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I've Got Buzz... And I Don't Know Why... Gibson..


Jon K

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Hey guys, first I'd like to introduce myself - my name is Jon K and although I am new here, I am an experienced soldered. I have just started picking up my guitar again and am glad I haven't lost any talent! Anyway, I noticed that I've got a ground buzz of sorts. If I do not make contact with any metal on the guitar with my hand, it buzzes audibly thru the amplifier (solid state Fender amp, but does it on every amp i've tried). If I touch the metal on the guitar, the buzz goes away. This is really frustrating and I'd like some help.

The guitar is a Gibson Smartwood Exotic I purchased used years back and it looks like someone tried shielding the cavity with paint and I have no idea what other work they attempted.

Problems:

1) Buzz noise when not touching metal - goes away (mostly?) when I touch strings/bridge/etc.

2) Neck pickup tone knob goes to "no tone" (dull, not bright) when turned fully clockwise, if I turn tone knob 3/4, that is the "brightest" tone, then even a slight turn from there it drops to lowest brightness right away, no gradual fade. So, it does seem to go "full bright" but it happens at 3/4 position, at anything about 3/4, it is full tone off.

guitar1.jpg

Thanks in advance guys.

I build engine control modules for cars, so soldering is not my fear - it's that I do not know much about inductance and such.

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Try connecting a multimeter (set for ohms) between any metal part (bridge, tailpiece, strings etc.) and the main ground on your output jack. Actually its easier to just use the ground part of your cord. If you get infinite reading then your bridge etc. is not grounded. When you touch the strings you are providing a path to ground and quieting the beast. :D

Shielding doesn't do a whole lot when humbuckers are installed. The whole idea behind shielding is to reduce the 60 cycle "hum" given off by single coil pickups. Thats why they call dual coils "humbuckers".

Edited by Southpa
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hi Jon,

the buzz you are talking about is pretty common even for HBs in places where the AC fields are strong.

even little things like flourescent lights can be wicked.

it's probably worse when you are near the guitar, but not touching it.

touching the strings grounds your body, so it helps shield the pickups and wiring, instead of coupling the hum into the pickups and wiring.

so, that part sounds normal.

someone may have mis-wired your neck tone control. remove the control cavity cover.

if you look at the tone pots with the terminals pointed "up", there should only be connections to the left and middle terminals. if there IS a connection to the right terminal, or if it's touching the shielding paint, fix that.

otherwise, your pot itself might be stuffed.

cheers,

unk

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Thanks for the input guys - does it appear as though the knobs are wired correctly? I am used to circuit boards and my soldering looks much cleaner than this... not sure if this is a factory job or not. Ok so - I am half considering redoing the wiring but I don't want to ruin the guitar - it does sound good right now, but the buzz isn't right (from other guitars i've played at least...) and the knob thing is killing me.

gibson2.jpg

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Hey guys - Ive got the back cavity cover off, the nuts and knobs are off the front, but I can't get the whole 4 pots to come out the back - is there a trick?

Just realized - there is a small black wire going to what looks like the bridge thru a small hole... hrm.

Edited by Jon K
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the pots are tightened down to the metal plate, then pushed through.

they prolly weren't aligned right, and then just jammed into the holes.

before you take the assembly out, you'll hafta unsolder all the wires from the pickups, switch, and string ground.

do you really need to take the pots out, or can you just clean up the mess with everything in place?

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the pots are tightened down to the metal plate, then pushed through.

they prolly weren't aligned right, and then just jammed into the holes.

before you take the assembly out, you'll hafta unsolder all the wires from the pickups, switch, and string ground.

do you really need to take the pots out, or can you just clean up the mess with everything in place?

I am not sure I can clean it up because the pots are so close to the wood body cavity. Is this paint really doing anything bad?

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yep, that's carbon paint, so it's conductive. it's like having a resistor connected to ground for anything that touches it. that's why that tone pot is acting strange.

you only need to make a definite separation between the terminal and the shielding.

also, is that carbon paint on the insulation at the end of the pickup wires? or is the insulation just 'melty'?

if it's carbon paint, you need to clean that off too, it will load down the pickups and make them sound dull.

again, you only need a short distance on the insulation that is completely clear of carbon paint.

you can use acetone (nail polish remover) on a q-tip to remove the carbon paint, but BE CAREFUL. acetone will also disolve the finish on your guitar.

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I'd just rip out the stock crap and get a replacement CTS/Hovland production kit from RS Guitar Works. The little wire you see going to the bridge posts is supposed to be there for the master ground for the electronics. The passive design uses YOU as a giant resistor to take the remnant noise out of the system.

If you want to further clean up the noise, go active and replace the whole shebang with an EMG setup. Looks like you live in a dorm so you probably have a big flourescent light in your room that's full of all kinds of noise.

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So wait, I need to remove this carbon paint from everything? Sorry for being naive - I just want to know what exactly to remove it from before I go pyscho.

EDIT:

Fixed! Thanks guys for your help!

It seems to have been that damned paint.

Ok so now, can anyone recommend a site or guide that will walk me through setting the guitar up properly? The action is alittle off and doesn't feel perfectly right.

Thanks again

Edited by Jon K
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