roahboah
Apprentice Shielder
Posts: 36
Likes: 0
|
Post by roahboah on May 30, 2007 11:16:26 GMT -5
First of all, thanks in advance for taking a moment to read my initial post. I hate being the new forum member and starting off with a question, but I'm gonna do it anyway!
I just had some Fralin PAFs put in my Les Paul, and I really like them. The one thing that I've noticed, however, is that there's a tad bit of noise extant with the new pickups that didn't seem to be there with my old ones. Details are:.
1. The new pickups are exposed-coil - no metal covers. I understand that this may cause a little more noise to be picked up. 2. The noise is orientation-dependent - that is, if I face the guitar directly toward my amp, it's noticeable and if I turn my guitar so the headstock points directly away from the amp, it's greatly reduced - basically negligible. I'm about two or three feet away from the amp in this scenario. 3. I've isolated it to the guitar, since another guitar through the same cable/amp combination doesn't exhibit symptoms. 4. The noise is also much reduced in the in-between position on the LP. It's loudest on the bridge, quieter on the neck, and negligible in the middle. 5. It is not dependent on me touching the guitar and/or strings or any other part of the guitar. 6. There are no pops or any other unusual sounds when touch the strings or metal parts of the guitar. 7. It's not noticeable on clean settings - more noticeable on higher-gain settings. 8. It's not the 60-cycle hum that I associate with single-coil PUs. I have a Tele and a Strat, and this is a different sound.
My gut feeling is that it's a shielding thing, because it's not a full-blown HUMMM and is gain-specific. I don't know, though - I guess that's why I wanted to run this by some folks who would know! thanks for any input, and let me know if you want more info. roah
|
|
|
Post by dd842 on May 30, 2007 11:46:48 GMT -5
First of all, thanks in advance for taking a moment to read my initial post. I hate being the new forum member and starting off with a question, but I'm gonna do it anyway! Nonsense! - we love questions around here. We'll try to help. Welcome! to GN2 ;D Are these overwound PAFs by any chance? It's kinda weird that humbuckers are making that noise ... but they are, so that's the end of that thought Well, I think that you are on the right track in that it sounds like a shielding issue ... it's dependent on orientation ... it's gain-specific ... Shielding it is an excellent first step because, even if it doesn't cure it, you are going to be way better off than you are. It also gives you an opportunity to closely examine the guitar for possible ground loops. Have you come here by way of the original GuitarNuts site? (i.e. have you already seen the resources there on shielding, etc.?) Dan
|
|
roahboah
Apprentice Shielder
Posts: 36
Likes: 0
|
Post by roahboah on May 30, 2007 12:02:28 GMT -5
Dan, thank you for the nice welcome! They are a bit overwound, I'd say. These are the 8/9k set from Fralin and are pretty strong. The tone is great - I'm really pleased! I did indeed find the forums via the original site and I had already viewed some of the shielding resources there. I guess I was really after a second opinion before I proceeded with shielding, but I felt like that's what needed to be done. From some searches I've done, it sounds as though I want to shield both the control cavity and the 3-way cavity. I really have no idea if there's a string/bridge ground at present in the guitar. It's funny - I've had a ton of HB guitars over the years, but these are the first exposed-coil PUs I've ever used. I just didn't think they'd be that noisy, covers or no. I'm not exactly the most adept solderer in the book, but I guess I'll have to dig out the iron and work on my skills to ground the shielding after it's done. It sounds as if copper's the stuff of choice. Any recommendations regarding sheeting/separate adhesive vs. adhesive-backed copper tape? thanks again for the assist! roah
|
|
|
Post by dd842 on May 30, 2007 12:25:21 GMT -5
The tone is great - I'm really pleased! I have read nothing but good reviews. I have not, however, seen any mention of the type of noise you are experiencing. Weird ... Correct - you want to shield everything AND you want to ensure good contact between each piece of material used in the shielding, and ensure that each cavity also has a good connection with the other. We're here - so let us know what's going on as you go and someone will be happy to dive in and help out. It is odd ... No sweat. Practice a little on some spare bits of wire, copper foil etc. (well, actually no etc. ... wire and foil is about it) until you are comfortable. Copper is the stuff of choice, indeed. You can use either sheet or tape, just make sure that there is good copper-to-copper contact between each piece of whatever you use (including copper tape - you may want to fold over the edge of each new piece so that you have copper, not adhesive, touching the other pieces ... or any other method you can think of that achieves the same result). You sound like you kinda have the gist of this already. But if you don't, just remember that it's fairly straightforward and there are lots of people here who can help. Dan
|
|
roahboah
Apprentice Shielder
Posts: 36
Likes: 0
|
Post by roahboah on May 30, 2007 12:36:15 GMT -5
Thanks, Dan! I'll let you know how things turn out. regards, roah
|
|
|
Post by dd842 on May 30, 2007 13:02:05 GMT -5
Thanks, Dan! I'll let you know how things turn out. regards, roah Cool please do let us know how it goes. We like happy endings, and new beginnings ... Don't be a stranger! Dan
|
|
roahboah
Apprentice Shielder
Posts: 36
Likes: 0
|
Post by roahboah on May 31, 2007 7:19:24 GMT -5
Okay, I've ordered copper and have gotten my iron and stuff out. I did a little more investigating last night of the symptoms and just had a quick couple of things to add - if anything sounds meaningful or points toward a specific issue that you know of, sing out.
1. Not only is the noise orientation-specific, it's also specific to the proximity to the amplifier itself. I turned the master up to about 5-6 on my amp and moved the guitar really close to it (about 6 inches away) and the buzz got really loud. Once again, this is not repeatable with another guitar into the same amp/cable combination. 2. I did notice a difference in having my hands completely off the instrument and touching any metal part or the strings. The noise increase with hands off is small, but it's there. Once again, no popping or anything like that, but it's a tangible difference.
I'm feeling a tad anxious about getting in there with an iron and stuff. I was thinking of taking some pics tonight just to show what the cavity looks like and if there are any glaring issues that folks could see.
Once again, thanks for the support of a long-time player, first-time solderer/noise troubleshooter.
|
|
|
Post by dd842 on May 31, 2007 11:46:01 GMT -5
Okay, I've ordered copper and have gotten my iron and stuff out. uh-oh, he actually listened to us ... this could be baaaaad ... I continue to suspect that shielding (with corrected wiring) will sort you out. I (we ... uh, meaning other members also, not "me, myself and my other three personalities"...) know what you mean. I hadn't been in the guts of an electric guitar before September of last year. Scary ... but you will see that it is also pretty straightforward, rewarding, and opens up a whole world of possibilities, once you begin to see that you can understand electronics. Your idea of pics is excellent as intended, and also gives you your only roadmap back to where you started in case thinks don't work out as planned (... they will, though ) Dan
|
|
roahboah
Apprentice Shielder
Posts: 36
Likes: 0
|
Post by roahboah on Jun 1, 2007 9:04:51 GMT -5
Hey, I had a couple of quick questions - thanks in advance from the noob!
1. Is it possible to remove the pots and all that other stuff without desoldering everything to put in the shielding? I just realized that I'm gonna have to take everything apart and had a dang anxiety attack!! Heehee.. 2. If I do get my hands on a multimeter, what is the method for testing continuity and/or correct wiring with same?
I know these are some stupidly basic questions, but you'll have to forgive me - I've never even contemplated the kind of stuff I'm gonna be trying soon on the innards of this guitar!
thanks, roah
|
|
|
Post by dd842 on Jun 1, 2007 13:48:06 GMT -5
Yes, I think you can do that. The actual shielding job becomes a lot easier if you get everything out of the way, IMHO, but I guess you can just take the nuts off of each of the pots and pull the shaft through the guitar body and out of the way (you may want to put a little piece of tape on each pot so you know where it goes when you replace it, though). It will be similarly tricky in the pickup cavity, because you will have to work around the wires running from the pickup to the control cavity. I would kinda like to see some pics before commenting on the following ... but I'll just let her fly, and you can let me know if anything doesn't jive or look right at your end. You need some way of creating a connection between the shielding in the pickup cavities and the control cavity. The way I handled this was to place a "hoop" (made of a piece of springy/flexible copper strip - not flimsy foil) between the shield and the plate on the back of the humbucker. You should be able to find it at hardware stores or perhaps electronics surplus stores. After you have everything installed, don't forget to remove any wires running from the back of one pot to the back of another pot. You will no longer need them after shielding, and they will only serve to create undesireable ground loops. Chrisk has assembled an excellent reference article on the subject here: guitarnuts2.proboards45.com/index.cgi?board=reference&action=display&thread=1176413665He who asks a stupid question is a fool for five minutes. He who never asks remains a fool forever. Dan
|
|
|
Post by JohnH on Jun 1, 2007 16:30:56 GMT -5
roahboar - I think theres a couple of things worth checking before you rip everything out, based on some recent experiece I've had.
I have just got myself a new old LP Studio, '93 model - great guitar and way above the other half dozen that litter our house. I was planning to keep it stock for a while, in order to see how it sounded. But that lasted about 5 minutes once I saw what some previous turkey had done with the wiring.
Anyway, I fixed it up and when I had, it was a lot quieter. One of the main things that I thnk made a difference was to have fully shielded cables from the control cavity up to each pickup and to the three way toggle. That is, all the signal wires are within the shielding, and the braid is grounded. In my case, the pickups were in shielded wires, but the three-way connections, although they were in a shielded cable, the shielding was not grounded. I replaced it because it was also stuffed by bodged soldering
The three-way wire is the longest run on an LP, and with there and back wires, all connected to hot, it is capable of picking up noise.
On the pickups, the base of the pups should be grounded, and again all wires (one or four) should be within the grounded screen.
My LP has a covered pup at the neck and open coil at the bridge. There is a very slight increase in noise from the bridge pup, but only noticeable at very high gain. Its much less than for a single-coil pup.
If you want to test this difference due to open pups, you could first confirm the pup back plates are grounded, then temporarily wrap some aluminium foil over the pup, make sure it connects to ground and then see it it made a difference.
I have not yet done cavity shielding (confession) on this LP, and the guitar is already very quiet. Mine has a Gibson feature which is a grounded metal plate behind the controls. This does some of the job of cavity shielding.
I hope some of that may be useful
John
|
|
roahboah
Apprentice Shielder
Posts: 36
Likes: 0
|
Post by roahboah on Jun 5, 2007 11:07:18 GMT -5
John, thanks for the input!
Before I dove into everything myself, I decided to bring it back to the shop that performed the work, diplomatically describe what seems to be the issue (quiet as mouse before pickup install, not-so-quiet post-install, you tell me what's changed) to find out if they can isolate something. The job they did was clean and nice-looking - perhaps something small got missed. I should hear back from them today, hopefully. I'll let you guys know! thanks again, roah
|
|
roahboah
Apprentice Shielder
Posts: 36
Likes: 0
|
Post by roahboah on Jun 14, 2007 20:11:00 GMT -5
Well, some moderately frustrating news - guitar shop that did the work 'added more grounding' (even *I* don't know what that means), and they report that the hum is still there. Their opinion was that we should contact Fralin - although I'm not really sure what I'd say besides 'yeah, you know those humbuckers you sold me? They're not bucking the hum!' This doesn't seem terribly logical to me. My first impulse was to get a little more proactive with them and simply say that the only thing I DO know is that the guitar didn't hum before they did the work and it does now. I feel like arguing with them is futile, though, and I just want to get the guitar away from them now. Perfectly nice guys, but beginner or not, with enough time (and perhaps some assistance from all you wonderful people) and patience, I'm hopeful that I can get to the bottom of the issue myself. It makes me a little sad, because this is my favorite axe and I don't want to screw it up worse than it is, but I feel like this is a good opportunity for me to figure out a poser of a problem and feel all empowered. Anyway, I might be popping some questions as soon as I pick it up and start looking at stuff. If anyone has knowledge of an online tutorial or other resource that covers the basics of using a multimeter to test wiring such as this, I'd appreciate the sharing of same. thanks, roah
|
|
|
Post by michaelcbell on Jun 14, 2007 20:48:47 GMT -5
Now there's the attitude that makes us Nutz. Keep up the good work and I for one would be glad to help in any way I can.
|
|
|
Post by sumgai on Jun 15, 2007 13:40:36 GMT -5
ro, +1 for determination in the face of The Enemy! ;D My old standby trick for when I run into "The Wall" (I get stuck)...... Return everything back to the way it was, and start over. If it wasn't humming before you went to the shop, have them return everything to pre-shop condition, pickups and all. No "additional grounding", no new pickups, nothing. If they want money for their labors, argue that they didn't accomplish the mission as promised, and see what happens. If you have to pay for them to 'restore' your axe, consider that versus doing it yourself. Will they do it correctly, do you trust them, how much will it cost, etc. All are valid questions to balance against doing it yourself, I'm sure you can see. If the guitar just can't be restored to original (as you started with), then someone has "introduced" a new problem, and that'll need treatment. IMHO, you've got the chops to straighten it out, you've obviously got the patience and determination, so flail away - we're here to backstop you if and when. HTH sumgai
|
|
roahboah
Apprentice Shielder
Posts: 36
Likes: 0
|
Post by roahboah on Jun 16, 2007 5:00:52 GMT -5
I guess if I thought that there was value in telling the shop to return it to pre-install condition, I would - but right now my overwhelming desire is to get my guitar back from them and never bring it back! They've been nothing but nice, but they work slooooowly and I don't want to wait three weeks just to get it back to square zero. I just feel like I'd rather have the guitar on my bench where I can start figuring this out for myself. I'll be singin' out with the beginner-level questions as I do this, don't you worry! ;D I think what I WILL do once I get it back, I'm gonna take my time and maybe desolder everything, make sure all wires are what I think they are (and maybe label), and start fresh with best practices moving forward to do it right. I've also got some old pots/wires that I'm gonna practice on before I start operating on the LP, so I won't be quite so gun-shy when it comes to reassembly. thanks again, all - I'll update as soon as I have the old lefty back in my hands and have started some diagnoses. thx, roah
|
|
|
Post by sumgai on Jun 17, 2007 16:48:46 GMT -5
ro, Gee, do ya suppose that the shop doesn't realize that left-handed wiring is different from the stuff they're used to seeing? ;D
sumgai
|
|
roahboah
Apprentice Shielder
Posts: 36
Likes: 0
|
Post by roahboah on Jun 18, 2007 4:05:36 GMT -5
Okay, that really sparked my interest - please elaborate!! thanks, roah
|
|
|
Post by sumgai on Jun 18, 2007 9:21:28 GMT -5
ro, Well, don't quote me on this, because I'm ambidextrous, and I wish that all pots were sliders............ It seems from all accounts that if you wish to "ride the gain" on your axe, you tend to use the underside/outside of your little finger, and possibly the heel of the palm of your hand, to do so. Now as a right-hander, this is dead-simple....... pulling up your hand as you down-stroke your pick is not hard to learn, and it's effect is striking. But as a technology, it requires no additional thinking to use it - the world-wide standard for increasing the volume is to turn the control clockwise. QED. However, the motion itself does not translate well for a left-hander. That worthy wants to do the same thing to get the same effect - ride the control knob with same parts of his left hand, as noted above. However, most pots have a tapered response curve, meaning the percentage of motion (rotation of the knob) not a direct correspondence to the change in the resistance value. For a so-called "linear" taper, there is no differece, the rotation change percentage equals the resistance change percentage. But in our guitars (indeed, as in most things electronic in nature), we use "audio" or "logarithmic" tapered pots. And that's where the trouble starts. We expect a certain response based on that taper, and that carries through when a right-hander uses a right-handed guitar. But for a lefty, the equality breaks down. Left-handers know just as well as anyone else that clockwise means more. However, when "riding the gain" on their axes, the hand motion is reversed. Thus, they need what we call "reverse-taper" pots. (This is your "Aha!" moment. If your axe's pots aren't tapered like this, then you'll get odd results as you attempt your favorite licks. And when unknowing or inexperienced guitar techs mess around in there, they may forget the cardinal rule of axe-modding: "Do no harm to the user". Lefties are harmed when they are forced to think like a righty. Bad techie, bad! No Twinkie for you! That's not to say that the hum problem was introduced via this possible mis-wiring, but I can see where if the volume pots are wired one way, and the tone pots are wired the other (one righty, one lefty), then there may be trouble in Margaritaville. Just some thoughts before I've had my daily meds, so take it for what it's worth. ;D sumgai
|
|
roahboah
Apprentice Shielder
Posts: 36
Likes: 0
|
Post by roahboah on Jun 18, 2007 19:32:29 GMT -5
Okay, got the guitar back - got the meter out, plugged a cable into the jack, and tested from the ground of of the cable to the bridge, pickups, etc. IF the desired result is a resistance reading to determine ground/continuity, then that portion seems to be working normally. I've also tested the connections between pickups/switch and am also receiving resistance readings. I'm not positive that this is proving ground, but I think it is. I've also looked at generic LP/Gibson wiring diagrams and all actually seems to be connected correctly. The dude at the shop's take on the situation is that the only thing that would eliminate the wiring as a possible problem would be a new wiring harness. I didn't bother to mention that I didn't really need one before, but oh weeel... He also mentioned that 'floating caps' might be an issue (I assume this to mean that resistance is fluctuating in the caps themselves, or perhaps the caps are just bad at this point. These are the original barrel-shaped caps that came with the guitar in 1974. Dunno - I'm almost tempted to replace pots, caps, switch, jack, and all runs just to have it done. My feeling is this - say I do all this stuff, test and verify that I've done it correctly and it's still got some noise. That would eliminate the runs and point to noise from the PUs. Thoughts or ideas would be super-appreciated. Anyone ever heard of caps 'floating' or similar terms? thx, roah
|
|
|
Post by UnklMickey on Jun 18, 2007 21:12:28 GMT -5
"Floating caps?" Strange terminology. From a DC resistance point of view, a cap should look like an open circuit. In other words, it should read infinite resistance. The same as if it was completely removed from the circuit.
Replacing all the parts is over-kill, IMHO. If the pots make crackling noises when the knobs are turned, clean or replace them. Caps shouldn't go bad, unless they've been subjected to ridiculously high temperatures, during soldering. Switches, particularly the standard LP 3-way, are prone to failure, or intermittent contact.
cheers, Unk
|
|
|
Post by michaelcbell on Jun 19, 2007 5:52:47 GMT -5
It does seem odd, all of this...do you feel you could re-install the old pups, just for the sake of argument? I mean, that would quickly determine whether it's the pups or not without having to completely gut your axe.
|
|
roahboah
Apprentice Shielder
Posts: 36
Likes: 0
|
Post by roahboah on Jun 19, 2007 7:01:52 GMT -5
I guess I could reinstall the old pickups pretty easily - they're single-conductor PAFs, so it'd be a quick thing relatively speaking. I wish I had some metal covers kicking around - I'd be interested to see if there'd be a difference at this point if I just put covers on the damn pickups! I'm starting to think again that the wiring might be fine, and that it's a shielding-type thing. I think I have to just move and do the next right thing - kinda tough figuring out what that is, though. Resolder all the connections? Re-test ground? Shield the cavities w/ copper? Shielding's gonna require that I desolder and take everything out anyway, I guess. Whew.... What ya'll think? thx roah
|
|
|
Post by michaelcbell on Jun 19, 2007 11:40:46 GMT -5
shielding is always a good idea; re-wiring might fatten your sound a little bit, but won't effect noise, unless you use shielded wire. You can probably shield without much desoldering, though disassemblage will be necessary. Have you checked to see if the pups have a ground wire?
|
|
roahboah
Apprentice Shielder
Posts: 36
Likes: 0
|
Post by roahboah on Jun 20, 2007 4:35:20 GMT -5
Yeah, the new pickups do indeed have ground wires. I practiced soldering last night with some wire and junk pots last night, and boy oh boy do I suck at it! Actually, soldering isn't the problem - but desoldering is. It's tough to get the old solder away from pot connections effectively to loosen the wire. It kinda gave me a little anxiety about doing it for real! Yowtch.... ;D Oh, well - guess I'll practice a little more. My MIM upgrade project (see my other posts) will be a good starter to get me feeling better about it when the time comes. roah
|
|
|
Post by michaelcbell on Jun 20, 2007 5:40:53 GMT -5
Let us know how it goes... Desoldering can be a challenge. I don't have the 'proper' desoldering tools, but I've found that if you get your solder liquified, keep the heat on it while you work the wire out, then blow hard on the lug, that usually gets the job done.
|
|
roahboah
Apprentice Shielder
Posts: 36
Likes: 0
|
Post by roahboah on Jun 23, 2007 6:07:27 GMT -5
One more detail that is quite interesting that I hadn't really paid attention to before with this particular noise situation is this: The middle position is completely noise-free, even on high-gain situations. I scoured the forums on this condition, but couldn't find much. What, if any, is the significance that the in-between position is free of said noise? thx, roah
|
|
|
Post by sumgai on Jun 23, 2007 14:42:34 GMT -5
michael, Here's the proper tool to use for nearly any desoldering job: You depress the top (upper-right part, with the yellow cap) towards the body, thus cocking the spring. When you've heated the solder to melting, lay the tip directly into that blob, and push the yellow spring-release button (in the middle). The spring drives the piston back up into the body, thus creating a vacuum at the tip. The molten solder will easily flow right along, and the spot/connection will be clean of nearly everything! The model above (Edsyn DS017) is the most sturdy I've found, but it starts at about 11 or 12 bucks (Merkin), plus shipping if needed. (A few of the more greedy retailers will demand nearly 20 bananas for one of these babies - shop around.) You can find others at various locations, including Radio Shack, and they start at less than 6 bucks, but I don't consider them to be valid tools, they're too cheap and flimsy. My Edsyn has been with me for over 20 years! Alternatively, especially for close area work, you can use a desoldering braid, sometimes also called 'solder wick'. You lay it directly onto the connection, heat it with the iron, and as the solder underneath gets hot, it will flow into the wick. Remove the wick before the solder cools and melds the wick to your connection! Wick is fine for general work, but not as quick nor as easy to use. Plus, wick is non-renewable - when it's full of solder (which happens quickly), you cut off that part and use a clean portion of the stuff. With a solder sucker, you can clean out the chamber, and use it for years. You may need to replace the tip once a year, if you're a busy little beaver. HTH sumgai
|
|
|
Post by michaelcbell on Jun 23, 2007 21:39:19 GMT -5
Thanks! I'm toying with setting up some sort of electronics shop in my new house (closing Tues 1:00PM EDT = WOOT!), if that comes to fruition I'll def be in the market for the proper tools...
|
|
roahboah
Apprentice Shielder
Posts: 36
Likes: 0
|
Post by roahboah on Jun 28, 2007 3:34:08 GMT -5
Just a small update for you - in the interest of working to eliminate the PUs as noise antennas, I wrapped 'em in copper and grounded said copper to the pickup frame. Good news was it that was a nice clean job and I did it correctly - bad news is that the hum's still there! Dang. There's something significant about the fact that it's quiet as a dang mouse in the in-between position; I'm just not sure what it is! I'll do a little scouring here and I'm gonna have a fresh look at the control cavity tonight, hopefully. thx, roah
|
|