and tuners. Very pleased to find one.

Corvus

Nice result, and one fab looking guitar...