Mr. C.O. Jones Posted November 19, 2014 Share Posted November 19, 2014 Ok i posted a while ago a topic named: Grounding Issues? Time has past and the old hum is still there when i play with more gain or distortion, but I have more information about my problem and some questions to. I read the The Dreaded HUM is Gone !!! topic and thanks to that I know what i don´t have to do. But is there a save way to get rid of the hum? Well first thing i want to say is that i bought myself a digital multimeter to check everything. But this one has no beep sound, and i am not sure how i have to use it. The first one i bought was analog but it was broke and they exchanged it for a digital one. I know that this one works because i put it on ohm´s and measured the resistence of my pickups and the readings I got where right. It has to be the guitar because with my cheepa$$ Epi SG there is no hum at all. More info: when i touch the bridge tailpiece etc. the hum stops, when the piuckup selector switch is in the middle position it doesn´t hum, only when one pickup is selected. When i separete the guitar from my body without touching any metal parts it stops. Holding the guitar that way with one hand and going near the control cavity or the switch cavity with my other hand makes the hum appear again. It starts when my hand is a few centimeters away from the plastic cover plate. Questions: #1: How do I measure if the ground wire is ok, and what readings should i get? As i swapped the bridge for a new one I pulled out the bushing to check if there was good contact between bushing and wire and everything seemed to be ok. On the other end of the wire the connection to the PCB seems to be fine to. #2: Could it be because the LPJ has Alnico(57Classic/Angus Young) magnets and the Epi SG ceramic (600R/700T)? #3: Read a lot of stuff about shielding the control cavity makes the hum go away. Would this realy do it? #4: If the answer to the 3rd question is yes what is the best way to do it? I noticed that the control cavity of my Epi is painted black but i dont know if it is conductive paint or if they sprayed the whole body with cavitys and all ( the guitar is ebony colour). Well i think it's enough for the moment i'm sure the someone in the forum has the right answer to this issue. Thanks and greetz Marcos Link to comment Share on other sites More sharing options...
capmaster Posted November 19, 2014 Share Posted November 19, 2014 Some hum will always appear due to AC line power causing stray voltages and stray currents since earth/ground has a fairly limited conductance. In reverse (coil) wound/reverse (magnet) polarity dual SC PU or dual HB split coil circuits, hum will cancel out with both PUs on. Among my guitars are some with next to no shielding, others with some more. This is of no importance when putting my hands off the guitar, it will hum in any case when using magnet pickups. It's all the same with grounded and ungrounded amplifiers of mine - safely ungrounded, of course, there are double-insulated ones like my headphone and my acoustic guitar amp. When using only the piezo pickups of my hybrids through one single amp, there is no hum at all. In case I connect my hybrid guitars to a twin amp set up with the acoustic amp safely lifted from ground, there is very little hum in the acoustic signal path. Magnetic pickups will always put out hum and are also sensitive to static crackling, clicks and pops, regardless of setup. When evaluating the passive Hi-Z pickups I use for interference, EMG humbuckers are the best - I repeat it's definitely about passive Hi-Zs here -, followed by Fender Noiseless stacked single coils, typical side-by-side coil humbuckers like those made by Gibson, then there's a large gap, and the by far worst on principal are all the true single coil pickups and coil-split use of HBs except the combination I mentioned at the top of the post. There's a solution perfect for everything but the SC problem and widely used by artists: wireless systems. No ground hum on principal. You may even unplug and plug your instruments at high gains and high volumes without problem. Ask the pros using EMG humbuckers and wireless same time... Link to comment Share on other sites More sharing options...
Rabs Posted November 19, 2014 Share Posted November 19, 2014 Ok i posted a while ago a topic named: Grounding Issues? Time has past and the old hum is still there when i play with more gain or distortion, but I have more information about my problem and some questions to. What you say about touching the bridge is exactly how it should work.. Your body acts as the ground which is why the hum goes away when you touch it... If you had grounding issues you would have MORE hum when you are touching it.... Shielding.. Well theres several schools of thought on that.. Some say it makes no real difference some say it does.. I guess you will just have to try that yourself. And yes I believe that black paint is used as a shielding of sorts. Or at worst, if it bothers you that much, try getting some kind of noise gate pedal that will get rid of it. OR as a lot of us do.. just ignore it and carry on playing :) (and turn the volume to 0 when not playing). You will always get more hum with more gain.. that's just how it works. If there is no hum when playing clean then you have no problems.. Chances are that your Gibby pickups are just more sensitive. Link to comment Share on other sites More sharing options...
deeman Posted November 19, 2014 Share Posted November 19, 2014 I would recommend using a 3-prong to 2-prong adapter. never believe anything you read on the internet Link to comment Share on other sites More sharing options...
rct Posted November 19, 2014 Share Posted November 19, 2014 I would recommend using a 3-prong to 2-prong adapter. never believe anything you read on the internet damn you. damn it all. damn it all to hecks. I just got this pitcha, was headed here to put it up there, but no. damn it. rct Link to comment Share on other sites More sharing options...
capmaster Posted November 19, 2014 Share Posted November 19, 2014 Within all-metal frame cars is no hum. One day my son was wondering why plugging and unplugging aux sources like flash players to and from the audio system won't cause any noise. I explained the Faraday cage thing to him. However, there might be noises due to poorly filtered ignition and/or generator systems while the engine's running. Link to comment Share on other sites More sharing options...
Mr. C.O. Jones Posted November 20, 2014 Author Share Posted November 20, 2014 I think i can ignore it if its normal. I think that for the moment I will keep resting my hand on the bridge ir tailpiece when i'm not playing. And maybe in a future a buy a noisegate. I was worried that something could be wrong with my guitar, but thanks to all of you guys i feel much better now. Greetz Marcos Link to comment Share on other sites More sharing options...
norton Posted November 20, 2014 Share Posted November 20, 2014 I would recommend using a 3-prong to 2-prong adapter. ---------------------------------------------------- thank you for saying that, doing so works very well for me but be prepared to have all the self appointed electrical "experts" tell you that you are a "fool" and an idiot, etc, etc, etc it works because you are eliminating the amp to outlet ground and not the outlet ground itself in addition make sure any light or fan that has a dimmer switch is off and the more you can eliminate other possible causes even as seemingly trivial as a cell phone's proximity may help reduce hum Link to comment Share on other sites More sharing options...
Golden Posted November 21, 2014 Share Posted November 21, 2014 If your home circuit is correctly grounded and your guitar is correctly grounded and your amp is correctly grounded then your guitar is an extension of the pre-amp, this doesn't mean you won't get hum. As with single coils your picking up "outside" interference and it will vary as you move around, these are RF and EMF signals picked up by the "pick-ups"acting as an antenna. Now, when you place YOUR hand on the strings? YOU ARE THE GROUND? Let me know what you disagree with. As far as checking your guitar circuit you are checking continuity and point to point. If you have continuity on your meter point to point "your meter will signal". In which case you have a ground. However there are a array of issues which can internally cause a hum. Sorry I cannot say without going through the circuit. First, does the same think happen with "all" humbucker guitars in question or just this one? If just one then theres an issue. Peace from the mouth breathers Link to comment Share on other sites More sharing options...
Golden Posted November 21, 2014 Share Posted November 21, 2014 Oh and this............"it works because you are eliminating the amp to outlet ground and not the outlet ground itself" No idea what that means? If you use a two prong plug you have no ground because there is none. Its plausible your receptical "two-prong" is grounded at the box, but without a 3-prong outlet your amp and further extension of the circuit is not grounded. So when you plug a two prong adapter in you still have hummmm no ground? Your ground, third prong of the amp plug, plugged into a two prong adapter becomes a "dummy" its of no use and no value. So how does it effectively ground the amp and further the guitar? I honestly realize you have less noise because your box is "now" grounded and it would be quieter. But your guitar and amp are not grounded to the circuit, the house circuit is grounded but there is NO WAY for the continuity to magically extend through a dummy plug. Be it thats the case you can use the wire or loop to connect a wire from the dummy 3-way and connect a wire from there to the box screw. Then you will be grounded be it half assed. Most adapters have a connection-contact terminal for this reason. Link to comment Share on other sites More sharing options...
Golden Posted November 21, 2014 Share Posted November 21, 2014 damn you. damn it all. damn it all to hecks. I just got this pitcha, was headed here to put it up there, but no. damn it. rct Note the loop on this bottom of this adapter? Its for grounding your dummy plug to the house box which we all "assume" is grounded? Follow? Geez norton it behooves me to begrudge you the information while being insulted. Link to comment Share on other sites More sharing options...
rct Posted November 21, 2014 Share Posted November 21, 2014 My electrician has a capo. rct Link to comment Share on other sites More sharing options...
Rabs Posted November 21, 2014 Share Posted November 21, 2014 My electrician has a capo. rct Is it an Amp one? Link to comment Share on other sites More sharing options...
stein Posted November 21, 2014 Share Posted November 21, 2014 More info: when i touch the bridge tailpiece etc. the hum stops, That IS the indication the guitar is grounded properly. You can't play the guitar without touching the bridge or the strings. So what are you concerned about? Some "humbuckers" have more hum than others. It isn't an indication something is wrong or that one pickup is better than the other. Link to comment Share on other sites More sharing options...
stein Posted November 21, 2014 Share Posted November 21, 2014 I would recommend using a 3-prong to 2-prong adapter. ---------------------------------------------------- thank you for saying that, doing so works very well for me but be prepared to have all the self appointed electrical "experts" tell you that you are a "fool" and an idiot, etc, etc, etc it works because you are eliminating the amp to outlet ground and not the outlet ground itself in addition make sure any light or fan that has a dimmer switch is off and the more you can eliminate other possible causes even as seemingly trivial as a cell phone's proximity may help reduce hum umm..uhh... Generally speaking, you DON'T want to eliminate the amp ground. The outlet having a ground or not really is of little consequence if nothing is plugged into it. Put another way, if the amp ground is not plugged into it, the fact the outlet has a ground does nothing for you. I mean both for noise or safety. As for safety, you are much, MUCH more likely to be shocked by a problem with a tube amp than a problem by the wall plug. The amp being grounded helps to protect you, because if and when a problem happens with the amp, it is more likely the "shock" will go to the ground rather than find it's way to you. Personally, my experience is most things are quieter grounded than not grounded. Makes me wonder what you may be actually experiencing there in reality. I wonder what it is your electrician did. What he found. Link to comment Share on other sites More sharing options...
Eracer_Team Posted November 21, 2014 Share Posted November 21, 2014 If anyone missed it He said his Epiphone doesn't hum. Its just his Gibson Link to comment Share on other sites More sharing options...
Guest Farnsbarns Posted November 21, 2014 Share Posted November 21, 2014 If anyone missed it He said his Epiphone doesn't hum. Its just his Gibson Conductive paint in cavity, different, possibly cooler, possibly closer matched coils. It doesn't mean the Gibby is faulty, just different. Link to comment Share on other sites More sharing options...
Guest Farnsbarns Posted November 21, 2014 Share Posted November 21, 2014 I would recommend using a 3-prong to 2-prong adapter. ---------------------------------------------------- thank you for saying that, doing so works very well for me but be prepared to have all the self appointed electrical "experts" tell you that you are a "fool" and an idiot, etc, etc, etc it works because you are eliminating the amp to outlet ground and not the outlet ground itself in addition make sure any light or fan that has a dimmer switch is off and the more you can eliminate other possible causes even as seemingly trivial as a cell phone's proximity may help reduce hum I cannot believe you missed the sarcasm! Actually, I can, you're playing an amp with no ground, ignoring a bunch of smart guys/players who, well, aren't qualified but unanimously agreed that it's not smart, 2 amp techs, 1 qualified and certified electrician and one qualified but no longer certified ( out of date ) eIectrician. Not only that but, really, a kid with a gsce in physics could be sure it's wrong by reasoning alone. I could believe just about anything to be frank. Your electrician, if I understood correctly, said, and I'm paraphrasing, that's it's not SAFE, safe, but you'll probably be OK. I would ask that you don't now go around telling others, who seem to pretty much know better already, that it's fine. Link to comment Share on other sites More sharing options...
badbluesplayer Posted November 22, 2014 Share Posted November 22, 2014 Flourescent light dimmers are an insidious source of amp noise according to Bruce Egnater of Egnater Amps. If you have any dimmers in your house, turn them off. That might help. Link to comment Share on other sites More sharing options...
Jimi Mac Posted November 22, 2014 Share Posted November 22, 2014 Flourescent light dimmers are an insidious source of amp noise according to Bruce Egnater of Egnater Amps. If you have any dimmers in your house, turn them off. That might help. That and worn/aged florescent lights/bulbs/tubes in the room can also be an insidious source of amp hum, and that wouldn't change the fact that it happens more in one guitar than another, some are more responsive/sensitive to EMF in the room than others for numerous reasons. From how I understand it, the 3rd prong in the electric plug only grounds the amp cabinet/structure. It's for any buildup of static electricity or stray voltage that gets into the metal structure of the amp either accidentally or thru a shortest pathway for voltage due to some design or function issue of the electrical circuit in the amp. Voltage can jump gaps unexpectedly, especially with spikes/surges and such things can cause stray voltage to go outside of their normal path. Then when you touch the structure you can become the ground path for such stray voltage. It is not part of the engineered/designed electrical circuit for where the electricity is supposed to run. It has nothing to do with the normal electrical operation of the amp. Having said that consistent/constant vibrations near/around a running electric current can cause their own EMF and it essentially can be come a solenoid of sorts and if you touch it (grounding it) and it has enough stored energy in the structure you can release that energy and that can cause a static pop/zap that can even be deadly if in amperages of a high enough sort. It's not voltage that kills, it's amps. But that is a rare thing and an exception to normal potential. Does the cabinet structure have to be grounded for the amp to function as designed? No, but it is safer and will eliminate the potential for the structure of the amp to store stray voltage/electrical energy. Given knowing the history and performance of the electrical circuit in the place you are plugged into; your home, vs a place you have no idea about the integrity of the electric circuit; a bar, somebody else's jam room etc., it's not wise to eliminate the structure ground anywhere other than a place you are very certain is very stable and safe. If you don't have surges, spikes, fluctuations in your home other than during storms or other rare extreme occasions, you could get away with trying it there to see if it makes any difference. I suspect it won't... I don't believe you get more noise with a proper structural ground. A release without a proper structural ground can also cause electrical damage and fry components in the electrical circuit of the amp. So if for whatever reason it does end up storing a stray charge in the structure and you ground it by touching it, you can in fact fry parts of the circuit even if it doesn't injure you with enough amps to cause you any harm... Always best to have it structurally grounded, but in a controlled environment with a history of stability and strong/proper circuit grounding thru the neutral side of the circuit, in a building circuit that has a good ground, is unlikely to cause an issue... Those structural grounds are also a tad misleading because they are nothing more than a limited ground path to bleed off stray charge. They often don't really go to a good ground if the building isn't wired properly and I've seen many instances where such a ground simply goes to an electrical outlet box and the then that box isn't actually tied into a 3rd leg wire to an actual ground, but there may be enough metal in the outlet structure "ground" to carry away spikes and surges to dissipate enough so they will not cause damage and don't carry enough amps to get back to the source. Maybe... Sh!t happens and it's always better to be safe than sorry... It also will cost less in replaced or repaired equipment too... Link to comment Share on other sites More sharing options...
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