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Post by bigjeelittlo on Apr 10, 2011 16:15:42 GMT -5
I just got a lower end Greco SE450 that plays and sounds great, but hums too much for my taste, and I'm going to work with some 40 gauge copper foil and contact cement. It's a replica of a '69 Strat that was MIJ in 1979 (yes, I know I'll decrease value by shielding it).
The issue here is that the truss rod adjustment is accessed at the base of the neck, in the pit between the bridge pickup and the neck. A proper shielding job will make it difficult to adjust neck relief. I have surmised that I could create a movable piece of copper foil that would allow movement and replacement with a fair amount of ease, but thought I would ask if anyone here has dealt with this particular issue.
Thanks in advance for any thoughts.
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Post by newey on Apr 10, 2011 17:29:55 GMT -5
Go- Hello and welcome to G-Nutz2! Sorry I had to move your post, but it didn't belong in "References". That's OK, we give newcomers a free pass on that sort of thing.  As far as your question, I'm having a hard time visualizing why you would need to shield around the truss rod access. Does this guitar have a pickguard? While one should always try to shield as thoroughly as possible, small gaps probably won't make a whole lot of difference. If it's really a matter of shielding around the truss rod access, I'd say try without it. Maybe post some photos so we can see what your dealing with. |
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Post by cynical1 on Apr 10, 2011 17:39:50 GMT -5
First off, welcome to the Nutz house.  I just got a lower end Greco SE450... Looks like a Strat copy, right? Something like this:  If the truss rod adjustment is also a copy of a Strat, then the screw is partially buried behind the pickguard at the base of the neck heel and some dis-assembly is required to make said truss rod adjust anyway. While this is an option, and has been done successfully by many here on the board, might I suggest conductive adhesive copper tape or foil. It might cost a bit more going in, but once overlapped it conducts perfectly and requires no soldering between seams. And copper is generally easier to work with then aluminum. I'm sure the aluminum lobby will be flaming me soon on that one... Well, in my opinion, shielding the guitar should increase its value in that it will sound better and the shielding is an enhancement with no cosmetic detraction. The same can't be said for large plastic Hello Kitty stickers pasted all over the body...but I digress. Well, of all the guitars I've shielded I've never put shielding on a neck, or in a neck pocket. By shielding the cavity and the back of the pickguard and properly grounding everything the small section comprising the heel of the neck should not even be a factor. So, shield everything besides the neck and neck pocket and you will be fine. Happy Trails Cynical One |
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Post by bigjeelittlo on Apr 10, 2011 21:28:40 GMT -5
Apologies for using the wrong forum category. Makes better sense to put it here, though I admit I was hesitant to initiate something in a category that began with "lutherie," as I am at best a hack.
Thanks much for the responses. I agree that a small opening should not make much difference, but I was concerned about the proximity of the neck pup to what will be the opening in the shield. Good idea to try without, because it would be easy to add some copper if need be.
As for copper tape vs. foil, point well taken. I'm not much of a solder expert, so the less, the better. But don't I need the foil for the pick guard? Or can I use tape there as well?
Will post pics tomorrow night after I get a chance to take some. And the Greco is a match with the picture in this thread, other than the white pickguard and knobs on mine. Love how it plays and sounds, even though it's one of the cheaper models.
Very grateful for responses...and this forum. Cheers!
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Post by cynical1 on Apr 10, 2011 21:46:42 GMT -5
You can use the foil for the pickguard. If you've got one big piece then it'll work better with the contact cement. If you coat the entire back of the pickguard and work the foil from the bridge end to the neck end, using a credit card or plastic squeegee it'll go on flatter.
I use the conductive adhesive tape on everything because I scored 23 rolls of the 3M good stuff on eBay for 15.00 a few years back...I even shielded the cat...
Work slowly, remove obstacles from your work surface and watch the pet hair with the contact cement. And if you get a crease just live with it. You'll never get it out without tearing the foil when using contact cement. Just take a credit card and work the crease flat.
And a little contact cement goes a long way. Brush it on very sparingly or it'll run everywhere when you start to card it out.
Happy Trails -
Cynical One
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Post by bigjeelittlo on Apr 10, 2011 21:57:36 GMT -5
I use the conductive adhesive tape on everything because I scored 23 rolls of the 3M good stuff on eBay for 15.00 a few years back...I even shielded the cat... Hate it when the cat has too much hum... ;D Thanks much for the good advice! |
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Post by Yew on Apr 11, 2011 2:51:31 GMT -5
You can use the foil for the pickguard. If you've got one big piece then it'll work better with the contact cement. If you coat the entire back of the pickguard and work the foil from the bridge end to the neck end, using a credit card or plastic squeegee it'll go on flatter. I use the conductive adhesive tape on everything because I scored 23 rolls of the 3M good stuff on eBay for 15.00 a few years back...I even shielded the cat... Work slowly, remove obstacles from your work surface and watch the pet hair with the contact cement. And if you get a crease just live with it. You'll never get it out without tearing the foil when using contact cement. Just take a credit card and work the crease flat. And a little contact cement goes a long way. Brush it on very sparingly or it'll run everywhere when you start to card it out. Happy Trails - Cynical One I thought creases where a guarenteed fact in a shielding job? |
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Post by newey on Apr 11, 2011 5:40:53 GMT -5
"Creases! Foiled again!"
;D ;D ;D ;D ;D ;D ;D
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Post by cynical1 on Apr 11, 2011 6:26:24 GMT -5
"Creases! Foiled again!" ;D ;D ;D ;D ;D ;D ;D I think there's a Contempt of Forum or a censure in there somewhere for that one, counselor... HTC1 |
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Post by JFrankParnell on Apr 11, 2011 9:20:28 GMT -5
"Creases! Foiled again!" ;D ;D ;D ;D ;D ;D ;D I woulda got away with it, if it weren't for you metaling kids  |
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Post by cynical1 on Apr 11, 2011 9:51:50 GMT -5
I woulda got away with it, if it weren't for you metaling kids No you wouldn't. We could Cu. HTC1 |
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Post by thetragichero on Apr 11, 2011 12:41:26 GMT -5
I woulda got away with it, if it weren't for you metaling kids No you wouldn't. We could Cu. HTC1 +1 for that bloody brilliant! |
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Post by bigjeelittlo on May 16, 2011 22:52:17 GMT -5
In the unhappy ending, the audience goes home, frustrated and empty, almost lifeless...  The hum is not better after a thorough shielding. Next step is to try to isolate the source, though I fear it's the pickups themselves. Words of wisdom are welcome. Giving up is not yet an option. |
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Post by irwired on May 17, 2011 9:57:08 GMT -5
I would suggest that you start by checking that the ground circuit
has good continuity with a multi meter.
Your bridge and tremolo should be part of the ground circuit.
Basically check every connection on the ground side you shouldn't have more than 2-5 Ohms resistance between any two points.
Note that each piece of foil is an electrical connection.
It is a good idea to check your meter by setting it on the Ohms scale and touching the leads together. Do this a few times to make sure you get the same reading each time. I have run across meters that are so erratic they are useless as a rubber yard stick. ;D
Good luck
Wirey
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Post by bigjeelittlo on May 18, 2011 13:22:28 GMT -5
Thanks Wirey. I'm good with the conductivity, I think, as my meter shows less than 2 ohms on every pair of connective points. Touching of the meter poles shows zero ohms, so I think the meter is good.
So, I started last night with process of elimination...turning off all devices save those completely necessary, going direct to amp, going direct to board, using a guitar with humbuckers to determine if there was noise in the path that was not due to pickups. I even did the "find the point of least noise" dance in several locations around the room.
I'm down to one of two things:
1) I've got a ground loop (see below)
2) It's a '79 Greco SE450, and it was born noisier than any Strat or Strat copy I've ever played or heard.
Since I can't live with #2 unless I rule out #1, I need to ask for more wisdom. My "Rookie Solder Flinger" status is going to show in a big way, but I do want to note that there are no "Hello Kitty" stickers on my guitar, or really anywhere in my life.
My means of defining a ground loop is to state that if I can find a way in any path, point A to ground, for the current to come back to point A before reaching ground, I've got a loop. Is this a bad definition? Seems so, because the copper-plated underbelly of the pickguard, teamed with the copper-coated cavity and strategically placed copper overlap to body top that run to pickguard screwholes is an infinte set of loops.
Is there any way to be definitive in determining if I've got a ground loop?
P.S. - You might be wondering what an electrical nitwit like me is doing with a multimeter. A friend of mine left it at my house 25 years ago, and never reclaimed it. It's really his, but I suspect he has forgotten about it.
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Post by newey on May 18, 2011 14:10:14 GMT -5
There is the additional possibility that both #1 and #2 are correct.  While a ground loop could theoretically be generating some noise, some savvy members here have done some testing which leads to the tentative conclusion that it is unlikely to be a factor. A ground loop can (again, theoretically) generate noise by acting as an antenna. Just as with an antenna, length matters. The short ground loops likely encountered inside a guitar shouldn't do anything. Your shielding is not a meaningful ground loop because it is not carrying any signal from your pickups. A ground loop can't put noise in your signal unless it is part of the signal carrying circuitry. The likelihood is very high that the source of your noise lies elsewhere. |
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Post by cynical1 on May 18, 2011 14:24:36 GMT -5
While I'm no expert on this, I would have to go along with newey on the ground loop not being a significant factor in your noise issue.
I would also agree with irwired that a faulty ground may be your culprit...it's definitely your prime suspect.
And it is possible that the pickups are just noisy...do you have spares laying around to test the theory?
HTC1
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Post by irwired on May 18, 2011 17:17:25 GMT -5
Just a thought
If you put your hand on the strings does the noise level change?
Wirey
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Post by bigjeelittlo on May 18, 2011 17:36:35 GMT -5
First, thanks Gents, for your time and good thinking. It has occurred to me that the guitar has a ground loop, a bad ground and is also noisier than the average Strat/copy. Last night, I almost had myself convinced that I'd just use the guitar for those blues/funk needs, which allows me to avoid the drive that makes the hum so friggin' annoying. Then I remembered...I'm not wealthy enough to have a guitar for that purpose alone. Ground is to the neck end of the tremolo config, with a big dab of solder and the wire running to the copper that coats the cavity. I established contact with one of the meter poles on the solder and the other on the copper that coats the cavity, and I saw less than two ohms resistance. This tells me that all elements are conductive, but it doesn't tell me if ground is solid. I guess I just assumed that the good lutherie people at Fujigen were qualified in this sort of thing. Is there a way to verify the quality of the ground? Wirey - no change in the hum when I put my hands on any part of the guitar. C1 - No spares. In fact, I've never owned a single-coil pickup until now. I've played plenty and heard even more, but never an owner. Thanks again, Gents. |
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Post by cynical1 on May 18, 2011 17:53:44 GMT -5
Then I remembered...I'm not wealthy enough to have a guitar for that purpose alone. Do not feel like an orphan on that score... So, did you star ground everything, or did you ground to the pots? And your jack solder connections are good, right? One suggestion I can make regarding the pickups is this...eBay:
Bill Lawrence WILDE Strat pickup set 280/280/290All kidding aside, but if the guitar is noisy, whether you touch the strings or not, it's either a ground, or some other systemic issue yet to be determined. I feel your pain on this one, too... Have you tried taking pieces out of the loop to see if one part or component is the culprit yet? It's about as much fun as getting your gums scraped, but sometimes it's the best way to nail down the problem. Happy Trails Cynical One |
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Post by bigjeelittlo on May 18, 2011 18:13:59 GMT -5
Star ground and jacks were soldered by a repair guy because I did not trust my solder work. He did a nice job...really clean and with good copper wire. WIre to the output jack is shielded. I am planning to double check it tonight, but I think it's all good.
Heh...already checked with Lawrence, GF, Stewmac and others. I have a Greco SE450 that has a pickguard with pup holes that are 3mm too small for standard Strat pups. I thought of buying an entire pickguard assembly, but no guarantee that the screwholes will match, and that just seemed like well beyond. Of course, now it doesn't seem so outworldly. I also thought of some fine-grit sanding of the pickguard to effect the 3mm width, but the pickup screws might not align.
I'm starting to think that drilling some new pickguard holes might be the only choice. This is becoming an expensive guitar...wish I could sell it for what it's worth by now.
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Post by cynical1 on May 18, 2011 19:19:28 GMT -5
Well, if the wiring checks out, and the components are good...the solution is obvious...
And for 3mm, about 3/64" on each side, opening up the pickguard should be pretty simple. Re-drill 6 holes and you're done.
And yes, Virginia, the "unique fixer upper" is generally equal to or greater than buying a guitar in working condition...
Keep the faith. At least the Wilde pickups are noiseless, so if they squeal then we were looking in the wrong place all along...
HTC1
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