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Post subject: 72 Thinline Telecaster MIM Ground hum?
Posted: Mon Apr 11, 2011 4:51 pm
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I just bought a used 72 Thinline, and I'm pretty sure it has a grounding issue. There's a lot of buzz that sounds like ground hum that goes away when I touch the strings or hardware. The most dramatic kill spot of the hum is the bridge. I looked into grounding the guitar, and it sounded to me like the wire from the volume pot to the bridge must have been disconnected or something, but I just removed the bridge, as well as the pickguard, and all the wires were exactly where they were supposed to be. I downloaded the wiring schematic and it matched exactly.

I have a new bridge that I want to install because the other one was all rusty and junk, but I don't want to close everything back and put strings on just to find out the buzz is still there. I tried putting the bridge in place, making sure the grounding wire was there, and there's still a lot of buzz. Should the buzz be gone if the bridge is in place and all the wires are connected but the pickguard and strings aren't there? Any thoughts?


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Post subject: Re: 72 Thinline Telecaster MIM Ground hum?
Posted: Mon Apr 11, 2011 5:19 pm
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You have humbucklers, so the only buzz you are getting should be a 60 cycle ground hum from ground loops and possible a lack of ground shielding. Ground loop hum will quiet when you touch the strings or bridge, even when the bridge is properly grounded.

Go to my posting in the Telecaster forum entitled "Complete Telecaster Build Pictorial"
viewtopic.php?f=7&t=53915

In that pictorial, I show you how to shield your guitar and eliminate all ground loops by changing your ground wiring to a a "star grounding" system. What you must absolutely do is eliminate any ground wire that runs from the back of one pot to the other.

You can solder all ground wires to the back of one (1) pot, if you must solder ground wires to your pots.
I think that using an independent "ground star" is much better method.
Use your copper shielding in the control routing to ground the control plate, or else run a dedicated wire to ground the control plate.
Get a 2" wide roll of copper tape from Stewart McDonald for shielding your guitar.

Additional explanation of this shielding and grounding method may be found at Guitarnuts.com:
http://www.guitarnuts.com/wiring/shielding/shield3.php


Last edited by MickJagger on Tue Apr 12, 2011 10:30 am, edited 1 time in total.

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Post subject: Re: 72 Thinline Telecaster MIM Ground hum?
Posted: Mon Apr 11, 2011 5:35 pm
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Hmmm... thanks for the help, but that's a bit over my head. I've actually looked at that guitarnuts page before, and thought it was too hardcore for me. Is there a simpler solution?


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Post subject: Re: 72 Thinline Telecaster MIM Ground hum?
Posted: Mon Apr 11, 2011 6:16 pm
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There is one wire that runs from the back of the tone pot to the back of the volume pot. Were you saying if I eliminated that wire, I'd get rid of the ground loop? I'm assuming I can't just cut that wire right?


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Post subject: Re: 72 Thinline Telecaster MIM Ground hum?
Posted: Mon Apr 11, 2011 6:18 pm
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Can you explain where all the wires in your star ground pictures come from? I don't really follow the guitarnut strat shielding plan, but the tele plan doesn't involve the star.


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Post subject: Re: 72 Thinline Telecaster MIM Ground hum?
Posted: Mon Apr 11, 2011 8:42 pm
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RickWall23 wrote:
Hmmm... thanks for the help, but that's a bit over my head.
I've actually looked at that guitarnuts page before, and thought it was too hardcore for me.
Is there a simpler solution?

The answer is that there is probably no simpler solution if you want to eliminate all hum.

RickWall23 wrote:
There is one wire that runs from the back of the tone pot to the back of the volume pot.
Were you saying if I eliminated that wire, I'd get rid of the ground loop? I'm assuming I can't just cut that wire right?
Can you explain where all the wires in your star ground pictures come from? I don't really follow the guitarnut strat shielding plan, but the tele plan doesn't involve the star.

If you have a ground wire that is soldered onto the bottom of both pots, that runs from pot to pot, snip it off.
See paragraph 17 and Figure 4 in "Shielding the Beast" (Strat) at Guitarnuts.com:
http://www.guitarnuts.com/wiring/shielding/shield3.php

If you have any other wire soldered to the tone pot, I would move it to the bottom of the volume pot, so that all ground wires attach to the bottom of the volume pot.

The ground wires that I show in the picture of the "ground star" are all of the ground wires in the guitar which connect to the ground wire coming from the input jack at the "ground star."
These wires include:
2 ground wires from the noiseless neck pickup.
2 ground wires from the noiseless bridge pickup.
1 ground wire connected to the volume pot terminal where the capacitor connects, which also grounds the pot casing.
1 dedicated ground wire soldered to the copper shielding in the control routing area.

The copper shielding under the neck pickup and under the bridge pickup are grounded by wires that are soldered to the copper shielding in those areas,
which run to the control routing area and are soldered to the grounded copper shield in the control routing area.
As noted, the control area shielding is grounded by a dedicated wire soldered to the copper shielding that runs to the ground star.
If you are attaching all of your ground wires to the bottom of the volume pot, the dedicated ground wire to the control area copper shielding would attach to the bottom of the volume pot.

By overlapping some of the copper shielding tape onto the face of the guitar around the neck pickup, this will ground the copper tape that should be applied to the entire back of the pickguard.
I also put electrical tape on top of the copper shielding, directly under the positive wire contact point, under each pickup, to assure that the pickups do not ground out on the grounded copper shielding.

You will also most likely find a ground wire from the bottom of the volume pot that runs to one or more screws that are screwed into the bottom of routing in the guitar.
DO NOT REMOVE OR LOOSEN ANY GROUNDING SCREW THAT IS ATTACHED TO THE BODY OF THE GUITAR.
The screw is installed into wet metallic grounding paint that does the same thing as the copper shielding tape.
Loosening this screw will break the contact with the shielding paint and ruin any shielding provided by the metallic shielding paint.

I went to the "star grounding" method of wiring, and grounded copper shielding, after I installed noiseless pickups into an 83 Tele, when I had the same problem as you are having.
Below is a picture of the "ground star" method of grounding a Telecaster. The "ground star" will be covered with electrical tape.
Combined with grounded copper shielding, "ground star" wiring completely resolved the ground hum that I had when I took my fingers off the strings, bridge or the input plug.

Image

Here is a modern Telecaster wiring diagram.
I would move the ground wire from the jack, that is shown soldered to the tone pot, to the volume pot, to be soldered with all other ground wires, if you are following this wiring diagram.

Image

If you follow all of these step, your guitar should be dead quiet with humbucklers.
But you must shield the wires with a copper grounded shield.
Also, it's a good tip to twist the ground and positive wires together as they run to the pickups.
You can see the yellow positive pickup lead twisted together with ground wires from the bridge pickup in the above photo.
This will also help to eliminate electrical interference as well.

Here is a high res. picture which shows all ground wires attached to the bottom of the volume pot.

Image


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Post subject: Re: 72 Thinline Telecaster MIM Ground hum?
Posted: Tue Apr 12, 2011 2:43 pm
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Thank you so much! That is incredibly helpful.

I think I've decided I'm going to attempt to do all of this. I know how to solder, I just don't know what to solder. Your last post pretty much explains everything though.

Couple questions though.

1. My guitar just has the bridge, neck, and control cavities connected in it so I can just do copper tape on the whole thing and not worry about wiring each together since the tape will be connected. I'll just need to solder each piece of tape together right?

2. Pickups grounding out kind of scares me. The guitar nuts page says that if my pickups are metal covered (which they are) they're already grounded so I need to make sure the pickups don't touch any of the copper tape shielding on the pickguard or on the wood of the guitar. Is that correct?

3. Here's a wiring schematic for my guitar http://support.fender.com/service_diagr ... 1_SISD.pdf I'm getting that the black and bare wires grounded from each pickup is supposed to be wired to the back of the volume as a ground. Is that correct? I'm also concerned that my neck or bridge pickup is wired wrong because the black wire is wired to the top left and the brown to the bottom right on the neck pickup and the opposite on the bridge pickup. Does that make sense?

4. Last thing. I've read that swapping the 250 pots for 500 pots is a good idea since I'm using humbuckers. Does that sound like a good idea to you and if so will there be any difference between how I wire the 500 pots?


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Post subject: Re: 72 Thinline Telecaster MIM Ground hum?
Posted: Tue Apr 12, 2011 6:32 pm
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RickWall23 wrote:
1. My guitar just has the bridge, neck, and control cavities connected in it so I can just do copper tape on the whole thing and not worry about wiring each together since the tape will be connected. I'll just need to solder each piece of tape together right?

Yes, you can do it that way.

Just run a spot of solder over the copper tape somewhere along the seams between two separate copper tape to assure that the ground continues. Some copper tape adhesive is not conductive.

Obviously, you can't do that on the back of the pickguard, but my experience indicates that solder links between copper tape strips on the back of the pickguard is not necessary.

It's easiest to cut out pieces for the floor of the route and then cut separate pieces for the walls of the route.

Just make sure you have some solder somewhere linking the floor to the walls and linking any separate pieces of copper tape.

RickWall23 wrote:
2. Pickups grounding out kind of scares me. The guitar nuts page says that if my pickups are metal covered (which they are) they're already grounded so I need to make sure the pickups don't touch any of the copper tape shielding on the pickguard or on the wood of the guitar. Is that correct?

If the metal cover is grounded, which I'm not sure that it is, it should not matter if it touches another ground.
A ground..., is a ground..., is a ground.

What they may be talking about is if your pickups have a large copper ground plate on the bottom, which many original Tele single pole bridge pickups have.

In any case, it should only be the hot wires (the Brown Wires) that could ground out on the grounding shield, if it is possible that they could contact the shield at the hot pickup terminal.

So if there is a chance that the hot wire could come into contact with a ground, it could muffle or eliminate the pickup's output.
Just put a piece of electrical tape on the copper tape where any possible contact with the hot wire may occur.
It's possible that you won't need this. You have to decide.

If you somehow mistakenly ground out the pickup, don't worry, it won't hurt anything. You will just have to correct the problem.
Using a bit of electrical tape if needed, should eliminate this possibility.

RickWall23 wrote:
3. Here's a wiring schematic for my guitar http://support.fender.com/service_diagr ... 1_SISD.pdf I'm getting that the black and bare wires grounded from each pickup is supposed to be wired to the back of the volume as a ground. Is that correct?

Yes, unless you are opting for independent "star grounding."
If all ground wires are attached to the Volume pot, it is in effect, a "ground star."
Snip the ground wire that runs between the bottom of each of the pots.

RickWall23 wrote:
I'm also concerned that my neck or bridge pickup is wired wrong because the black wire is wired to the top left and the brown to the bottom right on the neck pickup and the opposite on the bridge pickup. Does that make sense?

I'm not sure that I understand what you mean.
The brown wires are the hot wires from each pickup.
If you are saying that the wires are reversed on each pickup, don't worry about that.

The brown wires are hot and should go to the switch terminals as shown in the diagram.
I assume your switch is operating correctly switching from the bridge to the neck pickup.
If so, the switch wiring is correct.

RickWall23 wrote:
4. Last thing. I've read that swapping the 250 pots for 500 pots is a good idea since I'm using humbuckers. Does that sound like a good idea to you and if so will there be any difference between how I wire the 500 pots?

You may have 250K pots in there, or you may not.
500K pots are used with humbucklers to brighten up the sound and eliminate the "muddiness" that you may otherwise get using the less bright 250K pots.

Humbucklers, which are generally considered to be darker sounding than single pole pickups, so 500K pots, as are used to brighten up the sound. 500K pots are normally used in Gibsons.

If you think your guitar sounds "muddy" or dark, put in 500K pots.
Otherwise, if you are happy with the sound, keep what you have.


Last edited by MickJagger on Tue Apr 12, 2011 10:07 pm, edited 4 times in total.

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Post subject: Re: 72 Thinline Telecaster MIM Ground hum?
Posted: Tue Apr 12, 2011 9:28 pm
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Thanks a lot. I think that's all I'll need. I'm ordering copper tape today, and I plan on shielding everything and attempting a star ground. I'll post back in a few days or so if I have problems or with the results.


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Post subject: Re: 72 Thinline Telecaster MIM Ground hum?
Posted: Tue Apr 12, 2011 9:48 pm
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RickWall23 wrote:
Thanks a lot. I think that's all I'll need. I'm ordering copper tape today, and I plan on shielding everything and attempting a star ground. I'll post back in a few days or so if I have problems or with the results.

Cool!!
Good Luck!!
Don't forget some pictures!!


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Post subject: Re: 72 Thinline Telecaster MIM Ground hum?
Posted: Mon Apr 18, 2011 8:41 pm
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Just got the copper tape today!

Quick question. Since my Tele only has one continuous cavity and a pickguard that covers that whole cavity, would I be safe if I let the tape overlap onto the body in just one spot instead of all over?

I mean if the whole pickguard is coated in copper and so is the cavity, they only need one spot of connection right?


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Post subject: Re: 72 Thinline Telecaster MIM Ground hum?
Posted: Mon Apr 18, 2011 8:54 pm
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RickWall23 wrote:
Just got the copper tape today!

Quick question. Since my Tele only has one continuous cavity and a pickguard that covers that whole cavity, would I be safe if I let the tape overlap onto the body in just one spot instead of all over?

I mean if the whole pickguard is coated in copper and so is the cavity, they only need one spot of connection right?

That should be fine.
If when you finish, there is noticeable variable hum when you turn the guitar in different directions, than add more contact points.
Otherwise you're good to go.


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Post subject: Re: 72 Thinline Telecaster MIM Ground hum?
Posted: Tue Apr 19, 2011 12:35 pm
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So far so good. I'm about to start on the wiring so I wanted to doublecheck that I'm understanding this right.

I'm doing the star-grounding method so basically I just take all of the wires that are currently soldered to the back of the volume pot and solder them together along with one wire that's soldered to the coppertape? I should have ground wires from the pickups, the output jack, the copper tape, the wire that goes under the bridge, and the ground pole on the volume pot soldered together and detached from the back of the pot? Will it matter if these wires come into contact with the back of the volume pot or should I make sure the connection won't brush anything?

I can also just get rid of the wire from the back of the volume pot to the tone correct?

Sorry if I'm being repetitive. I just want to be sure.


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Post subject: Re: 72 Thinline Telecaster MIM Ground hum?
Posted: Tue Apr 19, 2011 1:17 pm
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RickWall23 wrote:
I'm doing the star-grounding method so basically I just take all of the wires that are currently soldered to the back of the volume pot and solder them together along with one wire that's soldered to the coppertape?

Yes. I recommend cutting the old soldered ends of the wire off, strip new portions of the wires, and twist them all together to be soldered to the ground wire from the input jack.

RickWall23 wrote:
I should have ground wires from the pickups, the output jack, the copper tape, the wire that goes under the bridge, and the ground pole on the volume pot soldered together and detached from the back of the pot?

Yes.

RickWall23 wrote:
Will it matter if these wires come into contact with the back of the volume pot or should I make sure the connection won't brush anything?

The "ground star" should be covered with electrical tape.

RickWall23 wrote:
I can also just get rid of the wire from the back of the volume pot to the tone correct?

Yes. That's the main ground loop and hum producer.


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Post subject: Re: 72 Thinline Telecaster MIM Ground hum?
Posted: Tue Apr 19, 2011 7:38 pm
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Good deal.

I think I'm going to try and make a Youtube Vid detailing all of this for future electronic noobs like myself.


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