zeegeit Posted January 2, 2006 Report Posted January 2, 2006 Hey guys! Well, I've finally finished my lap steel guitar (will post some pics later), the only thing is, i've got a weird issue with my pickup. I put a standard single coil pickup (no brand) in it, hooked it up with a volume pot, and an output jack (as that's the only thing I needed). Now I know that singlecoils aren't exactly noiseless, but I didn't think it would be this bad. I can hear the guitar through the amplifier, but the humming and buzzing is sometimes even louder. And that's where the fun starts.... I've tried grounding the bridge(I'm using a LP jr. bridge on this one) by connecting a wire from my grounding point(back of volume pot, is this good?) to my bridge, but to no avail. The weird thing is, when I touch the connector of my jack cable(it's a metal connector) while it's plugged into the guitar, the noise just disappears(when my father does the same thing, the noise only diminishes...am I a better conductor? ). Does any of you have an idea what this could be? Thanks! Jaap Quote
GregP Posted January 2, 2006 Report Posted January 2, 2006 Single-coils are notorious. The ebb and flow of the hum is due to standing in different parts of the room or holding it at different angles. All normal behaviour. You could also have a ground loop if you did something funny with your wiring. The best way to avoid ground loops, in my opinion, is to just send all grounds to a central spot (eg. a steel washer), then to ground. All that bent prong stuff and wiring to the back of pots are potential sources of ground loops. And yes, you might be a better conductor! It's entirely possible! Greg Quote
Guitarfrenzy Posted January 2, 2006 Report Posted January 2, 2006 GregP is guiding you in the right direction. Single coil pickups do pickup outside interference, but you can help to minimize it somewhat. Make sure that everything is grounded to the same place, no exceptions if you want to avoid a ground loop. You could shield pickup cavities, etc. too. Quote
zeegeit Posted January 2, 2006 Author Report Posted January 2, 2006 hey guys! thanks for the replies. Greg: I did read something on ground loops..I'll try rewiring the guitar so that the parts are grounded to a washer(or a screw ).Let's hope it works Guitarfrenzy and Lovekraft: I did read about shielding as well, and have considered this..it looks like the www.guitarnuts.com site has quite a nice tutorial, will look into that. But..still there's one thing nagging me. I have a squier jazz bass as well, and it shows the symptoms of a badly grounded bridge (i.e. when I touch the strings there's no hum), but the strange thing with the lap steel is, that the hum disappears when I touch the output jack or the pot..what does this mean? Quote
Mike Sulzer Posted January 2, 2006 Report Posted January 2, 2006 This really sounds way worse than it should be even with single coil and no shielding. Does this single coil pickup have a shield that, maybe, you have connected to the hot? Ground lops are a minor problem compared to shielding; humbuckers get rid of hum from magnetic fields, not so much of an issue for playing clean, so something is wrong. Quote
GregP Posted January 2, 2006 Report Posted January 2, 2006 zeegit: Your Squier is grounded properly, it seems. This is what SHOULD happen when you touch your strings! If you look at the electronics, you should even see a wire coming from the bridge (which connects, therefore, to the strings) to ground. You should do likewise if you haven't already. In addition to the process of eliminating ground loops, you need to connect your bridge to ground. This is done different ways for different guitars, but the only thing you need to concern yourself with is getting a wire from the 'strings' to ground. In other words, you don't solder to the strings themselves, obviously, but you need to make it electrically continuous. If your strings touch a wood bridge, you can't ground the bridge for obvious reasons. But using your craftiness and ingenuity, you need to ground a wire from any location that's electrically continuous with your strings. In a strat, this is often the trem claw! In a telecaster it's any part of the bridge. In an LP, there's usually a small wire that leads from the bridge post (the post connects to the bridge, the bridge connects to the strings-- electrically continuous!). I've done modified GuitarNuts shielding for both my electrics (with help and guidance from LoveKraft and others!), so if you have any questions, I'm pretty familiar with the sometimes-ambiguous wording. Greg Quote
Mickguard Posted January 2, 2006 Report Posted January 2, 2006 That's NOT normal single-coil behavior. The normal hum from a single coil is quite mild, if you ask me, I don't understand what all the fuss is about. Maybe it gets to be a problem if you lay tons of effects pedals in the signal path. Otherwise, as long as you're not sitting in front of a computer monitor while you play, it shouldn't be that bad. One thing you didn't mention though --did you ground the jack too? Are you sure? Sounds to me like that's not grounded...unless you touch the jack with your hand. Quote
GregP Posted January 2, 2006 Report Posted January 2, 2006 You'd be surprised at the role your environment plays in the amount of hum, Mick. I literally cannot use single coils in my apartment, and that's with a carefully-shielded and star-grounded axe. I'm right next to a telephone junction box, which provides the lines to my building. And I'm in a concrete basement apartment-- concrete and metal being the enemies of an EMI-free zone. I still agree that it doesn't sound like it's wired up correctly just yet, but a single coil can and will produce godawful hum in the wrong environment. That's why the GuitarNuts tutorial is called "Quieting the Beast" rather than, "Taking the last wee bit of edge off an otherwise nearly-silent instrument." I turn off my CRT monitor (I have one LCD and one CRT) when I play guitar, and have no other fluorescents or sources of EMI inside my apartment itself. Heck, I've tried turning everything off completely, and still no good. It's that junction box and all the concrete. Greg Quote
zeegeit Posted January 2, 2006 Author Report Posted January 2, 2006 (edited) Hey guys, nothing has happened so far, but I just wanted to reply to some of your questions. Mike: As far as I know, the pickup doesn't have any shielding..it just has a red(hot) and a black(ground) wire coming from it.. Greg: I've tried grounding the bridge already...well ..err actually I connected a wire from the bridge to the back of my pot(which could be bad practice, but anyways) and it didn't help..the hum remained. I haven't tried shielding it though..maybe that would improve it. However, I've tried playing it at various locations, including in front of my CRT monitor; the hum remained the same(at least from my point of errr.. hearing ) so I'm not sure yet whether shielding would remove the hum. I will try shielding it when I have the time, however. Mick: I'm just using the guitar without any effects..just guitar--->amp (simple small practice amp..I've tried hooking it up to my brother's halfstack, but the screeching and humming was just unbearable ). I did ground the jack.. connected a wire from the back of the pot (where the pickup and pot itself are grounded) to the output jack ground. - EDIT - allright..it's a really good thing that I've still got a nice 3 foot board left to hit my own head with...I just took it apart again..and noticed something. One of the little copper strands of my pickups ground wire was touching the output jack...that's what was causing the hum..I took it off, resoldered it and tried grounding the bridge again; the hum decreased significantly, and now when I touch the strings, there's no noise at all(before, I could ground the bridge and touch the strings and nothing would happen)... so I think I've found the culprit...sorry for only noticing this now..would have saved you guys some hassle Edited January 2, 2006 by zeegeit Quote
GregP Posted January 4, 2006 Report Posted January 4, 2006 Hey, if my time were THAT valuable, I wouldn't be posting in the first place, I'd be off saving the world or making fat stacks or something. I don't mind the 2 minutes it takes to write a response. Grounding the bridge to a pot isn't a horrible idea as long as a ground loop isn't created. Ultimately, that's really the only concern: "ground loop or not". It's black and white, and if you don't have a ground loop you're in the clear. Shielding actually makes it trickier to avoid ground loops, because at that point in time, your pot is touching the shield and therefore adding itself to THAT circuit. Then if you have a wire connected to your pot, you have a strong potential for a ground loop. Star grounding is a good idea in any event, but I think it's particularly useful for avoiding pitfalls in a shielding project. If you HADN'T already solved it, I would have mentioned that you definitely had a problem anyhow-- when you're sitting right in front of a CRT monitor, your level of hum WILL increase significantly even with humbuckers. I use this trick on PURPOSE at times to help trouble-shoot my setup. So if the level of hum didn't change either way, you definitely had an unnatural level of hum, as you discovered. Just thought I'd add that for posterity in case anyone's looking at this topic in the future via the "search" function. Greg Quote
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