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Post by lpf3 on Aug 17, 2008 15:00:02 GMT -5
Hey guys ,
I'm shielding my Affinity Squier Tele & doing the T-Riffic mod , using push pots for my phase & series switching . I'm also replacing the bridge pup . The new pup has a bare ground wire coming out of the coil & soldered to the baseplate . The conductor wires will be fed to a push pot for series/parallel .
Should I cut this bare ground wire that comes out of the coil at the baseplate & run a new wire from the baseplate to ground ?
I'm using the existing neck pup & it also has a baseplate . There are no ground wires from either the baseplate or the metal cover , I'm planning to connect the cover to ground . The conductor wires from this pup will be fed to a push pot for phase reverse .
Should this baseplate be grounded as well ?
Thanks ,
lpf3
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Post by newey on Aug 17, 2008 15:51:10 GMT -5
Yes, you do have cut that wire, but I believe that you wire a separate ground from the coil end of that wire, not from the baseplate. The baseplate should ground to the shielding if you follow the Tele shielding instructions.
That's all IIRC, I could be wrong on this . . .
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Post by ChrisK on Aug 17, 2008 18:15:48 GMT -5
How many wires in total are coming out of the new bridge pickup?
The T-Riffic mod has the bridge (-) connected to ground anyway.
The neck pickup has no shield/cover connection and you're going to run a third wire for this anyway, which is what the mod teaches.
The isolated wires coming from the neck pickup are used for both series/parallel as well as out of phase. In essence, the bridge pickup should remain grounded.
Now, if this wire to the baseplate IS common with one of the bridge coil leads and you leave it grounded, thing's will work fine. Just connect that wire to the ground.
I should point out that the ground lead on a Tele pickup is usually the bridge string ground also. I usually run a separate bridge plate/string ground wire in Teles.
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Post by lpf3 on Aug 30, 2008 17:59:23 GMT -5
Hey , guys - Sorry it took me so long to respond to your quick responses...... Mucho Mayhem At Work & I've had a hard time gettin anything important done newey newey - I think you were talkin' about the wire to the neck pup cover , my guitar didn't have one anyway so I added one & connected it to ground . Thanks . ChrisK Chris - a total of 2 wires ( 1 gray & 1 white ). I assumed the wire to the baseplate was a jumper from ground so I went with it ... worked out fine , I added this green wire & tucked it up under the bridge like so ... This guitar is an Affinity Squier Tele , I've heard them being totally disparaged by others , but I like mine for some reason . The new bridge pup is a Bill Lawrence Black Label & wow ! what a difference . It's got tons of bite & sizzle , & still plenty full .... I'd recommend it to anyone who wants a good stock replacement pup . The mods ? Well , I did the full shielding job ( another huge difference ) & the T - Riffic mod using push pull pots . I uh ,er , hmmm , whew , well I just didn't like either the series setting or ( especially ) the phase reverse . So I went back to the stock switching . Seriously . Maybe it was the way the two pups work together . As it was there were some phasing issues between the Lawrence & the stock neck pup & I had to swap the + & - leads on the neck pup to get it to work . I went with 2 500K pots & a .047 tone cap , 6.8K at the neck & 6.7K at the bridge & this guitar sounds great in all 3 positions . Another mod I did was to drill out the top loading bridge & the body for string thru ferrules : This seems to make a difference too , but it's harder to tell . Last but not least , it came with a white pickguard , so I made this black one .... Thanks for puttin up with such a long post , & as usual thanks fer all yer help -lpf3
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Post by dannyhill on Jun 21, 2012 9:09:48 GMT -5
I have a question here that has been bugging me for a while. I have something similar here, it's this: The bridge pickup plate is connected conductively to the ground lug of the jack via both screws/bridge plate/copper/ground wire and green wire/copper/ground wire. I can't see the ground wire but I assume it is there somewhere. Isn't this a ground loop? In my case I have just one wire conecting the bridge pickup plate and -ve on the pickup to ground and the bare wire under the bridge (connecting via screws to the bridge plate of the pup) to ground. That is factory wiring by Fender. Is that green wire even needed?
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Post by dannyhill on Jun 21, 2012 9:10:06 GMT -5
BUMP
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Post by ashcatlt on Jun 21, 2012 11:22:28 GMT -5
So....
You posted a fairly cryptic question (maybe I haven't had enough coffee yet, but I'm having trouble picturing) in an old thread and then bump it after a minute?
Take your Ritalin and then post some pictures or a better description of what's going on in your guitar. Then wait patiently.
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Post by dannyhill on Jun 21, 2012 12:04:07 GMT -5
What a friendly welcome! I bumped it cause I understood that otherwise it might be days or weeks until it got read being an old thread. Sorry about that. Let's try again.
LPF3 was discussing an issue with his pickups and I noticed in his photo that he ALSO had what I think I have and that is a ground loop.
In his photo: The bridge pickup plate is connected conductively to the ground lug of the jack via both screws/bridge plate/copper/ground wire route AND via the green wire/copper/ground wire route.
(I can't see the ground wire but I assume it is there somewhere.)
In my case I have just one wire conecting the bridge pickup plate and -ve on the pickup to ground and the bare wire under the bridge (connecting via screws to the bridge plate of the pup) to ground. That is factory wiring by Fender!
I.e. Is the green wire in the photo even needed?
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Post by ashcatlt on Jun 21, 2012 13:28:48 GMT -5
Maybe that was a little snarkier than it needed to be. Like I said, not enough coffee... But, you know, your first post would have bumped the thread sufficiently.
We have to assume that lpf found some way of conducting all that shielding stuff to the jack sleeve, else none of it does any good. Of course, we all know that thing about "butt...u...me..."
Looks like he missed the point of newey's post. The green wire is redundant. I wouldn't call it a ground loop myself. In fact, it might just be more reliable than depending on the screw connection. But I can guarantee that it doesn't have any noticeable negative impact on noise performance.
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Post by 4real on Jun 21, 2012 15:51:04 GMT -5
I thought there was a good thread kind of debunking 'ground loops' inside gutars on this site with empirical testing to prove the point.
I think the important thing with stuff like attaching to the bridge wire and shielding is that different metals in particular, or just oxegen and moisture will oxidise and have metals react in differnt ways that will affect conductivity.
To be sure, it is wise to make a good solid connection to the ground with a wire, even if it does seem to be a bit 'redundant' Eventually the shielding ground will oxidize as will any metal but, a good connected wire will not!
In a vaguely related aspect, many people get shorts, or intermittent faults or create similar 'time bombs' with shielding where a connection or switch might touch...a super switch is bigger and more connections that could easily touch something to ground. For such precautions, a bit of protective PVC tape on the shielding or the connections will ensure that this will not happen...just like a wire connection is an added assurance that no corrosion will later bite you in the arse.
But, yeah, contry to common 'law' the ground loops in guitars has been debunked here with a test to create a lot of ground loops as I recall and actually measure the differences and there were none. That's not to say one wants miles of excess redundant wires floating around, there are good practices (I always use green for ground as here for instance) but for the tiny amounts of wire such precautions make, there is absolutely no noise created by it...only reliability!
hope that makes sense...that is a big bump up from 2008 LOL
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Post by newey on Jun 21, 2012 17:44:34 GMT -5
4real is right, we have pretty much debunked the idea that ground loops are significant contributors to noise. There is always the un-debunkable argument that says one might find oneself playing in a particularly "noisy" environment, electrically speaking,where it might make a difference. The short lengths of wire usually found in a guitar are unlikely to contribute, however.
But Dannyhill's basic question is:
That question we can answer with a definite "no". If it ain't carrying signal, it can't be a meaningful ground loop.
Dannyhill is describing two separate paths to ground from the bridge plate. Neither is carrying signal, therefore neither can result in noise being introduced into the signal chain.
And lpf3 was right back in 2008, I misread his original post as "neck", thus resulting in some confusion back then!
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Post by lpf3 on Jun 21, 2012 20:20:51 GMT -5
In his photo: The bridge pickup plate is connected conductively to the ground lug of the jack via both screws/bridge plate/copper/ground wire route AND via the green wire/copper/ground wire route. (I can't see the ground wire but I assume it is there somewhere.) The ground wire is there. In my photo, see that narrow piece of shielding tape that's applied over the rest of the shielding? That is holding the bridgeplate ground in place and the green wire that I added is soldered to that. It was my first electronics mod & that was my way of wearing a belt and suspenders. ;D No. It's there because I misunderstood Chisk's comment: I mistook the bridge plate for the bridge pickup plate & that's where the separate ground wire came from. In hindsight, ya notice Chris didn't get back to me after I put up that pic? ;D ;D ashcatlt wrote:Ash is right- it doesn't hurt anything. In fact, it might even still be there after several subsequent mods........... the shielding is working as it should- nice & quiet. And yes- all my grounds go to the jack sleeve via the vol. pot. newey wrote:At first I thought you were referring to my old signature about voting for Joe Walsh. ;D ;D Either way- thanks for the new sig....... ;D lpf3
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Post by dannyhill on Jun 22, 2012 3:45:10 GMT -5
Wow! Thanks guys for all the input. I'm sorry if I have not picked up on the debunking of ground loops here. Elsewhere on the web, people do seem to be concerned about including Deaf Eddie. newey: I can see your point about two shielding paths to ground not making a ground loop as they carry no signal, but if my tele bridge pup plate has the shielding lug hard wired to the -ve end of the coil (standard on Fender Teles) Then it IS in the signal path, as this is AC. Can anyone make a more technical explanation? Not that I'm cynical or anything :-) Thanks again, DH
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Post by newey on Jun 22, 2012 5:19:31 GMT -5
Right you are, DH. I was responding to your description of lpf3's setup, and he said:
That bare wire is a shield, not a pickup lead, he has two separate insulated pickup leads in addition to the bare shield.
But if your pickup doesn't have that, but instead has one of the signal carrying wires run to the baseplate, then you are correct, that would technically be a ground loop. If it's a concern, you can either disconnect it or isolate the pickup baseplate from the screws with some small rubber washers.
I believe it was JohnH, way back when, who did the ground loop testing, and if I could find that post I'd sticky it. He used outrageously long wires to create ground loops much longer than anything inside a guitar. IIRC, the final one used the entire HVAC ducting of his home . . .
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Post by reTrEaD on Jun 22, 2012 9:36:33 GMT -5
Maybe that was a little snarkier than it needed to be. Just a little. But something needed to be said. I bumped it cause I understood that otherwise it might be days or weeks until it got read being an old thread. I think it was appropriate to tag your question onto an existing thread. But the first post you made moved it to the top of the stack. The "BUMP" post just gave the appearance of impatience. You don't wanna be that guy, do you? I've replied to your posts before. And I've read through some of your posting history. You seem like a decent guy. I wouldn't want to see you go down the wrong path. The activity level of this board varies. Sometimes vigorous, sometimes quiet. It's true, at times you won't get a useful answer quickly. I'd suggest reserving bumps for at least a day or two, and maybe not in all caps. Thanks guys for all the input. I'm sorry if I have not picked up on the debunking of ground loops here. Elsewhere on the web, people do seem to be concerned about including Deaf Eddie. There's a lot of questionable information on the web. There's some right on the original Guitarnuts site. Such is life. When it comes to "ground loops" in a guitar, there is a teeny, tiny grain of truth there. Any two signals (in this case pickup output and hum from the shielding) that share the same path can affect one another. The current from the hum and noise on whatever wire that carries it to ground can produce a voltage across a resistor (wires ARE resistors, albeit very small ones). So if the current is large (it isn't) and the resistance of the wire is appreciable (it isn't) this would result in the signal from the pickup riding on a modulated ground. A small portion of the hum from the shielding would be seen at the input of the amplifier. But since the hum current is extremely low and the resistance is extremely low, the amount of voltage generated at our "ground" reference for the pickup is inconsequential. There are cases where ground loops are a serious issue. But guitar wiring isn't one of those cases.
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Post by dannyhill on Jun 23, 2012 2:49:05 GMT -5
Thanks reTrEaD! You know, it's almost as if I didn't understand how stacks order, bumps and forums work!?! Well now I do With regards to ground loops in the wiring (not the shielding), I'm more worried about Eddy currents being induced in the loops, and moreover pickup AM signal (a ground loop is an antenna). I therefore aim to have all of my guitars shielding connect at only ONE point to the -ve/ground 'bus', ideally where the -ve wire from the jack connects, or directly to the jack. I think I will snip the wire under my bridge pup and add an extra wire either to the copper shielding or straight to my grounding point for all shielding on the tele plate. Now, I'm probably just being @n@l, but this page made sense: www.mylespaul.com/forums/tonefreaks/122705-more-grounding-misconceptions.htmlThanks again! DH
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Post by newey on Jun 23, 2012 6:27:17 GMT -5
You can certainly do that, DH, or isolate the plate from the bridge.
The link you provided makes the essentially unanswerable argument I noted above, the "what about the neon beer sign" (or other extremely electrically noisy environment) argument.
The reason that the argument is essentially unanswerable is that no shielding is perfect, and at some point we can always posit some circumstance under which any guitar will produce noise, despite having HBs, shielding, no ground loops, etc.
Unless you were to do some ground loop testing while in such an environment, there would be no way to know if the noise was from a ground loop, or just being induced through your pickups despite shielding and all else.
It's sort of like quantum physics and its uncertainties- we can never say for sure, all we can do is give odds- and as RT noted above, the odds that a ground loop contribute to noise is low.
A ground loop is an antenna, but I've never heard of anyone picking up AM radio that way, or noise from an AM radio source. The source of most noise in guitars is the 60Hz mains current in your house (or the bar where you're performing). And the biggest antenna in your guitar will always be your pickups, which are wound with thousands of feet of wire, as opposed to a few inches of ground loop.
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Post by reTrEaD on Jun 23, 2012 9:15:36 GMT -5
Yes, you are definitely being anal. But that's okay. I wire my guitars like that, too. Here's an interesting point to put that all in context... Boththe signal common and shielding MUST share a common path. The braid of the coax of your guitar cable. This is heaps a lot longer than any wiring inside your guitar. Bottom line: If you want to take the time and effort to keep the shielding and signal common separate when you wire up your guitar, it won't hurt anything. But ripping apart existing wiring to "fix" a problem that is inconsequential, is like pissin' into the wind.
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