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Post by luisgarciaalanis on Sept 10, 2010 13:23:44 GMT -5
Hello guys, The story: Let me make this story as short an compacted as possible.. on 2008 I got a Gibson Les Paul studio that hummed like crazy.. I took it to the shop and it had a lose soder on one of the pots.. it made the hum less but it was still huming. I bought new pickups (semour duncans) and had them professionally installed and the hum still there. The guitar tech said that is normal for guitars to hum on high gain amps. Months later I open the back of the guitar and there is a tangled mess horrible job they did on my poor LP... so I go a head and remove all the electronics on the guitar and wire a pickup directly into the jack.. STILL hums, so I tried the stock pickup as well and still hums, in fact I tried wiring the pickup on a table directly into the jack and still hums!!! So I have tried 2 sets of pickups.. Next I tried is a new house.. took my guitar to a couple of guitar shops (wired with the PUP directly on the jack.. and it hums but other gibsons also humed on those amps... So far tried 3 amps at home (1 tube, 1 hybrid and 1 solid state with no ground on the AC line because the AC to DC adapter of the Roland microcube doe snot have it) also tried on 6 more amps at guitar shops and it hums. Tried other guitars on the guitar shops and they seem to hum, humbuckers seem to hum like crasy on a distortion channel.. I finally decided to buy copper tape and shield all the internals of my guitar and rewire all... it made no difference so I gave up The good story: Now I went to guitar center last Wednesday same store where my guitar humed a long with other guitars and I found they had a Slash Custom AFD guitar (6,000 dlls guitar) I pluged that guitar into an amp of my same model and brand and it was dead silent!!! it WAS AMAZING! imagine having a guitar plugged on to a Vox VT50 amp on the insane channel having the attenuator, volume and gain knobs maxed out and having the guitar be total silent except when playing (of course). So that BS of a guitar can't be quiet is just BS... I also tried another Les Paul studio crappier than the one I had and it was also silent... also tried 2 more amps a VT30 and a Marshall and the guitars were silent So back to the DAWING BOARD: 1) I should test to see if my guitar jack is wired backwards. - For this I plan to check on the continuity between the bridge and the guitar cable part that is not the tip. 2) This is a question for you guys, should I remove the metal base that holds the pots on the gibson and put the pots direclty on the wood? 3) I want to fully rewire the guitar so I will stop by a guitar shop and see if they can sell me some shielded wire. 4) Should I still get new pots? 5) can something be wrong with the output jack other than being reversed? 6) Should I remove the copper shielded I installed on the internals of the guitar? do I run the risk of adding ground loops because of it? 7) I want to isolate where the problem is, I stil have the original pups of my guitar, can I wire one to a new jack and expect total silence? Thanks Luis
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Post by newey on Sept 10, 2010 14:48:00 GMT -5
Luis- Hello and Welcome! #1 is a good place to start, let's rule that out from the beginning. #2 I doubt the metal plate is contributing to the noise, but if it can be easily removed without destroying anything, it might be worthwhile to try that. #3 Rewiring the guitar is a brute-force type of approach to the problem, but it might be worthwhile. Does your guitar have the selector switch on the upper bout? If so, a shielded cable for that long run up to the switch may help. #4 As long as you're rewiring the whole thing, might as well get new pots. Pots are not normally a huge noise source, but since it hums the same with 2 different sets of pickups, I'm thinking the undue level of noise is coming from elsewhere. Your testing so far eliminates out-of-guitar noise sources, since you've tried it in different environments. Now, from your post, you're a high-gain kind of player, and in general, hi-gain set-ups will be noisier. If your goal is to eliminate it entirely, that may be unrealistic- but hopefully you can knock the noise level back to a tolerable level. The Slash Signature edition you played may have some super-duper noiseless pups on it for all I know- ought to have something on it for that amount of money! #5 Other than miswiring it, or having a bad connection, not much else can go wrong. One thing to check is that the tip prong actually makes connection with the tip of a cable. These can get bent sometimes during installation. Usually, though, it's obvious when you plug a cable in that there's no "click" of the tip connecting if the prong is bent outward too much. #6 I wouldn't remove the shielding. I would check for continuity across various parts of the shielding to make sure it's all electrically connected, and then check that it is properly grounded to the barrel of the output jack. Ground loops shouldn't be a concern. #7 As far as the original pups are concerned, I understood you to say that you had roughly the same noise regardless of which set of pickups you used. But at this point, you may end up trying anything and everything to isolate the source.
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Post by JohnH on Sept 10, 2010 17:42:51 GMT -5
A coreectly wired LP should be one of the quiter guitars around, particularly if it has covered pickups. All the main runs of wires are shielded, from the pickups, to the jack, and up and down the body to the toggle switch. The pot cases are grounded too. That metal plate is grounded, and thats a good thing. The only unshielded parts are the caps and very short wires in the cavity.
To make all that work, each braid has to be connected to ground by some route - ie eventually connected to the jack barrel connection. You can check that with a multimeter. Also, the base of each pickup (and so the covers if they have them) and the bridge get grounded.
If any outer braid is instead connected to hot instead of ground, hum will ensue. Also, a disconnected braid will not do its shielding job.(provided it is not carrying the main signal, only one end of a braid needs to be connected. Try touching a few points. If they should be grounded, but instead are hot, youll get hum. Touching strings or pickup covers should reduce hum.
At high gain though, you wont get silence. Thats why metal heads have noise gates. Im wondering if some of those sim channels that you tried had noise gates and so were cutting the signal to zero until you played?
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Post by luisgarciaalanis on Sept 10, 2010 19:40:20 GMT -5
#2 I doubt the metal plate is contributing to the noise, but if it can be easily removed without destroying anything, it might be worthwhile to try that. It can be removed no problem.. I know standards/classics/studios have this base but Custom's don't. #3 Rewiring the guitar is a brute-force type of approach to the problem, but it might be worthwhile. Does your guitar have the selector switch on the upper bout? If so, a shielded cable for that long run up to the switch may help. Yes my guitar has a selector switch for the pickups. The selector switch has 4 terminals, 1 is the ground, the other one are Bridge pickup, neck pickup and return. I installed all shielded wires, however I don't know what to do with the grounds, do they need to be wired on both sides? like imagine a signal/hot wire coming from the the pot to the switch, the shielded wire will have its shield soldered to the back of the pot and then will run all the way to the switch, but should the shield on the switch side be wired to the ground leg of the switch as well? and the ground leg all the way down to a pot making a loop? the problem here is that each hot line will have a shield and also the return line from the switch has a shield... #4 As long as you're rewiring the whole thing, might as well get new pots. Pots are not normally a huge noise source, but since it hums the same with 2 different sets of pickups, I'm thinking the undue level of noise is coming from elsewhere. Your testing so far eliminates out-of-guitar noise sources, since you've tried it in different environments. What brands do you guys recommend? Now, from your post, you're a high-gain kind of player, and in general, hi-gain set-ups will be noisier. If your goal is to eliminate it entirely, that may be unrealistic- but hopefully you can knock the noise level back to a tolerable level. So they said even at the guitar store but the salesman was blown away by how quiet those guitars were (I was asking if they did some type of special setup). You know guitar stores are noisy by nature so there might have been some noise there, In fact I remember hearing what I hear at home but just 30-40 times less. The Slash Signature edition you played may have some super-duper noiseless pups on it for all I know- ought to have something on it for that amount of money! Hopefully that is not the case #6 I wouldn't remove the shielding. I would check for continuity across various parts of the shielding to make sure it's all electrically connected, and then check that it is properly grounded to the barrel of the output jack. Ground loops shouldn't be a concern. It was a PITA to install but it might be useless specially on the duct to the PUP's and tot he switch, I ended up wasting a lot of copper tape I don't know if it makes a difference to use paint, or if ground loops can arise due to the tape. But I tried wiring the PUP to the jack and it as still noisy, however I did not remove the jack I just unsodered the metal plate, removed that and solder it directly to the jack along with the bridge ground. Do you guys ever shield your Gibsons/Humbucker guitars? #7 As far as the original pups are concerned, I understood you to say that you had roughly the same noise regardless of which set of pickups you used. But at this point, you may end up trying anything and everything to isolate the source. it was quite a similar nose maybe a bit louder on the stock PUP's To make all that work, each braid has to be connected to ground by some route - ie eventually connected to the jack barrel connection. You can check that with a multimeter. Also, the base of each pickup (and so the covers if they have them) and the bridge get grounded. I have checked the screws of the PUP against the back of the pup and then against the shielded tape on the interior of the guitar. But I will do a quick test again. I have not tried the covers, I know they are aluminum (for the Seymour Duncans) I will check ground of them. If any outer braid is instead connected to hot instead of ground, hum will ensue. Also, a disconnected braid will not do its shielding job.(provided it is not carrying the main signal, only one end of a braid needs to be connected. Try touching a few points. If they should be grounded, but instead are hot, you'll get hum. Touching strings or pickup covers should reduce hum. I should touch the shielded tape to see if the guitar makes more or less noise, I will do the same with bridge, strings (back of the pots).. etc. At high gain though, you wont get silence. That's why metal heads have noise gates. I'm wondering if some of those same channels that you tried had noise gates and so were cutting the signal to zero until you played? No I have the Vox VT50 at home and it has noise (no gate) I have a Roland microcube and it has noise (no gate) I have P1-EX from ax84 I built myself with no gate and the ipod line out test works great on all 3 amps (amplification with Zero noise) so the amps are fine its the guitar. I have two guitar cables, a cheapo one and a Monster one. Thanks for the responses guys Luis
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Post by luisgarciaalanis on Sept 11, 2010 2:23:22 GMT -5
OK I used the continuity tester of my DMM and the jack seems to be wired fine, I get continuity from the strings to the ground of the guitar cable and from the pup covers and from the pup screws. I don't get continuity from the hot tip of the cable to those places..
Also I plugged the guitar and the noise does not increase of decrease if I touch the strings or if I touch the ground inside the guitar like the shielding coper tape or the the pots..
if I touch the tone caps or the signal wire the hum gets worse..
what do this tell me?
Thanks Luis
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Post by JohnH on Sept 11, 2010 16:17:56 GMT -5
hmm..all that sounds mostly fine. Do you get continuity from the jack barrel to all the grounded points and the outer braids of wires?
How is the hum with just a loud but clean amp setting?
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